Author Topic: Lipo powered Lipo warmer?  (Read 396 times)

0 Members and 1 Guest are viewing this topic.

Offline Zeecue

  • Contributor
  • Posts: 15
  • Country: dk
Lipo powered Lipo warmer?
« on: November 29, 2018, 09:53:53 pm »
Hi

As I have quite a few powertool batteries that don't like to be cold and perform at the same time I was thinking about making a warmer/heater for them.
The batteries I'll use for the "supply" is Makita 18V 4-9AH batteries.
I was thinking about using a PTC heater, most I can find is 12V or 24V with a set temperatue at 60-120 degrees C, but how will they perform on a 18V supply?
A temperature at around 20 degrees Celsius would be my target temperature.
Any inputs will be appreciated.
And thanks to the nice people on the Eevblog IRC channel for helping me so far.

Sent from my MI 8 Explorer Edition using Tapatalk

 

Offline spec

  • Frequent Contributor
  • **
  • Posts: 833
  • Country: england
  • MALE
Re: Lipo powered Lipo warmer?
« Reply #1 on: November 30, 2018, 10:31:06 am »
Hi Zeecue,

Presumably you don't like using LiPo batteries at a low temperatures because you are concerned about stressing, or even damaging them. If that is the case, don't worry.

So long as the batteries are above a critical temperature, which IIRC is around 0 degC (TBC), they will be fine.

A lower temperature does mean that the battery will have less capacity, its terminal voltage will be lower, and its internal resistance will increase, but not enough to cause a problem in most applications.

But the ironic thing is that batteries self-heat anyway when they are sourcing current, especially in power tools, so effectively there is a heater already built in. It's the battery core temperature that counts, not the case temperature, although the two are related.

In general, with most components, the biggest negative impact on reliability is temperature.

If you would like further information on batteries, including LiPo, just Google, Battery University for a well-written guide.

PS: In certain products like, mobile phones, e-cigarettes, laptops, and power tools, the batteries have a hard time. The charging and discharging regime is designed to give maximum capacity, rather than good battery life, so in these applications battery life is quite limited anyway.
« Last Edit: November 30, 2018, 10:50:56 am by spec »
 

Offline beanflying

  • Super Contributor
  • ***
  • Posts: 5055
  • Country: au
  • Toys so very many Toys.
Re: Lipo powered Lipo warmer?
« Reply #2 on: November 30, 2018, 10:46:02 am »

A temperature at around 20 degrees Celsius would be my target temperature.
Any inputs will be appreciated.
....

Move to a better climate  ;D

I wouldn't worry about them when in use unless that use will be light and sporadic as mentioned in the last post they will self heat internally in reasonable use. You want to keep them stored prior to use as you suggest circa 20C would be a good place to start. Grab one of these and run it off a car or plugpack and not waste your power tool batteries https://www.ebay.com.au/itm/12v-Portable-Car-Fridge-Cooler-Warmer-Thermoelectric-Camping-Caravan-7-Liter/253999514149?hash=item3b238d0225:g:6wcAAOSw~bhb-7se:rk:9:pf:0
Coffee, Food, R/C and electronics nerd in no particular order :)
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf