Eaton APR48-3G 1.8kW Light Compact Charger PSU


100 MW
Dec 5, 2011
Stockholm, Sweden
Eaton APR48-3G Rectifier Module (battery charger)

Very popular due to its size/weight/power ratio.
Can be obtained through me or ebay:
Weight is just a bit under 1.5Kg
Pretty quiet compared to others as well.

Nominal Voltage: 48V
Adjustable Voltage Range: 43 to 57.5V
Rated Output Power:
100Vac: 900W
120Vac: 1100W
208-240Vac: 1800W
Current Limit: Factory set to 37.5A

From left: Eaton, Adaptto Max-e, 1500W Cherokee CAR1248FP


Using powerful iron really helps and you dont have to remove the cover to solder on the wires.

Charging trough Adaptto Controller with 30A Coil
View attachment 7

This is how much it drains from the wall at 21A charging current

If you want to use it as a CV charger(skip this guide if you use Adaptto)
(The text and pictures are taken from another Board - thanks to KrOeNeN)
You need to modify it by cutting two of the traces and place a resistor on one of them.
Firstly, drill carefully out the pop rivets to gain access to the insides.
Slide out the board and flip it over.

First trace(marked with red cross) is for over-voltage protection. If you do not cut it, the PSU will shut down when voltage goes above 57.5-57.6V.
If your fully charge voltage do not exceed the 57.5V you don't need to cut it.

Second trace controls the DC Voltage. It goes directly to the second control board. Same here, you need to cut it and solder on a resistor.
View attachment 4

Example below shows how to make it to a 14S charger, around 58.5-58.8V
Here is a 1,5 kOhm that makes 58.4 on the DC tabs. Or you can add potentiometer to adjust the voltage gradually.

It is possible to re-program Eaton so you can have lower voltage and lower amps, this is perfect if you have 14s battery with Adaptto system. Or you want to bulk charge to your preferrable voltage during a simple bulk charge.

First you need to get a 2USD USBasp USBISP 3.3V / 5V AVR Programmer, I used this one:
View attachment 3

Then drill out all pop rivets and open the case:
DSC07010 kopia.JPG

Then using pin out diagram to solder on the wires:

After that, download the software (, you will need:
-usbasp driver
-Khazama AVR programmer(software that extracts the original EEPROM file from the Eaton and writes back your modified)
-Eaton patch tool(with this one you modify settings in your EEPROM file, like voltage and amps)

Install driver and solder on the wires, connect USB programmer to eaton and plug in programmer to your computer. DO NOT plug in you Eaton to wall socket!
If done correctly you will see two Eaton LEDs lit up(one will flash):
DSC07019 kopia.JPG

Once Windows recognize USB Programmer, open up Khazama AVR programmer.
Choose ATMEGA32 in AVR scroll down window. You can test communication by choosing "Command" -> Read Chip Signature
Now you need to read your current EEPROM from Eaton. Command->Read EEPROM to buffer
Then you need to save it to a file. File->Save EEPROM buffer As... Save it to something like DefaultEaton.hex
Start Eaton patch tool, Eaton.exe
Open your saved hex file
You will see current values. Change to what suits you and press Patch
Open up Khazama and load you patched file. File->Load EEPROM file to Buffer
Now write the file to Eaton. Command->Write EPROM buffer to Chip
During write LEDs will turn of on the Eaton.
Then you will get Write OK in Khazama

DSC07020 kopia.JPG

Good luck!
Allex, can you tell me how you open the APR 48 case? It has all these screws or what looks like rivets. How do you unloosen them?

Also, in your wiring diagram you have only 2 wires for AC in. For 110 volts we have positive, neutral, and ground. Do you know which ones go where for a 3 wire setup?

Yup, those are pop rivets! Eaton deff. don't want us to dig inside. So you need to drill out hem to access the guts.
But if its just a soldering job on the main leads then you don't need to open it, there is enough room to solder with the top case on.

