Here is a good used source for 18650 batteries

[stj]

Re: Here is a good used source for 18650 batteries

i'll find out - a friend has one

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

i'll find out - a friend has one

Thanks

[eccerr0r]

Re: Here is a good used source for 18650 batteries

Thought I mentioned it... Homemade Grid tie "power wall"... down to conponents. more of a design challenge for a complete power arbitrage system. Use cheap power (solar, off peak grid electricity) to offset or overtake peak price power.

Expense of parts is one problem but with a surplus of random parts in my parts bin, I must use these when I can. Batteries are not in my surplus however.

Yes, planning to implement anti-islanding... and have an override!

[stj]

Re: Here is a good used source for 18650 batteries

honda used nimh until 2010

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

honda used nimh until 2010

Ok thanks

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

Thought I mentioned it... Homemade Grid tie "power wall"... down to conponents. more of a design challenge for a complete power arbitrage system. Use cheap power (solar, off peak grid electricity) to offset or overtake peak price power.

Expense of parts is one problem but with a surplus of random parts in my parts bin, I must use these when I can. Batteries are not in my surplus however.

Yes, planning to implement anti-islanding... and have an override!

While you are building this project can you please keep us updated on your progress with this project I sure would be interested in this project

[eccerr0r]

Re: Here is a good used source for 18650 batteries

Nothing's happening mainly because batteries are too expensive and I'm too lazy to get a circuit board etched since I've been having one heck of a time trying to get it to one layer...so I can self etch.

Also though most of the components on the board I have (salvaged and parts collection), there are a couple I don't, plus I need to write the microcontroller code. No board, no wanty to write code. Since I don't have code, no wanty to make board. Ugh. Vicious cycle. Really should put it on a solderless breadboard to see what it does...

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

Nothing's happening mainly because batteries are too expensive and I'm too lazy to get a circuit board etched since I've been having one heck of a time trying to get it to one layer...so I can self etch.

Also though most of the components on the board I have (salvaged and parts collection), there are a couple I don't, plus I need to write the microcontroller code. No board, no wanty to write code. Since I don't have code, no wanty to make board. Ugh. Vicious cycle. Really should put it on a solderless breadboard to see what it does...

Why get a development board and try it that way yes can cost some money but you have the building blocks that you need to see if your concept is a good one or not

[eccerr0r]

Re: Here is a good used source for 18650 batteries

Still need to write code...sigh. I think should do this, would open a lot more avenues to implement the actual circuit - the design I drew out was an H-bridge direct drive but with the code I could dabble with a safer, transformer design ...

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

Still need to write code...sigh. I think should do this, would open a lot more avenues to implement the actual circuit - the design I drew out was an H-bridge direct drive but with the code I could dabble with a safer, transformer design ...

I still would like to see what you come up with

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

I bought a few of these battery packs and they are very interesting for $29.00 for 24 batteries and the BMS protection board which they claim that also works but I have not tested it yet but I will let you know if it works correctly or not

This was also bought from Battery Hookup but unfortunately they are out of stock already again for the second time since they started offering this item

I am going to use this for a LED yard light that the switching power supply took a shit and can not be repaired because it has leaking capacitors and it is incapsulated with black hard plastic I guess that what this stuff is

This operating voltage is 32 volts and this battery pack has this voltage as well I just have to find a weather tight enclosure that will fit this battery pack/BMS board commination I already have the solar panels that I bought a while back that was also surplus but at the time the project that I had in mind had technical issues that I could not overcome at the time so they have just been sitting here collecting dust until now that I have found a battery pack that will work the LED yard light that also has issues and just repurpose both items to be used in another way

I am going to be testing this battery pack in 12 volt sections and one 8.4 volt section just to be sure that the milliamperes hours rating that they claim to be

I have found that the medical grade battery packs are most of the time are good quality devices and are easily used for projects

I will post some pictures of this project when I have completed it so you can see what I came up with

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

Here is another item from Battery Hookup that is also interesting item

https://batteryhookup.com/products/8...-cells-ibh9100

Now this one is hit and miss with weather or not you get good batteries or not I bought 6 battery packs and two had bad batteries in them but I can reuse the battery pack case for a project so I am not to worry about it not being good

But if you do get good ones they will be at or above 50% of charge on build in fuel gauge
One note you do have to use plastic pry tool to open the battery pack enclosure it does take some work to pry it apart but the enclosure can be reused for 8 (18650 battery cells )

One more note I am not sure that you can use the BMS protection board or not because I have not figure this out yet

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

Here is an update on this battery pack

The individual battery cells so far are testing at around 2100 to 2200 milliamperes hours = 3.00 volts @ 500 milliamperes working dropout voltage and 2400 milliamperes hours when battery tester shut off and battery is rated at 2600 milliamperes hours

Which means that the useable battery life is 90% when battery voltage reaches 3 volts under load around 80% to 85% if you use 3 volts at 500 milliamperes maximum dropout current

The one thing that I noticed about these batteries is that charging curve voltage is not very impressive it is steeper than what I expected to see I prefer to see less steep climb in voltage until it reaches around 3.8 and then level off and slowly climb until it reaches 4.2 volts

