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The first try to make a pack 13s6p
#1
So here is the plan. Build a 13sp6 pack from these batteries. I bought 100 of these and after all they appear to be crap. Tested them all and they vary all over the place. Voltage out of the box was everywhere between 4,18 an 3,75. Not really the best voltage for shipping and storing. Test revealed them to be mostly under 4000mAh, the lowest being 3532 and the highest 5241 mAh. Well after regretting this purchase I go now and it is good to learn spotwelding and testing! Angel

This is how it looks like now:

 

More to come...
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#2
What did you expect when buying cells named "double Power" Smile
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#3
Haha yeah you're right Daniel. So now I know.

I have ordered 10 5100 mAh Liitokalas for the test. Testresults are much better. Also 2 of these 5000 mAh, they tested the same as the 5100 which is (almost) all well above 5100. So I ordered 60 more of these 5100. I want to use them for the type of powerwall I want to build. That is packs of 1 kWh so with these Liitokalas that is 14s5p. Every now and then  I'll buy another 70 or 140. In the end it should be 20 kWh or so.
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#4
Acquiring cells was the most stressful part of my journey so far. I stumbled on Ebay alarmhookup in early days when they had New 36v 4.4ah ebike packs. I bought 1,000 cells at aprox $1.20/cell and thought that was expensive. Since they were new, I tried to go 'all new cell' but learned that I could not buy exact same cell except from China AND found costs went to $2.00/cell for used/suspicious packs. Then I realized I needed over 5,000 cells... yikes. I tried a couple of ebay purchases but got it in the short hair both times with cells that were about 60% of advertised capacity. Finally went back to Ebay alarmhookup and Ebay power2spare - who have always delivered exactly what they advertise. But by then, a year later, the price is more like $1.60-$2.60/used-cell at 2100-3000mah level... AND I've come to be thankful for these prices Smile

I'd love to go Nissan G1 (a lot less hookup work) but don't trust that advertised have 80% or more of their life left. Or LifePO4 Prismatics - but these seem more expensive than good/used 18650.

Its like a catch 22. You test the water and buy a few... but then its not clear that if you want to buy alot more (like $6,000) that they'll be available or that the rest will be the same quality.

In one ebay purchase I ordered a couple of hundred of the exact same cell type from 3 different sellers. In each case the cells were 1600mah instead of advertised 2200mah. In each case it was the same - when I complained/requested refund they said "How about if we knock off 15% from price". This tells me that many listings are probably from same source and/or using same misleading business practices. It just buyer beware when buying batteries. Again - a huge thank you to alarmhookup and power2spare for being *honest* brokers.
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#5
Made some progress. Pics:

 

As you can see the spotwelding is going well now. Next problem was how to get the last serie (B13) fused. I did it this way:


 



Spotwelded fuses to the positive side of the last row. This is the + of the battery. Put barley paper on top and fold the fuses around it. Then spotweld the fuses to a nickel busbar that is going to be the positive terminal. Spotwelding didn't go as expected so I improved the welds by soldering them as well. Now I need some kind of cover to be able to turn the pack around and spot the fuses and balance leads on that side. Easiest way to make something is with wood so here we go:

 

To be continued...
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