Anybody running a 48v DC Lithium battery bank? Used electric car batteries?

I am in the researching phase of my RV solar & lithium battery bank build.  I just discovered that there are some great deals on used electric car battery banks.  I found a kit on ebay that is 48v 7kWh for about $1000!  I'm considering 960w of solar panels on the roof of my 32' FR3.

Has anybody used them?  Anybody done a 48v setup?

Interesting. My guess is they are former hybrid packs. I think the BEV packs are much higher voltage.  (Not an expert).

What's the weight and physical size of those packages? Do you have a place for it?  You also need  a step-down transformer or module to deliver 12v to the house system and should have a 48v charger for back-up to the solar.

7 KWH @ 48v is about 600 AH @ 12v, so compared to the cost of about 6 LiFeO4 12v, the $1000 sounds pretty good. Does it have a BMS built in at that price, or would you have to add that?

I suspect you are talking about these Nissan Leak battery packs.
https://www.ebay.com/itm/Nissan-Leaf-Battery-48v-Gen-2-Lithium-Ion-7-kWh-132-Ah-Solar-RV-EV-Golf-Lot-14/123486112701
The ad claims about 70% capacity, so you have to discount the 7 kwh quite  bit.

All in all, it seems like it has potential for someone who has the skills and is willing to do the work. It's not a trivial undertaking.

48V is an industry standard bus voltage and there are lots of DC-DC and solar inverter solutions to get you from here to there.  The downside is to get appreciable 12V current you'll spend a bit on the converters but maybe with the economy of the battery price you'd still be ahead.  48V is also a common solar bus voltage if you have a large array of panels.  The downside I see is it's going to be a custom system and you get to be the engineer which is OK if you like that kind of thing, but it won't be plug and play especially if it comes to reverse engineering or coming up with a BMS.

Mark B.
Albuquerque, NM

This is the one I was looking at because it comes with BMS:  https://www.ebay.com/itm/Nissan-Leaf-48v-Battery-G1-Lithium-Ion-7-kWh-132-ah-2-x-BMS-60A-Lot-of-14/124114860556

I am also considering a setup with used BMW EV batteries which the seller shows the discharge graphs and claims 800-900wh per pack.  Seems like a more reputable seller, but more assembly/customization might be needed:  https://batteryhookup.com/products/bmw-oem-3s-12v-85ah-869wh-battery-module

I will have to check with the ebay seller to see if they have a discharge test chart, or if the test them before selling in the lot.

Considering one of those battery packs with this AIMS 48vdc 4000w pure sine inverter/charger:  https://theinverterstore.com/product/4000-watt-pure-sine-inverter-charger-48-vdc-120-240-vac-50-or-60hz/

The 12v coach accessories is the other thing that I'm researching.  The only 12v accessories on my rv are the led lights, Fridge control board for propane use, stereo, exterior LED lights, and two 3-speed ventilation fans, and I think the hydraulic auto leveling system.  I would imagine there might be a reasonable solution for 48v step-down to 12v.  Worst case, maybe keep a standard 12v agm coach battery to handle those loads.

One downside that I've seen to this setup seems to be that I have not be able to find a DC to DC charger to charge the coach batteries with the alternator while driving.  I don't think that would be too much of a problem since I plan to have the inverter/charger and 960w-1280w of solar panels on the roof and a 5.5kw onan generator for backup

I have a 48 V lithium setup, mine is a bank of 16 CALB cells though. the used car battery route is inexpensive but
a minefield of problems as one cannot know the service history of the cells so becomes a "crapshoot"

for charging, I chose a 2200 Watt 48 V inverter/charger/ATS
i have 960 W of panels and a Victron 150/35 mppt controller
for 12 V supply I use a 360 Watt buck regulator of the type used on golf carts.
lastly, a small 12 V AGM for the trailer emergency brake breakaway switch and tongue jack.
certainly not the norm for an RV. my reasoning was to reduce weight so lead acid was not an option. secondly, FLA would
require external space i did not have, so lithium installed internally was the choice. 12 V was not an option for
2200 Watts of inverter and also voltage drop from cell bank interconnect was an issue too.
my cells are arranged in two banks of 24 V, each bank hidden in the dinette slide out bottom storage area.


I do not have a commercial BMS. i do however have a monitoring system to measure the cell voltages.
for me as a professional engineer it's not an issue to bottom balance the cells and just keep an eye on them from
time to time. otherwise i would suggest you install a commercial BMS and top balance the cells.

pm or post if you need more info.

Alright, so I ended up placing an order for 16x new 280Ah LifePo4 cells.  Going to involve a little DIY but I think the capacity (13.44Kwh) will be worth the trouble!

Please let us know what you did to install them and how it works out. Photos would be great!