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g450 avatar image
g450 asked

Generator automatic start and stop needs momentary signal

Hello everyone.


Set up is this:

BMV712

Venus GX

Old model of Multiplus

Kohler 5kW marine Generator


I would like to automatically start the generator if the voltage drops bellow 12.00V.

The problem is that the generator requires a momentary short to start and to stop, but BMV712 can only do relay closed to start and open to stop. If i wire it to the generator as is the genset will start and immediately stop.

1. What do I need to translate open/ closed relay of BMV712 to momentary impulse to start and to stop?

2. Can Venus GX send a momentary signal?

3. Is a newer MUltiplus able to do momentary signal to start and stop the genset?


Thanks


BMV Battery MonitorGenerator
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cleaver avatar image cleaver commented ·

I just used 2 timed relays. made by DEI and were called 528T relays. Ebay for 15.00 per USD.

Set them both up the same to the generator relay and then cut loop on one 528T.

Then one pulses when relay closes and the other when the gen relay opens.

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cleaver avatar image cleaver cleaver commented ·

Okay so I had to modify my setup from what was stated above. I connected 1 relay to each relay 1 connection. grounded the common and used NC/NO to trigger relays.

I have 100ft (30m) of 18awg wire and run the 2 wires to complete the loop on the momentary push button.

Catch #2 the light would come on and generator would then give a error code "blink".

I found after numerous tests, I had too much time on the momentary signal. These relays work but are almost too long of a signal. I got the time down to 5 sec.

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2 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

With Victron devices this is not possible.
But you can use multi-functional time relay like an Eltako MFZ12DX-UC with the EAW function.
https://www.eltako.com/fileadmin/downloads/en/_bedienung/MFZ12DX_23001005-1_gb.pdf
(or you find a cheaper relay with only EAW function)
This will give you an impulse if the BMV/GX relay engages and another impulse if the BMV/CCGX relay disengage.
I would recommend you to use the GX relay because you have way more options with this.

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g450 avatar image g450 commented ·

Looking for EAW only timer.

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g450 avatar image
g450 answered ·

Thanks

(or you find a cheaper relay with only EAW function)

Does anyone tried to shop for this on Aliexpress?

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Matthias Lange - DE avatar image Matthias Lange - DE ♦ commented ·

The Eltako EAW12DX-UC has only the EAW feature and is a bit cheaper.
EAW is the german shortcut for "Einschalt- und Ausschaltwischer" I don't know the correct translation to find it in english.

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