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Topic: Coaches with miswired house batteries (Read 590 times) previous topic - next topic - Topic derived from Re: House batteries n...

Coaches with miswired house batteries

Quote from: Skillagalee –
U320 with 3 lifeline 8d AGM house batteries.

FOT said the batteries were hooked up wrong and only drawing on one battery. 

Quote from: Carol & Scott –
We recently encountered something similar.  It appears that our batteries were wired incorrectly and 2 out of the four 8a8ds were sick. 


So we have 2 coaches with batteries wired incorrectly.  Do we have any info on where these installations were done?  It would help others in the future to know this since batteries are not cheap.
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: Coaches with miswired house batteries

Reply #1 –
In an effort to answer Michelle's question, I offer the following:

Based on PO's records our 4th battery was installed at MOT.  The 4th battery was added to the middle of the string.  We replaced 3 of the 4 batteries with Lifelines and that is what we are currently using - 765 amp hours of total charge available or 382 amp hours to use 50% of the total available.  So far in our limited dry camping experience the 3 8as have been performing well.

Our LP tank had been removed and that is where the 4th battery was installed.  The battery cables were attached to the existing 3 8a8d  bank.  It appears that if the 4th battery was wired into the bank correctly either using buss bars and equal cable lengths or to the beginning or end of the string, the 4th battery and the bank probably would be functioning properly.  Increasing the battery bank may also requires the gen to run longer to replace the charge spent while not plugged in or running the gen set.  It depends on how many amps you use while dry camping.

(Am considering how to add additional house battery capacity.  At the moment leaning toward adding two L16s and a separate inverter for the res. refer.  and adding about 960 watts of solar with appropriate controllers to assist charging the battery banks.  The 2 L16s will live in the area where the LP tank resided.  The addition of solar should allow us to run the gen set less often.)





Scott & Carol Seibert
2001 42' double slide U320 - Sold
Previous - 2002 36' U320

Re: Coaches with miswired house batteries

Reply #2 –
My question to add to Michelle's ( the Jeffe) would be " how were these batteries actually wired to be incorrecttly done?"
A simple drawing is all we need (or photo) so that other members can simply look at it and decifer if theirs are ok.
I have a buss bar setup so simple to add to.
JohnHm
Coachless, now use aircraft. 2003 Ford Travelair TC280 class C. Super shape. Just for 1 yr .
1994 Ford E350 ClassC,total renovation inside and out. Now sold.
2000 U295  36' Cummins 350 c/w Banks Stinger, Resonator upgrade,Solar, LED lites.Residential fridge with slide out pantry. Build 5674. Sold
ex 92 GV 022C ored Cummins. Sold
ex 95 GV240 cat 3116. Sold
2017 Mini cooper s & 2016 land Rover LR2 HSE  LUX.
jhaygarth@aol.com    SKP #130098
treat everyone as you would like to be.

Re: Coaches with miswired house batteries

Reply #3 –
I have a drawing of how our batteries were wired.  Will try to find it and take a  pic to post.  Busy today so will try to get up this PM.
Scott & Carol Seibert
2001 42' double slide U320 - Sold
Previous - 2002 36' U320

Re: Coaches with miswired house batteries

Reply #4 –
It is almost impossible to mis-wire multiple house batteries, as long as all negative terminals are connected together and all positive terminals are connected together.
But there are lot ways to not optimize them: terminal & connections not sparkling clean, connecting the main cables to the same battery, dirty batteries, etc.
Also parallel-wired batteries, even if all is perfectly wired, often to not equally share in the load and charging, and nothing can force them to equally share.  So one battery may get more 'worn-out' than the others.

Re: Coaches with miswired house batteries

Reply #5 –
If you have a DC clip on amp meter and can access the battery wiring, it is possible to check what each battery is doing. Put a heavy load on the inverter, say a griddle that draws 1200 watts, this will be approx 100 amps at 12 volts. The exact value isn't important. Using the formulas in the attached diagram, compare the batteries, healthy batteries should provide approximately equal current under load.
Peter and Tammy Fleming
1991 U300 GV 40 - Sold, owned for 4 years
Downsized to Roadtrek Popular 210 class B

Re: Coaches with miswired house batteries

Reply #6 –
Quote from: prfleming –
If you have a DC clip on amp meter and can access the battery wiring, it is possible to check what each battery is doing. Put a heavy load on the inverter, say a griddle that draws 1200 watts, this will be approx 100 amps at 12 volts. The exact value isn't important. Using the formulas in the attached diagram, compare the batteries, healthy batteries should provide approximately equal current under load.

In your middle picture would it not be for the third battery amps  C-(A+B)
2014 ih45  (4th Foretravel owned)
 1997 36' U295 Sold in 2020, owned for 19 years
  U240 36' Sold to insurance company after melting in garage fire
    33' Foretravel on Dodge Chassis  Sold very long time ago