Any way to use Longmons (2.2v -> 5.4v) on LTO Cell (2.0v to 2.6v)

OffGridInTheCity · Nov 15, 2025

I use Batrium as my BMS for both my powerwall and trailer battery bank of 18650 cells - and really like Batrium.

I was thinking of doing an LTO battery - something like 23s13p for 260ah @ 48v nominal. This would be a 23*2.0v=46v low and 23*2.6v=59.8v hi.

The issue with Batrium mons is that they're designed for 2.2v to 5.4v range per cell - https://wiki.batrium.com/en/product/cell-monitor/longmon

Is there some way I could fool the longmon (add a resistor or some easy circuit or something between the + and - of longmon -> cell) so that the longmon sees the 2.0v to 2.6v as at least 2.2v -> xx ? I'm guessing that Longmon calibration (if Batrium allowed me) would not be wide enough to compensate for 0.2v difference.

I would be OK with inflated voltage readings as I can compensate in the overall operational settings of the Watchmon as long as they were relatively (pun) accurate.

OffGridInTheCity · Nov 16, 2025

Would something like this work - e.g. bi-directional voltage boost. LTO --> +0.2v (or maybe a bit more) --> Longmon. Longmons have 2a max balance. Longmon balance would 'pull' current from battery -> unit -> longmon, so it this would work current flow wise?

https://www.amazon.com/Converter-Adjustable-Voltage-Regulation-Connector/dp/B0DSZ9G3ZS

Korishan · Nov 16, 2025

I dunno if that'd work, but I'd think it would not, especially how close the voltages are to both sides.

Definitely something that Jaron with @Batrium could answer tho. But, he was "Last seen Feb 17, 2021", so not sure if he's checking here anymore.

OffGridInTheCity · Nov 18, 2025

We're edging toward buying a remote property in high dessert of Southern Oregon - and we're likely to only visit once every 6 months. The winter temps can go as low as 4F and average 25F. Think shipping container environment.

I'm considering LTO because I don't need to do anything for temps. 18650 is way cheaper but I need a box and some heat - which is OK but not sure heater would run 6 months with no human intervention.

Any comments welcome on the 2 bolded questions....

**Is it reasonable that an 18650 box with heat would function with no oversight for 6 months?

LTO wise I see.....
BatteryHookup - https://batteryhookup.com/ - has used 20ah cells for $8 each but require work to break apart for re-use

where as Alibaba also has cells for $16.80 / 45ah (~ $8 / 20ah as in BatteryHookup) ready to hookup - https://www.alibaba.com/product-det...019.html?spm=a2700.7724857.0.0.f8996051RHtHbe

**Is it safe to order via Alibaba as far as getting something reasonable (say at least 40ah vs 45ah advertised) for the prices they offer?

Dala · Nov 18, 2025

Consider trying an EV battery? I use my LEAF battery down to -30*C (-22*F), most EV packs work all the way down to -40*C/F

The EV batteries also run great without any intervention. Have not touched my EV pack for ~8months now, it just runs!

OffGridInTheCity · Nov 18, 2025

Dala said:
Consider trying an EV battery? I use my LEAF battery down to -30*C (-22*F), most EV packs work all the way down to -40*C/F

The EV batteries also run great without any intervention. Have not touched my EV pack for ~8months now, it just runs!

Isn't LEAF a lithium-ion chemistry (32F/0C low for charging)? Does a LEAF battery pack have heaters or insulation ?

I'm asking because an EV battery pack (600lb +) is too heavy/awkward for my circumstances but I could do the Leaf Cells (and would like that solution), maybe in a box so simulate the EV battery pack container.

Dala · Nov 19, 2025

OffGridInTheCity said:
Isn't LEAF a lithium-ion chemistry (32F/0C low for charging)? Does a LEAF battery pack have heaters or insulation ?

I'm asking because an EV battery pack (600lb +) is too heavy/awkward for my circumstances but I could do the Leaf Cells (and would like that solution), maybe in a box so simulate the EV battery pack container.

95% of EV batteries can be charged with low rate at -40*F (NCM/NCA/LMO etc.). Some have heaters, but most don't. Just avoid LFP for prolonged -40*C weather

If space/weight is an issue, look into the CMFA EV platform (30kWh) https://github.com/dalathegreat/Battery-Emulator/wiki/Battery:-Dacia-Spring-‐-Renault-K‐ZE