Battery Capacity Checker

Here are the pdf's of a programmable battery capacity checker and charger. It is much more expensive than any I have seen before ($222.66 all-in for Canada), BUT it is much more capable. It handles all the chemistries forum members would use; the exception is LiPO, which requires a balance charger similar to that used to charge the RC battery bricks.

Posted by: @zander

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I am sure a few of us would like to build a battery capacity tester. I think we are all very aware of all the fakes on the market, so testing their capacity would be useful.

Doing a capacity tester and a charger with the same circuits would be a bonus.

The 18650 is an obvious target, but can it be done so more/any size can be tested? Chemistries in descending order of importance are LiFePO4, Li-ion, LiPo, NiCad, and NiMH.

Bonus suggestion: If more than one battery can be tested at once that would be great.

@zander, (Ron), I found this circuit that might interest you: https://www.instructables.com/DIY-Arduino-Battery-Capacity-Tester-V20/ for a battery tester that can check the differnet types of rechargeable batteries..This could be modified to check more than one, but his just gives you a general idea of how to do it. I might build me one for fun...lol, but I like the idea of designing one that will do more than one, and can be a charger as well..

Regards, LouisR

@inst-tech I have that one. I did a full test two nights ago, here are the results.

Charged a suspicious 18650 LiIon battery. Then ran it through that capacity tester and it registered over 3,000 mAh. I then put it back in a mid prices charger and when it started it said the battery was at 80% !!! and when it finished charging it had only put in 534 mAh. One of those devices is in error.

I have a top of the line RC charger capacity tester (all 4 slots) (all chemistries except LiPo which needs a balance charger) coming later this week. 

Side Note: I contacted the local Canadian seller of 18650 batteries (mostly for the vape fools) and asked him about the 2 for $6 18650 batteries. Since 10 would cost $30 plus $15 shipping and if I wasn't happy with them another $15 to ship back at. All I wanted to know is if he could guarantee the batteries were at least within 10% of stated capacity. He said he could not but had some coming next March that were. I bet they will cost $10 each.

I have 10 coming from Amazon, free shipping, free return if not acceptable.

I just noticed the amazon page is now 404, but clicking the store brings up a lot of 18650 deals. The best I can see so far is 10 for $35.99 + $3.99 delivery. 

If these batteries test good, I will order a few more from the same supplier and tell at least the Canadian members the exact Amazon listing.

@zander Well, that's disappointing that the tester isn't working properly..I you make the one I linked to in my last post, as you said you had one of those..At any rate,  have the 16650 Li-ion batteries for my Keyestudio Tank robot, they seem to work ok, 3.7V 1800 mAh..

I modified it to use Wifi instead of the BT as the app that originally ran on my old android phone used the BT, but the new android phone would not connect because of a driver issue..tried everything I could think of to get it to work using drivers that were suggested on the web to fix the problem, but alas, I decided to write a new RC control app using MITApp Inventor, and used an esp8266-NodeMCU-12E Wifi  to interface with the robot. It works ok.. but I'm still working on making that BT work on my phone...lol

I'm goint to try to prototype that Battery test circuit to see if I can find out what accuracy it produces.. I'll let you know when I finally get around to it.. kinda busy right now as the holiday season is upon us..Merry Christmas to you and yours..and stay well my friend..

regards,

LouisR

@inst-tech I suppose its possible the tester is right and my charger is wrong. The new charger/tester will break the tie so to speak. This new meter better be good, it's expensive.

1800mAh is low, are they perhaps LiFePO4?