[itchyback]

I have 16 tesla modules currently at 22.5v each. max i understand is 25v.
I'm looking for a charger to keep them alive while i finish my build. a golf cart charger or similar. can anyone recommend something in particular?

 

[Duncan]

Hi
I would just get a variable power supply - I got one off TradeMe (NZ EBay) for $60 - can be used for all sorts of things

Don't actually use it - just use your multimeter every month to check (after a few months drop the checking frequency)

My Volt pack sat around for about 8 months - still fine

The last module that would not fit in the device sat for an additional two years and it was still in the middle of the charge range when I gave it away

 

[jhuebner]

And remember to not have them lurking around fully charged, will wear out the electrolyte.

Lithium self discharge is amazingly low

 

[favguy]

Find the voltage range of the cells, then discharge to the 60% charged voltage figure. Store the cells somewhere cool and your cells will then sit for years if needed with negligible degradation. Check periodically with a voltmeter just in case, but you're unlikely to see any change in voltage and almost certainly won't need to charge them.

 

[Jimbo69ny]

Find the voltage range of the cells, then discharge to the 60% charged voltage figure. Store the cells somewhere cool and your cells will then sit for years if needed without any degradation. Check periodically with a voltmeter just in case, but you're unlikely to see any change in voltage and almost certainly won't need to charge them.

Mine are being stored cool. I live in Central NY and they are in my unheated garage. haha

 

[itchyback]

Thanks for the feedback. I wondered if i need a special charger. Cheapest i found was $200aud. More than i wanted to spend but $60nzd is doable. I need to research 'charging curves'.
Theyre kept under a thick blanket in a coolish garage. 22.5v is a about 62%. So theyre probably close to optimal s.o.c. ill check regularly for now and get a charger soon. Theyve been sitting 12months so far. Id better get a wriggle on!

 

[boekel]

Just monitor, the're already at a good storage voltage.

Most important with the Tesla modules: moisture / dirt. keep 'm dry!!

 

[rbzig]

I have a pack out of a Think Car. The pack is 8 years old and counting. The batteries are still in the original shipping container. Never charged and still right in the middle of there charge. All 3.44 some 3.43 volts. The range is 4.1 high 2.5 low.

 

[dtbaker]

batteries in a box will keep for years.... batteries in a pack with a monitoring system connected will experience parasitic drain over time and go flat unless charged periodically.

 

[Hondo8]

I have 16 tesla modules currently at 22.5v each. max i understand is 25v.
I'm looking for a charger to keep them alive while i finish my build. a golf cart charger or similar. can anyone recommend something in particular?

Solar may not be what you are looking for, however Will P at https://www.youtube.com/watch?v=kF_cVEYxj3E&t=204s , has several examples of simple chargers, and a good knowledge of Tesla module charge limitations. As I remember the cheap charge controllers can keep the battery modules between 24 and 92% with an Amazon solar panel for maintenance purposes.

 

[dtbaker]

Solar may not be what you are looking for, however Will P at https://www.youtube.com/watch?v=kF_cVEYxj3E&t=204s , has several examples of simple chargers, and a good knowledge of Tesla module charge limitations. As I remember the cheap charge controllers can keep the battery modules between 24 and 92% with an Amazon solar panel for maintenance purposes.

if Lithium batteries are disconnected from all parasitic loads (like BMS and environmental heat/cooling) there is almost no self-discharge. So, if the batteries are disconnected from all external loads, don't worry about it.