Can use a 48V Overkill BMS in - 20 degrees environmental?

Merlin

New Member
Hello friends,

I have ordered 32 Lishen Cells from James Mo, Dongguan Lighting, which was a really great support at all by the way.
These cells can Handle to charge from -20 until 60 degrees so I can use the Battery Bank outside in a insulated Box.

My question is,

Can I use a Overkill 48v BMS outside in the box in such cold environmental? I know that you can enter in the app cut off low temperature on -20 degrees.
But can I use this BMS all day long in wintertime reliable?

Or I need another BMS for this kind of setup, there will going easily in cold temperatures.

I would be very thanksful for thoughts and Help of you.

Thank you!
 

Short_Shot

Photon Sorcerer
CHARGE at -20c?

I very much doubt that. Lifepo4 should not be charged below 0c. Are they something other than lifepo4?

You can DISCHARGE to -20c though.


Most of us that have low temp requirements will use a battery heater to alleviate this, and if it's cold enough we insulate the battery box.
 

Merlin

New Member
CHARGE at -20c?

I very much doubt that. Lifepo4 should not be charged below 0c. Are they something other than lifepo4?

You can DISCHARGE to -20c though.


Most of us that have low temp requirements will use a battery heater to alleviate this, and if it's cold enough we insulate the battery box.
Hello short short.

Sure You are right. But These are a Speciale Serie from Lishen Lifepo4 202 Ah. You can get these cells with only with 202 Ah and they are able to charge on -10 at 0.3 c and until -20 with 0.2 c. Discharge until -30 degrees.
Attached you can find the datasheet.

So but, can I use the overkill 48v 100amp in such an environment?
And will cut off charging on -17 or -20 degrees or know somebody a better BMS for such cold environment?

Thank you for your help!
 

Attachments

  • 34546e41b5b61dcad37363bf76f254c8.pdf
    824.6 KB · Views: 3

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
These cells are Yttrium Doped which allow for Cold Temp charge BUT it is Low Current charging only.
0.3C = 60A, 0.2C=40A
The JBD (Overkill) BMS should be fine with turning it on/off.
FYI: Most MosFET Based BMS' only allow for 50% Charge rate. So a 150A BMS will only allow a max of 75A Charge input. *Also factor in a 20% derating to allow for margin. Advertised Capacities tends to be to the "max spec" of the components.
The Charge Current relative to Temperature is not handled by a BMS (not until you get into seriously high end stuff) so whatever method you are using to charge will need to have some form of control.

Now typically LFP has a Max of 0.5C Charge Rate but these particular ones allow up to 1C or 202A at room temp (25C). (NB: Under the Specific Conditions as specified in Spec Sheet) If you have multiple packs in parallel of course you divide both Load & Charge between the packs during operation.

1633967269689.png

Hope it helps, Good Luck.
 

RCinFLA

Photon Sorcerer
Even with 'special sauce' to improve low temp performance you are going to lose a lot of extractable capacity and max discharge current performance from cells at colder temps.
 
Last edited:

Merlin

New Member
These cells are Yttrium Doped which allow for Cold Temp charge BUT it is Low Current charging only.
0.3C = 60A, 0.2C=40A
The JBD (Overkill) BMS should be fine with turning it on/off.
FYI: Most MosFET Based BMS' only allow for 50% Charge rate. So a 150A BMS will only allow a max of 75A Charge input. *Also factor in a 20% derating to allow for margin. Advertised Capacities tends to be to the "max spec" of the components.
The Charge Current relative to Temperature is not handled by a BMS (not until you get into seriously high end stuff) so whatever method you are using to charge will need to have some form of control.

Now typically LFP has a Max of 0.5C Charge Rate but these particular ones allow up to 1C or 202A at room temp (25C). (NB: Under the Specific Conditions as specified in Spec Sheet) If you have multiple packs in parallel of course you divide both Load & Charge between the packs during operation.

View attachment 68435

Hope it helps, Good Luck.
Hello Steve,

Yes that was helpful!

So is it possible to build a 16S 2P with 32 cells with two 48v overkill 100 amp or maybe better to go with 404 amp 16S one 48v skill 100 amp? I mean it's just a 3.1kw PV and 3000w inverter on it.

Thanks.
 

Merlin

New Member
Even with 'special sauce' to improve low temp performance you are going to lose a lot of extractable capacity and max discharge current performance from cells at colder temps.
Yes. True. I mean - 20 degrees are just at the night for example. Over the day may - 12 and if the battery is insulated good might be -8 degrees. Hope that will work out well with not so much lost.
 
Top