RC-Monster Forums - View Single Post

BrianG · 11:14 AM

Well, keep in mind that charging 4900mAh batteries at 12A is almost a 2.5C charge rate, which may not be the best idea depending on the particular battery. Plus, if the pack has any kind of imbalance, it would be really hard for any balancer to equalize the cells in that short of time, and you run the risk of one or more cells getting beyond 4.2v before the CC/CV threshold.

Generally, 1C works fine and runs a little over an hour to charge a fully depleted pack, so that's not bad really.

You don't absolutely NEED a super high current PS.

If you are just going to charge a 2s 4900mAh pack at 1C, you only need a PS capable of ~4A @ 14v (or ~4.5A @ 12v).

If you want to charge two 2s 4900mAh packs at once at 1C, you need double that (~8A @ 14v or ~9A @ 12v).

If you want to charge two 3s 4900mAh packs at once at 1C, you need 11A @ 14v or 13A @ 12v.

As the pack capacity and/or cell count and/or charging C rate goes up, so does the power requirements. You could get by with a cheap 12v supply for now, but then upgrade later when you power requirements increase, but it tends to be more expensive in the long run...

	(#15)
BrianG RC-Monster Admin Offline Posts: 14,609 Join Date: Nov 2005 Location: Des Moines, IA	12.02.2008, 11:13 AM Well, keep in mind that charging 4900mAh batteries at 12A is almost a 2.5C charge rate, which may not be the best idea depending on the particular battery. Plus, if the pack has any kind of imbalance, it would be really hard for any balancer to equalize the cells in that short of time, and you run the risk of one or more cells getting beyond 4.2v before the CC/CV threshold. Generally, 1C works fine and runs a little over an hour to charge a fully depleted pack, so that's not bad really. You don't absolutely NEED a super high current PS. If you are just going to charge a 2s 4900mAh pack at 1C, you only need a PS capable of ~4A @ 14v (or ~4.5A @ 12v). If you want to charge two 2s 4900mAh packs at once at 1C, you need double that (~8A @ 14v or ~9A @ 12v). If you want to charge two 3s 4900mAh packs at once at 1C, you need 11A @ 14v or 13A @ 12v. As the pack capacity and/or cell count and/or charging C rate goes up, so does the power requirements. You could get by with a cheap 12v supply for now, but then upgrade later when you power requirements increase, but it tends to be more expensive in the long run... Last edited by BrianG; 12.02.2008 at 11:14 AM.