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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: jjrbus on May 19, 2008, 06:52:15 PM

Title: Solar battery charge
Post by: jjrbus on May 19, 2008, 06:52:15 PM
I purchased 2 new group 31 start batteries. They do not seem to hold thier charge as well as the old batteries. I took them back they test good.
I am thinking of adding a solar trickle charger. They all seem to be 6/12 volts. Any technical reason I could not add just one to my 24 volt system?
As always wisecracks, suggestions, and good old abuse greatly appreciated.  Jim
Title: Re: Solar battery charge
Post by: Tenor on May 19, 2008, 07:06:57 PM
As I understand and have been told, wire your 2 gp31's for 24V, and get solar panels that put out 24V or higher and use a solar controller with "MPPT" technology to keep your batteries properly charged.  Look up "Blue Sky" solar on google.  They invented the MPPT technology and it really is the way to get the most from your panels.  With this voltage setup, you can charge house batteries and start batteries.  I hope this helps a bit.

Glenn
Title: Re: Solar battery charge
Post by: H3Jim on May 20, 2008, 05:38:46 PM
is there a reason they don't hold a charge?  (and why you had to replace the old ones?)  maybe you have a slow drain somewhere.

Good advice on the MPPT technology, but first things first...
Title: Re: Solar battery charge
Post by: jjrbus on May 20, 2008, 06:38:51 PM
Thanks for asking!!!  I tried different things at first I thought the Battery and holding tank monitor was going bad. I unhooked everything except the ground wire. The batteries just slowly over a period of weeks lose thier charge. Much faster than the old batteries.
Title: Re: Solar battery charge
Post by: Sojourner on May 20, 2008, 10:00:31 PM
Jim...What voltage are you getting between disconnected terminal and the post? Report please. You may qualify for 4 oz of 1999 diesel fuel from my bus.

FWIW

Sojourn for Christ, Jerry
Title: Re: Solar battery charge
Post by: jjrbus on May 21, 2008, 08:07:23 AM
2.1 volts on the 200 volt setting???? The batteries are showing 26.1 volt  That is with a digital multimeter. That terminal leads to a disconnect switch which is turned off!  What did you pay for the fuel in 99?