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nicolas-poitras avatar image
nicolas-poitras asked

Hughes Power Watchdog and MultiPlus II

Hi all.

Am using a portable Hughes Power Watchdog with EPO along with a MultiPlus II in my Airstream. Working great with no issues.

Thinking of moving to the hardwired version of the Power Watchdog to simplify set up at camp sites. Noticed Hughes now has a warning that their 50A EPOs may be incompatible with MPIIs. Again, I’ve had zero issues but this warning is making me question hardwiring a unit.

Called Hughes. They believe the issue may be tied to the MPII load balancing between lines 1 and 2 which somehow sends power to the neutral. That is then interpreted by the Power Watchdog as an open neutral which triggers a shutdown. Two questions:

1) If that is the true issue, any way to turn off load balancing in the MPII settings?

2) Any ideas on a setup that would easily allow me to bypass the hardwired Power Watchdog in case of problems?

Thanks in advance for your thoughts on this.

Multiplus-II
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carlrx7 answered ·

i resolved the open neutral error by adding a tiny load on one leg between the power watch dog and mpII. Hughes is currently working on a fix in production to be more compatible with the mpII.


Something like a transfer switch was enough to allow the pwd to see the neutral. When I removed mine I added a killawatt on l2 to show current on the neutral.


Note: this is only an issue on 120/240 hookups. The 180 out of phase cancels out load on the neutral during the mpII changeover. Some parks have 120/208 which will have the aveverage current of L1+L2 across the neutral.

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nicolas-poitras avatar image nicolas-poitras commented ·

Thanks. This is helpful and encouraging! Can you be a bit more specific on how you added load on one leg between the Power Watchdog and MPII?

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carlrx7 avatar image carlrx7 nicolas-poitras commented ·

The power for my multis route through two sub panels. I simply added a circuit to the incoming panel. If you don’t have service/sub panels then you could “test” by splicing an extension cord into the output of the power watch dog. Plug in a lightbulb or tool battery charger or something that draws very little. Hughes recommended a load of 15w but I got away with a load as small as 5 watts.

If yours is already working fine, then going to a hardwired version should be fine as well. Install it as the first device from the cord inside.

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skyler avatar image skyler commented ·

@carlrx7 What did you use for your "tiny load"?

I'm currently using a 15W light bulb, but I'd like to simplify it by using something like a 2k ohm 10W resistor which would draw about 7 watts.

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