Another charging question

ctusdenny · 12-17-2011, 08:52 PM

We've had our Dolphin LX for a couple months now. Just today I finally had a chance to use it and I'm perplexed a bit. Here goes....

Driving down the road, we flipped the inverter switch on and got TV working while rolling down the road. Everything worked just fine.

When we pulled up to the RV site, I plugged in the 50 amp service and shut off the inverter switch. TV still worked, turned the refer to AC, ran the heat pump, all was good.

After a few hours I noticed there was an error displayed on the refer: low DC. I checked the house batteries and sure enough, it showed 10.1 vdc. So, obviously the batteries weren't getting charged

I went outside and opened the compartment just forward of the entry/exit door. In there is an inverter + some white box next to it. I noticed the white box had a little slide switch on it in the "off" position. So I turned it "on".

Is that white box the battery charger? If it was off, how did the inverter power the TV while we were on the road? This is my first MH, so I'm learning as I go.

M&EM · 12-18-2011, 09:34 AM

Denny,
I believe the white box you saw was the inverter. The switch being in the off position may enable a remote switch that you use some where inside the coach. In my coach that remote switch was located near the controls for the step in the entry way. There is another box in the electrical compartment that is a converter(black in color). That does the battery charging from shore power. From what you have described so far any/all of the three components could contribute to the problem. Additional testing and info is needed to isolate the cause.

Marty

ctusdenny · 12-18-2011, 04:08 PM

Thanks, Marty. That makes sense.

Well, I definitely have a charging issue. I had 50 amp shore power plugged in. I can verify I was getting power because the heat pump ( electric heat) would come on and the microwave. Plus, I could use any AC outlet in the coach and all had power.

What was strange is that when I would start the engine, after about 15 seconds, all the lights in the coach would get brighter, the fan for the LP heater would speed up, etc. So the coach was definitely using battery power even though I had the 50 amp shore power connected. I guess that is what I don't understand really. Why would anything in the coach use battery power if I am connected to the shore power?

Anyway, after going through the night with the LP heat on only, my house batteries were at 9.6 volts in the morning. I drove home this afternoon, and they are fully charged now again after the drive home. I assume the engine alternator charges the batteries when the motor is on?

Any suggestions of where I can start looking for the charge issue when I'm on shore power?

Sidewinder · 12-18-2011, 04:23 PM

Quote:

Originally Posted by ctusdenny

Thanks, Marty. That makes sense.

Well, I definitely have a charging issue. I had 50 amp shore power plugged in. I can verify I was getting power because the heat pump ( electric heat) would come on and the microwave. Plus, I could use any AC outlet in the coach and all had power.

What was strange is that when I would start the engine, after about 15 seconds, all the lights in the coach would get brighter, the fan for the LP heater would speed up, etc. So the coach was definitely using battery power even though I had the 50 amp shore power connected. I guess that is what I don't understand really. Why would anything in the coach use battery power if I am connected to the shore power?

Anyway, after going through the night with the LP heat on only, my house batteries were at 9.6 volts in the morning. I drove home this afternoon, and they are fully charged now again after the drive home. I assume the engine alternator charges the batteries when the motor is on?

Any suggestions of where I can start looking for the charge issue when I'm on shore power?

Put you multi meter on the batteries when you are plugged in. You should get at least 13 volt reading if you get less you have lost your Converter that charges the batteries when you are on shore power.

M&EM · 12-18-2011, 05:14 PM

The converter output goes to the DC distribution board via a 50 amp resettable circuit breaker on that board. There should be a reset button on it. On mine, there was an additional auto reset circuit breaker in series with the dc converter output cable as it came from the factory. I found poor crimp connections on that cable on mine. If you have no signs of charging voltage at the batteries when on shore power with engine off, you may want to check out the circuit breakers and cabling from the converter.

If the coach batteries are originals(7 years old), you may have weak batteries. The inverter should still be able to carry your dc loads unless a cell is bad.

Monacoach · 12-18-2011, 05:26 PM

Quote:

What was strange is that when I would start the engine, after about 15 seconds, all the lights in the coach would get brighter, the fan for the LP heater would speed up

The lights and furnace fan all run off battery power. Could be that your converter is not charging the batteries while plugged into shore power.. hard to tell though......... I would first test the batteries..........

ctusdenny · 12-18-2011, 05:42 PM

Thanks, guys. I'm new to this whole MH thing and I have a lot to learn.

Anyway, the batteries where supposedly replaced this last spring (I just bought this MH a couple months ago). I see they have dates of 5/11 stamped on them (2 x 6 volt set).

Since I'm back home now, and don't have 50 amp shore power to test, can I test the output by disconnecting the batteries and measuring the voltage with the generator running instead?

Sidewinder · 12-18-2011, 06:16 PM

Yes or just plug your coach into a 15 receptical from your house. You will need an adapter but you should have them anyway

ctusdenny · 12-18-2011, 06:19 PM

Also, here is a picture of the bay just forward of my MH door. I assume the white box is the inverter, and the box on the right (with the fan) is the converter?

If so, can I take a reading off the + and - leads you see on that converter when the generator is running and it should read some voltage (?13 or 14 volts)? would the be the same as if I were plugged into 50amp shore power?

By the way, that little fan on the converter never came on the whole time I had the 50 amp service online. At least I never saw it come on at all.

Also, do you know where there is a wiring diagram for the inverter/ converter and those boards I see in this bay? That might be helpful for me to understand all this.

Sidewinder · 12-18-2011, 06:27 PM

No picture showed up but Yes you should get a 13.5 +++ out of the converter. Can't help with drawings
Opps just got the picture and yes

tomwalt · 12-18-2011, 06:33 PM

My 2 cents - you on the right path. The Converter has the fan and it should read between 13 and 14VDC when plugged in. It is a fancy ac to dc converter to provide 12V power while plugged in and charge the batteries. Read the nameplate on it then you can get the owners manual online for it.
The converter should read 13 to 14VDC when the generator is running as well.
P.S. It sounds like your Inverter is working right to me. The reason everything worked while you were driving is that your engine alternator was doing the charging. This tells me the converter is the only item not doing it's job.

Sidewinder · 12-18-2011, 06:38 PM

Quote:

Originally Posted by ctusdenny

Also, here is a picture of the bay just forward of my MH door. I assume the white box is the inverter, and the box on the right (with the fan) is the converter?

If so, can I take a reading off the + and - leads you see on that converter when the generator is running and it should read some voltage (?13 or 14 volts)? would the be the same as if I were plugged into 50amp shore power?

By the way, that little fan on the converter never came on the whole time I had the 50 amp service online. At least I never saw it come on at all.

Also, do you know where there is a wiring diagram for the inverter/ converter and those boards I see in this bay? That might be helpful for me to understand all this.

In your photo the converter fan is not running. I hope this picture was taken before you started the genny. If the genny is running and the fan is not on you have another problem.

ctusdenny · 12-18-2011, 06:51 PM

Quote:

Originally Posted by Sidewinder

In your photo the converter fan is not running. I hope this picture was taken before you started the genny. If the genny is running and the fan is not on you have another problem.

I took this pic today when the generator wasn't running. However, I had the MH plugged in to the 50 amp shore power yesterday, and I never saw that little fan come on at all.

M&EM · 12-18-2011, 06:55 PM

Quote:

Originally Posted by ctusdenny

I took this pic today when the generator wasn't running. However, I had the MH plugged in to the 50 amp shore power yesterday, and I never saw that little fan come on at all.

Denny, check your ac circuit breaker panel for that converter circuit. or plug the converter into a different outlet.