Here is a good used source for 18650 batteries

[sam_sam_sam]

Originally Posted by eccerr0r

Not really much of a design but swiped an existing design on thingiverse and something like this will hold the two packs together...

I am also taking about when you have the finished product also thanks

I am also going to be on vacation next week and I will have time to finish one of the projects that I have been work on for last week or so that I have been testing the two half battery packs that I modify and I have the test results and will be about 30 amp hour battery pack I just have to hook up the BMS protection boards and charging controller in the enclosure if it will fit if not it will be external mounted

[eccerr0r]

Oh... never ever ask me about finished products. Even if it is designed well, it will look like something that belongs in the ghetto mods thread

[sam_sam_sam]

Originally Posted by eccerr0r

Oh... never ever ask me about finished products. Even if it is designed well, it will look like something that belongs in the ghetto mods thread

I am no better than you about this ( functionality to me is more important than anything else anyway )

[eccerr0r]

hmm... need to add a place for a screw terminal barrier strip for reconfiguration and strain relief...
Torn right now whether to use it as 2p 24V or 2s at 48V... so many things need power...

[sam_sam_sam]

Originally Posted by eccerr0r

hmm... need to add a place for a screw terminal barrier strip for reconfiguration and strain relief...
Torn right now whether to use it as 2p 24V or 2s at 48V... so many things need power...

You could have a selector switch to go from 4p 24 or 2p at 48v so you would have both

[eccerr0r]

well, the implication is that I put the 2P in the electric scooter as transportation, or use 2S for my battery backup... Difficult to use for both at the same time as the scooter would need a very long cord!

[sam_sam_sam]

This is a new listing for anyone who is interested in buying some batteries in a box

https://batteryhookup.com/products/3...s-fully-tested

I have bought some of these batteries but they were in a heat sink tubing with a BMS protection board the issue with them is that these were seriously low on charge around 1.5 to 1.8 volts but they have changed up with no issues so far and they have been at least 2.2 to 2.something up to 2.5 amp hours and the self discharge seems to be ok from what I have seen so far

[eccerr0r]

Just need a welder...

[sam_sam_sam]

Originally Posted by eccerr0r

Just need a welder...

Are you wanting to make your own or are you going to buy one

If you are going to make one microwave transformer modify and SCR controller is the easiest way to build your own with a microsecond timer module but you have to do a lot of trial and error but you can get sat factory results but time consuming to get the results you want

If you do a capacitor discharge device a little bit more complicated to do choosing the right type of SCR is the hardest part of this type of battery stud welder

If you buy one the ones available from EBay and other places have an issue with the controller boards they do not last long either the SCR failure or controller failure is the most common issue with these devices

( This stems from the fact that you can not use this transformer with out a controller because of the fact that it pulls so much current [ where as a microwave transformer can be used with out a controller with out tripping the breaker however it does not get as hot of a weld in the same amount of time and the controller does not stay energized long enough to be used with a microwave transformer] )

The only ones that do not have such a failure rate is one that the transformer used is under powered but the controller seems to last the longest

[sam_sam_sam]

Here is a new item at Battery Hookup

https://batteryhookup.com/products/p...ah-18650-cells

Someone might be interested in

[sam_sam_sam]

Here is something new at battery hookup

https://batteryhookup.com/products/2...-2250mah-w-bms


https://batteryhookup.com/products/p...ah-18650-cells

[sam_sam_sam]

Battery Hookup has these back in stock again

This is a very good buy I have bought over 100 of them and I have tested about 40 of them and they all have tested at least 1999 milliamperes to 2250 so well worth the the money

The few I checked the BMS protection board have worked but I have been removing most of that I have tested so far them so I can use the battery holder that I have for them once I have tested all of them that I have so can match amp hours for this battery battery pack that I going to build

https://batteryhookup.com/products/p...r18650cg-18650

[sam_sam_sam]

Buyers be aware of this item

https://batteryhookup.com/products/2...r-module-w-bms

And in all fairness to Battery Hookup they do not say what battery life is left in these batteries

The issue with these battery packs is that they have tested to only have half of stated amp hours not that they are bad cells but that they only have half of the life left ( these batteries are made in Taiwan )

Also they are made in Japan as well which to me are the best ones to have

I had bought some that were in a enclosure that I wanted to use them for a project that I have in mind and was hoping that the batteries in them I could have used them in this project but will remove them and use some much better battery from the same company and the same type of battery cells

