can I use five 12v power supplies in series to charge 52v battery?

[diplomatically]

I'm eventually building a 52v li-ion battery (14s10p, 18650 cells) for my first e-bike. I have a ton of 12v server power supplies (all the same make and model) laying around - I guesstimate their actual voltage output range to be 12.2 to 12.4 volts. I've already figured out the pin outs to convert them to basic power supplies. I understand a 14s 52v li-ion battery fully charges to 58.8v; can I throw five of those 12v power supplies in series to make a power source for a charger? If so, what is the actual name or type of device do I need to do the actual charging part? If not, how do get 60v (or 61 to 62v) down to 58.8v for charging?

 

[www.recumbents.com]

Short answer - yes, if they are isolated.

You will need to either babysit them until your battery is charged or figure out some way to shut them down when your battery gets to a certain voltage. I'm sure there's a circuit for that or something on ebay that will do it.

Warren

 

[billvon]

I'm eventually building a 52v li-ion battery (14s10p, 18650 cells) for my first e-bike. I have a ton of 12v server power supplies (all the same make and model) laying around - I guesstimate their actual voltage output range to be 12.2 to 12.4 volts. I've already figured out the pin outs to convert them to basic power supplies. I understand a 14s 52v li-ion battery fully charges to 58.8v; can I throw five of those 12v power supplies in series to make a power source for a charger? If so, what is the actual name or type of device do I need to do the actual charging part? If not, how do get 60v (or 61 to 62v) down to 58.8v for charging?

Sort of.

1) They have to current limit, not shut down, on overcurrent. If the spec sheet uses the term "hiccup" or "restart" for overcurrent protection then it's not usable.

2) You have to use anti-reverse-bias diodes across the outputs to prevent backfeeding and possible damage to the supplies.

3) Take 58.8 and divide by 5 then trim each supply to 11.76 exactly (as close as you can come.)

4) Cool them aggressively; if you use them as battery chargers they will be in current limit and dissipating about 25% more power than they are rated for.

5) When you charge with that, monitor voltage and current with one of those cheapo inline meters. When current reaches C/10 (say, 1.5 amps for a 15 amp hour battery) then stop charging.

 

[diplomatically]

Well I wasn't expecting to be able to directly connect a power supply to the batteries to charge it (albeit babysitting it), that's interesting. I was thinking there is something out there similar to smart chargers for RC hobby car/drone LiPo or NiMH batteries, but for e-bike li-ion batteries. Or maybe something similar to solar charge controllers for powerwalls/power inverters, but for e-bike li-ion batteries.

Is there something out there for this? Or maybe there's a hobby charger or solar charge controller out there big & smart enough to charge a 52v li-ion battery pack?