Hi,
Just had a customer ask “would there be any reliability concerns or poor performance using the Sofirn SP40 in the snow?”.
Will there be any issue or lower output in cold weather? I’ve never thought to ask about this before
Should work better if anything! Just be careful that the cell itself doesn’t stay very cold for long periods particularly while on low charge.
When most li-ion cells cold pretty cold their voltage drops, and that means output will too. It’s why I prefer lights with boost drivers as they can step the voltage up and still perform almost like normal.
There are cold weather li-ion cells out there but they’re expensive. If you’re not using it in temps below freezing I wouldn’t worry too much.
One or more reserve batteries can be carried under the clothing, for example in the type of money-belt/waist pouch sold in outdoor shops.
The lamp in question is a headlamp and there are several headlamp models with a remote belt-pack - intended specifically to allow the batteries to be kept warm in cold weather.
Most types of batteries don’t like the cold.
Okay, thanks for the input.
I’ll probably let him know it’ll better better to get a headlamp that uses primaries for best reliability. Gets to –4°C where he’s wanting to use it so I can’t give him a definite answer with standard lithium
You can get low temp lithium cells that are fine til –30 or –40C.
Other than less capacity there really is no problem using lithium cells in 0C temps, that’s not that cold, plus the heat from the LED and the cell itself will definitely keep it warm.
This is one I frequently see on AliExpress:
https://www.aliexpress.com/item/4000017407527.html
“Drive electronic devices in low temperature environments even at –40C”
I appreciate it, I’ll pass it on.
He ended up buying it anyway despite saying use a light that uses primaries. I guess it’s the cheap Sofirn price compared to many other brands
A Google search reveals several vendors offering this product (at circa $30), but not too many independent tests or much user feedback.
I did find a test of the 2018 version of the battery by a knowledgeable and respected member of this forum, and I quote his conclusion:
“The battery is a good quality LiIon battery and it sort of works in the cold. The ”sort of” is because it need to heat itself up to get some performance”.
My attempt to link to the full test doesn’t appear to work, but it can be found by going here: List of tested batteries
…….and scrolling down to Nitecore 18650 2900mAh NL1829LTHP (Black-yellow)
In addition, here is a warning (on same battery) quoted from a vendor’s website (illumn.com):
PLEASE NOTE:
LOW TEMPERATURES AT –40F WILL STILL REDUCE CAPACITY BY 30% OR MORE AND REDUCE OUTPUT CAPABILITY TO 0.58A.
THE BEST WAY TO INCREASE PERFORMANCE AND LONGEVITY IS TO WARM THE BATTERY ABOVE –4F
DO NOT CHARGE THIS BATTERY WHEN IT IS BELOW 0C, PLEASE WARM THE BATTERY UP FIRST.
So the buyer can pay “sort of” $30 for a battery which “sort of” works in the cold - and perhaps he/she will be “sort of” happy with its performance.
If anything –4 probably just causes higher average brightness on high mode. Iirc the turbo mode of the sp40 was time limited but it still got warm on high mode.
I had the best experience when using my Xhp50.2 FT03 in –10 to –15. It allowed it to sustain 100% output without worrying about too much heat.
The question is regarding –4 celcius.
Is there a better choice if you want 20 lumens for 2 hours? 20 hours?
Is there a better choice if you want 100 lumens for 2 hours? 6 hours?
Is there a better choice if you want 300 lumens for 2 hours? I think the answer is an 18650 type headlight is better then any of the wimpy little things using primary lithium batteries even at lower temperatures than that.
I am not sure if that test completely applies to this battery - although some considerations may be similar - because the product I linked is not the NL1829LTHP but the NL1829RLTP. This seems to be a newer version of that cell.
However, I admit some conclusions may be the same :+1:
I stand corrected! I copy/pasted the model designation from The Ali Express site into Google and somehow the HKJ test came up, after having scrolled through dozens of vendors.
Nonetheless, it appears to be basically the same battery with the addition of USB charging (same manufacturer, same capacity, and the same designation except for the “R” - which is presumably for “rechargeable”) - the current 2020 version of the one HKJ tested in 2018, although the new one is rated at 5A, whereas the older one was 8A.
Having said that, I would be absolutely delighted if battery technology could provide us with cells which work reliably at very low ambient temperatures. I remain sceptical, however, and until I’m convinced otherwise, I’ll use a headlamp with its belt-pack carried under my clothing next to my tummy. It’s very low-tech - but it works!
Yeah –4 C isn’t even the kind of temps I’d start to worrying about keeping my batteries warm. Leaving a light in the car in the winter at –20 to –30 C and then expecting it to work flawlessly when needed is the kind of thing to be concerned about and where lithium primaries become a good option to have as a backup.
My research shows –40c minimum operating temperatures for some lithium-ion (most? are –20c). Lithium primary batteries are –40c. So some in really cold environments probably should look into the cold temperature lithium-ions.
- –4F is –20C which is VERY cold, so unless you live in northern canada or russia getting to the –30 or –40C, the cells will work fine.
2) As you may have read, the main issue with cold temps is charging the batteries, not discharging. You can damage them by trying to charge at low temps, but discharging simply has reduced performance.
3) It does not “sort of work” it works as you would expect. All lithium cells perform better at higher temperatures, but you don’t see people heating up their cells with a heatgun to get an extra 10% output do you?
4) I was mainly talking about 0C to –10C temps in my post, so a normal amount of snow and cold, and at those temps you won’t see anywhere near 30% capacity decrease.
5) when discharging a cell it will heat itself up, so that plus the insulation from the flashlight tube plus LED heat will mean that the cell itself will be quite a bit warmer than exterior temperatures after a few minutes of runtime.
6) If you’re so concerned about reduced capacity you can simply pay more for a higher capacity 3500mAh cell with high discharge rates.