Does a 5A charger harm battery

Hello I have read, heard, different leading statements on battery chargers. So here is my question, I hope that it does not make me sound too much like a beginner. Does a 5A charger cause any more harm to a battery then a 2A charger. I have heard and read that it does, also that it does not. So I thought that this site and it's experts would be able to set things straight. (BTW, I use a 48v 20Ah cellman A123).

Thanks Tom

You're charging the entire pack of multiple parallel and series cells at C/4 (20A/5A), and a BMS is involved, so it should not harm it.

Check the datasheets for the individual A123 cells. I think they can be individually fast charged at something like 4C (10A each cell) if you really wanted to. (Wouldn't recommend it, pack lifecycle, etc...)

Edit: Slowly charging might extend the lifecycle of your pack and maybe produce better balancing, but will take a lot longer.
Probably fine if you leave it in overnight for a day's commute and are okay with unattended charging etc... however even 5A for a pack this size is already kind of on the low end at %25 of the recommended charge rate.

If they're genuine A123s, the recommended charge rate is 1C (20A). The maximum fast charge rate is 4C, or 80A.

5A is not doing the battery any harm, but I don't think it'd be giving your pack much additional life over 20A either, and no less life than 2A.

Seriously, who wants to wait 10 hours for their pack to charge anyway?

In this case, certainly a 5 amps charger will not harm the pack. As said above it depends on the spec of the cell, and the size of the pack. In this case, doing the math shows you are way below the max charge rate for A123 cells.

It's worth noting, that in some cases the limit is what the bms can handle without overheating, not the cells themselves. Most bike bms can handle 5 amps.

Where 5 amps would harm the battery, is in the case of a 12 ah sla. That would be hard on lead that small. With lead, the slower the better.

My 12s 40Ah lipo pack I charge at around 6.25A and it takes around 2 to 2.5 hours to charge. Never got close to 3 hours yet. So a 5A charger would not take that long to charge a 20Ah pack.

Thanks to everyone that posted a reply.

Thanks again Tom

5A charger is fine. Limited by bms as it can only bleed down the high cells at a curtain in heat to blance the pack. But the cells can take a whole lot more it's just keeping balance with the bms.