This is good news. i have collected many dead makita 3Ah batts and am harvesting samsung-28A batts. getting the samsung 2.8Ah from mobility scooter or ebike packs so am getting a good supply of them. the samsung 2.8Ah spec says (20A incorrect) 5.6A discharge so should be fine for upping the makita packs.Korishan said:
Yes i will pass on the samsung 28a and save them for my camping packs. have vtc4 in good supply and really only need to repair a few power tool packs. the vtc4 graph looks to deliver 2000mah at high discharge so i will repack with these :shy:HughF said:I would expect the original Makita cells to be more like 20a discharge rated cells, you might be out of luck putting in some low current cells like you have there...
yes looks like the 28a is a no goer. i have sony vtc4 and will repack with thesekc8adu said:your 28a will fall on their face on the first trigger pull.
they are not good at all for high drain.
they are marginal in a flashlight at 3a.
if you want capacity try samsung 30q
Also make sure the discharge rate of the pack is the same or higher than the origonal battery. Working with high power density battery packs is a whole nother can of worms than a powerwall. I would know, I build ebike packs.Korishan said:
I did similar with my 12v ni cd battery for my drill. definitely not a flash job like yours but i still get to use the small drill. later i may look at putting in balance when i re do other ni cd batterieslike you have done. tks for the helpCrimpDaddy said:Not that this is going to directly help you, but I did a tool battery conversion and figure I share in case it gives you any ideas... I opted not to use a BMS, and used the manual monitoring / RC balance charger route to maintain the packs.
yes tks for info. i am still learning. gettingvtc4 from dyson packs and some lgdahd2 so i will be using these without mixing. just a pain getting the last 2 batteries out of the dyson holder. think i will revert to forcing them out and putting tape around the torn wrapperOvermind said:A Makita 3Ah will have 1500mAh cells, probably 15Q or equivalent Sonys.
As said by other members above, you must not use Samsungs of 2800mAh as they are low current cells and will fry. The power tool may actually start and work but at continuous use the cells will overheat to the point of fire. You need to use same type of high current cells. Replacing 15Qs with 30Qs will make you a 6Ah battery. Note that 25Qs are very easy to find so you may as well get these and make a 5Ah.
some of the battery packs show voltage before i pull the case apart. other battery packs show zero voltage. once i have pulled the battery apart i can take the bms off the pack. if i connect the bms to a 5s pack with wires and put a meter across the bms and if i get the correct readings will the bms be ok to put on a 5s pack and put the battery back to work on my drill. what does low voltage destroy on the bms? is it something to do with the charging of the pack?loyd said:You will need to get a new BMS / Pcb board. On the original ones there is a chip which destroys the board when there is under voltage / no voltage.
You can find them cheap on Aliexpress.
Overmind said:Today's power tools are very complex.
Inside a Makita battery there are 8 (14.4V) or 10 (18V) 18650's, and the BMS.
Here is there thedesign flaw: the BMS draws power only from the first pair of cells. If you leave it sitting for a while, the BMS will deep discharge that first cell to zero, while the others remain charged. Result: dead battery.
If you put it in the charger, the charger will mark the battery as bad (the data pins I was mentioning) and it's unusable forever.
I was trying to reply to your post on a different Makita battery thread you've posted on but it was more than 3 months old and I couldn't post on it. ? So I hope its OK to post it here.
Did anybody figure out yet how to reset or disable this on the original makita boards? Without replacing the boards with the not great ones that can be bought online.
I have a load of the batteries that won't charge and show 0V on the battery pins but if I measure the voltage on the cells they are perfectly fine and balanced with each other.
This is really "stupid" from Makita (I know it makes perfect business sense) because it forces people to dump these batteries and buy new ones or those who dare to open them up and replace the boards, but loose the balancing capability while charging.
Hi Korishan, i am not into ebike or car packs but if someone is building a pack should they use the same brand batt same capacity and what would the discharge rate be needed for the battery to use in ebike pack, cheers :huh:CUDAcores89 said:Also make sure the discharge rate of the pack is the same or higher than the origonal battery. Working with high power density battery packs is a whole nother can of worms than a powerwall. I would know, I build ebike packs.Korishan said: