5p of p45’s seemed like plenty for 14kw
2 Likes
I agree. The P50B won’t be available for months and only in very limited quantities so I don’t think that’s being considered by any retailers. Demand for the P42A and P45B is dropping as the initial excitement for these cells is fading and, as you mentioned, there are new extreme power cells coming to market and two of the best we can buy are already available…the JP40 and 40PL.
The 40TG and others are around too in limited quantities. So probably a combo of just time and new cells floating around (more just time IMO) pushing prices down.
7 Likes
Do people care about an extra 1/8 capacity from Bak 45D?
If 40TG performs somewhat competitively it would be worth waiting 20 more days for the €2.6 pc.
You do a fantastic job with having all the data it’s going to be great for the 5 different high current 4Ah. If you really need I can send you the Bak 45D from Nkon and I’ll get redemption for the case.
6 Likes
That would be awesome! PM being sent. Thank you!
3 Likes
With them being so cheap to get at the moment I am heavily considering building a small pack with them to see how they fare. I might be able to get the board up and running for it in a month or so if all goes well.
4 Likes
I have some on the way for Mooch but it would unfortunately take a few weeks or so for them to arrive and for me to get back then for them to get to Mooch.
It would be great to see how they compare and perform for you.
6 Likes
Looks like the JP40 US distributor added some cycle life testing data.
I’ve ordered 22 JP40’s, for a modest 10s2p pack.
Thanks for posting that.
Wow, that is a confusing pile of data to pour through. He loves that though, creating all sorts of variations. We’ll see if it leads to any practical conclusions about these cells or if he adds comparisons with other cells.
2 Likes
I was literally about to do that myself for a 10s2p pack, however I was informed the cells on the market are lower quality leaked cells. Bak 45ds coming soon though.
Well, that’s a kick in the balls if true.
The P45b was also in my sights, and a bit cheaper.
The 10s2p battery the JP40’s will be replacing was getting way too hot.
I temporarily slapped a newly finished p42a 10s1p in there, and still cant believe the torque increase.
However, it too is getting to hot. 52.8C on exterior heatshrink after a 4.19v to 3.23v drain.
Wish I could reliably measure cell resistance.
I’ve also heard that the JP40’s that are available now are pre-production and/or lower grade samples. But all the great test results everyone has been getting has been with those cells. No one has a higher grade JP40 to compare these against.
A lower grade cell, unless a total piece of junk, is typically just little lower in capacity and a little higher in internal resistance with perhaps a bit faster self-discharge. The difference is often not noticeable in actual use. They’re not “low quality” cells unless C Grade or lower and those are actually very hard to find as the manufacturers recycle those.
I don’t know what the full cycle life of these JP40’s is but so far they are holding up well in the testing I am doing for my Patreon supporters.
5 Likes
If it might help, all my test reports and the Ratings & Performance tables include the DC IR.
3 Likes
$4.75ea for jp40 21700.
I just grabbed a bunch
3 Likes
I have them and many more coming in few weeks. http ://diy500amp.store/products/ampace-jp40-cells
1 Like
Sorry if this was already mentioned, but I tested the JP40 about a month ago. Amazing cell.
Yep, it beats both the P50B and the EVE 40PL.
I also just made a spreadsheet and graphs of all my test results.
I tested it. Not super exciting.
On every parameter the JP40 outperformed it.
However the BAK did do a little better than the EVE 40PL on most tests.
Ampace for now is, by a pretty good margin, the best performing high-load 21700 in the world. I put my money where my mouth is and bought 200 of them for my next Surron pack.
4 Likes
The cycle life chart shows them being cycled to really low capacity which I’ve never seen.
If they’d been just cycled to 90% capacity I wonder how many cycles they’d get. Doesn’t look good
2 Likes
End-of-life at 60% is a pretty common spec for higher current cycling. Most of the big cycle life numbers we see are for verrrrry low current levels.
1500 cycles to 80% at a moderate power level is pretty darn good cycle life IMO.
Also, the cycle life numbers are just guaranteed minimums. I’ve been getting more than double those numbers in the abusive cycle life testing I’ve been doing for my Patreon supporters.
For example, the Samsung 50S was rated at 250 cycles for some end-of-life capacity loss (forgot what it was). This probably sounds terrible to a lot of people. But I had less than 1/2 of that capacity loss after 250 of those cycles.
7 Likes
I thought cells were considered at their end of life at 90% or 80%. Don’t they become more dangerous at 60%, Or lower?
1 Like
Do you think the released to market JP40 cells are good/safe enough to use in a pack? Or is it still too early to say?