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diy solar

diy solar

DIY 'Chargenectifier'

I wonder if you can do some kind of ducted hood that covers the entirety of the printed structure. And then on the other wider side some much larger, slower running fans with good static pressure rating. And then disable the tiny screamers?
These little fans have a monitor built in, if you stop them, unplug them, the unit complains with error... but I agree it would be nice to move to larger fans.
 
I see one controller for 4 units, good stuff. I think putting them all on the same bus was a good decision, allows the units to communicate for load balancing as they ramp down... 16kW what a beast. And I agree, more control and much more fun than an off-the-shelf-system.
One ESP32 is powerful enough to control all four units. Also it's more robust to adjust the output voltage of all four units with just one CAN bus command instead of relying on two completely uncoupled and different WiFi based devices. As you've mentioned, ramping up and down is also a lot easier with just one unit. I hope I can finish the installation in the next 5-10 days and will provide feedback how everything (hopefully) works.

I think that most of the time I will use only 8kW but it's good to know to have 16kW in case I need it - for a double conversion system it's a chance to need this power sometimes... we'll see.
 
Are they output limited at 120V versus 240V?
Regarding the spec sheet, it has an output power of 4,000W when using between 176VAC-300VAC input and only 1,600W between 85VAC-175VAC with "linear derating".

Because of "linear derating" between 85VAC and 175VAC the formula seems to be:

Pout(Vin) = 26.67*Vin - 666.67

This would be 2,533W for 120VAC input.
 
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Regarding the spec sheet, it has an output power of 4,000W when using between 176VAC-300VAC input and only 1,600W between 85VAC-175VAC with "linear derating".

Because of "linear derating" between 85VAC and 175VAC the formula seems to be:

Pout(Vin) = 26.67*Vin - 666.67

This would be 2,533W for 120VAC input.
Sounds similar to my baby Meanwell HEP-480-54A power supply. It's passively cooled and silent but at the far end of price per kw spectrum.
 
Just an update on the 24V front... I was eventually able to figure out a strategy for my connector issues.

2025_01_05_connectors.jpg

An IEC 60320 "C7" cord (a common laptop power cord) can be modified to fit the AC input connector by cutting out a slot in the middle and shaving a bit off the outside faces. Unfortunately, such cords are usually 18 AWG or smaller and are rated for a max of ~7A - so only good for about half power. (Assuming perfect contact mating - which it probably doesn't achieve the pins aren't the ones it was designed to mate with.)

Next step is probably to order some TE 929971-1 (Mouser) contacts and make my own connector if I want to run at full power.

For the DC output, I was able to hand swage the wire receiving part of some copper lugs that were intended for 4 AWG wire to snugly fit the 8mm DC contact pins. So far I've run these up to ~65A for 30 minutes without excessive heat. (Difficult to tell the difference between the connectors/wires just being warmed by the fan output and any self-heating from a poor connection.) I can't recommend this strategy - so proceed at your own risk (obviously) - but it seems to be working for me. From there I bolted my DC cables lug to lug with the custom swaged connectors and wrapped the whole thing in electrical tape. 🫣

The CAN bus connections can be achieved with Dupont style connectors on pins 5 & 6 and GND connected to the negative DC output.

1736080616589.png

On the software side, PurpleAlien/R48_Rectifier/rectifier.py was a good starting point and worked mostly as-is.

Other than changing the voltage range validation to make sense for 24V, I also had to change the endian-ness of how floats are packed (Ln #61). I suspect this is a bug for interfacing with both 24V and 48V rectifiers, but don't have any 48V rectifiers to test that.

Git:
- return bytearray(struct.pack('<f', f))
+ return bytearray(struct.pack('>f', f))
 
I know it works like this on mine, but I'll investigate this further. It would be strange if they decided to change endian-ness between the different rectifiers...

Agreed, that would be weird.

I figured it out by comparing between what worked using Cangaroo based on this post and what didn't work from that script. It only worked when the left-most digits are the least significant. Which is how you'd get inputs like the examples in that post...

Python:
>>> import struct
>>> " ".join([f"0x{i:02x}" for i in struct.pack('>f', 41)])
'0x42 0x24 0x00 0x00'
>>> " ".join([f"0x{i:02x}" for i in struct.pack('>f', 58.5)])
'0x42 0x6a 0x00 0x00'
 
Amazing, thank you! You don't know how long I spent on DigiKey, Mouser, etc trying to find electrical contacts that might fit 😅

Ordered some. Will report back once I know how well they work...
I know your pain. There is pretty much unlimited number of different combinations on connectors and only some of them are available in quantities less than 100000.

This might be even better:
google "8mm ev electrical connector" lead me to TE website and digikey:
 
I know your pain. There is pretty much unlimited number of different combinations on connectors and only some of them are available in quantities less than 100000.

