The PCM LO4S30 Power Control Module that I used with the the four-series 60 AH LiFePO4 battery (LFP-G60 cells) is doing a great job keeping the cells balanced on recharge. After the 3rd PCM charge, the largest difference is now 12 millivolts. Recorded cell voltages, 12 hours after completing the charge cycle are:
- 3.585 V
- 3.590 V
- 3.580 V
- 3.592 V
Following the initial charge, which was performed on individual cells, the largest cell voltage differential was 68 millivolts. The first charge using the PCM was 56 millivolts, and the next was 24 millivolts. It appears that the differential is decreasing over time.
Since the largest recorded voltage differential following discharge has been 14 millivolts, it appears that the PCM is doing its job well — reducing the risk that any individual cell might become over discharged or overcharged.
Now that you’ve had some experience with LiFePO4 batteries I was hopping you could point me in the right direction. I’m trying to get a battery pack to run my (soon to be ordered) KX3.
I’m considering a 6.6Ah LiFePO4 battery that has a built in PCB controller. As near as I can tell – the specs on my Nomad 27 solar panel are 12-15V unregulated output, should be in spec.
Have you had a chance to charge from solar with out a separate controller?
Vince
KG7CLI
Hi Vince,
Yes I have charged from a solar panel without controller, but I also kept an eye on the battery voltage and removed the panel when the voltage got up to about 14.5 volts.
There is a risk in attempting to charge a battery without a controller, especially a battery like your 6.6AH unit with built-in PCM. While it depends on your particular PCM, many will open circuit the charge path if the battery voltage is too high, or too low. At that point your solar panel will go to its maximum open circuit voltage. “12” volt panel often put out 18 to 22 volts in that condition.
If you have a radio attached to the circuit at the same time, it will be exposed to the 18 to 22 volts and may be damaged.
So using a charge controller is a good idea. However I believe that the Nomad panels do put out less voltage than some others, but I’ve found their specs to be pretty broad.
Why not invest in a small charge controller and be safe. I really like the one sold by BuddiPole because it is VERY small, light, and uses Anderson Power Pole connectors.
73, Bob, WB4SON