Hi , trying to work out the time to go , I've set the floor to 20% and with a 100ah battery and a 46 watt load says 22.58h.
With a simple bit of maths you know that 46 x 23 = 1,058 , it is a first discharge so does it's get closer with time ?
asked
Smart shunt , time to go.
When doing the multiplication 46 x 23, you are calculating Wh (Watt x Hours). To Calculate this back to Ah (Amp * hours) you have to divide by the battery voltage. Assuming the average voltage is 13.2V, you actually get 80.15 Ah, which I would say it pretty close to 80% (due to the 20% discharge floor) of 100Ah.
Kind regards,
Thiemo van Engelen
It should sync correctly after a discharge, charge and synchronise cycle with the caveat, if you have all the settings correct.
Dont work with watts work with amps. Also it will have a greater capacity at a lower C rating draw (all batteries "have more capacity" when you have a low draw from them.)
Check your battery C rating. For example it may be 100ah at C10. So its capacity drained out over 10 hours. If you are drawing it out over 20 hours, you would have more capacity. The opposite is true, if you draw it our over 5 hours you will have "less capacity". That is why there is also the peukerts exponent in the equation.
Battery charging and discharging is not as simple/linear as we would like it to be.
I've set the peukerts exponent to 1.05 and battery efficiency to 99% , I've not set the voltage when full yet and left it at 0.0 , not sure if that should be the 14.2v absorption voltage or the nominal battery voltage 13.6v ?.
Can't see anything on the battery about a rating at a temperature only the maximum charge and discharge , 50ah , 50amp so I guess that is 1c max
Hi , It is now confirmed I'm stupid !!! , Yes I later realised that my 1000wh was my figure I was using for about 80% discharge , so I guess I was calculating 80% of 80% discharge.
Didn't set the ( charge voltage when full ) so I got a 100% battery on sun up .
Thank You Peter A
