18650 cell pairs battery holder for DIY powerwalls

by paulkennett Aug 21, 2016
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Love the modification to the design, would you be able to post a file which has the groove on the larger packs as well so you have a choice to use either nickel strip or wire on the large packs.

Doh! Fixed those now. Version 9b uploaded

Cheers, Paul

Hi Paul,

What material do you use to print these from?

Thanks for your help,


Paul Kleinmeulman

Thanks for your quick reply Paul,

Been trying to get some quotes to get some printed. Do you do 100% fill? Some companies offered 50%. Cheapest so far was $285 for 14 plates so I will most likely invest in my own as I can get an Creality Ender 3 for almost that.

Why did you decide to go for the CR 10 Mini instead of the Ender 3?

Thanks again for your help, appreciate it.

Yes - I use 100% infill on these. I've designed these to use as little plastic as possible so I doubt there would be any price different between 50% and 100% as the infill only applies when a model has a "large" interior volume to fill. My battery holders are all less than 3mm thick.

I went for the CR10 mini becasue I saw some good review of it. I must confess I completely missed seeing the Ender 3. I've had a lot of fun building stuff with my old Printrbot so definatly have a go. Good luck!

Thanks so much mate,

My Ender 3 arrived from China in 5 days to Canvastown in South NZ (took 6 days for 3 rolls of PLA to arrive from Queenstown) ... Today I printed out the 2x9 and found that the groove for the wire only goes 3 cells in and not all the way across. I don't know if you can see it in the photo attached. Can you please fix it?

Unfortunately I can only print out the 2x9 with my 220mm square bed, otherwise I would have gone the 2x12.

Also is it possible to add the tiny voltage meter holder... I want to add that to mine as well.

Thanks so much for your help,

Really appreciate it.


Hi Paul

I fixed that mistake last week - if you download the STL file again it should be fine. (Let me know if it's not!) And I've added the latest voltmeter holder and also the doo-dad for adding a socket to the bottom end.

Cheers, Paul

Hi Paul

Think this is a good design but having problems soldering the banana plugs

Can seem to get enough heat into the joint is there some special technique I'm missing?

Also how much current do you think it will be safe to draw

Thanks geek

Hi Geek

Are you using "gold" plated bullet connectors or silver ones? (The gold ones work much better).

My estimate for current draw is up to 10 Amps. They can provide more than 10 Amps, but at some point you'll start to loose energy due to the strapping heating up. I haven't done any testing on that though yet. My electric lawn mower battery peaks at over 15 Amps - but not for long periods.

Cheers, Paul

It's the gold plated ones was a link from your page

Huh - my next question would be - what sort of soldering iron have you got - what power can it output?

Sorted it was using higher gauge wire multiple strands was getting a wick effect