Duff Batteries

dewaltdisney · Post by **dewaltdisney** » Wed Aug 21, 2024 5:07 pm

In my How Cheap thread viewtopic.php?t=109737 I revealed that the cheap mini chainsaw kit I bought had duff batteries. As you may know, electrics are not something I know too much about but I undid the dead battery to have a look. Now bearing in mind the battery is about two inches thick and rated 48v the one that did charge lasted only a few minutes and the other would not charge at all. I decided to undo the case on the totally duff one and I was surprised to see a ten-slot plastic cell carrier with only five cells in the top row (which accounted for the light weight) I could not see any loose wires so it must be related to the PCB in there. Would anyone knowledgeable on batteries please give me an insight? Is this down to some light-fingered worker nicking cells from the factory? I do not think it is worth buying batteries unless someone has a good source.

DWD

etaf · Post by **etaf** » Wed Aug 21, 2024 5:13 pm

do you have any photos
do the cells have a voltage on

dewaltdisney · Post by **dewaltdisney** » Wed Aug 21, 2024 5:38 pm

Beyond me to do it I blew my multimeter. Here is an image that has the same plastic carrier as mine https://cdn.instructables.com/ORIG/FHH/ ... t=boundswo. Mine has two rows of plastic carriers one with five cells and the other row empty.

DWD

etaf · Post by **etaf** » Wed Aug 21, 2024 5:49 pm

lithim battery cells maybe around 3.7Volts - but there are other types
and then how connected parallel and series to get the voltage and also the AH rating
perhaps this helps
https://www.engineersgarage.com/battery ... otections/

wine~o · Post by **wine~o** » Wed Aug 21, 2024 5:50 pm

dewaltdisney, Those cells are normally 18650's available from any vape shop or online.

Someone-Else · Post by **Someone-Else** » Wed Aug 21, 2024 6:15 pm

dewaltdisney wrote: ↑Wed Aug 21, 2024 5:38 pmHere is an image that has the same plastic carrier as mine

Just saying, wine~O is right that the batteries are 18650's, you may be able to get them in a vape shop (I got one on line) BUT that "carrier" you show in the picture, the batteries are spot welded in (It's quite common) so buying new batteries is pointless UNLESS the "Holder" you have you can remove each cell. I would suggest you try that first.

dewaltdisney · Post by **dewaltdisney** » Wed Aug 21, 2024 6:29 pm

Thanks all for the input, I saw that point spot welder in a YT video. Those vape shop batteries have bad press for bursting into flames do they not? I have to say that any attempted repair is totally beyond my skill set. I think that I have to face the fact that they are rubbish. I just wondered if it was normal to have just five cells in a battery obviously built for ten, or did the worker nick them for his vape?

DWD

Someone-Else · Post by **Someone-Else** » Wed Aug 21, 2024 9:14 pm

dewaltdisney wrote: ↑Wed Aug 21, 2024 6:29 pmI just wondered if it was normal to have just five cells in a battery obviously built for ten, or did the worker nick them for his vape?

Depends on the initial design. So in your case, I would say it is "normal" to have just 5 cells, but if another company wants them they can have 10 cells put in.

big-all · Post by **big-all** » Wed Aug 21, 2024 9:35 pm

the recognise start point is 3.6v per cell so 10x 3.6=36v
now some will count the over volt when charging off around 20% so 10.8v tools [3 cells]turn into 12v 14.4v [4 cells turn into 17v 18v [5 cells ]turns into 20v ect
the most you can get from 10 cells with a high speed charger is 35x25% so 45v so your saw should be called 36v but because half batteries can only be 18v

dewaltdisney · Post by **dewaltdisney** » Sun Aug 25, 2024 3:42 pm

Well, this saga continues. The new saw lightweight batteries are still a mystery. One battery is definitely defective and will not charge at all, the other one charged but only lasted a few minutes in use the other day, I put it on to recharge anyway. Today my original saw ran dead after 20 minutes use, which was inconvenient. I thought I would try the new saw and battery again and it strangely worked for a good hour which helped me finish what I was doing. As it was still running I thought I would charge it again. My old battery and the useless battery I put in the freezer as I read this could help reset them. Neither will charge now so I am down to one dubious battery. Strange.....

DWD

Someone-Else · Post by **Someone-Else** » Sun Aug 25, 2024 3:44 pm

Putting them in the freezer is a waste of time, urban myth.

dewaltdisney · Post by **dewaltdisney** » Sun Aug 25, 2024 7:27 pm

Rearrange these words into a well-known phrase or saying = Straws clutching at was I

DWD

dewaltdisney · Post by **dewaltdisney** » Mon Aug 26, 2024 3:27 pm

Update, I would be lost without my mini chainsaw so with only one dubious battery working I decided to buy another. The market is awash with them and I have bought one off eBay for £23 this time. Of course, I could have bought another bit of duff kit but I checked all the reviews and there were no moans. This one has an oiler for the chain, interchangeable 6 and 8 inch bars and chains, and two batteries. With these two batteries and my only good one hopefully I should have a degree of faith in having the two saws working over the time I need them.

We shall see, I may have made another mistake. I will report back.

DWD

dewaltdisney · Post by **dewaltdisney** » Thu Aug 29, 2024 7:58 pm

The new saw kit arrived today and I immediately put both batteries on charge. They charged for a couple of hours before the green light went on so the test now will be how long they last in work. For the money it is a nice saw and the chain oiler function looks like a good addition. I think that these saws are just a much a risk as the same saws sold for £30 to £40 so we shall see. I will keep the old saw for spares. Update to follow.

DWD

dewaltdisney · Post by **dewaltdisney** » Sat Aug 31, 2024 10:08 am

First use yesterday, the first battery lasted for an hour and a half, obviously not continuous running but it was cutting all through that time. As I was delimbing the thicker branches to separate out the thinner stuff to go through the chipper it gave out. I swapped batteries and the saw carried on to the completion of the cutting. As soon as the battery showed signs of going I put it on charge so it was not completely flat before recharge. So far so good.

DWD