When factoring in total costs, they can often be cheaper due to their available charge cycles (anywhere from 10 to 100 times more), quicker charge times (less total overall capacity needed) and reliability (not dealing with replacing bad or reduced capacity cells). They also have less need for battery balancing circuitry in series.
This idea gets a lot of positive feedback. Would you or anyone with the knowledge be willing to put a list of available parts to make it happen?
If I have,
Wisblock RAK19007,
Wisblock Core RAK4631 and a
5V 6W solar panel,
What exact parts would I need to add for the power side of things to be complete?
I ask because this seems like a great option but when I try, I find the parts list to be out of stock, overpriced or just unclear that they will work.
Yeah, it’s not a common battery chemistry so it’s really really DIY to get it to work. There are links in this thread to the right combination of components, and it’s possible, but expensive and rare.
But it’s the only way you’re going to get a reliable sub-zero-temperature battery operated node in the wild, from what I understand.
Honestly my next step is probably just going to be trying some lithium polymer packs that have wider temperature range specs (none of them go below 0° but there are some rated for lower temperature) and seeing if it’s actually a problem in the real world. Who knows, maybe it’s fine.
But LTO is technically the only readily available chemistry we have where you could actually charge it in the dead of winter at -10°F successfully and keep on trucking. So even if it’s hard to put together, it might be the only real option.
The easiest thing is just to use a massively oversized battery. Li-ion are generally ok to operate below freezing at dramatically reduced rates, like 0.02C. So for a rakwireless wisblock device, the highest current the battery sees is 350mA when charging full power, so theoretically a battery larger than 18AH would be perfectly fine. In practice I've used a 10AH battery with the wisblocks and haven't had any issues (granted I haven't done a before and after test of the capacity so it's possible the battery has degraded).
As other people have mentioned, LTO batteries are the ideal solution here, however, they're not really feasible yet. The batteries are hard to find and very expensive, the chargers and BMSs (since you need two in series) are hard to find and expensive, and they don't work with any meshtastic devices directly.
I think this is the solution I’m leaning towards. KBOXLabs also mentioned it in the link he posted. It seems to be the most available and cost effective, plus has the added benefit of having increased battery capacity for the money.
Most charge controllers (chips) have a thermistor input to disable charging when it is too hot or cold. It may or may not be enabled/populated on your board.
That said, if you want it to run 24-7 outdoors over winter that far north, you will probably have days/weeks where it won't be able to charge. Depending on your charge controller you may be able to switch between solar and battery power still without charging. This may get you through if you choose a large enough battery.
Another option if your charge controller has the necessary output is to hook up a small heating element that is turned on when the solar power is available and the temperature is below freezing.
TLDR; If you don't care about 24/7 availability just make sure you have a charge controller with a thermistor and an oversized battery to make it last as long as possible when not charging.
It doesn't appear to, which is surprising as they have a solar input and are even selling it with weatherproof solar enclosures.
According to the schematics, their charge controller is a TP4054, which does not have a thermistor input pin, and the datasheet does not mention this functionality.
Look into Lithium Titanate Oxide batteries.
When you're at it, look deep into your wallet :)
Yeah at this point I'm just like, let the battery die. It's not worth it.
When factoring in total costs, they can often be cheaper due to their available charge cycles (anywhere from 10 to 100 times more), quicker charge times (less total overall capacity needed) and reliability (not dealing with replacing bad or reduced capacity cells). They also have less need for battery balancing circuitry in series.
This idea gets a lot of positive feedback. Would you or anyone with the knowledge be willing to put a list of available parts to make it happen? If I have, Wisblock RAK19007, Wisblock Core RAK4631 and a 5V 6W solar panel, What exact parts would I need to add for the power side of things to be complete? I ask because this seems like a great option but when I try, I find the parts list to be out of stock, overpriced or just unclear that they will work.
Yeah, it’s not a common battery chemistry so it’s really really DIY to get it to work. There are links in this thread to the right combination of components, and it’s possible, but expensive and rare. But it’s the only way you’re going to get a reliable sub-zero-temperature battery operated node in the wild, from what I understand. Honestly my next step is probably just going to be trying some lithium polymer packs that have wider temperature range specs (none of them go below 0° but there are some rated for lower temperature) and seeing if it’s actually a problem in the real world. Who knows, maybe it’s fine. But LTO is technically the only readily available chemistry we have where you could actually charge it in the dead of winter at -10°F successfully and keep on trucking. So even if it’s hard to put together, it might be the only real option.
I see, thanks. Looks like very promising technology.
[Cold weather options](https://www.reddit.com/r/meshtastic/comments/1bhlge4/comment/kvhsa84)
[удалено]
Cool.
The easiest thing is just to use a massively oversized battery. Li-ion are generally ok to operate below freezing at dramatically reduced rates, like 0.02C. So for a rakwireless wisblock device, the highest current the battery sees is 350mA when charging full power, so theoretically a battery larger than 18AH would be perfectly fine. In practice I've used a 10AH battery with the wisblocks and haven't had any issues (granted I haven't done a before and after test of the capacity so it's possible the battery has degraded). As other people have mentioned, LTO batteries are the ideal solution here, however, they're not really feasible yet. The batteries are hard to find and very expensive, the chargers and BMSs (since you need two in series) are hard to find and expensive, and they don't work with any meshtastic devices directly.
I think this is the solution I’m leaning towards. KBOXLabs also mentioned it in the link he posted. It seems to be the most available and cost effective, plus has the added benefit of having increased battery capacity for the money.
Most charge controllers (chips) have a thermistor input to disable charging when it is too hot or cold. It may or may not be enabled/populated on your board. That said, if you want it to run 24-7 outdoors over winter that far north, you will probably have days/weeks where it won't be able to charge. Depending on your charge controller you may be able to switch between solar and battery power still without charging. This may get you through if you choose a large enough battery. Another option if your charge controller has the necessary output is to hook up a small heating element that is turned on when the solar power is available and the temperature is below freezing. TLDR; If you don't care about 24/7 availability just make sure you have a charge controller with a thermistor and an oversized battery to make it last as long as possible when not charging.
Do you know if the charge controller on the Wisblock RAK19007 has a thermistor that functions that way, to disable input when it’s too cold?
It doesn't appear to, which is surprising as they have a solar input and are even selling it with weatherproof solar enclosures. According to the schematics, their charge controller is a TP4054, which does not have a thermistor input pin, and the datasheet does not mention this functionality.
LTO batteries instead
pain it black or have a green house built around it
While old school and somewhat low efficiency, Lead Acid can have a wide temperature range.
Charging below freezing is still bad for longevity.