DC System
Printed From: myHanse.com
Category: Hints & Tips
Forum Name: 350
Forum Description: 350 Hints and Tips
URL: https://www.myhanse.com/forum_posts.asp?TID=7239
Printed Date: 27 March 2026 at 03:41
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Topic: DC System
Posted By: Swanji
Subject: DC System
Date Posted: 15 February 2013 at 12:22
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Hi Folks We have been forced to replace our engine battery as well as our domestic batteries. Instead of replacing them with wet cell batteries, we are wanting to turn this unhappy situation into an advantage by increasing capacity and changing the battery type. We are wanting to increase the 2 domestic batteries that will be linked in parallel to a total of 300aH so are looking for 2 x 150aH batteries. As we do not wish to discharge the batteries by more than 50% and the last 20% can take a long time to recharge, this will give us an effective 100aH per day which we have calculated will be sufficiient. We are also wanting to change the battery type to AGM which has lower maintenance and can be used as a starter battery or as a deep cycle domestic battery. We will at the same time be fitting a alternator to battery charger to ensure that the AGMs are not overcharged which they are prone to doing without a smart charger. So all good in theory. The problem appears to be the size of the battery compartment under the port bench in the saloon. Has anyone done this exercise and if so, what type of batteries did you use? We will be doing this Direct Current upgrade quite soon so any advice would be much appreciated. We have had a good quote on Exide batteries but they don't fit. The other problem is battery availability in Croatia. ------------- Onwards and upwards Nidri, Levkada, Ionian, Greece Hanse 350 #7, SY Evolution, standard keel, 3YM20 sail drive, 3 cabins, cherry wood interior, teak decks, feathering prop |
Replies:
Posted By: Brufan
Date Posted: 15 February 2013 at 13:09
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I still have the original recent set of batteries includes in optional 'crusing pack' Engine battery is above the engine itself in the same compartment : 70 amp AGM from Victron. Domestic battery is also under port bench : 140 amp AGM from Victron There's no A to B system but a Cyrix automatic battery coupler. This works fine for what I need even tough a second Domestic battery should be an (heavy) improvement. I never had problem while charging AGM batteries from Volvo 115 Ah alternator. My only issue is that battery charger (STERLING PRO CHARGE 20) charges only service batteries unless you activate the 'start assist' switch on the Cyrix. I use Victron AGM batteries for several years now (on my former yacht as well). This is a very good stuff and I never had nay problem with them. ------------- Bruno hanse 355 - 57 S/Y Spicy Ginger White hull, 2 cabins, Volvo D1-30, Selden rig, removable mainsheet track system, Simrad (now B&G)-Jefa autopilot. |
Posted By: Swanji
Date Posted: 15 February 2013 at 13:41
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Hi Brufan You have a vested interest in our boat having sailed on her  thanks for the feedback.A question. Where did you mount your battery monitor? Also, I am thinking of using the seat at the nav table to fit the alternator to battery charger, the shore power battery charger (which also needs replacing and is currently fitted under the port side bench without an inspection hatch  )This would make access very simple in future. We are also fitting an inverter which we are thinking of putting into the middle of the table in the saloon as there is enough space there and it wouldn't interfere with the autopilot computer. Anything else you've done that we may want to consider? ------------- Onwards and upwards Nidri, Levkada, Ionian, Greece Hanse 350 #7, SY Evolution, standard keel, 3YM20 sail drive, 3 cabins, cherry wood interior, teak decks, feathering prop |
Posted By: Brufan
Date Posted: 15 February 2013 at 14:18
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Hi Swanji, I have no (not yet) battery monitor except Philippi Voltmeter & gauges panels. You should consider weight distribution. Two large domestic batteries (45 kg each) + battery charger + ... on the same side. If I fit a second domestic batteries I will use the starboard bench. By the way I remember that on H350 the starboard bench is "moulded". On H355 Hanse made same savings. There's no more moulded locker. You are directly on hull so the locker under the bench is two times larger. (I hope you see what I mean with my poor english language). If I had a H350 I would remove this moulded part which is useless. ------------- Bruno hanse 355 - 57 S/Y Spicy Ginger White hull, 2 cabins, Volvo D1-30, Selden rig, removable mainsheet track system, Simrad (now B&G)-Jefa autopilot. |
Posted By: CharlesP
Date Posted: 17 February 2013 at 01:28
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Bruno - what is the start assist switch? Where do I find it? Is it on the Cyrix? On my 320, I thought the Cyrix first charged the engine battery, then switched to the house battery. Charles ------------- 'MERIDIAN LADY' 320 Nr 536 2010 Medway |
