charging on adaptto bms


100 W
Sep 2, 2013
help me understand charging for the adaptto. or help me confirm that I understand (I know for the experienced this is dead ass simple).

to start my setup.

adaptto mini-e with onboard bms
motor: cromotor v2
battery:(just ordering now) 20s9p of 18650 25r cells(made up of 5 x 4s9p pack in series, balance leads to bms). = 72v(nom) 22ah battery.

that gives me roughly 1500watt hours of battery

now the beauty of the bms is that I just need a power supply, heres where I'm double checking I understand. Most chargers are rated as Watts. so a 500w charger could be 12v @ 41A or 48v @ 10.5A. For my purposes higher volts is better to help keep temps down. Even some pc power supplies say they are rated at 1000w, but because they are 12v output, that not ideal correct? this is why people are running to server psu's as they can output to 48v.

a 48V @ 10A charger would be a 500W charger. this would be a roughly 3 hour charge time (1500wh pack) correct?

I guess where I struggle is that to get decent chargers it seems like a pretty good expense. I need 2 chargers (1 for work and 1 for home)

most 1000w 48V psu's I've found are in the 250$ + shipping, so this puts me at 500$ worth of chargers to have a work/home setup.

am I missing where people are finding cheaper 1000w chargers? Is it simply the convenience of a 90min charge that people are going to these 1000W + chargerS? I supposed I could buy a 1000w charger for home and a cheaper 500w charger for home as I'm usually there for a full 8 hours.

other info is that both work and home I only have access to 110V ac outlets (no 220 currently) How low of a Volt psu can I go before heat will become an issue? ie is a 12v 40A charger a bad idea?
what have other people done?


100 W
Jun 25, 2013
For charging with the adaptto the bms is not necessary, you only need the charger coil to connect to the controller. The minimum voltage recommended by adaptto to charge the battery is 24v. You can connect in series a couple of 12V power supplies and get the necessary voltage that you want.

It's better a hith voltage PSU than a high current, because the controller will heat less to step up to the voltage of the battery.

The total voltage of the power supplies connected to the controller need to be less than the LVC of the battery.

I am running 12V 700w server power supplies in series. I bought 5 units reconditioned on ebay for about 100USD+ shipping and can charge with 2 or more in series. If I connect all the 5 I can charge my pack in less than an hour (22s 40ah) :twisted:


100 W
Jan 23, 2014
Spokane, Wa
I did the same thing as striker54. Connected several hp server power supplies together to get the supply up to 48v and 47amps. I found floating the dc ground to be really easy. It's totally doable for under $100. Just keep in mind that you may have to use a couple separate 120v circuits to power the supply up without popping breakers. [SMILING FACE WITH OPEN MOUTH] lots of info out there on how to do it depending on what power supplies you get.