H3-45 batteries dead. Help?

Ace · January 09, 2015, 04:20:14 PM

You might have luck charging the two of the four to get you going. The middle two are your 24v leg and each single battery is 12v. You'll probably see the larger cable/s going to the middle two. If you don't have a 24v charger, charge each of the middle two individually and it should start and after its running, IF all else is good, it should charge the other two!

robertglines1 · January 09, 2015, 05:04:13 PM

one other check.. Might be a extra power wire someone put on one battery for a accessory. It prob is (if there is one) not turned off by master. Bob

Jon · January 09, 2015, 05:46:32 PM

CB 19,20, and 21 are always powered to retain the DDEC memory. The disconnect will not shut them down.

Having said that however, all three of my Prevost coaches would go for months without charging and with the master on and still have enough power to start the engine.

If your issue is not a bad battery, start looking for miswiring or a phantom load.

scanzel · January 09, 2015, 06:21:11 PM

Check to see if you may have a Vanner equalizer that may be providing for a 12V load that may still be on even after turning off the battery switch. When I bought may used Prevost someone had the radio connected to 12v but when the switch was off the radio was still drawing 12v and after a few weeks the batteries were down.

Boomer · January 09, 2015, 06:30:33 PM

Does it not have the onboard charger where you plug in 120AC at the plug near the battery bay door? If so, just plug in power.

kemo3ce · January 09, 2015, 06:43:24 PM

IT DOES HAVE A PLUG NEXT TO THE BAY!! but I'm not sure if it works and the last thing i want to do is to plug it in and have the fourth of july show up in january how do i check to see if this is working safely. also yes it does have wire running to batteries from somewhere else, so it could have something stealing power directly.. i reckon i turn off the master and walk around with my multimeter trying things to see if they are drawing current? Thank you for letting me know these things this is my first bus so i have a lot to learn..

eagle19952 · January 09, 2015, 09:19:51 PM

a DC clamp on meter at the batttery will better tell you if there is a draw....with and without the master on/off.

There are techniques to make any amp meter read down to milliamps.

niles500 · January 09, 2015, 11:31:06 PM

If you have a Vanner converter for the center tap, you may just have to reset the CB - HTH

blue_goose · January 10, 2015, 05:21:42 AM

Your bus is connected to the batteries even if the switch is off. Your ECM and ECU are powered up all the time and should stay that way and not be turned off. Over the road buses were meant to be used all the time and not parked. If you are going to leave it parked you need to get a battery maintainer, not a battery charger. A battery charger left on will kill your batteries for good. If you don't want to spend the money for a good 24 volt float charger, get one for each battery from Harbor Fright for $9.99.
Jack

luvrbus · January 10, 2015, 05:36:39 AM

The chargers Prevost uses are good they have a float and won't harm the batteries if it works use it

Ace · January 10, 2015, 06:24:13 AM

I meant to say mine was a 24v float charger but used the term charger in general! Sorry for the confusion!

Oonrahnjay · January 10, 2015, 07:30:41 AM

Quote from: blue_goose on January 10, 2015, 05:21:42 AMYour bus is connected to the batteries even if the switch is off. Your ECM and ECU are powered up all the time and should stay that way and not be turned off. Over the road buses were meant to be used all the time and not parked. If you are going to leave it parked you need to get a battery maintainer, not a battery charger. A battery charger left on will kill your batteries for good. If you don't want to spend the money for a good 24 volt float charger, get one for each battery from Harbor Fright for $9.99.
Jack

Thanks Jack, that's good info for this thread. But I have a basic question (in this case, "basic" is probably spelled s-t-u-p-i-d -- remember, I have never been able to figger out how them little electrictrons run around and hold hands etc.) about using two smart chargers. I have the usual 24V battery setup -- two Group 31 batterys with a - to + jumper.

On my bus (1976 model), the battery isolator switch does just that -- it *really* does completely isolate the batteries. But I wonder about just attaching a smart charger (I use a couple of Stanley float chargers, as shown below) to each battery.

These chargers seem really good (I use them on my car, individual batteries out of a vehicle, my generator-start battery, etc.) but I wonder. If there's a bad cell in one battery or high resistance someplace, will the "smart" circuitry be "fooled" into giving an incorrect or incomplete charge. Is it better to remove the jumper between the two batteries so that each smart charger is reading only the battery that it is directly connected to? Or does it matter - I can see that the charger would charge and read the load between the two battery posts and work correctly on that battery.

(I guess I should add that what I've been doing seems fine -- my batteries are four years old and if I charge them fully and come back 4 weeks later, the chargers go to "Float" in about 90 seconds. And that's even after a storage maintenance guy switched on the master, then when he was told by the owner not to move my bus without me being there, he walked away and left the master on for about two weeks -- that was the middle of the summer of 2013 but the batteries charged right back up and have seemed fine.)

luvrbus · January 10, 2015, 07:54:35 AM

I use those mine are the Dewalt I bought mine a lot cheaper than you could buy a Battery Tender,only draw back is when a battery falls below 9 v you need to take a 9v battery and trick it into charging lol they are not so smart

moosemanusa · January 10, 2015, 07:59:19 AM

I've had the same problem, 2 batteries only running in 12v (on this unit the 24v power (AC Unit) is provided only from Alternator power.

In this cold weather the batteries are taking a kicking, I forget the model of the batteries but they are big, like 3 truck batteries type size.. takes 2 people to lift them. Unit has a main battery disconnect. I can only assume the cold weather is the cause, they were new back in March last year.

I've been looking at Solar panel battery tenders as I park the buses towards the south and the fronts receive a lot of sunlight, I would have to run a direct cable to the batteries for the charge because of the cut off switch.

My neighbor works for Interstate Batteries and I was going to ask him why their batteries would suffer so badly (being so large) and in a (in grand scheme of winters of Texas) moderately only cold temps.

Reminds me, I better go check them now as I need to use the bus later! dont want the dreaded "room room ....... oh dam"

Oonrahnjay · January 10, 2015, 08:26:46 AM

Quote from: luvrbus on January 10, 2015, 07:54:35 AMI use those mine are the Dewalt I bought mine a lot cheaper than you could buy a Battery Tender,only draw back is when a battery falls below 9 v you need to take a 9v battery and trick it into charging lol they are not so smart

Same one, different name -- prolly made by Yan Ming Errectrical Company and Pool Room in Shanghai, what ever name you want to put on it, they'll do it. Works really well, as far as I can tell - of course, with a max of 6 Amp (8 for a short time), it won't charge a really rundown big battery quickly, but the idea is to not let them get run down.