Turning off House Batteries kills 50amp!?!

[RickO]

I was doing my battery maintenance today and decided to remove and clean all of the cables from the battery terminals. I disconnected the house batteries first via the "Aux Battery Disconnect" switch but as soon as I threw the switch, it killed the 50amp service to the coach. I expected the inverter to keep even the 12v running but no dice. It went dead along with the 50amp.

My Powerline EMS has been acting funny the past few months... it doesn't protect 20/30 amp circuits by properly sheding loads, the load lights don't even light...and I'm going to be visiting Forrest City after the GNR to have it looked at with a few other things, but this surprised me.

Anybody have any ideas? Am I missing something silly? I also tried to leave the Aux Bat Switch in the on position but when I disconnected the cable everything went dead again.

[makemecrazy]

Mine does the same thing. Surprised me at first too. It's sort of like pulling the main breaker in your home.

[AFChap]

Mine certainly doesn't work that way. I use the battery disconnect switch to disconnect 12v item every time I run the equalization cycle on the house batteries. But perhaps something is different about newer models... I would check it with Winnie Owner Relations to make sure that is right.

[pameridan04]

Ricko:

Mine does the same thing. I was camping a few weeks ago. I hooked up to 50 amp service, Aux switch was on.

I said I don't need this now that I am hooked up, turned off the Aux Battery switch and lost all power.

It seems if you want power to the coach, the Aux Power Switch has to be on.

I also find that I don't see any amp read outs in 50 amp mode on pannel. Just says 50 amp.??

Regards Jim P.

[RickO]

Hi Jim P... I still haven't gotten around to calling Winnie to check on the proper operation of the chassis battery switch but I'm pretty sure it is normal not to see any amp use on your panel when hooked up to 50 amp. I never really understood why but that's the way it is for most of us I believe. If you want to know how much current you're drawing you can switch to generator temporarily.

[AFChap]

It is called "Aux Battery DISCONNECT Switch" because it disconnects the house battery bank from all 12v loads...lights, radios, thermostats, refer control board, etc. It normally will NOT disconnect loads from the chassis battery bank. And it does not disconnect shore power from the coach. There is still power coming in.

The load center will not show amps used when on 50a shore power. I guess that is because they figure there is no way you are going to use more than the 100a you have available on the two power legs. You only see amps used when using 20a, 30a, or generator. ...and do you know how many amps your generator could potentially put out so you know you are pushing the limit? You have to do some math ... i.e. my Onan 7500 has a potential of apx 62.5a ...watts / voltage = amps.

[RickO]

Right you are Paul but their choice of wording has always made me smile because it starts to feel like a "who's on first" skit. Both my Aux Battery Disconnect switch and Chassis Battery Disconnect switch have to be "on" in order to NOT disconnect the batteries.

Maybe it's twisted reasoning but it just seems to me if a switch is labeled "disconnect"... when one turns it "on"... something should get disconnected. Instead we turn "off" the disconnect switch to disconnect the batteries.

Now, was I don't know on second?

[RJay]

Rick,
I think what going on has to do with the EMS. The EMS has normally open relays that control the circuits connected to it. When connected to a 50 amp service all the relays are closed allowing the circuits to be fed from the 50 amp service. But there are a couple of 12VDC relays that control low voltage applications such as thermostats and when battery voltage is lost these relays will open. Did you have to reset the the main breakers at the AC panel?

[cyko]

I've never heard it explained this way, but I think the reason that there is no current display when hooked to 50 amps is that the current used is divided between two different 120-volt lines, and it would require more instrumentation to "add up" the total. The situation is complicated by the fact that the two currents are out-of-phase, so they don't add up in a simple manner. When hooked to 30 amps, the two lines are driven in parallel, and the total current can be measured at the source.

[RickO]

Quote:

Originally Posted by RJay Rick, I think what going on has to do with the EMS. The EMS has normally open relays that control the circuits connected to it. When connected to a 50 amp service all the relays are closed allowing the circuits to be fed from the 50 amp service. But there are a couple of 12VDC relays that control low voltage applications such as thermostats and when battery voltage is lost these relays will open. Did you have to reset the the main breakers at the AC panel?

Thanks RJay, this makes sense. I don't think I had to reset the breakers but this happened six weeks ago and digging deeper hasn't made it's way up my priority list yet.

[RJay]

Quote:

Originally Posted by cyko I've never heard it explained this way, but I think the reason that there is no current display when hooked to 50 amps is that the current used is divided between two different 120-volt lines, and it would require more instrumentation to "add up" the total. The situation is complicated by the fact that the two currents are out-of-phase, so they don't add up in a simple manner. When hooked to 30 amps, the two lines are driven in parallel, and the total current can be measured at the source.

cyko,
When connected to 50 amp service the EMS goes to sleep, it doesn't measure anything so there is no current reading and all and all the circuits in the service panel are energized. For a 30 amp service, since the EMS current transformer is connect to the neutral, the load current of each connected load is “learned” as it is energized by the EMS and the EMS will connect the appropriate load based on how much current is available from the total load seen by the neutral.

[azloafer]

Quote:

Originally Posted by pameridan04 Ricko: Mine does the same thing. I was camping a few weeks ago. I hooked up to 50 amp service, Aux switch was on. I said I don't need this now that I am hooked up, turned off the Aux Battery switch and lost all power. It seems if you want power to the coach, the Aux Power Switch has to be on. I also find that I don't see any amp read outs in 50 amp mode on panel. Just says 50 amp.?? Regards Jim P.

I only get an amp readout when my generator is on. Shore power just lights up the 50 amp light. I wish it did show the amps when on shore power, but I am told that this is normal. Joe

[pdq_bc]

Quote:

Originally Posted by pameridan04 ...I also find that I don't see any amp read outs in 50 amp mode on pannel. Just says 50 amp.??.....

Hi Jim:

i have had direct communication with the manufacturer on this - for i wanted to know too!
below is a cut & paste of the reply.

regards, pdq
(peter)


If your Powerline unit is p/n 00-00740-xxx then we connected to 50 Amp
service the remote current display area is disabled.
If your part number is 00-00911-xxx and you are connected to 50 Amp service, the remote current display area is disabled as well.
Prior version of the EMS would behave the same, meaning the remote display would be disabled.

[RickO]

Doesn't seem to be much question that the EMS is working as designed when not showing current draw when hooked to 50 amp shore power. I think RJay's speculation was "why" it can't show the draw.