Posted By: Swanji
Date Posted: 17 February 2013 at 06:23
Hi Brufan We currently have all 3 batteries mounted under the portside bench in this moulding as you describe it. I think the moulding is there to prevent spillage in case the wet cell batteries were to leak but I may be wrong. It definitely is causing us a problem in finding replacements for the batteries we have which are Varta 60 for engine and 2 x Varta 110 for domestics. The shore power battery charger is also under the portside bench so what I was planning to do wasn't changing the weight distribution. I am wanting to fit higher capacity batteries though so I don't know if that will make a difference or if AGMs will be lighter than wet cell lead acids. The other thing I have read in Nigel Calder book is that it is important to keep the domestic batteries together and not to split them as you are suggesting as this will involve different operating environment, longer cables, therefore higher resistance. Putting the engine battery in the engine compartment though may make sense as this would free up one of those moulded areas for the shore power charger and alternator to battery charger. It would also place the weight more to the center. Where is your mounted engine battery mounted in the engine compartment? Is it near the raw water filter where if I recall correctly there is some space? The other thing is did you fit the Cyrix connector to act as a jump start cable to start the engine with the domestic batteries? I notice that you have an upgraded 115 aH alternator which obviously is key to being able to recharge the batteries quickly. Our is the original alternator but I don't know if it is 60 or 80 aH. It is not easy with your boat so far away. Thanks for your help and happy birthday for yesterday ! ------------- Onwards and upwards Nidri, Levkada, Ionian, Greece Hanse 350 #7, SY Evolution, standard keel, 3YM20 sail drive, 3 cabins, cherry wood interior, teak decks, feathering prop |
Brufan wrote:Posted By: Johan Hackman
Date Posted: 17 February 2013 at 08:32
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When I had to replace my domestic batteries I upgraded the Hanse original setup with a separating relay. In hindsight, I would rather have got rid of the engine battery and used the space for three domestic batteries. With AGM batteries and a battery monitor you don't need to have the batteries separated. You can start the engine on the domestic batteries and with the monitor you will not risk running out of juice. Just a thought. Johan -------------  http://www.johanhackman.se" rel="nofollow - http://www.johanhackman.se |
Posted By: Swanji
Date Posted: 17 February 2013 at 09:34
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Hi Johan Interesting point having one battery bank. I see Skipper has done the same on his boat. So the conventional wisdom of having a separate engine battery for engine and windlass - I am assuming that our windlass is connected to the engine battery on the H350 - to ensure that you never run out of power no longer applies on account of the monitor? It also means that the alternator to smart charger no longer needs to decide which battery bank to charge first. Some of these chargers work on the engine first, domestic second and the latest models sense when the particular battery bank has returned to a float charge and then switches to the next bank. The latter normally charge the domestic batteries first and then the engine battery. Anything that is simpler on a boat works for me. What is the downside of linking all three batteries as you are suggesting providing you have a good battery monitor? ------------- Onwards and upwards Nidri, Levkada, Ionian, Greece Hanse 350 #7, SY Evolution, standard keel, 3YM20 sail drive, 3 cabins, cherry wood interior, teak decks, feathering prop |
Posted By: Brufan
Date Posted: 17 February 2013 at 12:24
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The 'start assist' switch is something you can add very easily to any Cyrix. When you activate the switch, domestic batteries are linked ton engine batteries for 30 seconds. This allows you to start the engine event if your engine battery is too weak. You can also set a ON/OFF switch for this but that means that as long as the switch is ON the battery are still linked. ------------- Bruno hanse 355 - 57 S/Y Spicy Ginger White hull, 2 cabins, Volvo D1-30, Selden rig, removable mainsheet track system, Simrad (now B&G)-Jefa autopilot. |
Posted By: Brufan
Date Posted: 17 February 2013 at 12:38
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Swanji, Here's a picture of a H355 (not mine actually) The engine battery is above the engine.  The second pictures is the domestic battery bench (port side) with Cyrix & charger on my yacht (very original set - picture taken on delivery day)  Hope it helps ------------- Bruno hanse 355 - 57 S/Y Spicy Ginger White hull, 2 cabins, Volvo D1-30, Selden rig, removable mainsheet track system, Simrad (now B&G)-Jefa autopilot. |
