New trailer build with old solar controller

[Niskibum]

Wondering if my Tracer2215BN will work ok until system upgrade. I am doing a cargo to toy hauler conversion this summer, and have decided to upgrade to Lithium. I have purchased 2 SOK 12v 100ah batteries, and already have two 100 watt solar panels and a Tracer2215BN solar controller with an MT50 that I was using on my old trailer to charge lead acid.

I only use DC while boondocking, no converter, so just running lights, vent fans, water pump, and an Iceco fridge, so not a huge load.

I will probably be adding more panels in a year or two, and will upgrade the controller then since the Tracer is only 20a, but would like to use my existing one to save money until then. I have read a few threads on here, and have watched Will's video on setting up with the MT50 for Battleborn batteries.

Will the Tracer work for my setup without degrading the SOKs or causing damage, and will the settings for the Battleborns work the same for the SOKs?

I believe the answer to both is yes, but would like input from more experienced people. Thanks

 

[rickst29]

Yes, it will definitely work fine for now, and also work after you upgrade to no more than 4 panels.

I've seen a 2215BN actually performs current-limiting at slightly more than 20A, when the "maximum charge current" parameter has not been reduced via MT-50 programming. In your configuration, the maximum power into the batteries should be no more than 3.60V * 4 cells per battery, 14.2 Volts at 20A = 288 Watts. The rest will be "left in the panels", Unused.

Some persons suggest lower Boost Voltage values, to help batteries last longer. BattleBorn videos have some rather "high" charge voltage specifications, there is better advice in many posts on the forum. (Search "epever settings" to find them). Be absolutely positive that lead-acid "Equalize Voltage" is reduced to be no higher than "Boost Voltage", and you should additionallly set your "Equalize Time" to zero. "Float Voltage" between 13.3V and 13.6V is widely used by forum members.

(I use 13.6V in my Lithium installations, because nearly all of those RVs and Trailers are kept indoors most of them time. During their occasional trips, a slightly aggressive "Float" value helps to assure the RV batteries to become filled before nightfall. I have done installations with both BattleBorn and homebuilt batteries.)

Unlike some problem reports on the forum with Tracer "AN" controllers, the discontinued "BN" models do a fine job while running "over-paneled" and reaching their output current limits. I've got a "30A" Tracer-BN configured to limit maximum current at 28A, and it's slightly over-paneled with about "500W" nominal attached. (Although the real panels don't reach that power level, because they aren't angled into the sun).

- - -

What can and does reach that limit in my own configuration, pretty consistently when batteries have been pulled down low, is the otherwise "unlimited" power source within my tow vehicle: a 36.0 volt boost/regulator device. It has no internal power/current limiter, and will release all of it's "magical blue smoke" if over-utilized by Solar input power consumption (amps) from my Tracer. But it has not failed, in many years of use.

My own Tracer, programmed at 28A, behaves properly, limiting maximum output power into my LFP battery string to no more than 14.2 V * 28.0A = about 398 watts in Boost mode. Due to MPPT power consumption and substantial wiring losses from the TV, that's pulling 475 watts from the Booster/Regulator, which runs cool all the time (it's rated at 540 watts maximum output power, 15A.) The Trace will not pull more than about 88% of that rated power on a continuous basis, and it has NEVER attempted to pull too much.

 

[Niskibum]

Thank you very much for the detailed reply, that helps a great deal.