[gary]

I think the best way to answer is to start by saying converters have different approaches to how the coach electrical systems have been set up. But generally when there is not shore or generator power inverters are taking battery power and turning that 12 or 24 volt DC power into 120 volt AC power to be used by some or all 120 volt circuits.

When 120 volt AC power is available through the generator or shore power, the inverters pass that power through to the circuits they normally power (usually via an internal relay) and also change their role from inverting to that of a charger.

The nuances of how inverters work and how they are used in a coach has changed as the technology has developed and that is a complex topic that goes way beyond the simplistic explaination above.

[Jerry]

Do the vanners play a role in house battery charging when running down the road? Thanks for the info.

[Archived]

Yes and No.

It’s important to understand inside the sheetmetal there are 3 different functional devices; a battery charger, an inverter, and a transfer switch.

The Trace 4KW inverter/charger is a very feature rich product. As I understand it, it does allow 50A service (approximately 6KW) to pass through it. While on inverter derived power the maximum load would have to be managed such that you don’t exceed 4KW (roughly 33A). This, again as I understand the Trace 4000, would force the owner to manage their load so that they didn’t overload the inverter.

A very cool feature of the Trace 4000 is the ability to augment commercial power. Let’s say you are supplied 30A shore power connection and need 50A service, the inverter can supplement shore power to give you 50A service.

While on shore or generator power the batteries are not supplying current through the inverter. They are instead connected to the charger. The exception to this is when the inverters are augmenting shore power as in the example above. This is limited to Trace 4000s.

Many coaches are equipped with 2.5KW – 3KW inverter/chargers from either Xantrex, Magnum or Outback. These inverter/chargers can not augment shore power like the Trace 4000. Their internal transfer switch is rated to support the maximum inverter load and therefore can not pass 50A shore or generator power through them. Because of this they will have circuit breakers dedicated to inverter supported loads and shore/generator supported loads. The good thing with this configuration is that the owner does not generally have to do any power management when on inverter power. That’s not to say power management may not be necessary, but that it’s not generally necessary when on inverter power. Of course you probably can’t turn on the 1500W hair dryer and 1500W microwave and anything else at the same time. But you don’t have to remember to turn off all but 2 air conditioners, as an example.

FWIW, I have never configured a Trace 4000, so my information is based on what’s stated in the owner’s manual and from knowledgeable members of this forum with Trace 4000s.

[Archived]

Thanks for the info guys. Have a magnum 2500 watt here (installed last fall) and trying to find out how things work. All i know up to now ,is that it does work. On my old coach when I cut shore or gen set power I manually have to turn inverter on if I need it. I know vanners convert power to engine12/24 volt but was told it would hit house batteries also. There is a heavy gauge wire running up to battery and was wired in to other inverter that went south on me. It was original equipment from 1991. I will check and see if wire is tied in to the new one somehow.

[Ronald]

Vanner does make battery chargers, although I’ve never heard of one being installed in a Prevost conversions. The Vanner product most, and all later model Prevost’s, have is a battery equalizer. It’s sole purpose is to equally draw 12V from 2 halves of a 24V battery bank.

Asking what charges the house batteries while driving and only having alternator power is difficult to answer. This is likely the biggest area of electrical difference between converters. Here are the options for alternator only supplied power and all are likely to be found on one conversion or another:

• No charging of the house bank.
• A dedicated alternator for house batteries.
• House battery charging through a isolation diode or relay. (unless your house bank is 24V the 12V would be derived from the Vanner equalizer and be current limited. This is probably not a good idea given the possible 12V house battery bank load.)

BTW, if I was buying new inverter/chargers I would buy Magnums. Easy to use, relatively simple, and a good reliability history.

[Archived]

Glen,

There is no standard way of charging house and chassis batteries while driving. Some converters use a large 50DN alternator to charge both sets using an isolator to prevent one set from draining juice from the other. Some converters use a 50 DN, 12 or 24 volt to charge the house, usually those without OTR because they want that 270 amps to power some AC units while driving. They use a smaller alternator for the chassis batteries since the chassis does not have the large OTR AC electrical loads from the two big motors.

There are other ways as well, but you will either have one alternator with an isolator or two completely separate systems.

All chassis battery banks and some house battery banks use Vanner equalizers. The purpose is simply to insure all batteries in a set that is wired to produce 12 and 24 volts are charged equally.All that is important to know regarding an equalizer is how to verify it is functioning properly. Some coaches have a Vanner monitor to detect an imbalance, others require you to use a meter to check both voltages.

[Archived]

When I lost one of the Chinese AGM’s a while back the imbalance light on dash lit up going down rode. Took it out of loop and a month later another quit charging (Internal short i guess) and light came on again. I could shut knife switch off and kill battery bank and lmbalance light would go off. Who knows. I think my camper is haunted.

[gary]

Batteries are going to make your day or ruin your day. One bad battery can drive you crazy trying to figure why your electrical system appears to have gremlins.

If you take very good care of youir batteries, and replace them at the end of their useful life even though they are still functioning life is good.