Headway cells in cold conditions ?

[pm_dawn]

Hi !

I've just bought a couple of headway cells to build 4s pack to drive xenon trail lights.
But since it is cold here where I live I would like to know if someone has any data on the capacity of the cells in cold conditions.
what capasity can I expect in -10 celsius and in -20 celsius.
I have tried to search this forum for info but I have not seen any real curves or tests at these temperatures.

Does anyone have any data on them?

Best Regards
/Per Eklund
Mid Sweden

 

[thomas]

Im waiting for a batch of headway starter batteries and a cba III and plan to do some cold use tests on them.

Will probably take a month to arrive but Ill leave a thread about the tests.

 

[pm_dawn]

OK !

I'll try to set up a test myself then.
I'll put the fully charged cell in the freezer and run a discharge test on it while in there.
I have a BT-6 so I can discharge at 0,5C at max. But for my test I guess it is OK I plan to discharge only 0,3C in the Xenon application.
I will give me atleast one curve at -18 degrees Celsius. that is appr. 0 F

I'll set it up as soon as I can.

Regards
/Per

 

[pm_dawn]

Hi !

OK i have now done a first test on one singel Headway 10ah cell the "S" version.
I chareged it standard Life with my BT-a610 3.0 A charge rate. When full I put the cell in the freezer overnight to really let it get frozen.
Then I ran a standard discharge with the BT @3.2A to test the capasity when cold. It gave me a result of 7.2Ah down to 2.0V.
After that I took the cell out of the freezer and did another discharge @3.2A it gave med another 1.75ah.
I have after that tested the cell in room temperature (18deg Celsius) and get 9ah from the cell.

So from my little test I would say that the will deliver 80% at 0.3C in -18degC.
And the other 20% can be delivered if I take the temp up to room temp again.

I know this is a low discharge rate but I can not go higher than 5A, and I will do that test also.
But for my application it was the real deal. running an xenon headlight for enduro riding will pull about 3 amps.

I will do some more tests with the cell monitor logging the discharge also.

Thats all for now.
Anyone else tested there headways ?
I thought I would get 10ah from it but only got 9, do I have to brake them in ?

Best Regards
/Per