battery charging problem

[bmH1065]

My batterys were new this summer. Hadn't started it for a couple of months. Started right up. I took it for about a 20 mile drive. A couple days later the batterys were dead. Must of left light switch on or somthing. I disconnected batterys and put 12 volt charger on. Next day battery was fully charged. Switched charger over to second battery and charger tells me that the polarity is reversed and will not charge hooked up + to +, - to -. It souldn't be reversed should it? Don't know what I should do. Thanks.

 

[atankersdad]

Remove the jumper between the 2 batteries and charge it.

 

[bmH1065]

batteries are disconnected. No battery cables on battery. Thanks.

 

[glcaines]

I have sometimes unhooked battery cables and then re-jumpered the batteries so that they were hooked up in parallel and charged both batteries simultaneously. It's easy to do with jumper cables.

 

[rockman]

Are you sure that the batteries are hooked up right? TMs can help. Also if you check the output of the alternator with the truck gauge or a meter, you can adjust the voltage by removing a set screw on the top of the alternator and turning an inset screw. My truck was initially undercharging as the needle was always in the yellow. I adjusted it so it stayed in the green.

 

[robr]

or put one of these in for about $100.00
dont have to remove any wires once you install it


ProMariner ProMite On-Board Marine Battery Charger - 10 Amp - 2 Bank
MFG # 31310
ProMite On-Board Marine Battery Chargers

Amps: 10
Banks: 2
Volts: 12/24
Cable Size: 6'/6'

Fully Automatic Charging

• Charges and Conditions batteries with a built in safe maintenance mode for long and short term storage Automatic Charging For Lead or Gel Batteries
• Optimized charging output for Lead or Gel Batteries
  Waterproof and Shock Resistant
• Saltwater tested for coastal boating Dynamic Thermal Output Control
• Provides appropriate charging amps to your batteries while maintaining recommended charger temperature
  Built-in Protection
• Reverse polarity, ignition & temperature protection
  LED Power and Charge Indicators
• At-a-glance power and charging status
  Pre-wired for Easy Installation

Voltage - Charger Input 120v Portable No Amps - Output 10A Voltage - Output (Volts) 12/24v Banks 2 Battery Type Lead Acid/Gel Manufacturer Warranty 1 Year

 

[glcaines]

Are you sure that the batteries are hooked up right? .

I once bought a car that had positive ground and a brand new battery was installed backwards. The owner was so disgusted with his car problems he sold it to me real cheap. I had a very quick fix. It is always good to check if the batteries are installed with the correct polarity and there is double the chance of a screw-up with 24V MVs.

 

[Stalwart]

As I said in the duplicate thread, which I have since deleted:

I had this happen, one battery reversed it's polarity. When testing voltage across both batteries in series I got 0 volts. Each measured aprox. 12.6V but one was reversed. It was a pair of 6TL's and I replaced them with a new pair of group 29 civilian type batteries, no problem since. The batteries were connected correctly, one simply reversed polarity. I know it doesn't seem possible or likely and I wouldn't have believed it if it hadn't happened to me.

 

[TacticalDoc]

trickle charger
and make sure your generator is set properly

 

[Stan Leschert]

If you have a battery that really does have reversed polarity (use a meter), this is not fatal. Remove said battery from the truck circuit. Apply a small load to it (a single light bulb will do). leave the load on until the battery is COMPLETELY discharged. Then check the fluid levels (if possible) and proceed to charge it correctly. A trickle charge (2 amps or less) would be best. I have brought a couple back to life in this manner. Be prepared to leave the charger on for a long time...up to 144 hours. good luck. PS, 6TL batteries at Wally world are not that expensive.

 

[Stalwart]

Isn't it strange that a battery can do this in an otherwise correctly connected and operating system. I've brought many batteries back except that one, mainly due to the use of pulse charger.

 

[bmH1065]

Thanks, I will do more checking when snow goes away.

 

[bmH1065]

After thinking about how the batterys are hooked up, I think they are hooked up wrong. I thought I had hooked them up the way that they were. Had them hooked up that way since last summer with no problem. I worked a long time ago in an Import car shop and several times had MG's, Austin Healeys that had pos grounds hooked up backwards. Would like was suggested, drain battery, jump off of good battery and recharge it. Hope it works. Thanks