SOK batteries replacing AGM batteries in a Roadtrek 190

[robert540]

I am new to this forum and posting questions. I have a 2015 Roadtrek 190 Popular motor home with factory installed solar panels. In preparation for new batteries I replaced the original Epever Tracer solar charger/controller with a lithium capable Epever Tracer 4210AN charger/controller with the MT-50 display. This week I replaced 4 original 6 volt AGM batteries with 2 SOK 206 AH LiFePO4 batteries. The Roadtrek has a factory installed Sure Power Industries 1315-200 Battery Separator Switch that automatically connects the coach batteries to the Chevy battery when either side is above 13.2 volts. This allows the original Tripp Lite APS750 Inverter/Charger and the solar panels to charge the Chevy battery when the unit is parked and connected to shore power, and allows the alternator to charge the coach batteries while driving. As part of the battery upgrade, I added a Victron 12/12-30 Orion DC to DC charger between the battery separator and the SOK batteries. The SOK batteries each measured 13.1 volts out of the box. After a day in the Roadtrek, the MT-50 shows the SOK batteries at 13.7 and fully charged. I only use the Tripp Lite unit as a charger because the coffee maker and microwave needed a 3000 watt inverter to operate. So after one day, I have questions and hope that someone has knowledge or experience that would help me address the observed issues. First, the Tripp Lite ran continuously until I disconnected the shore power, and I suspect that because the SOK batteries had voltage above the 13.2 volt connection trigger, the battery separator switch was trying to increase the voltage of the lead acid Chevy battery. Research indicated that by removing the Ground wire from the battery separator switch, the cross charging could be disabled. I removed the ground wire and the Tripp Lite stopped continuous charging. Research identified that one person addressed this problem by installing a dash mounted switch to activate the battery separator switch on demand, like when they were driving the RV, or once per week to charge the Chevy battery when parked and on shore power during camping or storage; a second person used a relay under the hood to use the ignition activated power to complete the Ground connection on the battery separator switch. I like the idea of using the relay for an automated solution, but need to figure out how to wire the relay correctly so that that 12 volts on the coil closes the normally open ground connection. Has anyone else with an RV and a battery separator switch handled this issue, or is it really not a real issue? Before the conversion, I spoke with Tripp Lite and their official advice was to not use it to charge lithium batteries. More research on the internet lead to a Battle Born web page that explained how to configure the Tripp Lite APS750 for use with their LiFePO4 batteries, by setting the Tripp Lite to charge wet batteries instead of gel batteries. Followup with both Battle Born and SOK supported this configuration. For reasons presently unknown, the Tripp Lite has a continuously ON red Load LED. I am still researching whether this is a problem. Has anyone a recommendation for a good shore power to LiFePO4 charger that would replace the 10 x 10 x 8 Tripp Lite APS750 in the very confined space of my Roadtrek cabinet? I appreciate any advice on these questions.

 

[robert540]

I wanted to update my first post. Five days after the SOK installation in my Roadtrek, everything is good and questions have been answered. Battery voltage is stable at 14.2 and the shore power charger rarely operates for more than a minute because the solar charger is maintaining the batteries. No power from the shore power source or the solar charger can pass back thru the Victron DC to DC charger thru the battery separator switch to maintain the Chevy battery when the RV is parked, so a 1 Amp maintenance charger will be added to maintain the Chevy battery. The Tripp Lite charger shows that batteries are fully charged, but still has a steady red LED inverter error light, but since that Inverter is off and the unit is not overheating while charging, the light may be ON to indicate it sees the 14.2 battery voltage above the usual AGM 13.6 volts as an overcharge situation. There is no need for any additional switches or relays.