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Open Roads Forum  >  Travel Trailers  >  General Q&A

 > Low Battery Voltage

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enblethen

Moses Lake, WA

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Posted: 06/29/22 09:35am Link  |  Quote  |  Print  |  Notify Moderator

The Incommand is in your TV, correct? Just because power is leaving the truck doesn't mean it is getting to the trailer's battery.
Need to measure voltage right at the battery.


Bud
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valhalla360

No paticular place.

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Posted: 06/29/22 09:53am Link  |  Quote  |  Print  |  Notify Moderator

Lots of unknowns going on:
- Somewhere around 10-11v is a fully discharged 12v battery. 6.3v is way beyond. You might be able to get it to work a bit but you've probably done significant damage letting it get so low. Even if you do get it to take a charge, don't expect it to do so for long.
- 13.6v is conveniently close to what the converter puts out while charging. A fully charged 12v battery should be around 12.7v with the charger off, so you likely weren't seeing if the battery was fully charged. You just saw the charging voltage.
- Cranking amps is not what you are after with the house bank. You want amp-hours.
- If the fridge is running on propane, it's drawing a negligible amount. Either the battery was already dead or you have something else drawing on the battery.
- Did you actually put a meter on the wires from the truck showing amps going into the battery? Just because, it shows 12-13v doesn't mean many amps are going in (or it could be the same as when the converter is operating and the battery is simply not taking a charge).

What I would do:
- Get a clamp on multimeter (doesn't have to be high end but make sure it does DC current). Learn how to measure volts and amps with it.
- Start with everything disconnected and off (preferably off for an hour or more).
- Check the battery voltage. (if below 12.0v, you are starting with a low battery...around 40% of full)
- Check if there is any amp draw off the battery. (if more than an amp, you have something beyond the propane sensor...track down what it is).
- Plug in and get power to the converter.
- Check the voltage and amperage to the battery. Voltage should be at least 13.6v if the battery wasn't full and possibly over 14v if the charger goes into bulk charging. You should be seeing significant amperage (check the rating on the converter but I would say at least 1/3 to 1/2 the rated amperage up to the rating). If it's only putting in an amp or two, you have a charging issue to track down.
- If the voltage is up and it's putting in significant amps, let it continue for at least a couple hours.
- Check the voltage after a couple hours. It may drop back to around 13.1v if the charger is in float mode or it may drop back to 12.7 if fully charged (probably not but possible)
- Turn off the converter, let sit for 5-10minutes (the battery will gradually drop back when the charging voltage is removed) and check the voltage. Ideally, you should be around 12.5-12.7v. If it's below 12.0v, it's not taking a charge.
- You can repeat the tests hooking the truck up to see if it's really charging off the truck.
- If the battery is showing fully charged, disconnect the leads to the battery (don't trust the disconnect switch), let sit for the night and check the voltage. The drop in voltage overnight should be negligible. If in the morning it's 6.3v, it can only be a bad battery.

Possible issues:
- Since you report 13.6v on the charger, the truck shows a connection and the slide worked once you plugged in, probably not the charging system (do run the checks though as it may be something unexpected).
- The battery is my best guess but if the cranking amps are good, that's odd. Usually that would suffer on an abused battery.
- You have a 12v load that you are not aware of. You need to track down what it is and why it is staying on.

Try to be systematic and return here with the results and people can probably give you better feedback.


Tammy & Mike
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Grit dog

Black Diamond, WA

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Posted: 06/29/22 10:07am Link  |  Quote  |  Print  |  Notify Moderator

One marginal "free with purchase" cheapo battery with likely a marginal converter charging it has no chance of running a fridge even on LP for 24 hours.
I'm in a similar boat, except I understand why my system is marginal and I have good batteries (plural). Cheap converter doesn't charge properly.
Except I use the camper very rarely and have onboard genny at my disposal. If I had the time to repair and/or the need for a more competent system, my WFCO converter would already be in the landfill and a PD converter would be in it's place!


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klutchdust

Orange, California

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Posted: 06/29/22 10:07am Link  |  Quote  |  Print  |  Notify Moderator

Any water in the battery? They need to be checked each trip.

theoldwizard1

SE MI

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Posted: 06/29/22 12:16pm Link  |  Quote  |  Print  |  Notify Moderator

klutchdust wrote:

Lwiddis wrote:

An RV battery or batteries drawn down to 6.3 volts is toast. You have an issue, yes, but buy new batteries when solved.


So if a battery gets discharged to that point it is no longer usable, even if recharged?
I had a battery that was dry, sitting in the garage zero charge in it. I filled with distilled water, trickle charged it for a few days and it went back in service with no issues.

It may not be completely dead, but your RV battery will never have it's full capacity.

I have run automotive batteries down to near zero (interior lights on) and after recharging they were able to start the car, but only because it had very short crank times and the charging system kept it at 100% while the engine was running.

Time for a new RV battery. Two 6V golf cart batteries have more capacity than a 12V marine/RV battery and don't cost much more.

If you want to run the refrigerator on electric while driving, get a DC-DC batter charger.

Krusty

Calgary, Alberta,Canada

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Posted: 06/29/22 12:32pm Link  |  Quote  |  Print  |  Notify Moderator

Does your fridge have a high humidity switch? If so, make sure it is not left on. It can draw the battery down.


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Mr. C

SW Virginia, USA

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Posted: 06/29/22 02:39pm Link  |  Quote  |  Print  |  Notify Moderator

The battery tested good again at the local garage. SnapOn tester. 405CCA tested at 450

Voltage 12.7 connected to TV, not running. 13.6 running. The same voltages are shown on the InCommand touch screen.

I've connected a different battery, turned on the fridge like last night and will see what's happening in the AM.

I'll have to get a DC clamp-on meter. Mine's AC only.

It appears there's no way to switch off the 12v to the tv antenna...


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pianotuna

Regina, SK, Canada

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Posted: 06/29/22 04:11pm Link  |  Quote  |  Print  |  Notify Moderator

theoldwizard1 wrote:

If you want to run the refrigerator on electric while driving, get a DC-DC batter charger.


As most fridges need 325 watts, a 40 amp dc to DC unit would work--but that requires a larger alternator.


Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

enblethen

Moses Lake, WA

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Posted: 06/29/22 04:18pm Link  |  Quote  |  Print  |  Notify Moderator

You need to verify voltage from TV and battery to the 12 volt DC distribution panel.
Is your refer a three way or a two way? If three way it should be set to LP.

Mr. C

SW Virginia, USA

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Posted: 06/29/22 04:28pm Link  |  Quote  |  Print  |  Notify Moderator

enblethen wrote:

You need to verify voltage from TV and battery to the 12 volt DC distribution panel.
Is your refer a three way or a two way? If three way it should be set to LP.


I will do this tomorrow. The fridge is 2 way and is running on LP...

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