Emerson/Vertiv R48 Rectifier

graememk

Started playing around with one of these R48 rectifiers, They are second hand on aliexpress. I think they are used as power supplies for telecommunication things.. Also very good at charging batteries.

They are programmed over CANBUS and can be set to whatever voltage you desire (usually come from aliexpress set to whatever you want. The workable voltage range of them is huge, from 80-300v! Seen it mentioned that it would be good to charge batteries off a generator, as it can handle the dirty power some give out, and not that expensive.

From another forum, they worked out the CAN communication details. using that I have done a rough esphome implementation of it. Will be able to change the voltage, output current, input current, and also the power data from it. (and set the "offline" presets too)

Used one of them lilygo T-CAN485 boards. Also printed a wall mount for it, Protect the terminals a bit more and some cable protection/retraint (stuffing glands can screw into the bottom of 3d print)

I'll be sticking the files up on printables at some point if anyone is interested. Its vented at the bottom, but wouldnt be IP2X rated (finger proof) Would need to add extra gratings in it to make it finger proof. It also locks into place with the locking lever. It rests on a internal lip at the bottom cover.

https://github.com/graememk/esphome-Emerson-R48-CAN

NedNew2

Excellent work!

unkel

Been using these for years. They are dirt cheap at about €80 shipped for a powerful continuous charge of over 3kW. Great if your hybrid inverter can't charge your batteries quickly enough.

Looking forward to implementing @graememk's handywork. Until now I was using these at the exact voltage they were programmed for (you can specify it when you order) and only at the max amps. On a 16A smart plug that I could control from Home Assistant. In other words: it was all or nothing.

on_the_roots

I'm probably going down this route soon. Thanks for sharing the configs, I would eventually play with CAN on this.

graememk

Mine actually came with a port (2.54 JST) to plug in the CAN connector

JohnySwan

https://www.boards.ie/discussion/comment/123092686#Comment_123092686

16 amp smart plug?

graememk

https://www.boards.ie/discussion/comment/123096569#Comment_123096569

I've had a few, opened up and verified the 16amp fuse.

I think only 1 of them are alive now, was using them to control immersions.

The 25amp sonoff handled it without issue.

JohnySwan

https://www.boards.ie/discussion/comment/123096643#Comment_123096643

Can honestly say I've haven't come across them, I assume these are imports?

graememk

https://www.boards.ie/discussion/comment/123096653#Comment_123096653

Got them in the local co op!( Or the sonoff, Amazon)

Ener-J was the brand but that's just a rebrand of the white label tuya manufacturer

May have a 16 amp internal fuse (non replaceable) but I'd say the biggest flaw is the 13amp plug. This rectifier will be on a 16 amp cee plug.

JohnySwan

https://www.boards.ie/discussion/comment/123096724#Comment_123096724

Must pick one up as my inverter only charges at 4500 watts.

unkel

FWIW my outdoor 13A smart double waterproof socket is also Ener-J brand and works in the Tuya app and was automatically picked up in Home Assistant too. And somehow or other, my outdoor only granny cable pulls well over 3kW and is one for 3 hours on end, which has not been a problem for that socket

graememk

https://www.boards.ie/discussion/comment/123096742#Comment_123096742

The granny lead normally have a temperature sensor in the plug too, so that's another layer of safety.

unkel

https://www.boards.ie/discussion/comment/123096751#Comment_123096751

The granny cable lives outdoors on or beside concrete driveway and stone walls. So it can't do any harm really even if anything should go wrong.

zoom_cool

What program voltage do you normally purchase for these Rectifiers there is 53.5v or 57v I assume the 57v or is the 53.5V enough to get your 16s battery to 90%

unkel

https://www.boards.ie/discussion/comment/123104016#Comment_123104016

53.5V divided by 16S = a bit over 3.34V per cell. Close enough to 90% SOC but why would you only want to charge to 90%? Make the battery work for you, squeeze every cent out of it.

This is 2025, batteries are dirt cheap and getting even cheaper soon. Minimise the pay back period. It is not 2015 when batteries were expensive and they needed to be handled with silk gloves

zoom_cool

https://www.boards.ie/discussion/comment/123104115#Comment_123104115

So the best pre-set voltage would be 57v then to get to 100% charge and fill up the battery

paddy236

There are a few different sellers on AliExpress. Can you give the link to the one you used?

championc

https://www.boards.ie/discussion/comment/123104221#Comment_123104221

The BMS will manage / prevent any cell going above your set limit (assuming 3.65v)

graememk

This one:

I went for a conservative 56v which would be 3.5/cell. I normally run with a 57v charge voltage so when the cells reach 3.5 v the Emerson will back off electrically, and the inverter can top the battery off to full

https://a.aliexpress.com/_Euc9Aos

zoom_cool

https://www.boards.ie/discussion/comment/123104649#Comment_123104649

Do you use the CAN interface on the module

graememk

https://www.boards.ie/discussion/comment/123104859#Comment_123104859

Planning to, but will be mostly for monitoring, Currently sitting on the desk.

zoom_cool

https://www.boards.ie/discussion/comment/123105017#Comment_123105017

Thanks for the info after this storm need backup plans :-)

unkel

https://www.boards.ie/discussion/comment/123104221#Comment_123104221

In my experience, the higher you set the charge voltage above the battery voltage, the higher the current that is used. As @championc said, there is no risk. The BMS will stop any charging as soon as one cell hits OVP

championc

I ordered one for 56v in order to allow it to back off a bit. The seller will configure to any voltage you like rather than being restricted to the options on the advert only.

So it's a bonus now having a method to reprogram the options.

I've mine connected via a TAPO Smart Plug, so 13A. Therefore, I don't want it hammering a constant 3kW for 3 hours

10-10-20

Do you just wire it up in-circuit with the solar inverter and just make sure to only run it when the solar is zero?

You might all be safer with a 20A/25A contactor instead of a relay or smart plug. Those aren't rated for high-inrush currents like you'd see on a high-output PSU.

https://www.eurosales.ie/categories.html?name=contactor&type=simple

championc

Inrush would be on the DC side into the rectifier. No issues whatsoever

graememk

Well the power ramps on the power supply (and also configurable)

But planning on putting it on a 20 or 25 amp sonoff pow2 I can't remember exactly. Been running an immersion on it without issue.

It's wired up in parallel with the inverter and battery.

Can actually run both at the same time. Just don't run it when running on battery because it would end up being a heater!

10-10-20

https://www.boards.ie/discussion/comment/123106353#Comment_123106353

AC side. It's the smoothing (bulk storage) and noise caps filling. Inrush causes the relay contacts to bind or erode.

Blakes77

A word of caution on these rectifiers
I have one and use it occasionally to boost my charging (Flatpack2 48V/3000W)
I have the canbus interface and was able to change the charge voltage as I wanted
I found the parasitic load quite high, around 75 watts, even when not charging. So if you have it connected to your batteries all the time you could be loosing over 1.5 KWhr a day. The other worry for me was when connecting to the battery there was always a fairly dramatic spark. Using a charge resistor made no difference to the spark.
So I use it as a backup, not everyday
Just passing on my experience

zoom_cool

https://www.boards.ie/discussion/comment/123107335#Comment_123107335

This is good to know so you would want to disconnect it with some sort of switch/relay when not in use then would you agree?

graememk

https://www.boards.ie/discussion/comment/123107335#Comment_123107335

75w Load from the AC or load from the DC?

I wouldn't be connecting it without some sort of isolator either, to prevent the spark.