DIY Electric Car Forums banner
1 - 4 of 4 Posts

·
Registered
Joined
·
86 Posts
Discussion Starter · #1 ·
So, I am looking to replace my 44, 8 year old Thundersky 100aH cells in my Bug with an equivalent prismatic LiFePO4 cell. The TS are still useful, but I think it may be prudent to make a change before it gets too late. Plus I may use the TS cells as a "powerwall" setup. I am not interested in Leaf, Tesla, 18650 etc. Because I don't want to reconfigure anything, or buy new components to accommodate a different tell type or configuration.
I have an opportunity to purchase some VERY low use(less than 200 miles and under 30 cycles) Calb CA100 cells from a forum member here. He has been conducting capacity tests on them and thus far has determined they are around 100ish aH each. They are almost 5 years old, and have sat unused at no more than 90% charged for the majority of their life.
Questions;
1. How concerned should I be with their remaining life span of these used Calbs?
2. How long should I expect they will last from this point on?
3. What is a fair price for cells I this condition?
My 7+ year old ThunderSky have around 50,000 miles on them(the first 14,000 were pretty abused, the last 36K from me have been very gentle), and they could probably last me another 5-10k of easy driving. So I don't need to replace right away, but also don't want to pay for new ones if not needed yet.
Does anyone out there have a set of Calbs and can chime in one their experience, and how many miles/years they have on them?
 

·
Registered
Joined
·
86 Posts
Discussion Starter · #3 ·
Thanks John...so that would be around $30 per cell. What is the expected calendar life of these cells if used properly? The seller is being very open about the cell testing by providing cellpro 6 screenshots with charge/discharge and resistance readings etc.
 

·
Registered
Joined
·
86 Posts
Discussion Starter · #5 · (Edited)
Thanks Matt, solid advice. I saw the Jehu video you reference, slightly unscientific analysis of his cells with some motivation for selling purposes. However, he had some good points. As for the seller, yes he is who you think since I have seen where you had some posts on his for sale thread. He is definitely testing them because his screenshots are with the current dates, plus I have no reason to doubt him.
As for price, yeah, we tentatively agreed on a price, but I want to insure my outlay of funds are going to give me a pretty good return on investment vs buying new Calbs, so I am seeking anyone here who has experience with long term use or storage compared to capacity degradation.
There is a really good dissertation i found online with scientific capacity testing of cell degradation due to temperature and calendar capacity loss.
https://www.google.com/url?sa=t&source=web&rct=j&url=https://uwspace.uwaterloo.ca/bitstream/handle/10012/12177/Catton_John.pdf%3Fsequence%3D3&ved=2ahUKEwj5p6Gf2p_cAhUGRKwKHeRbBYgQFjAEegQIBBAB&usg=AOvVaw3OUJjrq3GnnWwy52qjWw0g
 

·
Registered
Joined
·
86 Posts
Discussion Starter · #8 ·
Mike,

I plan on performing a capacity test on my TS cells after they are removed. That will take me a few weeks. I can get back with you afterwards. I may build a powerwall, so I will need to see how many cells I need to keep. I have 44 in my car and some extras as well.

Steve

PM me if I forget!
 
1 - 4 of 4 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top