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The data sheet for my batteries (link below) states a temperature compensation of +/-3mV/degree C. The default setting on my Smart Solar MPPT 100/30 charger is -16.2 and when I search the forums everyone elses seem to be in the teens or twenties. Is it reasonable for mine to be 3 or am I misreading something? Also, the current setting is -16.2 how do I make it a +/- value?
https://cdn.shopify.com/s/files/1/1579/5179/files/CR-240_PowerSheet_D06240_0213.pdf?16021135676618962151
I have a follow up question to this:
I have a customer who has six 6V batteries in series/parallel in a 12v system. The customer battery spec is showing the same ±3 mV/°C/cell as posted above.
A 6V battery is +/-(3cells x 3mV) = +/- 9mV per battery
So for Six 6V batteries in series/parallel would be 6 X 9mV =+/- 54mV, correct?
Does it matter whether in series or parallel or is it the total number of batteries?
Thanks for the help!
Pretty sure you are being led astray by an incomplete spec, see:
https://cdn.shopify.com/s/files/1/1579/5179/files/31DC130_PowerSheet_D12130_0213.pdf?16021135676618962151
This is the 12 V version of the battery it also lists this spec at +/- 3 mV/degree C.
But a 12V battery has double the number of cells as your 6V battery.
My point is the temp. coeficient is normally listed per cell, and this spec should be listed as +/- 3mV/degree C /2V cell.
So for a six volt battery it is +/-(3cells x 3mV) = +/- 9mV for the battery.
However if you had a 24V bank, it would be (24/2) = 12 cells
And temperature compensation would be 12 x3 mV = +/- 36mV.
( now your figure is similar to others you've seen).
As the temperature inversely affects the voltage the setting in Ve-configure would be -36mV/C.
The float voltage will drop by 36mV for every degree above 25deg C, and rise by 36mV for every degree below 25deg C at that setting.
Similarly, if your bank is 48V, then the setting is -72mV/deg C & a 12V bank would be -18mV/deg C, using these batteries.
