Alternative Battery packs

tentman

10 mW
Joined
Mar 4, 2018
Messages
25
Hello Guys

Down here in New Zealand we seem to pay more for everthing,and I assure you its not by choice!

The most cost effective packs I can find here are from Luna, and bless them, their packs are about NZ$1140 per kWh. High quality cells are about $13 each.

So I've been on the hunt for some time for a less expensive alternative and an interesting one has just come up.

Hitachi offer a backpack style power pack at 36V and 21 Ah, and from thier literature I believe it uses Samsung INR21700-40T cells, I assume 52 as these cells are 4000 mAh?? Any other thoughts on the number and configuration of the cells? Best of all this pack can be had here for NZ$660, which makes it very modestly priced at NZ$880 per kWh. For ebike use I think I would strip the pack from the back pack and repackage it. Would it be possible to reverse engineer/configure a charger for this pack that would give me recharging options like 80% etc.??
 
Have you considered DIY with loose cells from Queen Battery etc? There are some very promising options coming out these days.
 
I don't know how that translates into USD in relation to the cost of living in NZ versus the USA..

But i started this hobby out with a huge money restriction and also went the suggested route of a DIY battery pack.
Buying the things to measure and match cells in the pack, materials, tools, etc increased the cost of the first pack, but made the subsequent ones very cheap to build.

Manual balancing and avoiding the issue of a BMS reduced the cost as well.

Hitachi may lock you out of doing out of the box things with the BMS. This is becoming more common. You should factor in the cost of a nice BMS to the Hitachi pack in case the stock one decides to tell you to F off ;)
 
I'd also do some investigation into how easy or not it is to disassemble that pack. The cells might all be potted together or something like that, so getting them apart might not be that simple. I'd try to find a video of someone taking it apart before you invest too heavily.
 
Can't you just order the cells from nkon?

If i order 80 30q's from nkon it ends up being $5.21 AUD per cell and i imagine it would be almost the same in NZD
 
What voltage & capacity pack do you need ?
Personally, i would keep it intact as a backpack ( i run 36-42 v system). and prefer to use a backpack set up anyway,
Other options..
Tumic , in the sales section...sells both single sells (various brands) , v cheap, ....also premade 36v, 14ah packs for approx $200.. Sanyo and LG cells.. Cheap shipping, and a reliable supplier.
https://endless-sphere.com/forums/viewtopic.php?f=31&t=61608
 
I ordered 120 Panasonic PF cells from NKON. They ended up 4NZD each including shipping.

If you want a 36v 20Ah pack you would need 70 of these (10S7P, 70A discharge) and they will be 335NZD shipped or 4.7NZD each.

https://ru.nkon.nl/

As for a charger, you can get something like this 42v 4A charger and adjust the output voltage trim pot down so the terminal voltage is 41V instead of 42V. This would be by far the easiest way to do it if you don't need to switch between 4.1 and 4.2v/cell often.
 
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