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Just starting to make a powerwall
#1
Hey I'm new to this whole thing and I'm currently testing some cells I got.
Does anyone have any tips or ideas to help me out?

Also what should I have in my packs? 2000mah and up? Or is that too high?
How do you guys sort the good ones out?

Been looking up on jehu and hb powerwall and I'm really wanting to do this but I don't have much experience 
Any help is appreciated
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#2
I'm using cells 2000mah and up. I test each one to determine the capacity and sort them based on those results.
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#3
(01-23-2017, 01:32 AM)FireFrog Wrote: Hey I'm new to this whole thing and I'm currently testing some cells I got.
Does anyone have any tips or ideas to help me out?

Also what should I have in my packs? 2000mah and up? Or is that too high?
How do you guys sort the good ones out?

Been looking up on jehu and hb powerwall and I'm really wanting to do this but I don't have much experience 
Any help is appreciated

Greetings friend! I recommend you read other projects here in the forums and formulate your own way that suits you. There isn't a right or wrong way to assemble packs, or which capacity threshold to use. It all depends on what your end goal is. If you are trying to power your house and space is a concern, perhaps you would go with higher capacity cells. I will say this, be careful and learn as much as you can by reading or watching YouTube videos of others about safety and how this stuff works. You will find you may agree with some things, and come to your own conclusions on others. Some good people here on the forum to talk to, and search posts by would be:
http://secondlifestorage.com/u-3nergE
http://secondlifestorage.com/u-PaulKennett
http://secondlifestorage.com/u-Rerouter
http://secondlifestorage.com/u-mike

Remember most of us are not experts, just enthusiasts =P  - something to keep in mind.
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#4
I just ordered some tp4056 chips to charge my cells and a few dischargers
The previous charger from a local vape shop didn't fully charge to 4.2

I'll take a look around and try to make some conclusions
2000mah seems pretty solid choice for cells so I'll probably try and go for those

Also how do you guys get cells?
I ask stores if I can go through their bins large retailers sometimes say no but I met a cool guy at batteries plus and get some there
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#5
(01-23-2017, 03:54 AM)FireFrog Wrote: Also how do you guys get cells?
I ask stores if I can go through their bins large retailers sometimes say no but I met a cool guy at batteries plus and get some there

Asking your local shops is the best way. Unfortunately i was only able to find one place that would give them up. I have to pay for them but they're super cheap compared to buying on eBay. I would say eBay is your best bet though if you don't have anyone local. You can always email the sellers and ask about buying in bulk. If they're in the area, you can ask about local pickup to avoid shipping charges and other related eBay fees.
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#6
Do you think a scrap yard would have anything?
I also happened to get a used e bike pack from batteries plus, looking it up its 37v10ah pack not 100% if i can use it for a small project. My meter only picks up 11 millivolts or so and it doesn't have a charger cable to i might buy something to charge it and maybe have a e bike conversion too.
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#7
(01-23-2017, 04:22 AM)FireFrog Wrote: Do you think a scrap yard would have anything?

It never hurts to ask Smile
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#8
Only certain kinds of junk yards are allowed to deal with any sort of battery due to the nature of the item. I called up local eScrap technology recycling centers and buy laptop batteries for $1.50/lbs 

Be careful when charging cells that are below 2v - they are below their rated voltage, and this can sometimes lead to unstable and damaged cells. Currently, I have brought back many cells below 1v but have also had some become unstable after charging it up to 3.8v (the cells generally start exerting heat as a byproduct of being unstable) when this happens you can notice a fast decrease in voltage in a short period of time. (Some of my cells dropped from 3.8v and dissipate and stabilize at 2.3v in a matter of minutes). 

My reason for saying all if this is: you should always keep an eye on your batteries when charging, especially cells that could be damaged further due to a prolonged state below 2v.

I try not to charge my cells unattended for too long. I constantly do a quick heat test (back of the hand to the cell pack) to check for any cells releasing heat. 

If you find unstable cells, pull them out of your pack immediately, and replace with another. Rinse, wash, repeat.
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#9
Some of my cells get warm others hot, are the warm ones still good?

I also had some orange colored cells with no name brand with some suspicious brown liquid on it
Not sure if it's from the cells themselves or something else but I'm risking on charging those
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#10
(01-24-2017, 03:46 PM)FireFrog Wrote: Some of my cells get warm others hot, are the warm ones still good?

I also had some orange colored cells with no name brand with some suspicious brown liquid on it
Not sure if it's from the cells themselves or something else but I'm risking on charging those

It really depends on what is causing the heat. Heat isn't always bad, it's just a byproduct of work. If the cells in parallel are unmatched (I.E bunch of 1v cells and a few 3v cells) the 3v cells will heat up due to the fact they are dumping amperage into the other cells in order to reach equilibrium. Inversely, it's possible for a cell to produce heat while drawing amperage.

Just keep an eye out and if cells become too hot, remove them from the pack and try charging them slowly by themselves. If they still produce heat, chances are it's a bad cell. 

In regards to the brown liquid, without actually seeing a picture it is hard to determine what it is. It's either byproduct of some adhesive used to keep the pack together, or possibly even corrosion.
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