Posted By: Johan Hackman
Date Posted: 17 February 2013 at 13:03
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I don't have a windlass so my knowledge is limited but I think you have a separate battery for that. The engine draws a strong current from the batteries for a very short time whereas the windlass will be used for a longer time so I think it is wise to have a separate battery for that. I am thinking that separating engine and house batteries is something that we have got used to in the past when the house batteries were small and only occasionally used for navigational lights etc. You did not want to not being able to start your engine just because you were sitting up reading the night before. With bigger house batteries and better means to monitor them I think the need for a separate engine battery is much smaller. Johan ------------- http://www.johanhackman.se" rel="nofollow - http://www.johanhackman.se |
Posted By: Wayne's World
Date Posted: 18 February 2013 at 10:33
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I think the main reason for having two battery systems (house and start) is that it gives some redundancy if a battery completely fails. If you have a number of batteries connected and one internally fails it will quickly drag the voltage out of the other batteries. So if one fails the other will be useless within a realively short period - possibly one day. If you have two batteries or sets of batteries which are not directly connected and one battery fails which causes that bank to fail you would be able to use the unaffected bank to start the motor or keep the beer cold for a period. We recently had a N200 size sealed calcium battery explode onboard. It was in a sealed aluminum battery box so it did not cause any other damage except it also pulled down the other battery it was connected two. So if you have no other way of starting your motor I would stick to having a house bank and a seperate motor start battery. Just my thoughts on the subject. ------------- Wayne W Cruising, currently in the Pacific until the end of 2026. |
Posted By: Swanji
Date Posted: 18 February 2013 at 13:57
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Hi all Continuing the discussion on optimizing our DC system, with our boat standing for long periods of time in the winter, we need to ensure that the batteries remain topped up or otherwise risk damaging them. Even though AGMs can be left for longer, our sailing season ends in October and starts again in April which may be too long. I have thought of connecting them to a portable solar panel that could be secured in front of the mast on the foredeck to maximize sunlight. The purpose of the panel would simply be to keep the batteries fully charged but if it could perform the dual purpose of keeping our fridge charged while at anchorage then we break even or win. The thinking behind this panel is that it could be stowed when not required - against the hull in the port quarter berth. The alternative would be to mount a panel in front of the companionway as many owners have done. The downside to this arrangement though is that it will not be angled to,optimize its effectiveness, it will often be in the shadow of the main which will also reduce its output and it would need to be able to be walked on given its location. On the other hand, it may well be fit for purpose ie recharging the batteries when we are away for long spells and enabling us to use the fridge whilst sailing or at anchorage. Another question arises. Given that AGMs are very sensitive to overcharging would one need another regulator to ensure the batteries are not overcharged? My sense is that this would be required. Man these boats are complicated ... Personally and given our power requirements, solar power in not something I am particularly sold on given its inherent inefficiencies - iirradience levels, heat, angle of the sun, time of the day, shade caused by clouds, the boom, the sail, age of panels, resistance caused by cabling the list goes on.. Some experts say that you can count on about 25% of rated capacity to determine actual output. I think fuel cells or hydro generators are way more efficient and reliable than this if you are looking for an eco friendly alternative to running the engine and generating power with the alternator but there is a cost and i am definitely no expert. We have focused on our power generation on the alternator/engine route as itis reliable and effective. We just don't have a plan for keeping the batteries topped up while we are away. Any thoughts and advice much appreciated. ------------- Onwards and upwards Nidri, Levkada, Ionian, Greece Hanse 350 #7, SY Evolution, standard keel, 3YM20 sail drive, 3 cabins, cherry wood interior, teak decks, feathering prop |
Posted By: skipper
Date Posted: 18 February 2013 at 14:00
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I have 1 (one) battery bank (house and engine) all connected together but I protect my engine battery by a "battery brain" device which disconnect at a certain low level of voltage just in case.
