Someone remind me of the danger associated with connecting something like this parallel AAA battery tray to a Charger to charge 10440 cells?
If your Charger has steel (ferrous) battery contacts you could solder small Neodymium magnets on the wire ends (see below) of the tray above and connect them to the charger's + -
Then when charging you would place 2+ cells in the parallel wired battery tray. With 2 cells that would drop a 500mA charger output to 250mA.
However with unmatched cells this may be dangerous, but I'm not clear why. If one cell was at 2.8V and the other 3.2V what would happen if they were charged like this? Or a new cell was charged together with an old cell with higher resistance?
So right now I'm not advocating charging 10440 batteries with this setup.
With 2 cells in parallel the charge rate each would see should depend on the internal resistance of each cell. Not sure how uneven it could be.
If the cells were matched you can get away with it. Same type / brand, internal resistance, voltage, capacity, wear. Unless you always use two cells together they will wear / age differently even if they started out matched.
I’ve read people who did 10440s in parallel but it just doesn’t seem worth it. It use to be harder to find a suitable charger. Now there is the XTAR XP1 that does 250mA, good for 10440s. Mihalski needed even less current for 10250 tho. Those tp4056 usb CC/CV charger boards are the cheapest option if you can mod them. (Be sure the chip says tp4056 when you get it. Had an unlabeled chip do only CV at 4.25v, refunded.)
Besides some danger you’ll be reducing the capacity of your cells. Not sure how much or how quickly. 10440s don’t have a lot to begin with. I don’t want to give up any.
I said to myself I was going to check here tomorrow, see if anyone else wanted to respond… next thing I know I’m looking at this post. :zipper_mouth_face:
Hope I don’t sound like I’m telling people what to do or otherwise come off badly. :weary:
Thank you. All very useful information. Don’t worry, it’s all appreciated
I’ve charged two 14500’s and two 18650’s with my charger so far and it seems to work great.
I also found that I have another possibly useful little breakout board that, if combined with an ammeter could let me get some very interesting information.
At the very least I’ll rig something up with the LiPo fuel gauge in the next couple of days to see how useful the information I pull from batteries is. I’m not sure how I would go about connecting the charger AND fuel gauge to the battery simultaneously but it does seem to be supported.
Even though I have no skills in this area and know little to nothing about batteries and about the same about electronics, I’m tempted to start slowly (VERY slowly) figuring out how to build my dream charger
