Some New Preliminary testing of 21700 Tool battery cells to 2.00

[sam_sam_sam]

If anyone is interested in buying Samsung 21700 / 5 amp hour load capacity 25 amps for $3.95 for power tool battery cells
This is probably a Back Friday sale it does say for how long the sale last

https://www.18650batterystore.com/pr...ah-25a-battery

[sam_sam_sam]

These battery cells are supposed to be here today so shall see if they show up or not
I have to work tomorrow and maybe Sunday morning as well**pause***wow on the bright side I will have Christmas money

[sam_sam_sam]

Well the batteries showed up late yesterday afternoon nice heat shrink tubing color now it's time to do battery testing and match battery cells to each other

[sam_sam_sam]

Well I did not have to work today but I had to replace a metal security front door that has surface rust on the original door before it rust away so I going to refinish it and put on the small garage door which does not have one right now and install a electronic photo eye on the roof ( part of the mounting is under the gutter and part of it is over the gutter under the shingles ) [ homemade bracket ] to hold the electronic photo eye for light between the two garage buildings because what I have setup it is cycling on and off not good situation for the LED light bulb

[sam_sam_sam]

I hope to have the battery testing machine computer rack cart completed by this weekend up and running and doing some battery testing by the end of this weekend at least this is the plan anyway

[sam_sam_sam]

Well I have one side of the computer cart functioning with the eight channel battery testing up and running and testing a set of battery cells that I have tested a couple of times before but just have not wrote down the milliamperes on but this time I will because I need to put the 21700 battery holder jig on the machine and test some to rebuild two Milwaukee 8 amp hour packs

I now have to work on the right side of computer cart for the single channel battery testing machines shelf but I have to wait a little bit before I have project money to go further than what I have done so far

To make a single heavy duty shelf cost $42.00 for the shelving rails the support rails $25.00 each need 1 and half of another one and $25.00 for a 16 gauge sheet metal for actual total cost of a single shelf is around $100.00 but I do not want to the shelves to fall down because of to much weight on them this is the reason for the over kill

The second computer will sit on the same shelf that the other one is sitting on now
The right side will have the BMS testing station on this side I have two 5u empty enclosures that I going to use for the single battery testing machines and the 24 volt adjustable voltage and current switching power supply that I have talked about in another post all of the displays for the voltage and current will be in front of the enclosure with the display of the battery testing machine as well as but this is going to take some time to put in together and it be very time consuming process for this part of this project

Having a 40” monitor is a very big plus for this project to be able to see and being able to read the side bars of the graph cart a small monitor screen just dose not cut it

[sam_sam_sam]

Well I put the first set of 21700 batteries on the battery testing machine and it is now rocking and rolling and well on the way to rebuilding two Milwaukee M18 8 amp hour battery packs that are way out of balance and the battery cells just need to be replaced and start over again with a fresh set of batteries

[CapLeaker]

I saw your photos of the battery tester. Pretty nice setup you got.

[sam_sam_sam]

Here are the test results from the first batch 21700 battery cells the milliamperes hours are all over place when there are more than 0.100 volts all over the place but what is interesting about these battery cells load tested to 2.50 volts and it has almost reach 3.00 but all of this batch of battery cells are around the same voltage and they are testing above 5 amp hours the charge and more importantly the discharge curve really looks very nice

The one thing that you have to pay attention to is the parameters values that you are putting in because I did not catch the mistake until this morning that is the reason that you see very little charging curve time value instead of one amp it was set by default to 0.100 amps for the discharge for the load test

[sam_sam_sam]

Now I am going to build a battery testing system for testing the BMS protection board plus a way to make sure that the battery cells are matched before I make the battery pack

I have the 24 channel battery voltage monitoring module and a balancing board that is also a 24 channel device as well as I going to use 5 battery holders that are made for 21700 battery cells so all that I have to do is install the battery cells in the battery holder and then I will be able to see all of battery cells voltages in real time and compare the battery charging curve to the rise in the individual battery cells and see how close they are when the battery charging cycle ends at what voltage of each battery cell are when the charging cycle ends

[sam_sam_sam]

Well it takes almost all night to test one set of these battery cells because of them being rated for 5 amp hours
4.5 hours to charge up and a little bit over 5 hours to discharge them and this set of battery cells the milliamperes hours are also all over the place as well I show the results later on today or tonight once I see how well they recover from being discharged