------------- Cheers, Skipper Former owner of Hanse 342 2005 (Sparcraft mast, white hull, wheel steering, deep draft keel, short rudder) |
Posted By: Swanji
Date Posted: 18 February 2013 at 14:00
Hi all If there is a separate battery on our H350, then I haven't found it! I know the bigger model Hanses have separate batteries. Can anyone fill me in on what the status is on the Hanse 350/355. I imagine it would be the same on the H342 as well. ------------- Onwards and upwards Nidri, Levkada, Ionian, Greece Hanse 350 #7, SY Evolution, standard keel, 3YM20 sail drive, 3 cabins, cherry wood interior, teak decks, feathering prop |
Posted By: Johan Hackman
Date Posted: 18 February 2013 at 14:41
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I have written a lot about solar panels before. I shall limit myself to say just a few things this time. My solar panels don't cover for what I use. They make the battery bank bigger, if you see what I mean. I think of them as a "virtual battery". If you put your solar panels on the coachroof they will be working at all times when it is not dark. I mean, time is an important factor too, not only the angle. It means they will be working when you sleep in the morning and when it is too cloudy to motivate you to bring out your portable panel. My solar panel certainly tops up my batteries. If I leave my boat and the batteries are half way discharged they will be fully charged just a few days later. Johan ------------- http://www.johanhackman.se" rel="nofollow - http://www.johanhackman.se |
Posted By: Swanji
Date Posted: 18 February 2013 at 15:02
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Hi Johan Thanks for the input Would you change anything about your current installation - solar panel type, size, regulators or would you choose exactly what you orignially chose again? If not, please direct me to where you have specified your system. Is there any maintenance that needs doing to the panels on a regular basis, apart from keeping them clean of course? I like the idea of not having to do anything with the panels installed on the hatch - I guess I am inherently lazy  ------------- Onwards and upwards Nidri, Levkada, Ionian, Greece Hanse 350 #7, SY Evolution, standard keel, 3YM20 sail drive, 3 cabins, cherry wood interior, teak decks, feathering prop |
Posted By: Johan Hackman
Date Posted: 18 February 2013 at 15:54
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You want me to find the posts I have written about my solar panels out of my total of 2688 posts? That will take the afternoon! I simply refuse to do it! I will repeat it instead (which will bring me closer to my 3000th post): I have two panels of 44 and 22 watts from Naps connected to a regulator located in the vicinity of the batteries. I have a Batt-Meter, which I believe is a branded battery monitor that you will find under another name in other countries. I cannot stress enough the importance of a good battery monitor. And no, I would not change anything in my setup. I added the 22 watts panel after I had realised there was room for it. When I had my 44 watt panel fitted I was told they had fitted the largest one they could find. I only later found out that there was room enough for a smaller one too. There is no maintenance required but I think the efficiency will deteriorate over the years and you will eventually have to replace them. I have considered fitting another 44 watt panel in front of the mast but I have not decided whether to do it or not yet. Johan  ------------- http://www.johanhackman.se" rel="nofollow - http://www.johanhackman.se |
Posted By: Brufan
Date Posted: 18 February 2013 at 16:20
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Hi Swanji, I have no solar panel (and not planning to have one) I fitted the windlass myself. Same as Hanse's optional Lewmar Pro Series (but half the price...) I connect it (700 w) to domestic battery (145 Ah AGM) with 35 mm² cables (approx 3,5 m between battery & windlass). This works fine with a Delta Anchor 16 kg & 30 m chain (8 mm) + 15 mm rope. I don't think you need a separate battery for this appliance on a 35 ft yacht unless you pull up a 60 m chain twice a day. ------------- Bruno hanse 355 - 57 S/Y Spicy Ginger White hull, 2 cabins, Volvo D1-30, Selden rig, removable mainsheet track system, Simrad (now B&G)-Jefa autopilot. |
Posted By: panos
Date Posted: 18 February 2013 at 17:10
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Hi, There are many reasons to have separate starter and service batteries: 1) the nature of the two kinds of loads are completely different requiring different kind of battery types. The starter battery is best to be a normal cheap car battery. There is no good quality requirement since the battery is only used a few minutes per day (at a huge discharge rate) and the discharge is about (4 starts per day X 10sec X 100A) = 4X 10X 100/ 3600Ah= 1.2Ah so the battery actualy never discharges and battery efficiency is not important. The battery efficiency is the percentage of energy out over the energy supplied during charging. On the contrary the house batteries are always discharged to a point of 25% full and recharged. A lot of energy goes in and out and efficiency is very important. Imagine a battery with 70% efficiency vs one with 35%. The later will require double the charging time!!! 2) Besides the economy side as explained above there is the security issue. The car batteries can supply extremely high current required to start the engine without overheating since the lead plates inside are massive! The specialized service battery could overheat and get distorted or even worse get fire ( in extreme cases - look to the Boing Dreamliner airplane). In the worst case that a lead acid car battery gets hot the worst thing that can happen is to boil some electrolyte- not very bad just fill some water in. This is not true for AGM or gel batteries. 