Battery doesn't seem to be charging

[olcoon]

We are volunteering for the Forest Service this summer, and only have elec. for 4 hrs in the morning & 4 hrs in the evening. The battery doesn't seem to be charging to 100%. It will charge to about 75%, then will go down to about 25% before I turn on the generator again. We are using the Forest Service's generator, so can't really leave it running any longer. I was wondering if I hooked it up to a battery charger instead of the inverter on the camper if it would charge faster. Any ideas?

 

[Willym]

8 hours should be more than enough to charge the battery. How are you determining the charge state? I would not trust the little lights on the monitor panel. Get a voltmeter and measure at the battery terminals.

 

[olcoon]

I've been using the lights on the monitor panel. But I've used a volt meter once.

 

[TXBobcat]

Take the battery out and take it to Autozone, NAPA or some other Auto parts store and have it checked.

We had Interstate Battery in our BH and it burned out 2 converters because of a bad cell.

Went to the Gel batterys from Sams Club and have had no problem so far.

I have always had a bad deal with interstate battries.

BC

 

[MikeT]

Hello Olcoon.

I am new to this forum but do seminars regulary on R/V 12 volt systems. From the little I can gleam from your post - it looks to me like you are using more 12 volt D/C power that what can be replenished BACK into the battery.
Now say that -let me point out a few things concerning 12 volt batterys.
Lead acid Batterys
1 - The only way to determing if a 12 v battery is good is by using a hydrometer and testing each and every cell. Specific gravity should be in the 12.50 to 12.75 range for every cell. This can only be done if the battery is fully charged and then left off the charger for about 30 minuets.
2 - A 12 volt battery will only accept in the range on 15 to 20 amps per hour of charging time. A lot depends on the age of the battery and what is being used to charge the battery. For instance if your coach has a 45 amp Converter ( Converter takes 120v A/C power and converts it to 12v D/C power and this Converter is of the more modern 3 stage charger - even thos it has the capicity to "Put out" 45 amps of D/C power - your battery will only accept that 15 to 20 amps per hour.
3 - Also keep in mind that if you check a battery right after it has been taken off the charger - you will get a false reading because of what is known as the surface charge. You need to wait 10 to 20 minuets to get a true reading of the state of charge of your battery.
4 - All Rigs have what is known in the industry as "Hidden Power Draws" - For instance all your electronic boards draw minute amounts of 12v d/c power - You Propane/Carbon Manoxide detector draw power - ECT ECT ECT - all in all you can figure your R/V will use about 1/2 of 1 amp every hour - over a 24 hour period that equals 12 amps of power taken out of you battery.
5 - R/V batterys are designed to be cycled over and over - that is why whey are designed very differently then say a car/truck starting battery because a car/truck battery is designed to give a large burst of power for a short time frame. An R/V deep cycle battery with its very thick lead acid plates and with/stand the charging cycles - over and over again.
6 - R/V batterys usually have a Amp-hour rating. Most group 29 batterys are in the 105 or so Amp hour rating.
So olcoon says to himself - what the heck is am amphour.
The easiest way to explain an amp hour is if you have a fantastic fan in your R/V. if you run that fan on "Hi" for 1 continuous hour - you have just used 3 amp hours because a fantastic fan on high speed uses aprox. 3 amps.
7 - So now if you have a single R/V battery in your R/V and it has an amp hour rating of say 105 amps. Once you figure what you are using on an hourly basis - it is easy to determine what you are using every 24 hours.

Now one of the most things people ask me in my seminars is their propane fridgerator. Yes it is on propane and is using propane to make it work - BUT you need 12 volt power to operate the eyebrow(inside operating board) and the main board thats behind the fridge.

I hope I have not confused you to much and you have gained a little better understanding of the 12v D/C side of your R/V.

MikeT

 

[donr827]

Good post MikeT.
Don

 

[olcoon]

I took the battery to CarQuest & they checked it & said that it was OK. They put it on the charger for several hours & got it to full charge (even though it wasn't down that much). When I went back to get it, I bought another battery, so now I've got 2 of them. Things seem to be going fine now, even with having the furnace on during the night. Sometimes up here on the mountain, it gets down in the 30's! What I'm thinking the problem is that even though it was getting a total off 8 hrs charge a day, it was only for 4 hrs at a time. We didn't really use it that much during the day, maybe a few lights & sometimes the radio on for several hours, plus the ghost stuff (light on the radio panel, propane detector, etc). At night sometimes we'd stay up late with the lights on reading. Oh well, all is fine now, we still don't often show a full charge, but I'm more comfortable now with the 2 batteries!!!

Thanks for all the responses!!!

 

[porthole]

Two different batteries can add to your problems. The weaker of the two will draw down the better one.
If using two batteries it is best buy 2 at the same time of the same brand/size/age/model.


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