Hybrid lead/ lithium install
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Topic: Hybrid lead/ lithium install
Posted By: lide
Subject: Hybrid lead/ lithium install
Date Posted: 19 November 2024 at 09:41
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I am planning to install a lithium bank for my service battery. Currently there are 2 AGM 150Ah each. I will be removing one AGM and will add a lithium bank in parallel with the remaining AGM.
The Lithium will be paralleled through a Bank Manager to prevent overcharging the lithium. https://marinedcac.com/products/bankmanagertm-gen3" rel="nofollow - https://marinedcac.com/products/bankmanagertm-gen3
I'm looking for thoughts on what (if anything) I may need to change from the stock set up.
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Replies:
Posted By: Wayne's World
Date Posted: 19 November 2024 at 19:07
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Lide,
Sounds overly complicated? If the setting on your charger/inverter are set correctly there should be no over charging. If your engine alternator is suitable for the charging of lithium - again there should be no over charging. Your lithium/s should have an external or internal BMS which would be programable to stop over charging.
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Wayne W
Cruising, currently in the Pacific until the end of 2026.
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Posted By: Arcadia
Date Posted: 19 November 2024 at 20:56
FWIW, I have a “hybrid” system on my boat. Each bank is (3) lithium 230 aH in parallel with (1) 230 aH AGM on each side of the boat which can be chosen via an A/B switch. The internal lithium BMS is happy with the charging system as is the AGM. No additional switching is involved. When the lithium reaches full charge, the internal BMS’s shuts down the charge, but the AGM keeps the load on the alternator so no spikes. Also, the AGM will stay topped off by the lithiums since they float at above 13 volts. Also, if the lithiums shut down from deep discharge, the AGM will carry on so no black outs. This turned out to be a very successful drop in set up, providing 1,500 amp hrs of trouble free power for three years now.
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Leon / ARCADIA
2018 Hanse 588
Sag Harbor, NY
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Posted By: Arcadia
Date Posted: 19 November 2024 at 21:45
Correction. My AGM’s are 165 aH.
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Leon / ARCADIA
2018 Hanse 588
Sag Harbor, NY
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Posted By: Mark&Catherine
Date Posted: 21 November 2024 at 13:37
There is plenty of evidence that the hybrid system works. The only issue I have seen is the reluctance of some insurers to accept the arrangement.
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385 ubulukutu sail number GBR 3350L in Turkey and Greece with Mark and Catherine
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Posted By: 32mike
Date Posted: 21 November 2024 at 14:25
If the lithiums shut down from deep discharge, wouldn’t that also mean that the AGM is also at low voltage since they are in parallel? Therefore, wouldn’t the AGM also be dead, or near dead?
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Mike
S/V Dulces Sueños
458 #087
Tampa, FL
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Posted By: Mark_J1
Date Posted: 21 November 2024 at 14:46
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32Mike - no, when the LiFePO4 batteries reach the low point voltage in their discharge curve, the AGM is still sitting happy at 12.8v and starts to take some of the load. Off you push the LiFePO4 battery’s BMS all the way to cut-off the AGM is still at a relatively happy point in its own discharge curve. So you get graceful failure (or handoff) and can still discharge the AGM as normal. On the other hand while the Lithium takes the load the AGM is unstressed and takes a little power to keep it full.
Mark
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Hanse 400e "Grey Goose" Hull #31
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Posted By: Arcadia
Date Posted: 21 November 2024 at 14:53
Mark, you have it exactly right. At 165 aH, the AGM can carry on fine for most loads. Of course, starting the engine or generator would be advised at that point, but no rush and no black out!
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Leon / ARCADIA
2018 Hanse 588
Sag Harbor, NY
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Posted By: 32mike
Date Posted: 21 November 2024 at 15:02
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Ok, yeah, I just googled the discharge curves of the different batteries. So, basically, the lithium low voltage cutoff number is not that dead for the AGM. I’ve heard of this kind of setup before but seem to remember that there are drawbacks to it. Just don’t remember what they are. Why do the insurance companies not like it?