3) the starter battery stays always charged first and if it is isolated from other loads you can always start the engine and charge the service battery - this is called piece of mind. By the way the windlass is a high amp- low duration load and should be connected to the starter battery and only used with the engine running, at least during anchor retrieval. Anchoring can be performed with engine switched off since the power drawn is much less. Energy used while anchor retrieval (assuming 50m chain scope and maximum load during retrieval and 25m/min retrieval speed) = 2min X 60A /60min/h= 2Ah . Energy used use the fridge per day : 30% service factor X 4 A X 24 h = 29Ah Energy to ligth a normal 20w anchor light bulb for 8 h = 20w/12V X 8 = 13 Αh The energy to retrieve the anchor is almost zero! Energy supplied by .3m2 of solar panels = 200w/14V X .3 X 8h = 34Ah supplied but only about 50% stay in battery because of battery efficiency so battery charged 17Ah!!! My suggestion: insulate the fridge and change all light to LED. This is equivalent to tripling the service battery capacity. Let the starter battery separated Install a smart alternator regulator to get the maximum load out of the existing alternator. Do not install solar panels. ------------- Panos Hanse 630e - selling her - |
Posted By: Johan Hackman
Date Posted: 18 February 2013 at 17:52
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Please note that I am not giving anyone advice as to what setup they should use. I am just commenting on my own choice. And the irony is that when I installed the separating relay I forgot the cable to the ignition which meant that I started the engine on the house batteries (AGM batteries) for almost a year without knowing it. The whole idea behind the relay is that it should disconnect the house batteries when you start the engine. Johan ------------- http://www.johanhackman.se" rel="nofollow - http://www.johanhackman.se |
Posted By: Swanji
Date Posted: 18 February 2013 at 18:07
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Hi Panos Sounds like your regard for solar panels is lower than mine BUT I have always considered a small panel to be useful for keeping your batteries topped up while you are away from,the boat for long periods. Why would I be wrong in thinking this? How would you keep your batteries topped up if you left the boat standing for the long winter  from October to Aoril?------------- Onwards and upwards Nidri, Levkada, Ionian, Greece Hanse 350 #7, SY Evolution, standard keel, 3YM20 sail drive, 3 cabins, cherry wood interior, teak decks, feathering prop |
Posted By: panos
Date Posted: 18 February 2013 at 20:36
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@Swanji,
This I wrote a few days ago about solar panels. As you see I agree with you but still I wouldn't install the panels. I would consider to use a piece of plywood with the solar panels attached on it and temporary attach it to the boat with the correct south facing orientation. Before sailing I would remove the panel and store it in my car. ------------- Panos Hanse 630e - selling her - |
Posted By: Wild
Date Posted: 18 February 2013 at 21:17
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Swanji, Hello,
in the case you have AGM housebatteries there is no need to charge them during the long winter.
I have seen some test on AGM batt over a period of 15 months(average temp 20°C)
The batterie was disconnected with 12.78 V
after 105 days 12.70 V
after 466 days the still have 12.47 V
this is a self-discharge of 0.31 V
In a colder environment like northeurope they will discharge faster but still remain at a capacity of +80% after 6 months and this not a problem for deep cycle batteries.
Normaly you can use a AGM battery also as starterbattery just oversized the AGM with 20% to compensate the cranking amps.
------------- Wild and Wet Belgium 545e#268 |
Posted By: Swanji
Date Posted: 19 February 2013 at 05:55
Hi Johan Thanks for saving me that from that. If it was going to take you an afternoon to find, can you imagine how long it would have taken me Also, I have just tried to work out how you get to almost 3,000 posts. I am posted around 170 times in roughly a year. That means it would take me about 17 years  I can only imagine that your boat has evolved somewhat since you bought her. Ours is certainly undergoing an evolution. Seems like this is part of the Hanse experience  [Another great image by the way, I see Stamp ? Is using the boat as his kennel @Wild thanks for the info on the AGMs and that we don't need to worry about them during the winter. So fitting a solar panel over the hatch, would enable us to keep the batteries topped up even if they don't need to be, run the fridge while sailing, keep the LED anchor light powered all without running the engine for a few days. We generally dont stay anchored for that long though and would switch the engine on for some part of a day but maybe something for us to consider but not this year. Our expenses of fixing our boat this year have been spectacular if nothing else ------------- Onwards and upwards Nidri, Levkada, Ionian, Greece Hanse 350 #7, SY Evolution, standard keel, 3YM20 sail drive, 3 cabins, cherry wood interior, teak decks, feathering prop |
