Fuse size engine
Printed From: myHanse.com
Category: General
Forum Name: Chit Chat
Forum Description: Talk about anything to do with your boat
URL: https://www.myhanse.com/forum_posts.asp?TID=13781
Printed Date: 27 March 2026 at 01:23
Software Version: Web Wiz Forums 12.06 - https://www.webwizforums.com
Topic: Fuse size engine
Posted By: Johan Hackman
Subject: Fuse size engine
Date Posted: 09 December 2022 at 12:09
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I am fitting a fuse that will handle the situation in the event the battery bank is shortcircuited. The engine will be connected to this fuse and I wonder what would be a suitable size? I seem to recall that the current when starting the engine is 100A but I am not sure. Anyone with knowledge on this? Johan -------------  http://www.johanhackman.se" rel="nofollow - http://www.johanhackman.se |
Replies:
Posted By: Jojo
Date Posted: 10 December 2022 at 09:47
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my system is fuesd at 100A (same boat and engine as you) 4 LiFePo4 in my bank Remember a short this battery is like a Tig welder so the right fuse is crucial and the distance to other materials from the fuse it self A good video that explains the problem of a short and to have a fuse that are up to potential Amp that a lithium can provide http://https://youtu.be/SjzbQlsiiuk" rel="nofollow - https://youtu.be/SjzbQlsiiuk Regards jonas
------------- 3 Cabin, Hanse 342, Deep draft, Tiller version. |
Posted By: Johan Hackman
Date Posted: 11 December 2022 at 13:47
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Jonas, is the engine connected to the 100A fuse and if so, can you start the engine without the risk of blowing the fuse? I would love top see your battery setup. Do you have any pictures? Johan ------------- http://www.johanhackman.se" rel="nofollow - http://www.johanhackman.se |
Posted By: Jojo
Date Posted: 11 December 2022 at 16:22
Hi Yes it’s a 100A fuse from a good brand not china and a 100A disconnect low voltage protection I will remake this installation as it’s not to my standard But it is working well as is Looking has it lots to work with to for me and to make it safer electrical wise This was made 2017 by previous owner and battery are still working a week (4persons) without having to start engine or charge Hope this works for you   ------------- 3 Cabin, Hanse 342, Deep draft, Tiller version. |
Johan Hackman wrote:Posted By: Johan Hackman
Date Posted: 12 December 2022 at 10:07
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Thanks for the pictures! I am still trying to get my head around this. I think the engine draws 100A for a very short time when started. My coffee machine draws 43A. So if I am starting the engine and make coffee at the same time the current will be very high, albeit just for a brief moment. Will a slow fuse allow for that? Johan ------------- http://www.johanhackman.se" rel="nofollow - http://www.johanhackman.se |
Posted By: Jojo
Date Posted: 12 December 2022 at 12:49
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i can’t give you a advice It’s all about cable dimensions how much you need Regardless of what you do it seems like a pretty simple problem To not start the engine at same time as the coffee maker My point is if something draws that amount I would start the engine before I make coffee or likely I do as I always do on my stove Regards Jonas ------------- 3 Cabin, Hanse 342, Deep draft, Tiller version. |
Posted By: Johan Hackman
Date Posted: 17 December 2022 at 10:29
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I fellow forum member had the kindness to copy a few pages from a book on the subject and it all made me a lot wiser. According to the ISO standard, the engine is not required to have a fuse but on the other hand, this is for cars so the author himself would use a 300A fuse knowing that this will not cause nuisance blowing (a new expression to me) at the same time will blow in the event of a dead short. So I went for a 300A fuse that I placed as close as possible to the positive terminal on the battery bank, before the isolation switch. Johan ------------- http://www.johanhackman.se" rel="nofollow - http://www.johanhackman.se |
Posted By: Wild
Date Posted: 17 December 2022 at 16:10
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Hello Jonas A small remark When you remake the battery installation. All the positive cables who connect the battery’s in parallel must have the same length. The one on the positive battery on top of your picture to the one installed in the other direction is longer than the other connecting cables. ------------- Wild and Wet Belgium 545e#268 |
Posted By: Jojo
Date Posted: 17 December 2022 at 20:44
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The batteries can deliver some couple thousand A, if and when they are shortcircuit so that’s the only issue as those thick cables will burn white like a halogen bulb in milliseconds if not securely fused I have competition in F5B with those types of batteries only smaller and a 116A drain 2600w from a standard flashlight sice battery in 120-200s total engine time on each charge That give me a lot of understanding how those pro and cons are And the benefits is energy/weight and low discharge Of the pro comes some cons like in case of fire they produce oxygen so safe installations and monitoring charge and discharge in safe battery temperatures +5- +35 degrees Celsius never less or higher And a decent discharge will keep that range as the battery compartment is in the waterline Johan 300A then you have to cable up for that up to the fuse from the batterybank in case of a short Regards jonas ------------- 3 Cabin, Hanse 342, Deep draft, Tiller version. |