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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: jackhartjr on February 20, 2010, 03:38:14 PM

Title: Charging dead battery?????
Post by: jackhartjr on February 20, 2010, 03:38:14 PM
Hi folks, this is related to buses in that it is the toad.
On the Olds we will use for the toad, it sits a lot.  The battery is totally dead.
I have a charger that is apparently a 'smart charger' and it tells me the battery needs to be replaced, therefore it won't charge the battery.
If I purchase a cheaper version, will it go ahead and charge the battery, or at least get enough juice in it to hook the smart one up?
Thanks!
Jack
Title: Re: Charging dead battery?????
Post by: DaveG on February 20, 2010, 03:42:35 PM
I have done what you are talking about, using one charger then the other. My experience is that the smart charger does know best. You might get a little more use out of your battery, but plan on buying another soon. Long term storage-fully charge and disconnect one of the leads.
Title: Re: Charging dead battery?????
Post by: luvrbus on February 20, 2010, 03:44:48 PM
Jack, the way you fool the smart charger is with a 9v battery and 2 leads to the battery.  
Those things are not so smart after all lol

good luck
Title: Re: Charging dead battery?????
Post by: belfert on February 20, 2010, 03:52:55 PM
Yes, a regular old battery charger with no smarts will work.  You'll want to charge at the lowest possible rate like 5 amps or even 2 amps.  If the battery has been discharged down to nothing for a while you'll probably never recover the battery especially if it froze.  I discharged my bus starting batteries to zero and they froze.  Even with a trickle charge for a week they never recovered beyond about 9 volts.

It might be less expensive to just buy a new battery than to buy a non-smart charger.  I would install a Battery Tender charger and plug it in when the vehicle is stored.  I have a permanently mounted Battery Tender in the battery compartment of my bus that is plugged in when the bus is being stored.
Title: Re: Charging dead battery?????
Post by: bevans6 on February 20, 2010, 03:59:33 PM
I have woken up totally dead batteries (like 0.1 volts) with 10 or 15 seconds of an old fashioned transformer charger.  that gets them up to 2 volts or so, then my computer controlled charger will start to work.  My 8D's just went through this - I ran them down to nothing by accident, and they started the bus today, so who knows, maybe they will last another year.  I will say that my old charger was putting about 100 amps into the batteries, it was making a decent noise, so I did not leave it on very long!

Brian
Title: Re: Charging dead battery?????
Post by: Melbo on February 20, 2010, 04:49:54 PM
I like cliffords solution better -- I just did that last week.

Put a new battery in a truck and did not notice the courtesy lights were on so the new battery was dead two days later when I went to start the truck.

Hooked up the smart charger and it was so flat the charger would not start.

I didn't have any jumper cables with so I used a couple of feet of 16 gauge wire to get the charger started from another battery.

Charged up enough to start in about a half hour.

HTH YMMV

Melbo
Title: Re: Charging dead battery?????
Post by: jackhartjr on February 20, 2010, 05:40:17 PM
Clifford, please descibe that deal, "the way you fool the smart charger is with a 9v battery and 2 leads to the battery." 
Thanks
Jack
Title: Re: Charging dead battery?????
Post by: RichardEntrekin on February 20, 2010, 06:10:00 PM
If the smart chargers do not sense any voltage they will not come on. If the battery is dead, you have to trick the charger into thinking it is hooked to a viable battery with voltage. So, while the smart charger is hooked to the dead battery, you also hook up in parallel a voltage source. It's enough to make the brain in the charger think it should start charging. Once you get it into the charge mode, you can disconnect the trick voltage source.
Title: Re: Charging dead battery?????
Post by: gus on February 20, 2010, 07:22:50 PM
Never tried Richards method, interesting.

Bottom line is that most smart chargers won't charge if the battery is less than 10v so I use an old type charger to get it up to there and then let the SC do its stuff.
Title: Re: Charging dead battery?????
Post by: gumpy on February 21, 2010, 12:37:01 PM
Just jump the battery from your pickup or bus battery (12v side) for awhile and then connect the smart charger. It will charge enough in an hour or two to turn on the charger.
Jumper cables and a good battery are all you need.