Posted By: Swanji
Date Posted: 19 February 2013 at 06:03
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Hi All Again continuing this discussion on optimizing the DC system, I had considered keeping the existing alternator for powering the engine battery and fitting a high power second alternator linked to an alternator to battery charger for the domestic bank but felt this was an overkill for the kind of cruising we do. However, what did occur to me, was the minimum size of engine needed to power 2 alternators. We have a 3YM20 sail drive which I suspect is not big enough? Anyone with experience on required engine size for running 2 alternators? This factor alone could make me go for a bigger engine as an option I ever bought a new boat which is highly doubtful Not only do you have more power but you can add an additional alternator for extended cruising ------------- Onwards and upwards Nidri, Levkada, Ionian, Greece Hanse 350 #7, SY Evolution, standard keel, 3YM20 sail drive, 3 cabins, cherry wood interior, teak decks, feathering prop |
Posted By: Johan Hackman
Date Posted: 19 February 2013 at 08:21
17 years sounds like a long time but so does 7,5 years which is the time I have been hanging around this forum. That is a great portion of my life.  Maybe I should find another pastime? Knitting or crosswords? Johan Note the colour of the teak and Stampe's life jacket when my boat was new:  ------------- http://www.johanhackman.se" rel="nofollow - http://www.johanhackman.se |
Posted By: Brufan
Date Posted: 19 February 2013 at 08:33
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In Northern environnement (Netherlands) my AGM engine battery looses approx 0,5 V during a 3-4 months winter (completely disconnected). ------------- Bruno hanse 355 - 57 S/Y Spicy Ginger White hull, 2 cabins, Volvo D1-30, Selden rig, removable mainsheet track system, Simrad (now B&G)-Jefa autopilot. |
Posted By: Rubato
Date Posted: 19 February 2013 at 21:41
Swanji, I don't think a bigger engine would be necessary strictly from a load view point BUT quite often a higher power alternator requires a more robust drive mechanism (e.g. dual belts) without which a single belt will slip. And, of course, a larger or second alternator takes more room... ------------- Steve Hanse 400e, #168 |
Posted By: Swanji
Date Posted: 20 February 2013 at 05:10
Hi Steve According to Nigel Calder in his book Boatowners Mechanical and Electrical Manual, at maximum loads an alternator can require 4 to 5 horsepower at 100 amps. Obviously at reduced loads the alternator will need less power. This could cause unacceptable propulsive power losses. Our engine generates 22 HP. Adding an alternator is going to take a lot of the boats propulsive power away which I wouldn't feel comfortable with. I know that Simon of Gertha fame has fitted another alternator but then he has as 30hp engine which makes all the difference I would think. I bought the book by Nigel Calder on a tip from another Hanse forumnite - Chris I think it was - and I have to say it is incredibly useful. Not exactly an easy read though on some of the systems. At least for me  ------------- Onwards and upwards Nidri, Levkada, Ionian, Greece Hanse 350 #7, SY Evolution, standard keel, 3YM20 sail drive, 3 cabins, cherry wood interior, teak decks, feathering prop |
Posted By: Gran Onada
Date Posted: 20 February 2013 at 05:47
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Just for your knowledge, I just replaced the original Varta batteries by Victron Energy AGM, in the original space I managed to fit: 1 x 60 Amph for start. 2 x 130 Amph for service. This was a direct replacement with no need of any modifications. Trsus this helps. K. Regards ------------- Gran Onada IV - Hanse 350 #130 |
Posted By: panos
Date Posted: 20 February 2013 at 10:46
It is very easy to verify: The charging voltage for normal batteries could be - in worst case- as high as 15.4V and at 100A this gives an output power of 100 A X 15.4 V = 1540w The electrical losses (heat generated in the alternator windings and diodes) is about 10% so the electrical energy produced in the alternator is about 1700w of which 1540 w go to the batteries and 160w are consumed locally as heat. The mechanical losses ( heat produced in the belts by friction and slip and air movement by the alternator fan) could be as high as 40% of the power produced or 1700 X 40%= 680 w , so in total 1700 + 680 = 2380 w are absorbed from the diesel engine shaft. If we convert this to horsepower ( 1hp = 746w) we get the worst case result of 2380/746= 3.2 hp This is grossly overestimated and only valid for a short period of time since after a while both the charging voltage and the amperage will drop. But I do not recommend to have two alternators! It is best to just install a smart circuit to always draw the max output out of the standard alternator and keep a spare one and a spare charger. Besides being cheaper the big alternator belts will be pulling sideways at the engine shaft and possibly reducing the engine bearings life. ------------- Panos Hanse 630e - selling her - |
Posted By: Swanji
Date Posted: 20 February 2013 at 14:25
