Author Topic: Loosing voltage on engine batteries  (Read 6592 times)

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Offline urmine351

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Loosing voltage on engine batteries
« on: December 06, 2011, 05:21:31 PM »
I have put several sets of new engine batteries in mt 1997 Safari with a 3126 Cat.  If it sits a month and hasn't been started the batteries will be completely drained.  The house batteries are fine but the boost switch doesn't seem to work.  In my simple thinking there is a relay or something somewhere that the boost switch on the dash is supposed to activate.  This also is the only place where the engine and house batteries are connected.  Has anyone had any experience with this?  I need some help please.   thanks Joe
« Last Edit: December 07, 2011, 09:05:55 AM by Brett Wolfe »

Offline Brett Wolfe

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Re: Loosing voltage on engine batteries
« Reply #1 on: December 06, 2011, 05:52:12 PM »
It is reasonably common that a coach builder will leave you no means of charging the chassis battery from 120 VAC (shore power or generator).

It is also quite reasonable that parasitic loads on the chassis battery will discharge it within a month.


So, that brings up the question of how you store your coach-- indoors with 120 VAC, outdoors, etc?

Brett

Offline urmine351

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Re: Loosing voltage on engine batterys
« Reply #2 on: December 07, 2011, 12:37:06 AM »
I store it outside under a covered roof with 30 amp 110 hooked up.  But something is definitely draining the chassis batterys.  thanks Brett I appreciate all the help you can give me.

Offline urmine351

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Re: Loosing voltage on engine batterys
« Reply #3 on: December 07, 2011, 01:06:02 AM »
I went to start the coach about a month ago and the batterys were dead on the chassis side.  My daughter works with a girl who's husband has a truck repair shop in van buren, just across the bridge.  He came out and got it started with jumper cables.  when he removed them, it died, so he put them back and left them on to drive to his shop.  It sat at his shop, not hooked to anything for a week and when he went to get it to work on, it started right up.  He checked it out and said he couldn't find anything but he did install a 12 gague wire from a positive post on a house battery to a positive post on the chassis battery.  He brought it back to my storage and it sat for another week.  it started fine when i brought it home for a trip.  I went and got it on a sunday, was leaving on a wed.  when i went to start it, it would try but wouldn't turn over.  I tried the boost switch which is lit when you activate it, the lamp was not solid, it was rapidly flashing on and off. I went back to the battery compartment to try and jump it, when i opened the door, the little wire he had put in was in flames. I put it out with a fire extenguisher.

Offline John Ruff

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Re: Loosing voltage on engine batterys
« Reply #4 on: December 07, 2011, 06:07:27 AM »
You usually need to have voltage in your chassis battery to activate the relay to combine all batteries.  It seems like a Catch 22

John Ruff

Offline Brett Wolfe

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Re: Loosing voltage on engine batterys
« Reply #5 on: December 07, 2011, 07:14:27 AM »
Never, never use a small gauge wire, particularly one that does not have fuses at each end to connect two battery banks. No problem as long as both batteries are at roughly the same state of charge.  But, if one is charged and one deeply discharged, that wire turns into a resistance heater and can easily start a fire.

Since you have shore power where you store your coach the solution is easy.  The house batteries are already charged by your converter, charger or inverter/charger.  What you need is a means of keeping the chassis battery charged.  Here are two common methods of doing that:

http://www.lslproducts.com/TLSPage.html

http://www.xantrex.com/power-products/power-accessories/auxiliary-battery-charger.aspx

On another note, as deeply as your chassis batteries have been discharged, there is a good chance that they are shot.  Start by fully charging them for a couple of days.  Then swing by any place that sells batteries and have them load tested-- usually free.  If they are regular wet cell batteries (i.e. you can check and add water-- which needs to be done) you can go by any auto parts house and buy a battery hydrometer (under $8) and check them.  Again, check them only when fully charged.

Brett

Offline Brett Wolfe

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Re: Loosing voltage on engine batterys
« Reply #6 on: December 07, 2011, 07:16:30 AM »
You usually need to have voltage in your chassis battery to activate the relay to combine all batteries.  It seems like a Catch 22

John Ruff

John,

True.  Some battery boost/combine switches are fed by the chassis battery, some by the house battery and the BEST wiring is for it to be fed by BOTH battery banks with a diode in each feed line.  This latter set up covers all the bases.

Brett

Offline urmine351

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Re: Loosing voltage on engine batterys
« Reply #7 on: December 07, 2011, 08:52:34 AM »
Thanks so much Brett and John.  I will get new batterys and looking into this.  I have an older model freedom 2000 inverter.

Offline Brett Wolfe

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Re: Loosing voltage on engine batterys
« Reply #8 on: December 07, 2011, 09:01:48 AM »
Pull out the owners manual for the Freedom 2000 and be sure the "DIP SWITCHES" are properly set.

Newer inverters are usually programmable from the remote, but older ones have dip switches to service that function.

Programming includes telling the inverter/charger:

Battery technology (AGM, gel or wet cell)

Battery bank size (in amp-hrs)

Ambient temperature (basically summer/winter).

It is a smart charger, but only if you tell it what you want it to do.

Brett

Offline varners1380

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Re: Loosing voltage on engine batterys
« Reply #9 on: December 08, 2011, 05:57:29 PM »
Never, never use a small gauge wire, particularly one that does not have fuses at each end to connect two battery banks. No problem as long as both batteries are at roughly the same state of charge.  But, if one is charged and one deeply discharged, that wire turns into a resistance heater and can easily start a fire.

Since you have shore power where you store your coach the solution is easy.  The house batteries are already charged by your converter, charger or inverter/charger.  What you need is a means of keeping the chassis battery charged.  Here are two common methods of doing that:

http://www.lslproducts.com/TLSPage.html

http://www.xantrex.com/power-products/power-accessories/auxiliary-battery-charger.aspx

On another note, as deeply as your chassis batteries have been discharged, there is a good chance that they are shot.  Start by fully charging them for a couple of days.  Then swing by any place that sells batteries and have them load tested-- usually free.  If they are regular wet cell batteries (i.e. you can check and add water-- which needs to be done) you can go by any auto parts house and buy a battery hydrometer (under $8) and check them.  Again, check them only when fully charged.

Brett


Get the Tric L start.  Not uncommon to find drained batteries on older coaches.  In fact, when I bought my 2002, the seller warned me about the chassis battery draindown. I installed one and have never had a problem as long as it's plugged in.
Richard
2002 Itasca Horizon

Offline solarnomads

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Re: Loosing voltage on engine batteries
« Reply #10 on: December 09, 2011, 09:02:25 PM »
The TrikLStart will also maintain chassis battery charge whatever the house charge source, including generator or solar. We've had ours for 6+ years on same chassis batteries charged entirely through our solar electric system.