[sam_sam_sam]

This batch of batteries that I bought are good that they are testing over 5 amp hours but the amps hours beyond 5 amp hours are as follows
0.0500 to 0.1180 these battery cells are not match at all I can make two battery packs but the tolerance is not as close as I would like it to be I might have to settle for 0.250 between the first battery cell and the last battery cell oh well it is what it is

[sam_sam_sam]

I have to find a Milwaukee M18 battery single row pack that has several self discharging battery cells but I have miss placed it somewhere and need to find it again because this is going to be test subject for the BMS testing jig the reason it got miss placed is because I trying to get more organized and putting things that are alike together so that they will be easier to find when needed but right now I have to many things going on right now and to many things that need to be repaired but I am slowly working through it and hopefully I can get back to normal soon

One note I have finished testing this batch of 20 —> 21700 battery cells for the two Milwaukee M18 8 amp hour battery packs
instead of 8 amps it will be 10 amp hour battery packs

[sam_sam_sam]

Well I found the Milwaukee M18 single row of battery cell pack it was completely dead except one battery cell which only had a a little bit over a volt the rest of them were at 0.50 volts but I can not seem to find my 21700 or the 18650 battery holders to make the BMS battery testing jig so I ordered some more of them which I going anyway but maybe a month or so

The battery cells that I am going to use for the M18 eight amp hour battery packs are going to end up being ten amp hour battery packs have been tested and grouped together and ready to be tested by the Milwaukee battery charger and being loaded tested by a power tool to see how close are these battery cells really are

Here is the battery holders that I am using for the BMS battery testing jig

https://www.ebay.com/itm/167126845690?var=466835265123

More to come soon

[sam_sam_sam]

Update I finally finished the mounting of the 21700 battery holders on the cutting board now I have work on the Milwaukee battery pack jig part of it but I am not sure if I have the inter connecting wires between the BMS protection board and the battery holder connection points I will have to look and see if I have what I need to this part of this project

The first picture is for the three P and the five S so I can see how well balanced I have the battery pack in the second picture you see the one P and the five S I can see how balance a single row battery pack behaves

[sam_sam_sam]

Made slow progress on the Milwaukee battery BMS protection board jig board I had to modify the tabbing going the BMS board and put JST post instead of the tabbing so I had a soldering joint that would not rip off easily what a nightmare this was to do so that battery pack enclosure would fit back together again I will probably work on it some more next Sunday morning and afternoon but the project is slowly making progress which is the more important thing right now

[sam_sam_sam]

No real progress has been made this weekend because of working on the lathe that I am trying to repair but did make progress on the battery testing machine on the computer 5U computer enclosure that I have been working on but did not make a lot progress on unfortunately because of some other things I need to take care of

[sam_sam_sam]

Well now that I have a new 3D printer it is time to print some positive and negative ends for the battery testing jig that I going to make for testing power tool battery packs and the support rails to mount on the cutting board and brackets to hold the battery pack in place I just have to make time to just do it

I need to upgrade the motherboard on my older 3D printers to have the auto leveling feature on them and will start using them again but these two are one of the first versions that came out and are not comparable to the newer versions that print a lot faster but I do not really care about this as much as I care about having to level the printer bed every time I want to print and unfortunately the bed is a little warped so it would not print very well and was more aggravating to use it

[sam_sam_sam]

I have some Milwaukee XC M18 battery packs that are coming to there end of life sin drum and need new battery cells put in them I have them but I just have to build the BMS testing station out of one of them and use the battery holders that I on the cutting board and the BMS board out of one of them for I have to build the testing jig and hook up one of the battery testing machines that the mosfets board got damaged and set it up to monitor the voltage and current going to the battery pack and hook up the individual battery cell monitor module and get everything working together and start testing battery cells for this project because I use them at work on there impact gun that is for the nut driver bits and I use a light weight battery pack for this job that I have to every Monday afternoon when the production people go home for the day

I show a picture of the battery holders on the cutting board in post #35 of what part of is going to look like the reason for building this jig the battery cells that I going to use are slightly used battery cells these are not brand new and slightly use battery cells behaved differently than new ones do you have to do more testing for these type of battery cells especially if your battery cells have different milliamperes amp hours from each other