EG4 read/write cable

Could someone please give me the wiring configuration for this tool?
https://signaturesolar.com/eg4-lifepower4-read-write-cable/
I just need to know which wires to put into the D+ and D- on the RS485 and what pins they connect too on the RJ45 connector.


Thank you so much for the help

Pin-Out wire colors for RJ-45 connector & Dongle.
RJ-45 Pin #7- White/Brown wire to D+ on Dongle Terminal A
RJ-45 Pin #8- Brown wire to D- on Dongle Terminal B

Mark48vMagnum said:

View attachment 112896

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Thank you so much for your time in attempting to help me, But this is the RS485 USB Battery Communication Cable configuration. What I am looking for is the "Read/Write" cable configuration for flashing the BMS on the EG4 Batteries.


Thank you again

Mark48vMagnum said:

Pin-Out wire colors for RJ-45 connector & Dongle.
RJ-45 Pin #7- White/Brown wire to D+ on Dongle Terminal A
RJ-45 Pin #8- Brown wire to D- on Dongle Terminal B

Click to expand...

Thank you so much for your time in attempting to help me, But this is the RS485 USB Battery Communication Cable configuration. What I am looking for is the "Read/Write cable" configuration for flashing the BMS on the EG4 Batteries.

EG4-LifePower4 Read/Write Cable​

Signature Solar provides solar panels & components and full kits for off-grid, grid-tie and custom diy solar systems. Providing Solar 101 and hands on experience within the solar industry. Quality inverters, bifacial solar panels, complete solar kits, solar batteries. Holding best in class...
signaturesolar.com

Thank you again

I think this cable pin out will do both...
Have you spoken with the tech help at Signature Solar?
If so what did they say?

Mark48vMagnum said:

I think this cable pin out will do both...
Have you spoken with the tech help at Signature Solar?
If so what did they say?

Click to expand...

Just got a reply today so Here is what he said:

"The communication cable is pinned on pins 1 and 2, where as the read/write cable is pinned on pins 7 and 8"

But i think he has that backwards as per the page you sent in the owners manuel. Either way it is opposite end of the RJ45 connecter from the one that came pakaged with the battery that allows you to watch the BMS software.
Thank you for your help.

PS I am gonna make up a cable and flash my BMS to the updated firmware and I will come back update.

Let me know how it goes...

This is what the official read write cables looks like.
Pin 1 green - D-
Pin 2 white - D+

Hope this helps others!

So same Dongle as used for the Communications, but using different pin-out on RJ-45.
Good Info!

Mark48vMagnum said:

So same Dongle as used for the Communications, but using different pin-out on RJ-45.
Good Info!

Click to expand...

Yes sir that is correct!

timgiddens said:

Yes sir that is correct!

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So I should use pins 7 and 8 for communication with solar assistant? And i think i need to set the first battery to PIN 2 and the rest increment from there. And just plug into the #2 battery. This all look correct? Then i would need a different cable with pins 1 and 2 to flash firmware, right?

timgiddens said:

This is what the official read write cables looks like.
Pin 1 green - D-
Pin 2 white - D+

Hope this helps others!View attachment 113730

Click to expand...

If you lived near me I would buy you a beer or 2! thanks !!!!!!!

My cable had the pins 7&8 pinned, I changed it to pins 1&2 like your picture. Would not work for flashing the battery. I then tried the BMS tool and it was communicating correctly reading the battery data. Any ideas ? I was able to flash the EG4 inverters ok with a different cable. Flashing this battery is turning out to be a giant pain.
This proves that pins 1& 2 work for battery communications. Therefore it would seem pins 7 & 8 are used for read / write.
Going back to pins 7&8 again for another try.

EPicTony said:

My cable had the pins 7&8 pinned, I changed it to pins 1&2 like your picture. Would not work for flashing the battery. I then tried the BMS tool and it was communicating correctly reading the battery data. Any ideas ? I was able to flash the EG4 inverters ok with a different cable. Flashing this battery is turning out to be a giant pain.

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I tried my updated cable with pins 7&8 pinned. No luck. I even tried swapping 7&8 still no luck. I'm out of ideas. Wasted a lot of time on something that should be simple.

EPicTony said:

I tried my updated cable with pins 7&8 pinned. No luck. I even tried swapping 7&8 still no luck. I'm out of ideas. Wasted a lot of time on something that should be simple.

Click to expand...

Pick your model
Mine is EG4-LL
Latest update has a pinout for CAN and RS485

Xmasterfunk said:

Downloads - EG4 Electronics

EG4 is dedicated to ensuring that you have access to the most up–to–date product information at all times through our downloads page.

eg4electronics.com

Pick your model
Mine is EG4-LL

https://eg4electronics.com/wp-content/uploads/2023/05/EG4-LL-48V-100AH-Manual-2.0.0.pdf

Latest update has a pinout for CAN and RS485
View attachment 149463

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I can verify this is the correct settings. I messed around with this for 2 days following guides from Signature and they were all wrong OR updated for their newer V2 batteries that can stack 64 in a chain. It is a standard pass through cable wire pairing B. Not a cross over like was suggested from Signature solar.