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Mike
S/V Dulces Sueños
458 #087
Tampa, FL
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Posted By: Arcadia
Date Posted: 21 November 2024 at 15:16
Actually, I’m not aware of any insurance issues in the USA. Does anyone have any knowledge of this ? Also, I can say with confidence that I have had absolutely no drawbacks to this set up after three years and probably 500 cycles.
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Leon / ARCADIA
2018 Hanse 588
Sag Harbor, NY
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Posted By: lide
Date Posted: 21 November 2024 at 22:37
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Thanks Arcadia. Great to hear that's working out!
Did you need to change any other components? My concern is mostly about the alternator. If it tries to charge a fairly empty lithium bank it's going to push a lot of amps.
Also, in your install, I suppose the BMS of each battery in the bank may trigger at somewhat different times based on individual SoC. Do they come back online on their own once the charging source is removed?
I am mostly concerned about something like solar overcharging the lithium. The Bank Manager I linked above is supposed to gracefully disconnect the lithium bank once it detects that the lithium is fully charged based on its charge absorption rate. They claim that the BMS disconnect is meant to protect the battery from damage rather than a safe charging limit.
In either case I am trying to avoid adding DC/ DC chargers.
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Posted By: Arcadia
Date Posted: 21 November 2024 at 22:43
As far as charging goes. Yes, the Lithiums will disconnect one at a time from the alternator finally leaving only the AGM charging. This usually happens within a few minutes of each other. However, the BMS’s although disconnected from the charger, will always stay connected to any loads that are present. They do this seamlessly, so they are never truly disconnected. Only from any INFLOW of current.
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Leon / ARCADIA
2018 Hanse 588
Sag Harbor, NY
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Posted By: Arcadia
Date Posted: 21 November 2024 at 22:51
Also, my Volvo D3 is equipped with a 180 amp alternator which get pretty warm, but still alive after 3 years of lithium. The batteries I purchased have the latest generation of BMS. It cuts off the charge once the cell internal balancing function is done. This usually happens within 20 minutes or so of reaching 14 volts. So, it does protect from damage as well as overcharge. I spoke to the company and they told me that they programmed for slight under charge so that 95 percent of capacity is reached but lifetime is drastically increased in this way…as is safety. I like that. I’m familiar with the Battery Manager product and it is a good design. It was unnecessary in my configuration but may be useful with solar. However, as long as solar charge remains at 14 volts you will be fine.
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Leon / ARCADIA
2018 Hanse 588
Sag Harbor, NY
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Posted By: Arcadia
Date Posted: 21 November 2024 at 22:57
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The DC to DC chargers pose a problem in that they will drastically reduce your maximum charge current thereby increasing charge time. They will protect a small alternator from burning up however ! If you’re going to take advantage of the high capacity and fast recharge of lithium, you would be best served by installing a high output alternator that won’t self destruct. The batteries I used were exactly the same size as the AGM’s I removed so the physical install was easy. The only wiring I did was the selector switch and a bit of rerouting of the main DC board.
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Leon / ARCADIA
2018 Hanse 588
Sag Harbor, NY
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Posted By: Arcadia
Date Posted: 21 November 2024 at 23:00
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For anyone interested, after extensive research and testing, these are the units I used.