This might be even better:
google "8mm ev electrical connector" lead me to TE website and digikey:

Yeah, those look pretty good too. Probably won't throw more money at the DC connectors problem quite yet. If the SH8.0's turn out to be a bust, I might consider it. Thanks for the suggestions!
 
Just a short update.

Slowly things are coming together... as always, much much more work than expected...

It's a tight space to fit a pair of those units together with switches, fuses, lugs, controller, junction box, wires on top of each battery rack. I need some inches additional wire to be able to slide out the units to unplug the PCB connectors in case of service... big wires need a lot of space and there was no space left to place the junction box (with the 8/3 AC main cable and 2x 12/3 cable to feed each unit) on the wooden board also, instead I need to place it on top of the 3D printed rear unit bracket.

I'm looking forward to finish everything by end of next week (the ESP32 CAN controller software is already finished to control 4 units).

1736259560359.jpeg 1736259585166.jpeg 1736259622512.jpeg

1736259655796.jpeg 1736259680363.jpeg
 
Just a short update.

Slowly things are coming together... as always, much much more work than expected...

It's a tight space to fit a pair of those units together with switches, fuses, lugs, controller, junction box, wires on top of each battery rack. I need some inches additional wire to be able to slide out the units to unplug the PCB connectors in case of service... big wires need a lot of space and there was no space left to place the junction box (with the 8/3 AC main cable and 2x 12/3 cable to feed each unit) on the wooden board also, instead I need to place it on top of the 3D printed rear unit bracket.

I'm looking forward to finish everything by end of next week (the ESP32 CAN controller software is already finished to control 4 units).

View attachment 268338 View attachment 268339 View attachment 268340

View attachment 268342 View attachment 268343
I've finished the final installation and was able to do the first tests with a dummy load to check if the current limits and other settings and monitoring works (no batteries are connected so far on the DC outputs).

It looks like that everything is working - but...

This "beasts" are unbelievable loud! 🤯

Even with very low load they are very loud with a really bad screaming noise. I've used a water heater element with 7.5Ω resistance connected to 2 units with 52VDC for low current testing (about 2 x 3.5A = 7A total to test if low current limits are working).

I now have the same noise problem again which I had at the beginning with my EG4-6500EX AIO's. It costs me a huge amount of work to make these EG4-6500EX quieter. Even worse, it seems that these R4875G1 also don't have temperature controlled fans.

Now I'm a bit frustrated because I must make them quieter to be able to use them (instead of my AIO's AC-in's). I don't want to do the same temperature controlled fan modding which I've already done with the EG4-6500EX. The units have no space left inside the housing and everything is tight packed (I also don't know if this would work). So I think I need to test some passive noise insulation which @Brucey and @42OhmsPA mentioned (ducted hood, rockwool, double mdf, etc.)

@mpeterson mentioned to keep the output between 1-3kW to make them more quiet - but this does not work in my case.

Dammit... !

Btw. Are the Chargeverters (old and new) from EG4 are also very noisy?
 
A single Emerson is pretty loud as well, I'll have to keep that in mind when I add more.

I would bet the chargeverters are going to have the same noise level since they are essentially dual rectifiers in a box...
I have both the original (yellow) and the newer (black/grey) EG4 Chargeverters, - they are a bit loud.
(I made an alcove for them to be loud and alone!}

IMG_6374.jpg
 
Btw. Are the Chargeverters (old and new) from EG4 are also very noisy?
Oh yes, when I fire up my two I'm very glad everything's in a different building 150 feet away through the trees. Can't hear a thing from the house!

And they are temperature controlled, but they go from Jet Engine to Rocket Launch, so without removing the fans and ducting some larger/slower/quieter blowers into the housings, there doesn't seem to be a good solution, and they do throw off a lot of heat, so getting the external cooling wrong would probably cook them pretty quickly.
 
I have a number of inverters now, MPP 1012, 2724, 6048, and now the SRNE 12k's - but the Chargverters are louder than any of these inverters on high current. the fans are high pitch-ish not something you would put in your home without sound proofing a space. Then the cooling is going to be the next issue. Two of them make a pretty good heater for my use ! (I only need them when it's winter !)
 
I've finished the final installation and was able to do the first tests with a dummy load to check if the current limits and other settings and monitoring works (no batteries are connected so far on the DC outputs).

It looks like that everything is working - but...

This "beasts" are unbelievable loud! 🤯



@mpeterson mentioned to keep the output between 1-3kW to make them more quiet - but this does not work in my case.
OMG, I am feeling guilty, there must be something wrong with them, I can't hear mine, they are in the house under the stairs and my Victron MP2 is quite a bit louder. What happens when you switch the fan to max? is that even louder or the same? I wish I had a meter to measure the noise on my 75s. Maybe the bearings are dry from storage? if you take the sticker off the bearings and give them a drop of oil? Also at what voltage did you run the tests, I find that they are much more quiet over 53V. And yes, the fan is certainly temperature controlled.
 
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