Low Engine Batterries

[dale farley]

After letting my coach set for over a week with the 12V and 24V switches left in the "On" position, the batteries were too low to start the engine. The batteries are almost new. My quesiton is "is there any reason I can't charge each of the 4 batteries separately by just placing my charger across the 2 terminals of each battery? It appears to me that since each battery now reads almost 12V across the terminals, that I shouldn't hurt anything by charging each one separately that way. I assume a 24V charger would be better, but I don't have one at this time. Thanks. DaleF

[dalej]

There is a battery diagram on the door, if you look you can see where to hook for boosting or charging.

On ours 2 12s make 12v (their parallel) and 4 12s make 24v, (in series) so you will charge 2 12s at a time.

[dale farley]

I didn't notice a diagram, but I will look. I assume they are running 2 sets of 12V in parallel and then running those 2 sets in series to get the 24V. I assume that I can charge two at a time on 12v. I may have to just measure the voltage and see how they are hooked up. It's very easy to get confused with all the wires they have coming from each battery. Dale, are you saying you charge your's using a 12V charger?

[dalej]

Yes, just find the two parelled 12s

[truk4u]

Roadrunner,
I would first unhook and load test the batteries. You can charge them till the cows come home, but it you have a bad one it will pull down the others. Mine can set for months with no starting problem. If you want to hook up a 24 volt charger, just search for Battery Tender and take a look at my post.

[Lee Bornstein]

Just replace all 4 of mine cuz had similar problem (batteries were 5+ yrs old.)

Made mistake in purchasing batteries I'll probably regret in the future... Bought mine at local truck stop and neglected to buy "Maintenance Free" batteries.

Now, If I need to add water or check water level, I have to remove battery hold down and reposition some cables to access the water fill holes.

Paid about $300.00 for set of 4 batteries... If I woulda waited a day or two and shopped around I could have gotten set of 4 Maint Free batteris for $100 more and no water worries.

Caution when charging individual 12 Volt batteries "in circuit" - there is a voltage equalizer that manages 12V drain in 24 V circuit that could be adversly affected by the 12V charge. I would suggest removing all battery cables before using 12V charger.

Lee

[garyde]

I,m assuming you do not have a built in charger on a seperate 120 volt breaker that charges those batteries?

[MangoMike]

Check out this thread.

http://www.prevostownersgroup.com/forum/showthread.php?t=131&highlight=battery+tender

543

I installed this marine grade weatherproof charger (dual 12v) from Marine West, which is a three stage charger than can be left on at all times without the danger of overcharging your batteries. About $150.

Mike

[truk4u]

Dale,
Lee is dead on about the equalizer. My Marathon has two, one in the engine compartment for the start batteries and one up front for the house batteries. There are big warning lables from Marathon that state the equalizer ground must be unhooked prior to any battery work. I had to do this on mine for both the start and house battery work.

Aircraft Spruce has the 24 volt battery tender (3 stage) for about 79.00. I used the block heater 120 volt box in the engine compartment for power.

[jello_jeep]

Here is a link for the charger Mango Man dug up.. I am fixin to get one!!

http://www.batterystuff.com/battery-chargers/12-volt/marine-chargers/GU2611A.html

[Ray Davis]

I'm assuming it's safe to add a tender like Mango indicated, without it affecting the equalizer?

Other than lower current, why would charging in this manner be OK, while charging with a normal 12V charge not OK?

Thanks!

[truk4u]

I'm a little fuzzy on the schematics using an equalizer when dealing with 12/24volt systems, but Marathon told me not to use 12v and be sure to use the 24 volt leads for the charger. Without looking at my cabling (cold here in GA) I have 4 12volt start batteries hooked in series and somewhere in that nightmare they also pick up a 12 volt source. Red cabling is for 12v and blue for 24v.

Maybe we have an POG electrical person here that can explain the equalizer function. To cold for me to go look for the diagrams.:eek:

[Ray Davis]

Maybe we have an POG electrical person here that can explain the equalizer function.

That's an idea. I'll put it on the notes. We're meeting next week (fingers crossed) to try to flush out some more ideas for POG3. (How did I get roped into this one!)

[Jon Wehrenberg]

Ray,

At one time Vanner had an excellent technical paper explaining equalizers and why they did what they did. Unfortunately that went with the mountain of books when I sold the first coach. They may have some available for handouts.

As we get more coaches to these rallies it will not be unreasonable to invite suppliers of components such as Vanner equalizers, Michelin Tires, Allison transmissions, etc. to speak at our rallies. Often they have regional distributors who can do the presentations.