Question, the cable that shipped with my EG4 LifePower4 batteries recently in June of 2023 doesn't look like the yellow cable up above? I'm wondering if the cable that was included is this cable, but updated to look sleeker.

MaikaiLifeDIY said:

Question, the cable that shipped with my EG4 LifePower4 batteries recently in June of 2023 doesn't look like the yellow cable up above? I'm wondering if the cable that was included is this cable, but updated to look sleeker.

EG4 USB Read/Write Cable

Signature Solar provides solar panels, off-grid solar systems, grid-tie, and hybrid systems. Quality solar inverters, bifacial solar panels, complete solar kits, solar batteries. Featuring brands such as EG4 Electronics with their solar battery, LifePower4 and EG4 LLifePower4 and EG4 LL

signaturesolar.com

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Could anyone comment on which cable to order if looking for an additional cable the same as the one included with the EG4 LifePower4 batteries?

The "silence" of Signature Solar is quite AMAZING!

Storage14 said:

The "silence" of Signature Solar is quite AMAZING!

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Ah, sorry, this post was from before my time.

Yes they're the same cable. You can check that the pinout is in pins 1&2 to verify this.

I'm stumped...perhaps someone can shed some light. I have a USB cable and I'm fairly certain - from Signature Solar tech support - that I have the RJ45 end correctly wired with the black on pin 1 and the red on pin 2. Their old cable used the green and white pins but that evidently doesn't work on the newer batteries/software.

What no one is discussing is the USB-A connector...the part that you stick into your computer. Some people loosly call it a "dongle" and I'd love to know if there is something in that. Originally, I connected using my own DIY cable (see below) that was cut from a USB-A to USB-C cable with the USB-C end cut off and a RJ45 was connected "correctly" to that cable. But, the device manager (Win11) said my COM port was 4 and the BMS_test software would only populate COM 1 & 2 in their dropdown for "Port Number". I stuggled with this online with SS for hours. Once they saw a picture of my RJ45 connector correctly pinned, they stopped investigating my cable.

With no solution found, I decided to try the inverter cable (shipped to me from SS) with the BMS_test software. I plugged in the USB-A "dongle" end to my computer - IMPORTANTLY, I did not have the RJ45 end of the cable plugged in to the battery - and when I plugged it into my computer, I got a notification from Windows. That stumped me. How can connecting a cable with open ends notify of anything to anyone. Additionally, after this notification, the BMS_test software populated their "Port Number" dropdown with my COM 4. Very strange!! There is something in that cable's dongle!

There must be something in that "dongle" that is critical to Windows and the BMS_test software. I now see clearly that all working cables in messages above and elsewhere always have a big dongle at the USB-A end of the cable. No one seems to be talking about this end, but it seems more that just a USB-A connector.

Can anyone explain this and why no one is talking about it? Here are my two USB-A connectors.

SignatureSolarJess said:

Ah, sorry, this post was from before my time.

Yes they're the same cable. You can check that the pinout is in pins 1&2 to verify this.

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I think this cable should be included with a battery purchase at no cost, if the customer is to update the firmware to the most current version.
or Signature Solar to update all batteries to most current version prior to delivery.
The same should be for all inverters update to the latest firmware.

I've been down this wormhole for a few weeks and I can share what I know. Not an expert so don't trust me 100%

1) Yes, there is a chip in the USB end of these RJ45 to USB cables that allow it to communicate with the computer. I don't think you can just start hacking up USB cables and have your computer recognize anything.

2) There are two cables that are needed to get a EG4 PowerPro fully updated, and right now the "traditional battery firmware" files are missing from the available firmware download link on the EG4/SS website.

Cable #1 is a USB to RS-485 cable. This will go in the RS-485/CAN port and USB into a computer, and if a "traditional firmware" were available for download, you would use it to flash that firmware.

Cable #2 is a USB to RS-232 cable. This will go in the BAT COM port and USB into a computer, and the "heater logic firmware" will be updated using this cable/port combo.


It's all a bit of a mess right now. I was shipped an RS-485 cable with my new PowerPro. My first PowerPro didn't come with either cable. SS is shipping me a RS-232 cable after requesting one here/from service. From there I can get the heater logic firmware updated, but we are still lacking the other half of the files needed to fully update our batteries.

Scat said:

I think this cable should be included with a battery purchase at no cost, if the customer is to update the firmware to the most current version.
or Signature Solar to update all batteries to most current version prior to delivery.
The same should be for all inverters update to the latest firmware.

Click to expand...

Yes! These are included with our units, if anything is missing, please don't hesitate to reach out and we will get that sent out to you without charge!