PWM and MPPT question


Senior Member
Jul 26, 2011
New England
I happen to have an old PWM controller (Sunsaver 20L) from my old camper set up. I now have the 2 BB batteries with MPPT controller. I have an old 160 W panel, the frame of which was damaged by my stupidity but the panel still works. i have a saw mill shed where I use a 12 V winch to roll the logs on the mill and a 12V fan to keep the black flies at bay.

My question comes from being cheap... okay frugal ... in wanting to use what is handy to get by.
I was going to buy a cheap 100Ah LiFePo4 battery (recommended by Will Prowse) to run things at the mill, using the beat up 160W panel. I know that a MPPT is made for the LiFePo4 batteries BUT could I "get away with" using the PWM controller? I am not looking for performance but I also don't want to start a fire!
There is no requirement for a MPPT charger with LiFePO4. A PWM charger will do the job. I have been using a Bogart PWM charger with two Battleborn 100 Ah batteries for several years in my Hawk. The PWM charger must be configured for LiFePO4 parameters but it will work.

As far as your Sunsaver 20L charge controller goes, determine which version it is & contact Morningstar about configuring for its use in charging LiFePO4 batteries.

When finances permit, you will be better served with a more recent MPPT charge controller on LiFePO4 batteries but you can successfully make use of what you have now in the interim.

I haven’t updated to MPPT as I need an RFI quiet unit & while Victron products have a lot to recommend them, they are too noisy for use in amateur radio.

Thanks for the reassurance Paul. I hate fires! Just don't want to throw good money after bad. So I'll call the tech line in hopes they will answer. But the Sunsaver 20 L looks like a plug and play way to maker any adjustments
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