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Magnum ms2812 and new batteries

June 05, 2019, 10:05:51 am

House batteries are 7 years old and have been abused. Will probably replace them this Fall when going through Oregon.

Magnum inverter manual says to prevent damage to the inverter "to remove battery power from the inverter disconnect the battery positive connection before the negative connection."

So, first disconnect the dc positive lead at the inverter, then the negative leads at the battery bank, then the positive leads at the battery bank? Should I expect a tech to do it this way?

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Re: Magnum ms2812 and new batteries

Reply #1 – June 05, 2019, 10:13:02 am

I would disconnect the positive lead at the battery bank, otherwise you have a loose, hot cable when you disconnect from the inverter.  No need to do anything at the inverter if you're just installing new batteries.  Most techs should know what to do but you can't always count on that.  Discuss it with them and have them write it on the work order if you're concerned about it.

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Re: Magnum ms2812 and new batteries

Reply #2 – June 05, 2019, 10:32:22 am

Do you know by whom, or where, your MS2812 was installed?  In all but the most amateurish installation, I would expect (hope) to find a manual disconnect switch between the batteries and the inverter.  If you have such a switch, simply open it to isolate batteries.

See red cable in diagram at the bottom of this page:

Magnum MS2812 Inverter Charger

It would look like the big red switch in the photo (our coach).  Other items are the fuse, shunt, and (yellow) disconnects for solar controllers.

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Re: Magnum ms2812 and new batteries

Reply #3 – June 05, 2019, 10:35:03 am

Definitely do it in the sequence the manual says.  A friend recently had to replace his Magnum by not following the recommendations.

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Re: Magnum ms2812 and new batteries

Reply #4 – June 05, 2019, 11:45:37 am

Make sure the 120v circuit breaker to the inverter is off as well.

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Re: Magnum ms2812 and new batteries

Reply #5 – June 05, 2019, 03:35:55 pm

Inverter was installed in 2012 by Keith Risch at MOT. Everything was left OEM except the new inverter and remote.

Talked to Magnum tech support. First suggestion was pull the fuse in the positive cable. Next suggestion was disconnect positive cable at inverter. Will try positive cable at inverter first, easier to get to. Then do traditional battery disconnection.

Thanks

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