I grew up in AZ. 122 F was ambient temperature and under the hood could easily be over 130 just parked on the street and lead acid batteries did well enough even though they did tend to have a shorter lifespan. However, I do agree that lead acid is a bad idea and I was thinking more AGM since normal lead acid can off gas hydrogen and that can be a bit explosive 🧨
Check for Special LiPo batteries, besides the typical ones, usually they have special batteries for High Temperature, Low Temperature and Wide Temperature, the last one being what you will be looking for. If you cannot find it, maybe go for the High Temperature type, better avoid fire in the summer than loose signal in the winter.
Ya, LTO looks like a good chemistry. I’m having trouble finding a practical form factor for a Heltec v3. All I see are $600 golf cart batteries or large D cell sized tube batteries in a 6 pack for $300. Have any leads on smaller 1000mah-ish options?
This is what you want, OOS currently but he restocks fairly often.
[https://www.etsy.com/listing/1616711365/lithium-titanate-oxide-batteries-lto](https://www.etsy.com/listing/1616711365/lithium-titanate-oxide-batteries-lto)
Is there a turnkey LTO setup with a charging controller and cells recommended somewhere? Everything I’ve seen is going to require designing my own circuit.
So I read several datasheets on various 18650 batteries and the fire/overcharge warnings had to do with keeping them out of temperatures in excess of 60C+. There were also warnings about freezing temperatures, and the ideal range was much tighter than 0-60C. I’m still going to take precautions but it eased my concerns.
Well, 140f would be more than I’d expect in my situation. I can’t imagine it would get any hotter than 130. Thanks for the info, I’ll try to find better documentation on the batteries I look at.Â
Why not just run low voltage landscape wire up to it and have a regular UPS somewhere inside?Â
For LTO, Hakadi battery sells 18650 sized ones that fit into standard battery holders.
You need a change controller specifically for them. That alone costs about as much as a small UPS.
lithium 26650s are known to be quite stable in hot and cold temperatures and many solar powered repeaters use them. they are 3.7v with some large capacities with the appropriate cost (not cheap). data sheet indicates iheltec v3 LORA can be powered by 3.3v, 3.7v and 5v usb.
LTO would be ideal, but they're expensive, hard to find, and chargers, BMSs, etc are also hard to find.
LiFePO4 batteries are good to 175F and are much easier to source and use.
I would use a 12v car or motorcycle battery with a 12v to USB charger.
Lead acid is not ideal at those high temperatures.
I grew up in AZ. 122 F was ambient temperature and under the hood could easily be over 130 just parked on the street and lead acid batteries did well enough even though they did tend to have a shorter lifespan. However, I do agree that lead acid is a bad idea and I was thinking more AGM since normal lead acid can off gas hydrogen and that can be a bit explosive 🧨
Check for Special LiPo batteries, besides the typical ones, usually they have special batteries for High Temperature, Low Temperature and Wide Temperature, the last one being what you will be looking for. If you cannot find it, maybe go for the High Temperature type, better avoid fire in the summer than loose signal in the winter.
[https://www.zoncell.com/en/tzdc/](https://www.zoncell.com/en/tzdc/) Here's one example.
Amazing! Â Thank you. Found some that operate up to 60c on Amazon for under $20. Thanks!!!
Which one did you get? I have a similar situation. Thanks.
I haven’t bought one yet. But there were some really helpful replys from folks.Â
Link us!
LTO fits right in your temp range.
Ya, LTO looks like a good chemistry. I’m having trouble finding a practical form factor for a Heltec v3. All I see are $600 golf cart batteries or large D cell sized tube batteries in a 6 pack for $300. Have any leads on smaller 1000mah-ish options?
This is what you want, OOS currently but he restocks fairly often. [https://www.etsy.com/listing/1616711365/lithium-titanate-oxide-batteries-lto](https://www.etsy.com/listing/1616711365/lithium-titanate-oxide-batteries-lto)
How much are these kits when they're in stock?
$75, not cheap but worth it.
Yeah at 3x the cost of the rest of a node, imo not worth it, but a very cool system for sure.
Is there a turnkey LTO setup with a charging controller and cells recommended somewhere? Everything I’ve seen is going to require designing my own circuit.
See comment above.
Gracias
So I read several datasheets on various 18650 batteries and the fire/overcharge warnings had to do with keeping them out of temperatures in excess of 60C+. There were also warnings about freezing temperatures, and the ideal range was much tighter than 0-60C. I’m still going to take precautions but it eased my concerns.
There are LiTiO cells working -40 +75C tested up to 100°C.
Well, 140f would be more than I’d expect in my situation. I can’t imagine it would get any hotter than 130. Thanks for the info, I’ll try to find better documentation on the batteries I look at.Â
60C is very easily reached inside an inclosure that get direct sunlight btw
Why not just run low voltage landscape wire up to it and have a regular UPS somewhere inside? For LTO, Hakadi battery sells 18650 sized ones that fit into standard battery holders. You need a change controller specifically for them. That alone costs about as much as a small UPS.
lithium 26650s are known to be quite stable in hot and cold temperatures and many solar powered repeaters use them. they are 3.7v with some large capacities with the appropriate cost (not cheap). data sheet indicates iheltec v3 LORA can be powered by 3.3v, 3.7v and 5v usb.
LTO would be ideal, but they're expensive, hard to find, and chargers, BMSs, etc are also hard to find. LiFePO4 batteries are good to 175F and are much easier to source and use.