Author Topic: My Victron BMV-600S is now posting it's data online!  (Read 17862 times)

lyte

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Re: My Victron BMV-600S is now posting it's data online!
« Reply #15 on: July 02, 2015, 03:56:47 AM »
G'day, my BMV 702 actually has 2mm pitch, it appears to be a PH style JST connector (i.e http://au.element14.com/jst-japan-solderless-terminals/b4b-ph-k-s-lf-sn/header-top-entry-4way-2mm/dp/9492437) so this looks like the ideal plug: http://au.element14.com/jst-japan-solderless-terminals/phr-4/housing-4way-2mm/dp/3616204 (ignore the image)... but that wasn't my primary reason for posting.

I'm wondering what actual circuitry you put between the BMV and the Arduino i.e did you just hook up the RX/gnd wires and parse the serial or something better?

I was wondering about trying to do a MAX232 style circuit as the VE.direct doco seems to suggest it's regular serial (although the voltage levels don't seem to match).

Just curious as this thread is the only reference to talking to the BMV from an Ardiuno I can find.

kibi

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Re: My Victron BMV-600S is now posting it's data online!
« Reply #16 on: August 19, 2015, 08:51:41 AM »
G'day and sorry for my delayed response.
The BMV-600 transmits with a TTL serial signal level of 3.3V. It does not receive any data at all, or rather, don't send any data to  it. It can't do anything with any data sent to it and a 5V level signal sent to it probably won't do it any good.
The Arduino can fully interpret a 3.3V level signal as a high and therefore no level shifting will be required to talk to an Arduino. I have connected the Tx of my BMV-600 directly to the Rx of the Arduino. I am pretty sure that the same goes for the BMV-700 or BMV-702.

I realise that my very early posts in this thread discussed level shifting when communication with a proper RS-232 port on a PC. I built the level shifting circuit to interface the BMV-600's 3.3V serial to RS-232 in much the same way that Victron's $100 cable would do. I needed this facility to read the data stream into the Victron software and then into a terminal in order to begin figuring out how to get the Arduino code to work.

One of my posts on the first page of this thread has the Xively code attached to the post which you may use as an example for your project if you so wish.

This project seems quite popular in your part of the world. There is a Kiwi chap who has been running  a version of my code for the last few years in his home solar setup.
« Last Edit: August 19, 2015, 08:54:10 AM by kibi »

lyte

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Re: My Victron BMV-600S is now posting it's data online!
« Reply #17 on: August 21, 2015, 05:46:06 PM »
Thanks for the update. I did get it working in end (I eventually realised it was just 3.3v serial and eventually got one of my devices to read from it).

FWIW the BMV (well 700 series at least) should be possible to write to, but Victron haven't updated the documentation for it. I.e http://www.victronenergy.gr/upload/documents/VE.Direct-Protocol-(2).pdf references "hex mode" that allows doing things like updating settings (primarily I just want to do forced synchronisations as the BMV thresholds simply don't work) but Victron haven't released the hex mode documentation they reference and haven't even had the courtesy to respond to emails regarding it :(