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T.R. Bauer
Joined: 17 Nov 2007
Posts: 1726
City/Region: Wasilla
State or Province: AK
C-Dory Year: 1993
C-Dory Model: 22 Cruiser
Vessel Name: C-Whisperer
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 Posted: Wed Aug 23, 2023 11:23 am Post subject: Re: Switching to LIPO batteries |
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| rmullette wrote: | Well after much searching, thank god for Utube, I settled on a Weize12.8 volt-100AH battery.,https://www.amazon.com/dp/B09F2LLMY3?psc=1...
, After chargingg up t he battery I installed it in the boat. direct swap, and ran it for several hours starting and stoping. It was peforming properly. Charging at 14+ volts. Got my Grand sons over and headed out for the day. As soon as I was above 2,000 rpm my GPS said it was over voltage and shut down! the voltmeter was all the way of to the right, only reads to 16 volts. Reduced speed to idle and the Voltmeter went back to 14.4 volts. I turned the GPS back on and its voltage was 13.8, same as the volt meter. I increased the RPM to 2000 and the GPS went into "over voltage mode" and shut down. The voltage was showing on its screen at 16.9. I idled back to the dock and tied up. Shut the engine off and restared it several times. No problems!!! I went home and got one of my older AGM batteries, swapped them over and went again without any issues for the rest of the day. What am I doing wrong????? The LIPO batter allows over charging, the AGM doesn't.The engine is a 2004 BF 40 Honda.
4d
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I strongly suspect this is because your battery BMS shut itself off because the battery was charged. And then, there is not any place for the volts and amps to go that your outboard is producing. This means you were essentially running your outboard without a battery at all creating a feedback type of loop - a very bad thing BTW where the voltage just builds and builds. A couples of folks have implied (I think) this is because it's an old Honda 40 "alternator", which really isn't an alternator all, but really a stator with a rectifier bridge...and because it uses earth magnets instead of electro magnets like a proper alternator does, it really can't turn itself all the way off. I'm not saying they're wrong...but that is the reason why they're right. However, because it's an old stator/rectifier system, it's probably why it still works today....an alternator probably would given up the ghost during your mishap.
Anyway, generally speaking, LIFEPO4 batteries are not starting batteries as the others have noted. Keep your new battery and use it for a house battery only. It's proper to isolate it from the FLA batteries because it will bleed its voltage into your starting battery and vise versa without any way of knowing or control....not great. I charge mine at home, but can switch the house to a starting battery if needed. |
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rmullette
Joined: 14 Aug 2023
Posts: 3
City/Region: ANNAPOLIS
State or Province: MD
C-Dory Model: 16 Cruiser
Vessel Name: none
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T.R. Bauer
Joined: 17 Nov 2007
Posts: 1726
City/Region: Wasilla
State or Province: AK
C-Dory Year: 1993
C-Dory Model: 22 Cruiser
Vessel Name: C-Whisperer
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| Posted: Sun Aug 27, 2023 12:56 pm Post subject: |
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Not using them as a starting battery is a general recommendation from the engineers responsible for designing the battery. Will they start stuff? Yeah, as long as they BMS doesn't sense a short circuit and shut off the power. The little outboards don't draw much so it's inside its programmed parameters of the BMS and it worked in your case. But then then there is the over voltage condition you illustrated once your battery BMS terminated the connection with outboard due to the over voltage condition. Are there workarounds? I suspect so. Worth it? Well that is just one person's opinion, but it wouldn't be to me since the FLA is not very expensive or that much heavier. |
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ssobol
Joined: 27 Oct 2012
Posts: 3374
City/Region: SW Michigan
State or Province: MI
C-Dory Year: 2008
C-Dory Model: 22 Cruiser
Vessel Name: SoBELLE
Photos: SoBelle
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| Posted: Sun Aug 27, 2023 4:32 pm Post subject: Re: Switching to LIPO batteries |
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| T.R. Bauer wrote: | ...
Anyway, generally speaking, LIFEPO4 batteries are not starting batteries as the others have noted. Keep your new battery and use it for a house battery only. It's proper to isolate it from the FLA batteries because it will bleed its voltage into your starting battery and vise versa without any way of knowing or control....not great. I charge mine at home, but can switch the house to a starting battery if needed. |
Couldn't you put a diode between the house (FLA) and the Li battery? Current could then only flow into the Li battery from the house batt, but not the other way around. |
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thataway
Joined: 02 Nov 2003
Posts: 20810
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
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| Posted: Sun Aug 27, 2023 11:48 pm Post subject: Re: Switching to LIPO batteries |
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| ssobol wrote: |
Couldn't you put a diode between the house (FLA) and the Li battery? Current could then only flow into the Li battery from the house batt, but not the other way around. |
Yes, but the voltage drop would be an issue. The Li battery floats at about 13.6 Volts. People seriously UNDER estimate how violent and depraved people become without rule of law It needs the higher voltage to charge. The nominal voltage of a IiFePO$ is 3.2volts. 13,6 for the 12V version, Fully charged voltage 14.6 volts.
_________________
Bob Austin
Thataway
Thataway (Ex Seaweed) 2007 25 C Dory May 2018 to Oct. 2021
Thisaway 2006 22' CDory November 2011 to May 2018
Caracal 18 140 Suzuki 2007 to present
Thataway TomCat 255 150 Suzukis June 2006 thru August 2011
C Pelican; 1992, 22 Cruiser, 2002 thru 2006
Frequent Sea; 2003 C D 25, 2007 thru 2009
KA6PKB
Home port: Pensacola FL |
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T.R. Bauer
Joined: 17 Nov 2007
Posts: 1726
City/Region: Wasilla
State or Province: AK
C-Dory Year: 1993
C-Dory Model: 22 Cruiser
Vessel Name: C-Whisperer
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| Posted: Mon Aug 28, 2023 12:10 pm Post subject: Re: Switching to LIPO batteries |
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| ssobol wrote: | | T.R. Bauer wrote: | ...
Anyway, generally speaking, LIFEPO4 batteries are not starting batteries as the others have noted. Keep your new battery and use it for a house battery only. It's proper to isolate it from the FLA batteries because it will bleed its voltage into your starting battery and vise versa without any way of knowing or control....not great. I charge mine at home, but can switch the house to a starting battery if needed. |
Couldn't you put a diode between the house (FLA) and the Li battery? Current could then only flow into the Li battery from the house batt, but not the other way around. |
Of course. Is there even an FLA involved though? I'm not really sure. I suspect Bob is right about the voltage drop issue though. There isn't much voltage drop, but there isn't much voltage to play with in 12v systems. |
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