Generator startup and stop from BMV-712

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mocat asked Feb 20, '20

Generator startup and stop from BMV-712

Hi all need some help I have a Quattro 48/8000 and a bmv 712 great products serving me well, but in the interest of longevity for my expensive 215amphr victron AGM battery’s I would love for the genset to remote start at say 49.5 volts and shut down when it charges to say 57 volts..... simple you would think using the BMV relays NC NO but Kohler seems to put a spanner in the equation by complicating something that you would surmise is a simple thing to do my Kohler generator is a marine model kohler 9efkozd https://www.manualslib.com/products/Kohler-7-9efkozd-3799387.html

with a digital control module that prevents overvheating low oil pressure shut down and zillion other things, I also have a Kohler remote switch Part Number: GM32335-KP1 https://citimarinestore.com/en/index.php?controller=attachment&id_attachment=2172

at the helm with hr meter not a toggle but more of a button type you press it and release it to start and push it again to stop so I’m thinking it’s a pulse of sorts that takes place to start stop gen set sent to the control board one would think the helm switch is where you would make the connection to the BMV 712 for ease of wiring because basically there beside each other from what I read in the manual for the remote helm switch wire # 4 is start and wire # 3 is stop and wire # 7 Is neutral is it possible to get the BMV to pulse or am I missing something as you would think with the tens thousands of these units that are sold this would be a common necessity for seamless operation.
i have searched the forum for a answer to this issue and I can only find something similar for a Onan Cummings brand gen set.

I just don’t want to get this wrong because I don’t want to damage the control module on the genset as I think it’s worth something like $2k and I’m sure this would of been done a zillion times before and I might add the people at Kohler in Australia have just handballed this all over the ship to no avail.

Thanks in advance

Michael james

BMV Battery Monitor generator start on soc

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Answer 1 · 2020-02-20T12:06:33Z

JohnC answered · Feb 20, 2020 at 12:06 PM

Hi @mocat

You may not have a GX box, but there's still a little left in the Victron arsenal: This is a summary, but there's links for more info: https://www.victronenergy.com/live/auto-generator-start-stop:start

If you can't sort what your Kohler needs yourself, perhaps a Victron dealer could assist.

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Answer 2 · 2020-02-21T09:37:39Z

christyler answered · Feb 21, 2020 at 09:37 AM

If the gen start button worked as you say then the Cummins Onan setup withe the two relays discribed in the victron documentation will work for you.

It "converts" a contact closure switch, to a pulse for start and a pulse for stop.

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Answer 3 · 2020-02-21T20:55:51Z

mocat answered · Feb 21, 2020 at 08:55 PM

Hi all thanks for the input, I am amazed though with the amount of production boats sold with these Kohler generators on board and and after sale installations of Kohler gen sets besides Victron Quattros and multipluses with BMV 12 that there isn’t a easy to read and follow instruction sheet on what to me seems a necessity for successful operation.

Strange hey ....... has any body done this successfully out there at all with my model Kohler ?

4

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Mark ♦♦ commented · Feb 22, 2020 at 11:24 AM

Could you possibly run a quick test to start and stop your generator using 2x manual toggle or push button switches to confirm if the 'pulse' needs to be released before the generator starts or stops?

If it doesn't and it's not too sensitive to the exact 'pulse' length, then I think I can make it work using internal relays and a few 'assistants' in the Quattro.

Let me know if you get a chance to check/test and if your findings are promising I can advise further on this option.

Otherwise you need 2x DC time delay relays or timer circuits and a normal DC relay with NO & NC contacts.

EDIT: Since the BMV-712 relay has NO & NC contacts you don't need the additional normal relay, just the 2x time delay relays.

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mocat Mark ♦♦ commented · Feb 23, 2020 at 11:53 AM

Cool will do Mark, I will be on the boat tomorrow so I will test with some wire on #4 #6 #7 on the switch at the helm, just don’t won’t to blow the controller it’s with heaps,.... it does amaze me this hasn’t been done before there’s probably 40 of these Gensets in my Marina at Manly Qld atm, one would think it’s just the way to do it. I will keep in touch mark.

Cheers

Michael

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Mark ♦♦ mocat commented · Mar 02, 2020 at 11:02 AM

FYI - I tested one of these relatively cheap timer relays from Jaycar electronics and it provides a ~2 second pulse at the minimum setting.

The DT switch simulates the BMV relay (with NO & NC contacts).

Two of these timer relays connected to the BMV relay (one with the start/stop wiring connected opposite to the other) would also do the trick if you want to do it externally and cheaply.

Just beware that these require a 12v power supply and I see your system is 48v. You could easily power it off your genset 12v battery or use a small Victron DC-DC converter.

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mocat Mark ♦♦ commented · Mar 03, 2020 at 12:39 AM

Thanks Mark, I think we are on the same page. I tested the start stop toggle on the bridge yesterday and it seems like maybe a one second pulse, otherwise it reads it as a stop command and the engine starts and stops again. I am thinking of using a DC 12V Relay Module Adjustable Delay Time Switch 0-10 Second NE555 Timer Board of the Bmv using its timer disconnect function of just 1 minute to the NE55 - the one second pulse would of been sent to start engine from the NE55 and the one minute later contact will open again waiting for the stop command from the Bmv to come to the relay and again pulse the one second command and the Bmv will return to a closed contact again in one minute waiting for the next start command from the BMV and this will still leave my helm stop start toggle switch operable.

Does that make sense ?

Thanks

Michael

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Answer 4 · 2020-02-21T20:59:49Z

mocat answered · Feb 21, 2020 at 08:59 PM

Hi thanks for that, but from what I read the GXbox does what my BMV 12 will do it’s the sucessfull interface Of the BMV to my Kohler gen set that’s my problem.

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