Lithium Battery install ?

Originally posted by Olddawgsrule Response from WFCO "The converter you have is not an actual lithium converter but will charge to approx.. 90 to 95%.  We do not have a direct replacement converter that is lithium at this time." We already know it's not a lithium charger. Sorry to see they don't have a add-on or direct replacement. I'm awaiting response now from Progressive Dynamic's. Believe they do.

Mine is a combination system....keeping the lead acid batteries where it makes sense, (cost vs benefit) and adding lifepo4 for the additional auxiliary loads. 

Wow....dont get me started....

The tow vehicle charging circuit doesn’t go through the wfco battery charger. That just runs from an ac source. When you connect your tv to the trailer you are making a direct connection between the two 12v systems. That works ok because they are both lead acid batteries and the resistance of the wire runs limits the current flowing between the two even if one battery is at a lower voltage than the other. The same direct connection won’t work so well with two different battery chemistries. There are dc dc converters available that can do the job correctly and safely but they aren’t cheap.

The electronics in your Li battery are there to balance the charge on the individual cells. Eventually Li cells become unevenly charged because they never get floated or equalized like they do in a PbA battery. That circuit won’t replace a proper charge controller although some of them do have a high voltage cutoff built in as a safety backup.

Ok, I think maybe I understand but let me play it back. You want to replace the rpod House battery with lithium. You want to repurpose a solar charge controller you are presently using to charge a Li battery running a water pump. You are wanting to know if there are any issues if you place that charge controller between the existing battery cables and the new Li battery?

The main battery cables connect the battery to a buss which is in turn connected to the house 12v loads and to the WFCO charger via fuses in your panel. Since current needs to flow both ways in the battery cables that would not be a good place for the solar charge controller. If that controller is set up for the Li battery you can place it in the dedicated Zamp solar charge circuit feeding from the solar connection on the side of the trailer, if you have one,

If you want to charge your Li battery from an ac source I would not recommend using the wfco. It is set up for PbA batteries and is a poorly regulated charger so you could wind up with excessive voltage on the Li battery, which is very bad. Check the charging specs for your Li battery and get an appropriate charger.

You will also need to disable your tow vehicle charging circuit, or replace it with something else like a dc dc converter. Li batteries are actually easy to charge, you don’t need a fancy multistage charger like you do for PbA, but you must not overcharge them, ever.