Dead batteries

jthntrmn · 10-25-2016, 08:13 PM

Well after returning from about 9 days away on vaca, went to start up the bus and she was deader than a door nail. I had been starting it every week since we got it but maybe the onset of cooler weather hit it harder than I thought. Can anyone give some insight as I have never jumped a multi battery vehicle before. Any help would be greatly appreciated. Thanks

AlleyCat67 · 10-25-2016, 08:21 PM

I've never jumped one myself.... but as far as I know it is just like jumping any other vehicle, just make sure you have enough amps coming from the jump vehicle/battery bank to crank the engine. Diesels need more power to start than a gas engine.

GreyCoyote · 10-25-2016, 09:56 PM

Your best bet for jumping a diesel is to let it charge for a while first. Get the batteries up so they can help turn things over instead of relying on the boost vehicle 100%. If it was me, I'd leave it on the charger for 12 hours or so and then jump it. Once it starts I'd be prepared to let it run a couple of hours to bulk up the batts, followed by a couple of days on the charger to finish it up. YMMV.

I noticed something interesting about "big rig"'jumper cables. They are 4/0 gauge copper with heavy screw-type bronze clamps to make a really secure connection. Diesels are power-hungry critters!

milkmania · 10-25-2016, 10:20 PM

I ran my bus batteries down once (left a crucial switch in on position)
And was going to jump start it with suburban...
I left bus batteries connected as usual and clamped onto one battery, after 30 minutes of suburban throttled to 2000 rpm, bus would not turn over.

Disconnected one of the bus batteries and jump started the bus within seconds.
It actually kinda surprised me, as it was Plan B... And I wasn't looking forward to Plan C

That was on July 1st... Never left 'that switch' on again and have never had a problem since.

AlleyCat67 · 10-25-2016, 11:41 PM

Gonna have to do something with Jasmine or this might be me soon....

The other day I went to start her up, voltage was only 11.8 volts. Not a problem, she started right up, but still a bit of a concern... drove her around about 30-45 minutes to get a good recharge into her, and voltage reading while she was running was 14.0-14.2, right where it should have been. Got her back to storage and shut her down, making sure everything was turned off on the panel.... went back tonight to take some stuff to a storage locker I have there so checked on her again and voltage was again down to 11.8.

I see one of three possibilities..... a ghost load somewhere drawing power even when the key is off, one or more of the battery cables is not making a good connection, thus it's not charging like it should, or one of my batteries has a short or a dead cell in it. I know which I would rather it be... clean and tighten the connections (fastest and cheapest). Replace the batteries is the second choice... they probably need it anyway, they do look like they've been in place for a while. But they've been working adequately thus far so I haven't stressed too much about it... but it will need to be addressed soon...

Will be so glad when I get this move all done so I take the time to run this down, and get my conversion started.

SDR76 · 10-26-2016, 08:47 PM

I would charge it for a while and then jump it. OR I would jump it by directly hooking the cables to the starter and the negative to the block or chasis then jump it. This way there is less line-loss in long dirty cables. This is also assuming your batteries are a bit away from your engine. Also, the bigger the cables, the better.

jthntrmn · 10-29-2016, 08:56 PM

Is there a trick to getting the battery tray out? I released the locking handles but the tray won't slide a bit. I'm gonna use some penetrating oil to try to loosen it up but am I missing something else?

AlleyCat67 · 10-29-2016, 09:42 PM

I seem to recall that on my last project bus there were a couple of bolts holding the tray in position, you might see if that is the case, or maybe wing nuts on studs... though it's just possible that corrosion on the slides is keeping it from moving. You might take a flashlight and see if you can see anything like that.

Carytowncat · 10-30-2016, 03:57 AM

My battery tray takes a lot of force to slide out. Batteries are heavy and i have 3 in there. Reading this it just dawned on me that i could simply grease the tray.

Slip slidding awayyyy

Tango · 10-30-2016, 09:58 AM

My old BB had a "slide out" tray that took some serious force even to budge. Between rust, muck and two 8D batteries there was a fair amount to overcome. Once cleaned & lubed, it was a bit easier. The tray was only held in place with a pin/bolt that fit loosely into a slot.

2kool4skool · 10-30-2016, 11:27 AM

I found a parasitic draw and removed it, then mounted a 5w solar panel on the roof. With one 8D it keeps the battery topped off nicely.

My draw was 2 fold. One was the motor that controls the fresh air flap on the front heater and the other was the 2nd 8D battery.

I disconnected the 2 batts and charged them fully, then disconnected the chargers. . One held 12 plus over night, the other 10v.

jthntrmn · 10-31-2016, 02:09 PM

Thanks for all the help. I got the tray to slide eventually and jumped it off with my F-150. Thanks again!

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