Charge Controller Settings

[Brian H]

 So, after having a good hard look at the Deep Cycle Battery FAQ on Otherpower (thank you guys for hosting this GREAT reference!) and studying the the somewhat skimpy manual that came with my Xantrex C12 charge/lighting controller, I decided to make a few changes to the factory settings.

 There are 5 basic settings on the C12:

HVD - High Voltage Disconnect

HVR - High Voltage Reconnect

LVR - Low Voltage Reconnect

LVD - Low Voltage Disconnect

Nite Lite Timer

 The 2 that most concern me are the HVD and the LVD, neither of which are explained very well in the manual. The C12 came from the factory with the LVD set at 11.5v and the HVD set at 14.0v.

 I'll spare you all the mumbo-jumbo and just state that I increased both settings. The HVD is now set at 14.6v and the LVD is now set at 12.1v. The key concept I gleaned from studying the info contained here: http://www.uuhome.de/william.darden/carfaq9.htm#stages

 is to understand how charge/discharge battery voltage differs from battery voltage at rest. And also the subtle differences in the charge/discharge algorithms of the different battery types. I think I'm pretty close to optimal settings for my "hybrid" battery, but I welcome any insight you might have.

Cheers!

Brian

[AbyssUnderground]

I think your new settings sound better than the old ones. It now means your battery wont discharge as much and that it will get a better charge.

I too don't understand voltage vs charge percentage vs rest time etc etc etc but so far Ive not damaged a single battery Ive been using so I must be doing something right...

[Flux]

This is all very complicated, whatever you do will be a compromise.

The low voltage disconnect point is highly load dependent. With a heavy load 10,5v might be reasonable. with a very light load then even 12v may be going pretty low. I don't know of any controller that decides the cut off depending on load. The better Ah meters including Peukert are the only things that can give you a decent idea of state of charge. Even they struggle to decide the fully charged point and anyway they are not controllers.

If you have wet cells buy a hydrometer and keep an eye on sg.

Flux