Author Topic: State of Charge  (Read 8723 times)

offgridQLD

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Re: State of Charge
« Reply #15 on: November 19, 2013, 10:16:13 PM »
Because of their low self discharge, they don't really need float at all. 

Floating is very important to opportunity loads.  When I run a laundry in the afternoon, float allows my solar panels to power the laundry. If I turned off float, I would be using the batteries to do the laundry even though the sun was shining.    --vtMaps

I agree my system spends a lot of time in Float but its still doing a lot of work in float. Charging EV, washing, workshop loads and all kinds of house loads. Typically in summer any time after 9:30Am  by battery's are in float and all loads from 9:30am - 5:00pm are being held at bay (not being taken from the battery) by the classic  increasing it's output to hold steady float voltage under load.

 I often perform a little test to see what the potential output of my system is at any point over the day while one float. It's simply a matter of breafly switching on a load greater than my PV arrays potential output max (4000w) so perhaps electric oven 3000w + flick the kettle switch 2400w  total 5400w. I then watch the classic ramp up the float wattage output to try and match the load for example it might only reach 2950w and a see the voltage slowly drop below set float voltage. I know then that 2950w is the max energy available from my array at that time.

Kurt

Off grid system: 48v 16x400ah Calb lithium, Pv array one  NE facing  24 x 165w 3960w, Array two NW facing 21 x 200w 4200w total PV 8200w. Two x Classic 150,  Selectronic PS1 6000w inverter charger, Kubota J108 8kw diesel generator.