Lobstah
Northeast
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Joined: 06/28/2005
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jauguston wrote:You can use multiple charging devices at the same time. It is done all the time and each will contribute to the overall charge amperage. There is absolutely NO problem doing it.
Lets look at a example. My coach. Driving down the highway on a hot summer day. The engine alternator is charging the chassis batteries AND the house batteries as I drive. It is hot so I start my Onan QD 7500 generator to run our two rooftop airconditioning units. That powers up the entire coach 120v electrical system INCLUDING the Magnum Energy 100a converter/2000w inverter. So that is two. Now I have 800w of solar on the roof that is connected directly to the house batteries. That is three. Using my test meters I have proven that each are contributing to the total charge rate. One does NOT cancel another out.
Jim
While all of those different charging systems are "running" at the same time, I think you'd find that your Battery Control Center decides what's charging what. My converter in the Pace is NOT connected to the batteries, even though the cables look like battery cables. The cables actually run to the Battery Control Center located above my propane tank in a belly box. The ciruitry and relays on the Control Center determine what charging system is connect to what batteries.
This is the setup in my MH, and I grant it may be quite different in other coaches.
a different Jim 
2005 Pace Arrow 36D
Very Understanding Wife
2 Boxers
4 Cats
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Canadian Rainbirds
Vancouver Island (Winter: Mainland Mexico)
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Joined: 02/06/2008
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With most motorhomes of that age the converter/charger does not charge the chassis battery. More on that in a sec.
Also the converters of that era (we had a '97 for years) are pretty basic and unless you really babysit them they will not be good for the life of your batteries. Max 12.5 V could be a shorted cell in one battery or a bad charger. Do yourself and your batteries a favor and replace the converter (even if it is working) with a modern three stage smart charger.
As for the engine/chassis battery even our 2002 DP doesn't charge from the converter. We replaced the converter with a Xantrex Prosine 2.0 2 kw pure sine wave inverter with a built in smart charger for the house batteries.
We also have solar power for the house batteries.
Then we added the Xantrex Echo Charger which charges the chassis batteries from the house batteries whenever the house batteries are at 13.0 volts or more. This allows our chassis batteries to be maintained under shore power, generator or solar.
Of course the engine alternator charges all batteries when running.
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jauguston
Bellingham, WA
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Joined: 07/03/2005
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I can assure you I have done the testing. There is only one house battery bank consisting of 6-6v AGM batteries arranged in pairs for 12v and all three devices I mentioned are feeding their output to that battery bank at the same time. I made no mention of house battery charging devices charging the chassis battery. That is a unrelated different issue.
Jim
2005 Coachman Sportscoach Elite 402 40'
350hp Cat C-7 w/MP-8
7500w Onan quiet diesel generator
6-Kyocera 130w solar panels SB3024i MPPT controller
Pressure Pro TPMS
1987 Suzuki Samurai tintop Toad w/VW 1.6 turbo diesel power
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wny_pat
Western NYS
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Joined: 08/11/2007
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rvrepairnut wrote:wny_pat wrote:I think Jerry is talking about a 1996 National Dolphin Class A. Unless someone one has changed converter/chargers, he is probably boiling his batteries to a quick death. Unless the converter/charger is disconnected, I don't care what you throw at this coach, that converter charger is going to continue to boil the batteries and kill them. Even new batteries. I think that converter/charger has to be addressed and checked out first, unless the coach is never connected to a 110 vac shore power.
at a full charging rate of 12.5 I rather doubt hes boiling anything If he is not maintaining his batteries, which it appears he isn't, and has a old Magnetek or Parallax single stage charger in the system, I doubt he is doing his batteries any good.
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Jerry B
Lake of the Ozarks
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Joined: 06/11/2001
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My question is/was can I hook up a smart charger to maintain the batteries while living in the motorhome for extended times with the converter producing charging power. My converter is a dumb two stage charger like most are, a bulk charger and a maintainer. Best I can tell, it maintains at about 12.5 volts which is too low. I believe Jim answered mt question that I can hook the smart charger up in parallel with the converter without problems and get the float(maintainer charge) up to the desired 13.6 V or so. Thanks.
Jerry B
1996 Dolphin 535,F-53.
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Canadian Rainbirds
Vancouver Island (Winter: Mainland Mexico)
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Joined: 02/06/2008
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Jerry, the simple answer is yes you can BUT: The 12.5 volts maximum voltage leads me to believe that there is a problem with the batteries OR the converter. If the batteries will charge up to 14.0 or more with a smart charger then slowly go down to 13.2 to 13.8 after the bulk charge is done, then your batteries are probably OK and the fault is likelyin the converter.
I think that it is important to check the SG of each cell of your batteries to be sure that the batteries are OK. You will need to charge them properly with a known good charger to get an accurate max SG reading. SG should be in the region of 1.265 when fully charged. 1.25 to 1.3 is roughly half capacity. (1.0 is pure water!)
The SG in each cell should be within one decimal point. If the difference is more than that an equalizing charge MAY make a difference.
Art
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