Now the discharge curve is a little bit better but it is a little steeper drop when battery voltage is around 3.5 volts is when it becomes more steeper than what I expected it to be

I will use these batteries in another project because of the charging curve and discharge curve results

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

To add to the post above

The interesting thing about this version of this battery is that not all of these batteries have the same charging and discharging curves I have to wonder if there is some kind of quality control issue when these batteries were made

Because most of the time when you have a lot of batteries that are the same version they all have basically the same charging and discharging curves but not this series so I am a little confused about what I have been seeing with this series of batteries

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

Update on these battery packs

Pack number 2 the battery voltage was a lot better 32 volts instead of 28 volts on the first battery pack tested and voltages not really near each other

Radom checked on a few cells and voltages was around 4.0something which is a lot better than the first pack

So I am charging this battery pack up with the build in BMS protection board there is no current limiting on this battery pack either because it is done on the charger end of it

[eccerr0r]

Re: Here is a good used source for 18650 batteries

hmm... wonder how much I should pay for two 24V 6Ah (12Ah total) Li-ion battery packs for some unknown tool, supposedly new, purchase locally, but I can't refund them. Plan would be to harvest cells only but maybe I could use the BMS if it has one, or perhaps the whole pack. Wonder if it's worth the risk and how much I should pay max to take the risk...

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

If unknown use I personally would not pay more than a dollar per cell but I would at least measure the voltage of the pack to make sure that it does not have electrical issues

One note if there is no voltage on the output terminals of the battery pack it could be that the BMS protection board has locked it out and at this point I would not pay more than $0.50 per cell because you would be taking more of a change that there might be bad battery cells

The only way that I would consider paying more than a $1.00 per cell but a maximum of $2.00 per cell is if I was allowed to open the battery packs and check the the battery voltage but make sure that the voltage does not vary more than 0.500 volts because it has been my experience that if varying more than this then there could be issues with some battery cells and what brand of batteries that were used and milliamperes hour rating that they have all play a part in how much I am willing to pay for used battery packs

One note about 6 amp hour battery pack it could 2p or 3p if it is 3p I would not pay more than $1.25 per battery cell if it 2p then I would go to $2.00 per cell maybe a little bit more if the battery voltage per cell does not vary more than 0.250 per cell and you do not see any signs of battery cell leakage what so ever but my maximum would be $2.50 per cell

Do you know what brand name of the battery packs are because if you do I might be able to to tell you what brand of batteries that it might have in them

If you plan on using the BMS balancing protection board I would highly recommend that you buy the battery charger for the pack

One note if the brand names of the battery packs are RYOBI or Milwaukee or Kobalt I can tell you what brand name batteries are in them and they are a safe bet as long as you have have voltage on the battery pack but I still would want to open them up to see the condition of the battery cells

I hope this helps you

[eccerr0r]

Re: Here is a good used source for 18650 batteries

This is sort of a surplus store, so can't predict what they have. I also don't remember the brand name of the pack.

The theory is that they're new but possibly a return, but that could also mean it was defective... At 24V it is a weird number, at 6S3P it would get close to 24V 6Ah with 2Ah cells, else it would be 6S2P with "3Ah" cells. I think it's more likely 6S3P but it's possible it has something other than 18650s in it. They were definitely "dense" as in heavy for its size - assuming the package isn't lying and they put lead acid cells in them, but there's no way to get 24V of lead acid cells in that small of a package..

TBH I would not pay $1 for a used cell or even $0.50/cell for a bad pack (e.g. pay $4 for a dead 8-cell laptop pack?), but the chance these are good condition cells for a power tool made me think...alas it's still a gamble.

Not sure if I can sneak a multimeter in to test, nevermind open, unfortunately.

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

Here is a very very good deal I have yet to see a battery below 2.50 volts and few I have tested I got at 2200 milliamperes hours

I had ordered 30 of them

https://batteryhookup.com/products/3...cells-with-pcb

I just ordered 40 more

Here is a picture of the battery in question I still have a lot of batteries to process I have only done about 30 of them and I still have over 100 more of to test but have not had time to do I have been testing other batteries but I might get back to them soon I hope

Unfortunately they are out of stock on this item and I have not seen it return yet

The results are looking at the graph and where the voltage is at 3 volts is where I getting this value from not the total amount of milliamperes hours that when it reaches 2.8 volts as the SkyRc IMAX b6 tester shuts off at which is when it is at 100 milliamperes

[sam_sam_sam]

Re: Here is a good used source for 18650 batteries

Here is some batteries that I bought a couple of years ago and they were a disappointment because they are not 3.3 amp hours like it says on them but they do not heat up but when I first bought them they never had much higher amp hours rating that they do now

I will give them to someone who is interested in them just pay for the shipping I think I have 3 or boxes of them but there is only 6 to a box if remember correctly

Just PM if you are interested in them I do not want them to go to waste if someone else can use them the outside cover does not come with them however but they will be individual wrapped to not short out and I will test them to make sure that you do not get any that are DOA