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Hi Panos Nigel Calders calculation is as follows - a nominal 12 volt alternator s output is around 14 volts - we know that power in watts is voltage times amps - P=VxA - at 100 amps, an alternator is therefore producing 14 volts x 100 amps = 1,400 watts - there are 746 watts in 1 horsepower - 1 HP = 746 watts - therefore, in theory this alternator will require 1,400/746 = 1.9 horsepower to drive it - however alternators are only 50% to 60% efficient in energy conversion so this figure needs to be doubled to 3.8 horsepower - a further factor needs to be added for other energy losses such as drive belt and pulley friction. - this results in a power requirement of up to 4 to 5 horsepower at 100 amps - obviously at reduced loads, the alternator will need less power So I think that you are actually in agreement with him - it just depends of what assumptions are made for alternator efficiency or electrical losses and other energy losses or mechanical losses. My conclusion is that fitting a second alternator to a smaller engine may impact on safety by causing an unacceptable propulsive power loss which could be as high as 4 to 5 horsepower although probably closer to the 3.2 HP you have calculated.. So we also agree that on smaller engines I would not fit a second alternator. However it may make sense for larger engines assuming you need the power. ------------- Onwards and upwards Nidri, Levkada, Ionian, Greece Hanse 350 #7, SY Evolution, standard keel, 3YM20 sail drive, 3 cabins, cherry wood interior, teak decks, feathering prop |
Posted By: Brufan
Date Posted: 20 February 2013 at 14:43
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Swanji, You worry too much... Volvo Penta fits a 115 Amp alternator as standard even for their D1-13 (13 hp) and D1-20 (18 hp) engines. So my opinion is that you can easily retrofit this kind of larger alternator instead of Yanmar's original one without actuually loosing any propulsive power. This is better than fitting a second alternator which means machining an attachement system, a drive belt, ... lots of work and expense. ------------- Bruno hanse 355 - 57 S/Y Spicy Ginger White hull, 2 cabins, Volvo D1-30, Selden rig, removable mainsheet track system, Simrad (now B&G)-Jefa autopilot. |
Posted By: Swanji
Date Posted: 20 February 2013 at 15:59
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Hi Brufan That's a good point So here's my current positions which could change Unless you are looking to build in redundancy by having a second alternator and to save fuel by recharging more quickly, why would you want to fit a second alternator when it - is going to be costly - make life more complicated - there may not be enough space - may damage the crankshaft oil seal or bearing due to side loading - suffer some loss of propulsive power ranging from 2 HP up to 5 HP per alternator - places increased mechanical wear and tear on the engine The case for an efficient more efficient larger alternator with an alternator to battery charger is even stronger. Unless there is something I'm not getting here? ------------- Onwards and upwards Nidri, Levkada, Ionian, Greece Hanse 350 #7, SY Evolution, standard keel, 3YM20 sail drive, 3 cabins, cherry wood interior, teak decks, feathering prop |
Posted By: panos
Date Posted: 20 February 2013 at 18:03
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Hi, I believe all of us are saying the same : 1) it pays to increase the efficiency of the existing alternator ( or exchanging it for a bigger and better one ) and it is not recommended to install a second one. 2) a big alternator consumes 3 to 5 horsepower depending on efficiency and load conditions and engine RPM. it really pays to install a good alternator to battery charger (or smart alternator regulator as are sometimes called). ------------- Panos Hanse 630e - selling her - |
Posted By: Rubato
Date Posted: 20 February 2013 at 19:25
Fully understood but I guess what I meant was that I wouldn't worry about it (you may decide to) as the maximum load is not there all the time. I've been told that most people forget about the need to upgrade the belt/pulley system.... ------------- Steve Hanse 400e, #168 |
Posted By: Swanji
Date Posted: 12 March 2013 at 17:37
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Hi all We are about to start our DC upgrade and are busy purchasing the necessary components. We are able to source an alternator to battery charger from Mastervolt or Victron. I had hoped to get a 130aH Sterlimg alternator to battery charger which would allow for future upgrades to our alternator which I think is a standard 60H but not yet confirmed. Is anyone able to tell me which Victron or Mastercolt alternator to battery charger we should be getting that would be the equivalent of the Sterling AB12130 Thanks for any assistance. ------------- Onwards and upwards Nidri, Levkada, Ionian, Greece Hanse 350 #7, SY Evolution, standard keel, 3YM20 sail drive, 3 cabins, cherry wood interior, teak decks, feathering prop |
Posted By: Swanji
Date Posted: 13 March 2013 at 07:16
