Battery Question

The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.

mudshark

Well-known member
Joined
Nov 15, 2014
Posts
503
Hi All
In my Class A, the chassis battery reads 13.5 volts.
The deep cycle coach batteries read 12 volts. I don't know that much about deep cycle batteries.
Is 12 volts normal for a charged deep cycle? Or do they need to be topped off and for how long?
Thanks
 
No, 12.0 volts is not a fully charged battery. 

With your RV plugged into shore power, whatever charger you have should be supplying at least 13.4-13.5V.  If you have a 3 stage charger you may see charge voltages in the mid 14 volts for 1-3 hours and then taper off to the 13.4V range.

Once you disconnect from shore power and let the batteries sit for a few hours, not powering anything in the RV they should drop to about 12.6-12.7V, which is the fully charged voltage. 

Same goes for your chassis battery.

Here is a link to more detailed info:  http://www.marxrv.com/12volt/12volt.htm

It would help to know which Class A RV do you have, the number of batteries and what converter or inverter/charger you have.
 
Hi AStravelers
Thanks for getting back to me so soon!
I have a 2000 Fleetwood Bounder. There is one chassis battery and two deep cycle coach batteries. They are all new as of last year. We are waiting to sell my house and then spend a year traveling the country. As such, we didn't use it last year. I will find out what we have for an inverter.
Thanks for the link. I will check it out.
Jim
 
If your coach is plugged in but the house batteries are not being charged, either the PD 9155 is without 120v power or defective. Or perhaps you have the battery disconnect switch off, which disconnects the charger from the battery in most rigs.

If it's not plugged in, well that why it isn't charging...  The battery will lose power over time, even though you know about have everything switched off.
 
Hi Gary
When I plug into shore power I turn both disconnect switches to ON.
When I take it off shore power I turn the switches off. I read the article linked above. I am thinking the the low temps up here may be giving a false low reading. I really have to get a digital volt meter. My little analog is not right for this.
 
Hi Arch
Yesterday when I was checking voltage I popped the covers on all batteries. The coach batteries needed water in each cell but not much. The plates were nowhere near being exposed. Down about a 1/4 inch each cell.
The chassis battery only needed a little in two cells. I hooked the bus to shore power over night.
 
The Progressive Dynamics converters have two fuses on their output.  They are to protect the converter and wiring against damage in case the battery is accidentally connected backwards ... even for an instant.  The converter looks like a dead short to reverse polarity, even if it's off.

If they're blown, you won't get any output from the converter until they're replaced.
 
Thanks for confirming your converter, Mudshark(really like the screen name, BTW). 
Same coach, same year, same converter.
Guess this semi-answers the question raised in your other thread on whether or not my converter had at some point been changed.

With this setup, as I understand it, you can leave everything plugged in and turned on pretty much indefinitely, as long as you check the battery water levels periodically.  I live in mine, so it's never turned off anyway.  I haven't done much boondocking, except while traveling, so haven't paid that much attention to battery charge levels.  I did find, while researching the other thread that the batteries all connect to lugs on the outside of the Battery Control Center(Driver's side firewall, below the master cylinder).  Make sure those connections are clean and tight, also, as that's where the charge voltage from the converter is routed to the batteries.
 
Thanks Old Crow
Things are getting really weird!
I bought a cheap digital multimeter this morning. The chassis battery read 11.8 volts. The coach batteries read 12 volts. No power drain I can see.
Went to start the coach, chassis battery practically dead. Had to kick in the coach batteries to start. The bus is running right now. With both meters, (one digital and one analog), I get 14. 3 volts at the chassis battery and 14 volts at the coach batteries. So the engine alternator is doing it's job.

THIS IS STARTING TO DRIVE ME NUTS!!
 
OK, so the alternator works as expected. What about the voltage with engine off and shore power or genset active? That will verify your converter/charger operation.
 
Hi Gary
That was my next move. I shut the bus down and had lunch while things equalize.
I plan to go back on shore power and take voltage readings before and after to see where we're at.
 
My RV deep cycle battery is floating at 13.55 volts.

I leave it on shore power all the time when we are home...
If I have to leave it w/o A/C power, I just turn the big handle on the big 12 volt power switch that I bought from NAPA.

It is the same thing I had on my airplane, if the plane is parked, you turn that battery off.
 
OK Folks
I think I have it. I checked the house outside outlet that I had been using for the past two years. I got no power at the outlet. Checked the circuit breakers and found no problem. Switched to the outlet at the front of the house and it has a GFI with a tiny indicator light. Plugged the bus into that one. I took readings on all batteries before and after hooking to shore power and they did not change until I switched house outlets. Checked voltage in the bus and reading 120 volts now.

All three batteries are up .5 volts from this morning but I am not sure if that is because ambient temperature rose a bit from this morning or because I ran the engine for 1/2 hour before lunch or if the converter is putting out power now. What should I do going forward? Any suggestions?
 
While plugged into the good shore-power outlet, use your VOM and measure the voltage of the house-batteries. You don't need to disconnect them - just take a reading right at the battery terminals. That'll tell us if your converter (charger) is working or not. Make sure your house-battery disconnect-switch is on (connected) when you take the reading.

Kev
 
Hi Kev
I just went out there and checked all 3 batteries. All are now up to 13 volts.
Looks like the back outlet was the problem all along. I have no idea when it crapped out although it reads 120 volts now on my plug in volt meter. I will no longer trust it. Especially when I can look at the front one and see the ground fault light on. I will keep the bus on shore power for a few days and see where the voltage is.

I want to thank everyone here who jumped in with advice! Without your help I don't know what I would have done!!
Jim

 
That's why I like these forums.  In the process of trying to help you learn something, I learned something about my own coach.
Glad you got it figured out.
 

Members online

Forum statistics

Threads
131,749
Posts
1,384,209
Members
137,520
Latest member
jeep3501
Back
Top Bottom