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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: Scott & Heather on August 30, 2017, 04:23:57 AM

Title: Two vanners, how to connect to them
Post by: Scott & Heather on August 30, 2017, 04:23:57 AM
My bus came with two 50 amp vanner equalizers installed for my 12 volt feed. If I want to connect an inverter to them do I connect an inverter to each one or just one of them if I want the maximum 12 volt amps?


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Title: Re: Two vanners, how to connect to them
Post by: sledhead on August 30, 2017, 04:59:05 AM
if you use this inverter on the 24 volts from the coach it will work off the bus alternator as well as your 24 volt battery bank

at 24 volts the amp draw is 1/2 the draw that a 12 volt system would use

https://www.solar-electric.com/magnum-energy-msh4024re-hybrid-inverter.html (https://www.solar-electric.com/magnum-energy-msh4024re-hybrid-inverter.html)

dave
Title: Re: Two vanners, how to connect to them
Post by: buswarrior on August 30, 2017, 05:21:08 AM
Those Vanner Equalizers won't last long trying to balance inverter loads.

Even at rated capacity, 100 amps of 12 volt, in theory only gives you 10 amps of 120 volt, 8-9 amps in the real world after losses, and all the cabling between battery, Vanner and inverter have to be sized for 100 amps...

And then you need some meters to keep track that the Vanners haven't been fried, as that will start the battery murdering...

Lots of risk, with very little payoff? What are you going to do with 8 amps?

Use the Vanners, same as the coach did, balance some small lighting loads, and run the radio.

happy coaching!
buswarrior

Title: Re: Two vanners, how to connect to them
Post by: Scott & Heather on August 30, 2017, 06:01:39 AM
Ok perfect that's exactly what I needed to know. Ok...a 24 volt hybrid 4024 is in my future.


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Title: Re: Two vanners, how to connect to them
Post by: bevans6 on August 30, 2017, 06:07:47 AM
I actually do this, so I don't think it's a totally daft idea, but you have to have realistic expectations.  In my case I happen to have a 12 volt feed in my bedroom for lights, but no 120 volt outlets.  I have a small cigarette lighter type inverter that I use to plug in my portable radio, and my 12v feed is supported by my Vanner.  But that's the extent of it, maybe 10 watts at 120 volts.  In general, trying to run 12 volt inverters from a 24 volt battery bank is going to be pretty limited.  What a Vanner equalizer is inside is a switching power supply that runs off the 24 volt source and outputs a 12 volt supply voltage that is regulated to be 1/2 of the source voltage.  As with any power supply it has a maximum current level that it's happy with supplying indefinitely, and a higher surge capacity, but not great and it has a fuse/breaker to protect it.  Two Vanners will fight each other to a small extent, since the reference voltage inside each is developed with a 1% resistor voltage divider so they will be outputting slightly different voltages, and the higher one will try to raise the lower one up to match it, so will supply more current.  Again as with any power supply it will have an efficiency with which it can convert the voltage, so if it supplies 10 amps at 12 volts it might draw 6 amps from the 24 volt supply.  Irrelevant if the 24 volts is being supplied by an alternator, but important if it's from a battery bank.  The inverter is another switching power supply at it's heart, and again with a 10% loss of efficiency.  You'd be looking at around a 25% loss of efficiency getting your 24 volts down to 12 volts and then up to 120 volts.

With an understanding of all of these issues you can decide if your idea is workable or not.  Edit:  I see you've already been convinced!   ;D

Brian
Title: Re: Two vanners, how to connect to them
Post by: neoneddy on August 30, 2017, 02:51:06 PM
I'll second 24v Inverters and house system in general. 

It's much more efficient, still fairly safe, and I beleive the inverters themselves are more efficient. 
Title: Re: Two vanners, how to connect to them
Post by: Scott & Heather on August 31, 2017, 05:40:27 AM
Good info. I've never tapped into my  vanners in either coach so I was in the dark on this. I actually have four vanners I don't even use so if anyone ever wants to buy some cheap.....


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