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Hi all I have another question for those more experienced than I - that would be most of you The alternator maximum rated output is normally reached when the engine rpm is around 3000 rpm. But if you want to recharge while at anchor, your neighbors will become a bit tetchy if you are running your engine at this rate while they are trying to enjoy a quiet pina colada. If you wish to idle the engine at say 1000 rpm but still get the alternator to spin at 3000 rpm, then your belt tension ratio needs to be 3 to 1. This would be safe when motoring at say 3000 rpm because most alternators have a rated safe rpm of around 10000. So, how does one get a belt tension of 3 to 1? Do you need a different kind of belt? Does this increase wear and tear on the alternator? Is it worth doing? Do any of you do it? Seems like the way to go subject to what the answers are to these questions. ------------- Onwards and upwards Nidri, Levkada, Ionian, Greece Hanse 350 #7, SY Evolution, standard keel, 3YM20 sail drive, 3 cabins, cherry wood interior, teak decks, feathering prop |
Posted By: sailkoop
Date Posted: 13 March 2013 at 07:26
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Hi Swanji, I never heard that anybody change the Ratio of the alternator. If you are looking to the Liftime it make no Sense to go that Way. The common Way to create more load from the Alternator is to increase the Current or to install a second alternator to the existing one. I prefer the Way to increase the current of one alternator and install a bigger one against the existing! Up to 80AH should more than enough for your capacity. Than look to that Sterling stuff: http://www.sterling-powershop.de/de/Sterling-A2B-Lader-12V-80A.html" rel="nofollow - http://www.sterling-powershop.de/de/Sterling-A2B-Lader-12V-80A.html and you'll be happy. ------------- best regards Bjoern |
Posted By: Wild
Date Posted: 13 March 2013 at 09:24
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Swanji If you reduce the diameter of the alternator pulley , you will increase the speed. But most alternators are running on a ratio 1.5 and will supply max current between 1600 - 2400 rpm( rpm engine around 1.000-1.600 ) and than drop down a bit. They can have a max of 12.000 rpm ( if a car runs 8.000 rpm x1.5 =12.000 it is only for a short time) but the current supply will not be higher than at 2.400 rpm only the voltage will becomes a bit higher. A good smart alternator regulator will optimize this proces and the charging of your batteries a little. If this is not enough get yourself a bigger alternator. ------------- Wild and Wet Belgium 545e#268 |
Posted By: CharlesP
Date Posted: 13 March 2013 at 10:20
I fully agree. My Battery Monitor indicates that my standard alternator supplies maximun charge with engine revs of about 1200. Charles ------------- 'MERIDIAN LADY' 320 Nr 536 2010 Medway |
Posted By: samuel
Date Posted: 13 March 2013 at 18:40
Apologies to Johan for using his picture & to others for hijacking the thread but i have been drooling over that boat Can anyone really believe that the latest 34's can beat that version ------------- Daydream Believer- Hanse 311- No GBR9917T- Bradwell Essex |
Posted By: CharlesP
Date Posted: 13 March 2013 at 19:03
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The cockpit seems very cramped compared to later models. A wheel (or two) and wider cockpit is my choice for comfortable cruising. Charles ------------- 'MERIDIAN LADY' 320 Nr 536 2010 Medway |
Posted By: samuel
Date Posted: 13 March 2013 at 21:38
I am not so sure that big wide sterns are nice for sailing - not so nicely balanced as Johan's boat i suspect Also the side view is better on the earlier marques Only my opinion - the real test will be sales volume ------------- Daydream Believer- Hanse 311- No GBR9917T- Bradwell Essex |
Posted By: Sea-U
Date Posted: 13 March 2013 at 22:02
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I think they will be even wider in the future. With the right design it is more balanced than earlier, proper sail boats. My previous boat was 38 feet and only 3.05 meter wide, well balanced. I have the feeling my 370e is better. Think it has to do with the wide stern. When heeling the wet area is not so asymetrical. Ever seen the video of the guy diving from the keel?. -------------  Sea-U is a 370e #532 located SW Norway
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Posted By: Johan Hackman
Date Posted: 13 March 2013 at 22:43
I believe the 342 is the best version ever. Especially if it is blue and does not sport a sprayhood. Johan ------------- http://www.johanhackman.se" rel="nofollow - http://www.johanhackman.se |
Posted By: Sea-U
Date Posted: 14 March 2013 at 18:50
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Found the video where a man dives from the keel. These boats are quite contrary from old thoughts that a wide stern is bad. http://www.youtube.com/watch?v=qpuEtkQNWn8 ------------- Sea-U is a 370e #532 located SW Norway
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Posted By: panos
Date Posted: 14 March 2013 at 20:36
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Canting keel Special downwind boat Huge fun Upwind performance? We do need to return. Don't we? ------------- Panos Hanse 630e - selling her - |
Posted By: samuel
Date Posted: 14 March 2013 at 20:43
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The figaro 33 is a case where a wide stern makes the boat more stable the faster it goes down wind But as we know as the boat is going upwind the balance changes due to the distorted shape change This often induces broaching as the rudder lifts out of the water & air goes down the top of the rudder causing stalling I suspect Johan's boat would do this less than the modern 34 from Hanse or Perhaps an Elan( am i right in thinking the elan has 2 rudders to offset this?) ------------- Daydream Believer- Hanse 311- No GBR9917T- Bradwell Essex |