Recent content by jha07

The charger voltage is still over 60V. The problem is that as soon as one cell hits the charging cut off voltage, around 3.85V, the pack stops charging. And because of this, the other cells don't get a chance to get fully charged. And I've tried leaving the charge on for many days. I've also...

My Ping pack is about 1 year old now. I've only put about 50 cycles on it. And I've also had to replace cells groups twice. One when I first got the pack. It came with a bad cell. And the second time a few months later. The cell wasn't holding charge and lost capacity. It's been working fine...

That is interesting. The one cell from my pack that did swell happened when I took the pack apart to replace a bad cell group. The swollen cell was the next in line, so it had no compression. It sat like that for over a week while I was waiting for the replacement parts. It was during that time...

I'm not sure if he's selling you the same chargers I got from him. But if there are the same, both chargers are the same size. The 5A charger weighs a lot more though. Both chargers have fans. I find the noise from the 2A charger very annoying. When I use it overnight, I have to use it in my...

I have both 2A and 5A chargers. The 5A seems to be made much better. The 2A charge makes a high pitch noise when it's charging. The 5A is very quite. What are the cost of the chargers? I would go with 5A if it's not too much more.

Bummer. You've definitly had your share to problems. Were your previous damage cells bulged? The one bulged cell I got was also next to a bad cell group. At the time, I just thought it was coincidence. Maybe it wasn't. The other unbalanced cell I replaced wasn't bulged. It would be nice to know...

I don't have enough experience with bulged cells to know how they perform. It could be that they still can charge up to 3.7V, but have less capacity. The fact that you were able to get all your cells up to 3.7V in just one night means that it wasn't very unbalanced. That could mean the bulged...

How long did you leave it on the charger? It's possible that your pack is just out of balance and if you let it charge longer, the other cells will climb up to 3.7V. I would leave it on the charge for 48 hours and see if the voltage climbs.

I also had a bulged cell and this happened before my first cycle, so I'm pretty sure it's not caused by a high discharge rate. My pack arrived with with a dead cell group. I had removed the bad group and was waiting for the replacement cells. When the cells arrived, I noticed that the cell...

A 48V pack will have 16 cell groups. How many cells in a 20ah pack depends on if you have the 5ah cells or the 4ah cells. The first time I had a problem with the my pack, the entire cell group went bad and measured 0v. My second problem was a balance problem, and in that case, only one cell in...

The bms monitors each cell group, not each cell. So you could add more cells in parallel to a cell group. But you'd have to do this to every cell group for it to be useful.

It's not terribly hard to replace a cell on a ping pack. The tricky part is unsoldering the cell tabs from the board it's soldered on. The tabs are fed through a slot in the board, and it can be tricky to remove it. I don't believe you can just remove a bad cell since the bms is looking for...

If I had to guess, I would think he doesn't test every cell. Only because it would be very time consuming to do so. Also, my pack didn't have this balance problem at first. If it did develope after 10 cycles, you would need to cycle each cell >10 cycles to weed out this problem.

It would be nice to have extra cells, but I don't think if I'd want to offer a pack repairing service. Not that it's extremely difficult to replace a cell, but it can be time consuming. I spent over 2 hours on it. The balancing takes a lot of time as well. Besides, I think most people that have...

That is a possiblity. But seeing as I only put a total of 15 cycles on this pack, and I'm assuming the pack only starting going out of balance 5ish cycles ago, I don't think that's enough to make too much difference. Also, my motor draws an average of 8A, so even if all the work was done by 2/3...