Hi folks. Been a while. Long story.

So any of you old folks like furpod or Charlie put pencil and paper to the ROi of LiFePO4? 

My 2014 178 is going great. We're finally back on the road and I'm spending wayyy too much time playing with it while waiting for my Ollie to show up.

So my latest obsession has been with offgrid stuff. I love my Yammy 2400, but it's just so damn heavy and just not that much fun so I went with a Renogy 200 Watt Eclipse suitcase and a 1500 watt VertaMax inverter. Justification (especial inverter) is another post, but I had the extra cash and until My Ollie shows up in the driveway I figured what the hell. (yes, I am attracted to Oliver)

So an important part of the configuration is, of course, storage. My dual Duracell EGC2's are now exactly 5 years. They are still doing amazingly well. Probably because I monitor them, keep them exercised with a Progressive Dynamics Converter and don't abuse them. Anyway, I figure they are getting old like me and since I got this shiny new solar stuff, let's go for it and consider LiPo!!

Best I can figure...it doesn't make any sense. I can buy two new Duracells for about $250.00 (230 Ah). Two Battleborn LiFePO4s will set me back about $2000.00. So, for about $1000.00 I can get another 20 years of power or spend $2000.00 for bragging rights. My Medicare supplemental won't cover LiFePO4!!

I understand the weight/useable amperage/coolness factor, but in a battery bank of 250 AH or less (even 500 AH) in a small RV I don't get the ROi. 

What am I missing?

fred

P.S. I corrected the title and copy to correctly read LiFePO4 instead of LiPo!! Don't want anybody to think I was considering surgery to get rid of my coveted beer belly!! 

Sure, they are marketed as 'drop-ins' and they will work that way, but the benefits of an expensive LFP battery are minimized if you don't also upgrade the charger to take full advantage of the capacity of the LFP battery.

You can get by with one LFP battery in place of two lead acids, so there is some savings in weight and cost on the front end, but the purchase of a compatible converter/charger erases some of that.

It's easy and cheap to buy LFP compatible solar controllers..so that is an option. 

Another issue is the tow-vehicle to trailer charge line....again, the charge profile wont be correct. Your factory battery monitor panel will not even have a clue about state of charge of the LFP battery. It will read FULL until the LFP battery dies. 

Also, LFP batteries wont charge below freezing. The BMS will cut back, or cut off, the incoming charge at some temperature below 32f. BattleBorn BMS will cut off at 24f, and stay that way until the internal temps comes up above 32f. 

But if you are willing to go to all the expense, you can boondock much longer, and run a generator for a much shorter time to recharge the LFP...they will absorb all the amps you thow at them. Also the LFP batteries can stay at lower charge levels for extended time with no damage. They dont out-gas, and they should last a long time. 

I ended up building a hybrid system: Standard lead acid batteries (compatible with factory converter and monitor panel) for normal house loads like lights, radio, fridge electronics, etc, and the LFP for heavier auxiliary loads such as my ham radios, inverter, and laptop charging. Both systems are charged by solar and if needed, a generator. 

Electrical power when boondocking is no problem now. Of course, food, water, and propane still have to be replaced as they are used. 

If you buy salvage EV Li batteries it might depending on what you're wanting to do. I want to run a/c (NOT the existing horribly inefficient noisy roof air, a modern minisplit) and a Tesla battery module ought to work nicely. 5.3 kwh for about $1300 @ 55 lbs.  It will go inside under the bed where it will stay nice and warm in the winter. The minisplit condenser will go on the tongue where the PbA batteries are now. 

I have read about the system. Lowest cost kWh out there. Very cool and would run my side by side fridge mod!

Are you going to add the electric assist axel drive to the pod chassi? TV gas savings alone would justify that! 

fred

We're all having enough trouble just keeping plain old unpowered axles from bending or falling off rPods.  I don't think I want to add power assist on top of that 

if someone did do that they should just get the whole belly pan, drivetrain and computer assembly out of a Tesla, lift the trailer, and put it under there. Then you could program Tesla's autopilot to drive the trailer to your campsite for you so it was ready when you got there

I did that math once or twice..

I think the number of owners, for which it REALLY makes sense is pretty small. We have done 2 weeks on our GC2's, with no charging. We can do 3 days or more in below freezing temps. But we try not to camp to regular in those.. 

The one big advantage that made me do the math more than once is the fact that they can be discharged so deep.. and at such a high rate. With the right set-up.. off grid a/c is possible. Not 24/7, but enough to beat the highest heat of the day when needed...

To go 24/7 you have to get a different a/c. The new mini splits are about 2x the efficiency of the RV roof units. My calcs have me approaching 24/7 a/c assuming a sunny day with 1500 watts solar and a 5.3 kwh Tesla battery pack. I''ll still need charging from the tow vehicle for an hour or two  a day. Or, shut off the a/c for awhile during the day while out and about. I mostly want the a/c for those hot humid nights anyway.