In the last picture in the first post(the one with multimeter) you will see the correct wiring if you want to use the ground as well.
Allex said:
I sell them for 180USD :)


can i install 2x Eaton PSU to a max-e with a 70A coil and have 2 x21A charging current? The only 21A is not fast for my 16P Sony VTC5 with about 41,60Ah.
Today I charge with my Siemens charger with about 50,40V and 45A, so around 2250W. 2 x 1650W like your single PSW are welcome!
Do you have 2 pcs. PSU on stock?
Eaton can actually deliver more Amps. In the pciture the limitation to 21A was du to my higher voltage.
So if your pack voltage are lower than 20s it will pump in more.

I heard that you can use those in parallel as long as the output voltage is the same, for a total of 3,6kW.
My friend is currently in China and will bring 3-5 units for me.
Allex said:
Eaton can actually deliver more Amps. In the pciture the limitation to 21A was du to my higher voltage.
So if your pack voltage are lower than 20s it will pump in more.

I heard that you can use those in parallel as long as the output voltage is the same, for a total of 3,6kW.
My friend is currently in China and will bring 3-5 units for me.

Allex, this is clear, so how many max Amps are possible with one unit. Please send the max. Input (PSU)and output Amps (for charging).
Thanks for your helping hand.

-for example, a meanwell 1500W can hold 2160W
-can your Eaton also handel more then the 1800W?

-max output PSU: 48V x 37,5A: 1800W
-your charging W: 76V x 21A: 1596W
Allex said:
ecross, I dont know more than the datasheet, perhaps it can help you, in the first post. I never experimented with more than ~1800Watts.

Allex: Could you please set the PSU with the max output and show us your measurents?
Don't have any units right now and no controllers =)
Maybe current users of this PSU could help you out, probably best to ask in adaptto thread.
question: is it normal that the orange led always flashes during (normal) operation and if the psu is fully loaded it stays on constant?
i ask because i have done some work on it to get it fit in peli 1170 case (yes, together with the small coil) and i have not tested it before so i have no comparsion.

about the 1800W spezified power:

i have never seen more than 1730W on the Adaptto display at full load, but i guess thats normal because the missing 70W are the losses from step up conversion. this is probabaly the amaount of power which turns into heat in the coil and controller.

my Eaton is factory set to 54,4V (like everyone should be). with 2V vdrop setting and 30,5A supply current i can pump constant 1600W power into my battery without to have full stress on the psu. thats awesome compared to the heavy and bulky chargers i used before.
the conversion into peli case required some heavy thinking, but the great result was definitely worth all the time i have spent with it.
Show us pictures of you case!
That orange flash is normal yes.
Adaptto can show up to around 1700W, of course you will loose a few on the way there.
Allex said:
Adaptto can show up to around 1700W, of course you will loose a few on the way there.

i wonder if it would make sense to set the voltage to about 58V by doing the mods you posted in another thread.
with higher volts we could turn down supply amps a bit which should improve efficiency.

im going to post pics soon, but first i want to paint the aluminum cover and mount it again on the supply.
probably (if i have enough time) i will make lots of detailed descriptions and list up all kind of materials i used so other can convert it too.
this is my Eaton built into peli 1170 case with the small coil. The Fan is super silent compared to the stock little screamers and since the aluminum cover is attached to the heatsinks it also stays very cool!
will make a thread about it when i have more time..


Alex , as promised im here with elementary questions. Ive just got some LifePo4 prismatic cells from china(they fit). I intend to run them 15s (20AH) for
a nominal 48v. The battery seller recommends cv/cc, would you say this PS is so. I saw your earlier post on the mod to a higher volt and that I can do. Could I expect to get a 20 or so amp charge (@110v)? Could you explain the coil a bit? I was just going to bulk charge but, I do own a 30 amp coil I got for whatever options . Just seems simpler to bulk charge the batteries to me. Darned If I can figure the hows or whys of that coil.
Hi, do you have Adaptto setup? If no just bulk charge, if yes, it is neat to charge via controller, you will see how much time is left to a fully charged battery, cell status and so on.