https://www.litime.com/products/12v-230ah-plus-lifepo4-battery?currency=USD&variant=43846095339740&utm_source=google&utm_medium=cpc&utm_campaign=Google+Shopping&stkn=a05d7c18f02e&gad_source=1&gbraid=0AAAAApCuQrdAGXvaA5xDtPJzP94-rUwFa&gclid=EAIaIQobChMInaSnk8PuiQMVRVBHAR3fsh67EAYYAyABEgKA_vD_BwE" rel="nofollow - https://www.litime.com/products/12v-230ah-plus-lifepo4-battery?currency=USD&variant=43846095339740&utm_source=google&utm_medium=cpc&utm_campaign=Google+Shopping&stkn=a05d7c18f02e&gad_source=1&gbraid=0AAAAApCuQrdAGXvaA5xDtPJzP94-rUwFa&gclid=EAIaIQobChMInaSnk8PuiQMVRVBHAR3fsh67EAYYAyABEgKA_vD_BwE
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Leon / ARCADIA
2018 Hanse 588
Sag Harbor, NY
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Posted By: lide
Date Posted: 21 November 2024 at 23:07
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Thanks for the input WW.
The alternator is stock as is every other part of the system so far. I'm actually trying to avoid making the charging sources 'Lithium-aware'. Especially, since something like the alternator is charging the lead-acid starter battery as primary and will need to charge the lithium in parallel so it's hard to make every charging source optimized to stop charging when the lithium is full.
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Posted By: lide
Date Posted: 21 November 2024 at 23:13
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Thanks Arcadia. Great system!
Yes. looks like there's a high output alternator in my future. Though I was hoping the internal temperature protection of the stock alternator will reduce output as its temperature rises. Not sure if that's reliable enough.
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Posted By: Arcadia
Date Posted: 21 November 2024 at 23:32
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You can use a thermal controller to cut off the alternator field voltage at a preset temp. The alternator will stop output until it cools off and start again. Like a thermostat.
https://www.amazon.com/Temperature-Controller-Display-Digital-Thermostat/dp/B07VNVWCBS/ref=sr_1_21?crid=3U0DSPC0JSTMF&dib=eyJ2IjoiMSJ9.41cKDiPbjZmOK730WQddYag5jFcwLTZWjLfcqfIi6PPGjHj071QN20LucGBJIEps.1uGXnXigBXdgXyRpQlSgzDOviHCkld_siLG5Ymv7ZD4&dib_tag=se&keywords=thermal%2Bswitch%2B12v&qid=1732231461&sprefix=Thermal%2Bswitch%2Caps%2C106&sr=8-21&th=1" rel="nofollow - https://www.amazon.com/Temperature-Controller-Display-Digital-Thermostat/dp/B07VNVWCBS/ref=sr_1_21?crid=3U0DSPC0JSTMF&dib=eyJ2IjoiMSJ9.41cKDiPbjZmOK730WQddYag5jFcwLTZWjLfcqfIi6PPGjHj071QN20LucGBJIEps.1uGXnXigBXdgXyRpQlSgzDOviHCkld_siLG5Ymv7ZD4&dib_tag=se&keywords=thermal%2Bswitch%2B12v&qid=1732231461&sprefix=Thermal%2Bswitch%2Caps%2C106&sr=8-21&th=1
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Leon / ARCADIA
2018 Hanse 588
Sag Harbor, NY
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Posted By: lide
Date Posted: 21 November 2024 at 23:36
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Thanks. I'll keep a check on temps once it's all installed and then decide on either a supplementary cutoff or a high output alternator that has the additional benefit of high output.
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Posted By: 32mike
Date Posted: 21 November 2024 at 23:58
You could also go the external alternator regulator route. Wakespeed and, I think Sterling make one. There’s also a newer one called Arco Zeus, which is probably the priciest of the three. They can control the charging rate so as to not overheat your alternator.
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Mike
S/V Dulces Sueños
458 #087
Tampa, FL
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Posted By: coriolis2
Date Posted: 04 December 2024 at 09:14
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This is my €900 solution:
https://www.myhanse.com/agms-replaced-by-lifepo4s_topic12899.html" rel="nofollow - https://www.myhanse.com/agms-replaced-by-lifepo4s_topic12899.html
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"Coriolis" H350 #045 (ex Waarschip 570 #? 1987/1992, ex Waarschip 28LD #7 1994/2007)
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