charger for 48v 12ah battery - Solved by BikeMad

[jbzg]

Hey,

I bought MPII with 48v 12ah battery from my local dealer...

However, as I asked in other post, I am having troubles with the range my battery gives me. As I read on other topics someone has suggested that battery life might be caused by charger... I checked my charger and it says that output is 54.6, however as I understand 48v battery should be charged with 58.4, am I right??

[truly_bent]

Your question piqued my curiosity, so I checked out my own charger. It also came with the (LiFeP04) battery. I was a bit surprised to see it labeled only as "Li-Ion" (i thought it would show the specific battery chemistry) with a 48V output. I checked it with a meter however, and it read 58.5V.

This charger has a 3A output. I'll be buying this one soon: http://www.bmsbattery.com/alloy-shell/27-alloy-shell-600w-lifepo4li-ionlead-acid-battery-ebike-charger.html, which will speed my charge times up by a factor of 3.3.

Faster baby, faster...

[Bikemad]

I checked my charger and it says that output is 54.6, however as I understand 48v battery should be charged with 58.4, am I right??

Unfortunately it's not quite that simple, the charging voltage is determined by the number and type of cells being used:
 
The earlier 48V 12Ah packs used thirty nine 3.8V 4Ah cylindrical LiMn₂O₄ cells which were configured into thirteen groups of three paralleled cells connected in series to give the required voltage and capacity. The maximum charging voltage for these cells is 4.2V per cell, which works out to be 54.6V for the thirteen cell groups connected in series.



The later 48V10Ah LiFePO₄ packs are made up of sixteen 3.3V 10Ah rectangular cells. The maximum charging voltage for these cells is 3.65V per cell, which works out to be 58.4V for the sixteen cells connected in series.

Hopefully that answers your question.

Alan
 

[jbzg]

Thanks Alan, please can you confirm following,

I checked my battery, just to be sure, and it reads LFP-4812S. So, as I understand, these batteries should be charged with 58.4V charger, ie. I should ask for a new charger?


Also, can this hurt my battery? (since battery will not go through full- empty cycle for first 10ish times)

Thank in advance!

[Bikemad]

Your LFP-4812S is LiMn₂O₄ and must only use a 54.6V charger.

The newer 48V packs are labelled LFP-4810S-LT as shown here:


Earlier LiMn₂O₄ do not have the "-LT" suffix like this 36V 16Ah pack shown here:


Alan
 

[jbzg]

Dear Alan,

Thanks a lot for your prompt answers. I will give my battery another 10 full charging cycles, and I hope it will be fine then. However, based on your other reply, and based on the battery behaving, I'm pretty confident something might be wrong with it.

Lets hope for the best.