Home » Public Forums » GMCnet » Charging the house can take a long time like this,
| Charging the house can take a long time like this, [message #255715] |
Thu, 17 July 2014 16:11  |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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We are at a dry camp music thing. The Dulcimer Funfest in NoWhere MI (Evart). It isn't rally in the middle of nowhere, that's about four miles up the road.
We have electric only refrigeration and the most efficient dorm size (this is a 23 - remember) uses about half again more power than our Nocold did when it worked. Now I have a good running APU (Generator) and a PD9245 converter And a new this year Bogart Trimetric 2025 Battery monitior. (Trimetric is already highly recommended and they have a new number that does more.)
That is the big problem. Now that I have a very good picture of what all is happening, I don't like it at all.
From a battery at 57%, the best rate I could get was 25A. Trimetric said that and I believe it and I also believe (because I checked with a Fluke that the battery terminal was only 13.6V. So I checked at the PD's terminals, 14.4 just like advertised......
So, the little POS #10AWG that is OE is less than effective. My house bank is in the starboard (right) bow (front). I find it believable that the #10 could burn off 0.8V, but I don't like it. That means what should have been a 2 hour charge run is being more like 3 hours.
Has anybody replaced or parallel this cable with good results?
I am planning to get about 25' of #6 THHN (maybe #4)and then try to figure out how to get it there.
Yes, I will also harden up all the other places as well to make the whole charging circuit more solid. I am a little concerned about the frame as a the return path.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: Charging the house can take a long time like this, [message #255718 is a reply to message #255715] |
Thu, 17 July 2014 16:32  |
A Hamilto
Messages: 4508
Registered: April 2011
Karma: 39
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Senior Member |
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Matt Colie wrote on Thu, 17 July 2014 16:11We are at a dry camp music thing. The Dulcimer Funfest in NoWhere MI (Evart). It isn't rally in the middle of nowhere, that's about four miles up the road.
We have electric only refrigeration and the most efficient dorm size (this is a 23 - remember) uses about half again more power than our Nocold did when it worked. Now I have a good running APU (Generator) and a PD9245 converter And a new this year Bogart Trimetric 2025 Battery monitior. (Trimetric is already highly recommended and they have a new number that does more.)
That is the big problem. Now that I have a very good picture of what all is happening, I don't like it at all.
From a battery at 57%, the best rate I could get was 25A. Trimetric said that and I believe it and I also believe (because I checked with a Fluke that the battery terminal was only 13.6V. So I checked at the PD's terminals, 14.4 just like advertised......
So, the little POS #10AWG that is OE is less than effective. My house bank is in the starboard (right) bow (front). I find it believable that the #10 could burn off 0.8V, but I don't like it. That means what should have been a 2 hour charge run is being more like 3 hours.
Has anybody replaced or parallel this cable with good results?
I am planning to get about 25' of #6 THHN (maybe #4)and then try to figure out how to get it there.
Yes, I will also harden up all the other places as well to make the whole charging circuit more solid. I am a little concerned about the frame as a the return path.
Matt I looked at a voltage loss table on a solar web page and it says a 12V source pushing 25A on a #10 wire will lose 5% in 8 feet. The table says a #6 wire will lose 5% in 22 feet. Should have been at least #6 wire to begin with. #4 wire will cut your loss to a quarter of what it is now.
http://www.solar-electric.com/wire-loss-tables.html
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| Re: Charging the house can take a long time like this, [message #255721 is a reply to message #255720] |
Thu, 17 July 2014 17:04 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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Senior Member |
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Matt,
This is not really an answer to your question, but...
My '75 26 footer has the house batteries in the back, next to the generator. As I'm sure you know, there is a #2 battery cable running front to rear in those coaches with a terminal in the rear of the electrical cabinet. After hearing of a similar problem from Dan Gregg, I replaced the 10g wire from the PD-9245 to the terminal (a relatively short run) with a #6 THHN. The plastic conduit that held the original 10g wire was melted in places, so it obviously needed to be a heavier wire. Now, on the occasions when I start the Onan when the batteries are low, I will get a 38 - 40 amp charge showing on the Trimetric 2025 meter. It goes down rather quickly. Like Dan, I have a solar charging system (not as big as his) and a three way fridge. My batteries rarely need to be charged by the generator unless I am parked in shade.
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member
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| Re: Charging the house can take a long time like this, [message #255723 is a reply to message #255721] |
Thu, 17 July 2014 17:28 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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Move the PD9245 up front near the house battery on a short run to the battery(s). Your losses losses should be almost gone. I would not worry about the ground return You are using the aluminum house body, not the frame for the return. There is plenty of aluminum between the PD9245 and the house battery.
You do have the house battery ground connected to the aluminum body don't you?
If it bothers you, and you think the ground return is a problem, put a voltmeter between the PD9245 negative and the battery negative while charging the battery. This will measure voltage drop on the negative return only. I know you will need a long lead but he lead length will not hurt because you are not pulling any current. So there is next to no voltage drop because of the leads.
Good Luck
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Charging the house can take a long time like this, [message #255784 is a reply to message #255723] |
Fri, 18 July 2014 10:25 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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Ken Burton wrote on Thu, 17 July 2014 18:28Move the PD9245 up front near the house battery on a short run to the battery(s). Your losses losses should be almost gone. I would not worry about the ground return You are using the aluminum house body, not the frame for the return. There is plenty of aluminum between the PD9245 and the house battery.
You do have the house battery ground connected to the aluminum body don't you?
If it bothers you, and you think the ground return is a problem, put a voltmeter between the PD9245 negative and the battery negative while charging the battery. This will measure voltage drop on the negative return only. I know you will need a long lead but he lead length will not hurt because you are not pulling any current. So there is next to no voltage drop because of the leads.
Good Luck
Well,
Thanks to everybody.
I am kind of stuck because it is a 23 and there just about isn't any place to put anything that there isn't something already. I would like to move the PD up front, but there is the "Where" issue.
I sent a note (that I need to get a retraction for) to PD to ask if it was possible to to add remote sense as a feature. Problem: The converter attaches to the house fuse panel. I thing the 15.2 at the house fuse panel might make short work of most of the house lights..... Back to the drawing board.
If I come up with a great solution, I will let everybody know.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: Charging the house can take a long time like this, [message #255858 is a reply to message #255857] |
Sat, 19 July 2014 08:52 |
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WD0AFQ
Messages: 7111
Registered: November 2004
Location: Dexter, Mo.
Karma: 207
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Senior Member |
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Matt Colie wrote on Sat, 19 July 2014 08:08WD0AFQ wrote on Fri, 18 July 2014 22:03<snip>
Ain't it nice to have a "fuel gauge" for the house batteries instead of a dip stick meter??? Will tell you all kind of things about your energy consumption and fill ups.
Dan
Dan,
I owe you one on that. When I was thinking about putting one in and asking you about it, you said something like, "It tells me everything I need to know."
What you left out was that it may also tell you some thing you didn't know you needed to know.
Matt
LOL. You are correct Matt. Same thing happened to me. Caused me to make a lot of changes in our coach in regard to current draw.
Dan
3 In Stainless Exhaust Headers
One Ton All Discs/Reaction Arm
355 FD/Quad Bag/Alum Radiator Manny Tran/New eng.
Holley EFI/10 Tire Air Monitoring System
Solarized Coach/Upgraded Windows
Satelite TV/On Demand Hot Water/3Way Refer
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