LiFePo4 lithium battery charging questions
TL DR – I have some questions related to charging 12V LiFePo4 lithium batteries: *How to best use my solar to charge batteries? *Assuming I usually keep the lithium batteries at a partial SOC, what ...
Forum Discussion
3 tons wrote:ewarnerusa wrote:
Someone provided me a link to the Battle Born battery site where they go over some charging parameters for the Morningstar Tri-star PWM contoller.
https://battlebornbatteries.com/set-tristar-ts-45-ts-60-pwm-charge-controller-used-lifepo4-battle-born-battery/
Their parameters:
Absorption setpoint: 14.4V
Absorption time: 1.5 hrs
Float voltage: 13.40V
From my perspective, those parameters are fine, yet unnecessary - unless your plan is to just ‘set-and-forget’ the controller as part of a passive charging strategy…JMO
However, in actual camping practice, this is where a Li compatible shunt-based meter is your friend…By this method one can readily see when battery charging is completed…From my experience this typically occurs within a few minutes (NLT *15-20 min) after reaching 14.4v (my max voltage value), as follows:
Once the meter recognizes its user-programmed full charge parameters (i.e. capacity, voltage, peukert value, tail-setting interval, and restored to 100% SOC), this is when cell-balancing begins, as verified by the meter’s ‘slight’ to-&-fro rise and fall of amps vs volts until both values soon remain steady…When ‘opting for’ a ‘on-site’ FULL charge this is all that’s really needed - and this when I terminate harvesting…
3 tons
Their time in absorption seemed quite long. Their response to a comment mentions their practice of allotting 20 min of absorption per battery, so may be this particular setup was for 3+ batteries in parallel?
The float voltage also seems like it could be lowered based on the idea of not maintaining the battery at 100% SOC on a regular long term basis. I would think you could set the float voltage a bit lower and the battery's resting voltage would be higher than the float voltage. So the controller would not deliver any current to the batteries which are at 100% by this point based on whatever criteria the controller used for that. Although...suppose you wanted to use solar harvest as primary for loads when sun is available.... OMG I fall down the rabbit hole easily...
