Solar charging question

[skybadger]

I have a solar cell charging a 12v 70ah battery through a charge regulator. The load output is separate from the battery charge output. But the output does not sit at a regulated 12v. 

What should I expect ? As a general rule, does everyone then use a high current 12v regulator to the load or does your regulator provide a regulated load output ?. 

Cheers

Mike

 

[jambouk]

I’m unsure of the question, sorry.I run most of my kit from 12v batteries unregulated; it’s all fused but unregulated. 

I wouldn’t run off the battery during say light though as there would be changes in voltage quite quickly if connected to the solar panel. 

 

[skybadger]

I expect that a solar charge regulator should limit the voltage to the battery to its safe charging range, fypically 12.6 to 14v for a lead acid battery. However mine is putting out more than that and a new one I have just bought does the same. I bought some 12v regulators to manage the load side voltage but as yet not working...

I really don't like the idea of 19v across my lead-acids. 

[theropod]

The batteries themselves serve as a “shock absorber” for the excess voltage. Most solar charge controllers simply dump the output of the solar array directly into the battery bank. In a flooded lead/acid battery this presents no problem, but for sealed lead/acid, or absorbed glass mat, batteries this arrangement is unacceptable as over voltage will bubble the electrolyte and render the battery useless. Flooded lead/acid batteries just bubble a little, which mixes the electrolyte and this is a good thing as long as the proper level is maintained. The “load” option is a means to use the solar output for some other purpose when the batteries have reached a “full” state of charge. The controller will stop allowing current to flow into the batteries at a set point-somewhere around 14.5 V for most single stage controllers. My charge controller for our off grid system is a multi stage controller that changes what the batteries get depending on their state of charge, and once every 4 weeks goes into auto equalization mode where the uppermost voltage is held for 3 hours with very low amperage.

Bottom line: if your battery is a flooded lead/acid a little extra voltage will not hurt it at all as long as the plates are never exposed to air.