Reading my battery with pBMS tools over 3mtr via RJ11 to RS232 USB lead

Talk Electrician Forum

Help Support Talk Electrician Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Oldman22

Well-known member
Joined
Jan 5, 2023
Messages
152
Reaction score
65
Location
UK
Not quite solar pv but associated. I can with a laptop and the correct lead with is RS232 from an RJ11 port on the battery to a USB conversion male plug, log into pBMS tools and realtime read my Battery stats.
1684921464511.jpeg
My battery is in the garage and I want to read it from the comfort of my lounge, so I thought no problem just run a usb male to female lead through the wall to the garage and plug the USB end of the serial lead into the extension, its usb and that's good for 10mtr without loss.
So I pre tested a 3mtr USB male to female lead by sticking a memory stick on the end it read fine so lead is ok. What I failed to do was put the serial lead onto the 3mtr usb lead and try reading that!
Ran the extension through the wall, connected my pc to one end and the serial usb to the other, plugged the RJ11 into the battery and computer says Unrecognised attachment in usb port.
Oh dear me.
So just in case I tried another 3mtr lead, same result. Tried with my laptop in the garage and adding the 3mtr lead gives the same error, without the extension all is fine. So can I assume the output signals from the RS232 USB lead are so boarderline low as to be lost over 3 extra mtrs?
 
OK its been very quiet in here ;) I have figured it out and I will put the parts required here so if others come across the same problem it may be of help to them too.
The BMS RS232 socket is RG11/12 size and the cable is 6 wire to the Prolific PL2303GT USB to RS232 bridge controller.
As I found extending the USB side by 2mtr or more doesnt work, the controller signals must be boarderline over that distance as win 10 gave errors on the socket.
So I found that good old reliable Tenable did a 2mtr flat 6 wire (no crossover) RG12 both ends cable. https://www.ebay.co.uk/itm/382136994887
They also sell the required coupler https://www.ebay.co.uk/itm/383002423581
So for less than a fiver delivered you can extend the original lead by 2mtr.

I tested on a laptop and desktop and the pBMS tools opens and displays all the battery details, so job done.
 
Well done for solving it, and satisfyingly little spend too.

Now the fog has cleared you can enjoy at leisure ;-)

Sorry for the bad battery related pun, I couldn't resist.

Will be interesting to hear how you get on with the fogstars if you have time to post.
 
I just had some more batteries delivered today so more use for that extended lead ;)
 
oh my, is that another 15kWh?
No, two batteries to add to the one I had already so 15kWh total, more than enough for my use but I should be able to do some export in summer and buy cheaper & store in winter. That's the plan anyway.
 
RS232 max cable length is about 50 feet, USB2 is about 15 feet, 5m.

So for a reliable connection having a long RS232 and a short USB was the right way.
I couldn't get coms on USB longer than 1.5mtr in this instance :)
 
Top