onboard battery charger

[twopugsforme]

This year i bought a new boat. It came with a 12 volt tolling motor. I purchased an additional battery and am running them in parallel for longer life while on the water. I also bought a pro sport 12 charger from cabelas. I installed it and started charging the baterries. They charged for 15 hours and the charger never went to ready or maintenance mode. However, while charging them individually it worked fine.After several calls to the Mfg. they determined that the charger i bought isnt the correct one for my batteries. They said i need 20 amp, 10amp per bank. Does this sound correct? Both batteries are group 27. Should i send this back and upgrade( extra $100) , or go with a different brand?. Thanks in advance for any responses. Mike

 

[ajgraz]

Re: onboard battery charger

By what criterion did the mfgr decide the ProSport 12 was not the "correct" charger? It should be fine, if a bit slower than a ProSport 20.

How did you have the two banks hooked up? One bank to each battery, or combined to the parallel set of batteries? It could be done either way, but a smart charger may as well be done individual bank to each battery.

When you found out it worked fine individually, was that AFTER they'd been charging for 15 hours already? 15+ hours to charge some seriously discharged batteries (at 6amp/bank) is not outside the realm of possibility.
(And yes, a brand-new battery can be quite low on charge)

 

[twopugsforme]

Re: onboard battery charger

Both batteries are new. One came wit the boat, the other i bought new at walmart and installed it the same day i installed the charger. I have each bank from the charger to its own battery. I have tried it both ways, with my jumpers on and off. it will charge the batteries to well over 14 volts and still not kick over to ready/maintenance. Per the mfg. suggestion ( one fo several phone conversations) they told me to hook both leads from the charger to each individual battery to see which one might be causing the problem. The charger worked as intended both times i did this, but when work correct when hook to both batteries . I am confused.

 

[Silvertip]

Re: onboard battery charger

Having two batteries wired in parallel and then charged by a dual bank charger, the sensing circuitry in both outputs may be getting confused. Leave the batteries connected in parallel and hook just one out put to either battery. To the charger the two batteries merely look like one great big one.