There is a version of this battery that is made in China and buyers need to aware of this issue with this battery under NO circumstances should you ever let these batteries become very low on voltage let say if they get below 1 volt they become unstable and dangerous to keep in your house because the battery cell swells in size and no voltage on the battery cell

I have a lot of 19 of these left and I am not sure exactly what I should do with them because of this issue I had bought them for the BMS protection boards and was going to use them for some solar project that I had in mind but now I am not sure if I really want to do this but if I do anything with them they will be used in a metal enclosure for sure and each battery cell will have its own BMS protection board on it

The reason I know this is because when my battery testing machine had a malfunction and the discharge current became unresponsive and uncomfortable I did not realize that I had an issue with this until I saw that there was no battery voltage on the screen of the battery tester machine

So I tried to very slow charge this battery and everything was ok until the battery voltage was above 3.5 volt when all of sudden the battery voltage went down to zero volts again and the battery was swollen and no voltage and no heat to speak of which was weird ( but if this how the safety device is suppose to work it did do it correctly to remove the current from the battery and keep it becoming completely uncontrollable and unstable and catch on fire )

I took the battery outside and put on a metal plate where it still there

One note to me this version of a li-ion battery is nothing more than a glorified pouch battery in a small package

One other note I have several batteries packs that have these battery cells in them and have work very good and these were made in Japan which I have posted some pictures of them in another post a while back

[eccerr0r]

Damn. Found at the surplus shop one of these voltmeter/warning gizmos. It has 9 pins for 1S to 8S and a microcontroller will display the sum of all the voltages of the pack as well as sequentially display the voltage of each member cell that is in series. It also has a programmable alarm that will beep when a cell voltage drops below 3.5 to 2.7 volts depending on what you set it at (100mV resolution).

Wish I had this when I did my discharge cell killer even if it can't cut off...

[sam_sam_sam]

Can you please post a picture of it

[sam_sam_sam]

Someone might be interested in this offer made by Battery Hookup

https://batteryhookup.com/products/3...ested-90-99-99

[sam_sam_sam]

Originally Posted by sam_sam_sam

Someone might be interested in this offer made by Battery Hookup

https://batteryhookup.com/products/3...ested-90-99-99

Here is another item that I bought from them and the batteries happened to be Panasonic batteries made in China I will be running some tests on them and see if they are truly 4 amp hour as it is stated on the battery it self I will post some pictures of them when I have them ready to be tested

I know that the picture that they have are a different brand of batteries i bought 10 packs but I have only open one so far

https://batteryhookup.com/products/l...ies-1000-cycle

[sam_sam_sam]

Originally Posted by sam_sam_sam

Here is another item that I bought from them and the batteries happened to be Panasonic batteries made in China I will be running some tests on them and see if they are truly 4 amp hour as it is stated on the battery it self I will post some pictures of them when I have them ready to be tested

I know that the picture that they have are a different brand of batteries i bought 10 packs but I have only open one so far

https://batteryhookup.com/products/l...ies-1000-cycle

Well I put one pack on the battery testing machine and the voltage dropping a little bit faster than I expected it to be so I picked one cell to test not the hole battery pack I will have to check each battery cell individually to get a better picture of how good these cells are

[sam_sam_sam]

Originally Posted by sam_sam_sam

Well I put one pack on the battery testing machine and the voltage dropping a little bit faster than I expected it to be so I picked one cell to test not the hole battery pack I will have to check each battery cell individually to get a better picture of how good these cells are

Here is the data sheet for the Panasonic Nicad Metal Hydrate HHR series

https://b2b-api.panasonic.eu/file_st...leversion/3519

These are expensive at Digikey

With what charge on the one battery cell that I am testing it showed 3.2something amp hours

And according to the data sheet I can use a BMS protection board for 3 cells in series to manage the charging voltage requirement ( max voltage per cell 1.5something which would equal 4.5 volts versus 4.2 ) I going to a phone and tablet battery bank with some of these batteries and a solar panel

According to the data sheet the length of these cells are 2mm longer than the 18650 versus 18670

[sam_sam_sam]

I have finished testing the first Panasonic metal hydrate battery and they do have slightly more than 4 amp hours ( at 500 milliamperes load ) which is what I expected that they would have so I can proceed with what I have in mind for these batteries

One note they only have a 500 milliamperes load limitation if you want a steady voltage if load to 1 amp the voltage drops faster than what you would expect from them the same exact thing happens when charging them with a maximum of 1.3 amps load [ this was kind-a noted in the data sheet the recommended load of the battery is 480 milliamperes load ] ( I will post the results at one amp load in the next few days )