FunSteak
Well-known member
Now that battery pricing has started to come down, I took the plunge and upgraded to Lithium house batteries. I thought I'd write up what I purchased and what I did to help others considering the switch.
Our rig is a 2017 Minnie Winnie 26A, a class C. It was pretty standard, with a WFCO coverter/charger, Trombetta boost solenoid, and two group 24 lead acid batteries (<>80AH each). Batteries are located under the entrance step, and space is at a premium - no way to shoehorn larger batteries in there. Previously, I had added a Victron battery monitor and a Trick-L-Start. Other than those items, the charge system was stock.
What pretty much enabled the swap was finding good quality, group 24 100AH LiFePo batteries with built in BMS, and not for $1000 each. That hurdle was cleared earlier this year when Li Time released 100AH group 24 batteries that perfectly fit my needs. Best part? I got two for $575, shipped to my door! I believe the price has dropped a bit more since I purchased them.
These things are really, really nice. Very well reviewed. Built in BMS with all the usual safety items, hi temp, low temp, low charge, overcharge, and high discharge current are all covered. Reviewer testing shows excellent performance and confirms all the protections work as advertised. They are exactly the same size as the LA batts were, and fit perfectly.
My existing WFCO 8955 didn't support lithium charging profiles, so I replaced the charger/coverter section with something like this. That outputs 14.6V charge current (with the jumper in the correct position per instructions) and the new batts charge easily to 100%. I get about 550W of charge power from it. Very simple swap; just a few wires and two screws.
I removed the Trombetta solenoid to avoid overtaxing my alternator. This was necessary, but does have a drawback - now the "boost" switch on my dash is nonfunctional, so I can't jumpstart myself with the house batteries. I've started carrying a small jump box, just in case. The good news is that the wire that activates the solenoid is hot with 12V when the engine is running, so that was very handy for the next item I added...
To continue to be able to charge from the alternator when the engine is running, I also installed a Renogy 40A DC-DC charger. This requires a "D+" wire, which must be hot while the engine is running to enable the charger. I was able to easily repurpose the wire from the solenoid for this. Now, when engine is off, the charger is totally off and draws no power, so no parasitic drain on house batts while boondocking. When engine is on, I get around 500W of charge power to house batts. It's pretty slick.
I had to remove the Trick-L-Start, as it's not designed for Lithium and dumped a bunch of power to the chassis battery while boondocking, which is no bueno.
I made my own custom battery cables using this crimper and copper lugs. I used 0 AWG for the battery cables and 4 AWG for the DC-DC charger cables. I ran the battery cables to heavy terminal blocks to keep things clean.
Results: This upgrade is fantastic! I now have more overall Amp Hours and I can use way more of them since you can draw down a lithim battery much more than a LA without damage. It saves probably over 40 lbs of weight. It charges much faster (no current ramp down as you approach 100% as with LA batts.) As an example, when boondocking for four days previously, I'd have to run the genny for a couple hours each day to reach or get close to 100%. Now I might run it for an hour or two on day 3, if that's even necessary. When I start the engine to leave, it's at 100% well before we get home!
I'm very, very pleased. If you're on the fence about this change and boondock at all, I can't recommend it enough.
I'm happy to answer questions or fill in any details in this thread. Thanks for coming to my TED Talk.
Our rig is a 2017 Minnie Winnie 26A, a class C. It was pretty standard, with a WFCO coverter/charger, Trombetta boost solenoid, and two group 24 lead acid batteries (<>80AH each). Batteries are located under the entrance step, and space is at a premium - no way to shoehorn larger batteries in there. Previously, I had added a Victron battery monitor and a Trick-L-Start. Other than those items, the charge system was stock.
What pretty much enabled the swap was finding good quality, group 24 100AH LiFePo batteries with built in BMS, and not for $1000 each. That hurdle was cleared earlier this year when Li Time released 100AH group 24 batteries that perfectly fit my needs. Best part? I got two for $575, shipped to my door! I believe the price has dropped a bit more since I purchased them.
These things are really, really nice. Very well reviewed. Built in BMS with all the usual safety items, hi temp, low temp, low charge, overcharge, and high discharge current are all covered. Reviewer testing shows excellent performance and confirms all the protections work as advertised. They are exactly the same size as the LA batts were, and fit perfectly.
My existing WFCO 8955 didn't support lithium charging profiles, so I replaced the charger/coverter section with something like this. That outputs 14.6V charge current (with the jumper in the correct position per instructions) and the new batts charge easily to 100%. I get about 550W of charge power from it. Very simple swap; just a few wires and two screws.
I removed the Trombetta solenoid to avoid overtaxing my alternator. This was necessary, but does have a drawback - now the "boost" switch on my dash is nonfunctional, so I can't jumpstart myself with the house batteries. I've started carrying a small jump box, just in case. The good news is that the wire that activates the solenoid is hot with 12V when the engine is running, so that was very handy for the next item I added...
To continue to be able to charge from the alternator when the engine is running, I also installed a Renogy 40A DC-DC charger. This requires a "D+" wire, which must be hot while the engine is running to enable the charger. I was able to easily repurpose the wire from the solenoid for this. Now, when engine is off, the charger is totally off and draws no power, so no parasitic drain on house batts while boondocking. When engine is on, I get around 500W of charge power to house batts. It's pretty slick.
I had to remove the Trick-L-Start, as it's not designed for Lithium and dumped a bunch of power to the chassis battery while boondocking, which is no bueno.
I made my own custom battery cables using this crimper and copper lugs. I used 0 AWG for the battery cables and 4 AWG for the DC-DC charger cables. I ran the battery cables to heavy terminal blocks to keep things clean.
Results: This upgrade is fantastic! I now have more overall Amp Hours and I can use way more of them since you can draw down a lithim battery much more than a LA without damage. It saves probably over 40 lbs of weight. It charges much faster (no current ramp down as you approach 100% as with LA batts.) As an example, when boondocking for four days previously, I'd have to run the genny for a couple hours each day to reach or get close to 100%. Now I might run it for an hour or two on day 3, if that's even necessary. When I start the engine to leave, it's at 100% well before we get home!
I'm very, very pleased. If you're on the fence about this change and boondock at all, I can't recommend it enough.
I'm happy to answer questions or fill in any details in this thread. Thanks for coming to my TED Talk.