5 ms·

Lead acid is traditionally very forgiving with regards to temperature. How does the electrical performance of your battery vary with temperature, especially at

by krapht 11y ago

Lead acid is traditionally very forgiving with regards to temperature. How does the electrical performance of your battery vary with temperature, especially at extremely cold (-40C) and extremely hot (80C) conditions?

busterarm 11y ago
Exactly what I was thinking... ...and more on that point, I drive an RX-7 and my engine puts out _extreme_ amounts of heat under the hood. a 50C top-end probably isn't enough for driving on hot days. I would go for one of these without a second thought because a) though my car is light, reducing more weight helps out loads with performance and b) these things are known to kill alternators and I'd love advance warning of when I might end up stranded without having to test the battery's volts every day. I'd love to demo one of these.
- thrownaway2424 11y ago
  Battery relocation to the trunk is a standard mod for the gen3 rx-7, assuming you're speaking of that one.
  - busterarm 11y ago
    FC, but yeah I have a lot to do. I haven't done it yet because it's a 10AE and basically clean. Still would want a lighter battery though.
conjecTech 11y ago
Hey, co-founder here. It's very forgiving to temperature. Supercapacitors don't store energy using a chemical reaction, which make them a lot less finicky. On the low side, our power architecture also allows us to boost the voltage slightly if we sense that its cold outside, so we can account for the increase in resistance. It's also still go superior lifetime at high temps as well.
- chillingeffect 11y ago
  fwiw, Wikipedia says "The lifetime of supercapacitors depends mainly on the capacitor temperature and the voltage applied." [ 1 ] This picture shows a 10x decrease in life when the temp varies from 25C to 65C: https://en.wikipedia.org/wiki/File:EDLC-Life_time_curves.png https://en.wikipedia.org/wiki/File:EDLC-Life_time_curves.png [ 1 ] https://en.wikipedia.org/wiki/Supercapacitor https://en.wikipedia.org/wiki/Supercapacitor EDIT: I'm not trying to inject bad feelings here or contradict Ohm. I'm just clarifying the effect of temperature on supercap life. There is some effect on cap lifetime at high temps. I hope the product succeeds. I know sailors have using lithium batteries for a while now, but as mentioned elsewhere, they are shockingly expensive (like $6k).
  - deleted 11y ago
    [deleted]
  - conjecTech 11y ago
    Thanks for the comment. It is something we need to look into a bit more. Generally we haven't seen the capacitors be the limiting factor in lifetime, but they might be in extremely hot situations. I'll do some more work on getting a definite answer here so we can be more careful/specific about our claims in the future.
slxh 11y ago
but I think that lead-acid batteries can become damaged if you bring the charge below a certain value... usually not a problem with cars but...

by krapht 11y ago

busterarm 11y ago

Exactly what I was thinking... ...and more on that point, I drive an RX-7 and my engine puts out _extreme_ amounts of heat under the hood. a 50C top-end probably isn't enough for driving on hot days. I would go for one of these without a second thought because a) though my car is light, reducing more weight helps out loads with performance and b) these things are known to kill alternators and I'd love advance warning of when I might end up stranded without having to test the battery's volts every day. I'd love to demo one of these.

thrownaway2424 11y ago
Battery relocation to the trunk is a standard mod for the gen3 rx-7, assuming you're speaking of that one.
- busterarm 11y ago
  FC, but yeah I have a lot to do. I haven't done it yet because it's a 10AE and basically clean. Still would want a lighter battery though.

conjecTech 11y ago

Hey, co-founder here. It's very forgiving to temperature. Supercapacitors don't store energy using a chemical reaction, which make them a lot less finicky. On the low side, our power architecture also allows us to boost the voltage slightly if we sense that its cold outside, so we can account for the increase in resistance. It's also still go superior lifetime at high temps as well.

chillingeffect 11y ago
fwiw, Wikipedia says "The lifetime of supercapacitors depends mainly on the capacitor temperature and the voltage applied." [ 1 ] This picture shows a 10x decrease in life when the temp varies from 25C to 65C: https://en.wikipedia.org/wiki/File:EDLC-Life_time_curves.png https://en.wikipedia.org/wiki/File:EDLC-Life_time_curves.png [ 1 ] https://en.wikipedia.org/wiki/Supercapacitor https://en.wikipedia.org/wiki/Supercapacitor EDIT: I'm not trying to inject bad feelings here or contradict Ohm. I'm just clarifying the effect of temperature on supercap life. There is some effect on cap lifetime at high temps. I hope the product succeeds. I know sailors have using lithium batteries for a while now, but as mentioned elsewhere, they are shockingly expensive (like $6k).
- deleted 11y ago
  [deleted]
- conjecTech 11y ago
  Thanks for the comment. It is something we need to look into a bit more. Generally we haven't seen the capacitors be the limiting factor in lifetime, but they might be in extremely hot situations. I'll do some more work on getting a definite answer here so we can be more careful/specific about our claims in the future.

slxh 11y ago

but I think that lead-acid batteries can become damaged if you bring the charge below a certain value... usually not a problem with cars but...