Second Alternator for Charging House Batteries

[Bikerbill]

Adding a 2nd alternator to a Sprinter is not an easy task. Not only is there a bracket needed to mount the alternator, you will also need a new fan belt once yo install the generator BUT there are problems with the lower radiator hose and related parts which have to be "relocated." It CAN be done but not cheap. Best to order the new unit with the extra mounting bracket from the factory.

The Roadtrek E-trek with the engine generator system uses 8-6 volt batteries if you order maximum power. They also then power a 5000 watt inverter to provide all the 115 volt electric one needs for AC, m-wave, TVs, outlets--all at one time.

The reason the engine needs to be revved up for about 20 seconds to 2000 RPMs is to kick-start the exciter winding in the 2nd generator which is a one-wire system. Once it begins to charge the engine can drop down to idle and can be left ton idle for more than an hour, per Customer Support at Mercedes.

As for wilding the Mercedes engine at an idle in a "quiet" campground setting vs running an underbody propane or diesel generator there is no comparison of sound levels. I cannot see where anyone in a quiet campground could complain about the idling of the Sprinter.

Davydd's ARV needs the high idle option since ARV uses a Silverleaf computer to auto-start the engine and rev it up. I don't know if they leave it at high idle nor do I know if they use the same generator at Roadtrek does.

[slowmover]

High humidity, no breeze and diesel exhaust is when they'd rightfully complain. It's not always the sound, but how/where the exhaust collects and does not disperse.

[Davydd]

Originally Posted by Bikerbill

As for wilding the Mercedes engine at an idle in a "quiet" campground setting vs running an underbody propane or diesel generator there is no comparison of sound levels. I cannot see where anyone in a quiet campground could complain about the idling of the Sprinter.

Davydd's ARV needs the high idle option since ARV uses a Silverleaf computer to auto-start the engine and rev it up. I don't know if they leave it at high idle nor do I know if they use the same generator at Roadtrek does.

The Advanced RV second alternator is a Nations dual alternator I believe a 270 amp model with a custome 3-stage charge controller. High idle is the Mercedes Benz High Idle Fixed Package. My understanding is that alternator is custom built for ARV. It doesn't rev at 2000 rpm to kick start anything that I am aware of. The engine starts and idles at a little less than 1200 rpm. Normal idle is down around 850 rpm. It doesn't need Silverleaf. The Silverleaf is a fancy central touch screen reporter and control module for a host of functions. The actual control is external to that. At high idle it charges my lithium ion batteries at around 200 amps. I can also manually start and turn off my engine without keys in the ignition remotely with the Mercedes Benz key fob, a Drone security key fob, a Drone iPhone app and RVC-Air app on the iPhone that mirrors the Silverleaf. I can of course simply use the Silverleaf touch screen. You do not need a key in the ignition. Barely and lightly touching the brake pedal will also stop the engine. So one cannot hop in and take off since you have to touch the brake to shift out of park.

I really never need the engine idle to charge my batteries. I haven't done so yet with about 100 days on the road other than to test and demonstrate it. It is there as a side benefit of having the dual alternator to fast charge lithium ion batteries independent of the Mercedes Benz computer controls.

A Mercedes Benz diesel engine is quieter than an Onan generator but I would not go so far to say it is acceptable to idle in a campground for an hour where rules forbid generators. Campgrounds are getting smart to that and include engine idling as a no no along with generators of any kind. You should have to abide by the same rules in place for Onan type generators. I'm OK with that. The Autogen feature is programmable so you can program in quiet hours to match a campground's rules. That is easily done with the Silverleaf touch screen. You can also disable it entirely with the touch screen. Otherwise it will automatically start when the batteries drop a certain percentage of charge.

[Protagonist]

Originally Posted by slowmover

High humidity, no breeze and diesel exhaust is when they'd rightfully complain. It's not always the sound, but how/where the exhaust collects and does not disperse.

On the Interstate, the engine exhaust is on the curb side, right where everyone gathers under the awning. The generator exhaust is on the service side.

For that reason if nothing else, charging my house batteries using the engine is never going to happen. That goes double if I'm going to be camping a while and set up my Fiamma Privcacy Room to enclose the area under the awning; the exhaust would be inside the room!

[Davydd]

My engine exhaust is straight out the back of the van. That is a detail that can be dealt with but then it would add more cost in a retrofit case. But then I have already stated I think it overkill to try it with a simple standard 1 or 2 battery system. It is something Airstream will have to eventually totally engineer. They won't be competing with custom boutique builder Advanced RV on this but will eventually have to respond to Roadtrek's efforts.