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jessebattleb avatar image
jessebattleb asked

What are the detailed electrical specifications for the relay contact on the back of the BMV-712

we can not find any detailed electrical specifications for the relay contact on the back of the BMV-712. We looked in the BMV-712 manual to no avail.

We can find only a summary on the spec sheet indicating 60V/1A. That spec does not specify DC or AC current and voltage, both of which are critical.

Could anyone point us to the location of the detailed technical specifications for the relay contact?

The bare minimum information we need is:

Maximum DC and AC voltage between the ground of the unit and the contacts

Maximum AC withstand voltage between contacts

Maximum DC withstand voltage between contacts

Maximum AC current capability

Maximum DC current capability (almost always different than AC current for relays)

BMV Battery MonitorRelay
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6 Answers
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

I have heard back from Reinout.

Maximum DC and AC voltage between the ground of the unit and the connector: 70VDC and 50VAC.

Maximum AC withstand voltage between contacts: 50VAC

Maximum DC withstand voltage between contacts: 70VDC

Maximum AC current capability: 1A max. 50VAC

Maximum DC current capability: 1A up to 30VDC

0.2A up to 70VDC

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jessebattleb avatar image jessebattleb commented ·

Thank you Guy, much appreciated!

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Mark Owen avatar image Mark Owen commented ·
For clarification, this information is listed in the manual under "8 Technical Data" a bit obscurely as: "Potential free contact"; so if like me, you are looking for "relay" specifications you would never find it.
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Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

I am looking into this for you. I have also looked into this in the past and come up blank.

I didn't want to destroy one just for this info. Unlike the CCGX and Multi - it is not so easy to open the BMV to find the exact part for exact specifications.

This time I will just ask for you instead :)



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wkirby avatar image
wkirby answered ·

@Jessebattleb : Like you say, 60V and 1A are absolute maximums, but not both together.
Guy will confirm for us, but in the meantime I'd hazard a guess that it will be something like the popular Omron G5V-1. Datasheet should be able to provide the information you want.
https://omronfs.omron.com/en_US/ecb/products/pdf/en-g5v_1.pdf


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davenz avatar image
davenz answered ·

And what sort of ‘pin’ is used in the back of the BMV (700 in my case) relay connection. I can’t find any mention of it?

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boekel avatar image boekel ♦ commented ·

I have the experience that normal 'ferrules' don't stay put well, maybe extra long ones do...

But just a bare (stripped) wire gives a good connection with these and don't fall out. (push the orange tab to open the contact, insert wire and release tab)

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davenz avatar image davenz boekel ♦ commented ·

Thanks for that, I thought that might be the case. Is there any purpose for the larger orange oblong with a recessed top, next to each hole? I assume it’s just part of the fitting?

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davenz avatar image
davenz answered ·

I am thinking of using the relay to run a c20 battery capacity test, that stops when the voltage gets to 10.5 V

Any reason this would not work?

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boekel avatar image boekel ♦ commented ·

as long as you don't pull more than 1 A trough the BMV relay...
And you might want to check when the BMV drops out itself, I know the old BMV 600's needed at least 9-10 volts to work

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davenz avatar image
davenz answered ·

Good point, thanks.

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