Dual alternator kit for the Ram Promaster announced

[wincrasher]

Originally Posted by gerrym51

add battery capacity,put in inverter,put in 2nd alternator,improve wiring. unless you need the space for more batteries-keep the onan-you can have both

No, my boat needs a new anchor. The Onan would work nicely.

[booster]

Originally Posted by wincrasher

Maybe this sounds idiodic, but bear with me.

If you were going to buy this dual alternator kit to retrofit a van like mine, what else would you need?

Would you just need to replace the Onan with an inverter? What about this cooling of the alternator that's been mentioned?

Most likely, this kit would be made to use as a standalone, so you would not be using the existing wiring for the added power (it wouldn't be big enough anyway). That means you would have to add wiring from the new alternator to the coach big enough to handle the power.

You would then put in the big inverter and have to decide how it all would get wired up and used-which is what has been being discussed in the earlier posts above, by coincidence. What charger you have might make a difference, you probably would need a transfer switch for it if there isn't one already for the inverter. Depending on the skill level and understanding of 12v systems, that could be pretty easy to daunting.

The cooling of the alternator is a tough one, I think, to predict. We all know that running hot due to high output shortens their life. We all know that the big alternators can put a good sized load on the engine at idle, so the cooling system of the engine has to work harder, so hotter radiator and engine compartment. If you are not moving all that extra heat is tough to get rid of, moving not so bad. I guess I would say the problem could be a definite "maybe"! How much load would be the big issue.

As Marko has mentioned, even a stock alternator can run almost everything if you have enough inverter and aren't running things like the air conditioning and microwave at the same time (we have done that and even tripped shore power so the Onan would also have issues). I would suggest adding up just how much alternator output you would need to run the things you want to run. I think you will find you don't need near what the dual alternator setups put out. If you have tons of batteries and huge wiring, then a lot of power can go to charging batteries, but without that there is likely no need for a dual setup. An upgraded single alternator may be plenty for what you want to do.

[avanti]

The best way to think of of the whole inverter/battery/alternator thing is that all the 12V components form a power bus. They are all ultimately hanging off the same piece of copper conductor. There are sources and sinks of power. Some of them add power and some of them remove power from the bus. The battery can do either. It acts more or less like a giant capacitor, doing its best to smooth out supply and demand. Whether the alternator is "directly" powering component X is really a matter of definition. The effective answer is "yes".

I do have one question for those of you who have these alternator-centric systems: How big is the wire going between your chassis and your coach? Many up fitters seem to scrimp on this. Davydd says that his Advanced RV has a 4/0 cable. Those guys don't scrimp on anything, obviously. But, is 4/0 overkill or not?

[booster]

On our homemade setup, with just a bigger alternator, I doubled up on the 4ga that Roadtrek had in place, so 2X4ga. Fused at 160 amps. Alternator is 250 amps, so we could go over and cycle the breakers, but for us that would only happen if we were running the microwave and the batteries were very low. The microwave is in the 100 amp range, and the batteries close to the same when they are at 80% discharged, which would be extremely rare for us. We have wet cells, which allows us to do it this way, as they current limit (although they do charge at a higher than recommended rate). With AGMs, the batteries would accept all the alternator could put out, which would be too much for the wiring, so we would have use a Sterling 12v to 12v charger to limit the charge rate. The smart alternator regulators don't limit current, so they wouldn't take care of the problem. We can watch the total amps out of the alternator to the coach with the big ammeter I put in this winter, so if it looked too high we could let the engine idle for a while before driving. We only get about 120 amps to coach at idle, if we want to hold voltage.

[markopolo]

The 4/0 isn't overkill on Davydd's rig. His battery bank, if low, will take all the amps the alternator can deliver. It's a long wire run from the front of the van to the rear.

My van (one alternator) is set up a little different than most. It has two engine batteries; one under the hood and one right behind the drivers seat. It also has two house batteries in a cabinet right behind the drivers seat. The van has a standard isolator setup and also has a marine type multi battery bank switch. I can parallel "everything" if running the microwave oven off alternator power. Chassis and coach batteries are combined via the isolator and, at the same time, via the marine type switch. The weakest link, if everything is paralleled, is four feet of 4 gauge to the 1000w inverter. 3 or 2 gauge would have been a better choice. A larger inverter would have been a better choice too.

The marine type switch is handy. I can select the house bank or the engine bank or combine both. That's for discharging and powering by alternator and also charging via the converter and solar.

If I were to add a second alternator it would be for house loads and charging only. I go with a "1 wire" rev-the-engine to activate type setup with heavy gauge wire to the house battery bank. Fused of course. Then a PSW inverter with either a built in or stand alone transfer switch like Booster pointed out.

This inline inverter transfer switch http://www.classbforum.com/phpBB2/vi...php?f=9&t=2005 does the job in my van. It's rated 15A 120v so 1800 watts max. I think Booster uses it also.

[avanti]

Originally Posted by markopolo

The 4/0 isn't overkill on Davydd's rig. His battery bank, if low, will take all the amps the alternator can deliver. It's a long wire run from the front of the van to the rear.

So, how does the return work in such a capacious system? Is there also a 4/0 ground wire back to the chassis battery? Or does it depend on the chassis for the return? If the latter, there must be a pretty significant ground point somewhere in the back.

[markopolo]

It would be nice to know how the B manufacturers do it & why they chose their method. They could show a bit of support for the DIY community.

Do they route the return via the frame (or subframe for unibody's) or is it routed right back to the second alt?

Nations seems to indicate a full return run:

STEP 18: Install positive and negative cable to your secondary alternator and route to your desired battery.

in this GM dual alt doc: http://www.nationsstarteralternator.com ... NSTALL.pdf

It could be interpreted more than one way though.

In their single high amp alt install pdf http://www.nationsstarteralternator.com ... nGuide.pdf they stress the importance of upgrading the return.

[wincrasher]

Doesn't sound like too tough a project.

Only thing that complicates matters is if you retained your existing generator and/or installed an inverter.

On the Travato, since the house battery is already under the van, cable routing would be fairly easy.

[markopolo]

Using an inline inverter transfer switch makes for an easier integration. http://www.classbforum.com/phpBB2/vi...php?f=9&t=2005

I'd leave the existing shore power / generator transfer switch as it is in your Travato and add one (or two if needed) of those Xantrex inline inverter automatic transfer switches. They go "inline" - between the 120v AC panel breaker for the circuit you want to power via inverter (or shore or genset) and the load.

http://www.xantrex.com/power-products/d ... relay.aspx
Installation guide: http://www.xantrex.com/documents/Access ... tch%29.pdf

[wincrasher]

Originally Posted by markopolo

Using an inline inverter transfer switch makes for an easier install. http://www.classbforum.com/phpBB2/vi...php?f=9&t=2005

I'd leave the existing shore power / generator transfer switch as it is in your Travato and add one (or two if needed) of those Xantrex inline inverter automatic transfer switches. They go "inline" - between the 120v AC panel breaker for the circuit you want to power via inverter (or shore or genset) and the load.

http://www.xantrex.com/power-products/d ... relay.aspx
Installation guide: http://www.xantrex.com/documents/Access ... tch%29.pdf

So one for each circuit? Why not just one large one similar to the gen/shorepower switch to power everything? You think this alternator could adequately supply a 2500 watt inverter at full load?

[markopolo]

You could use a larger one if you can find it.

You have to think about managing the loads also. Does the fridge switch to AC automatically if an AC source is found for example. I set my old fridge on propane and it stays there until I manually switch it to AC. And you don't want to power the converter /charger via the inverter.

A typical household circuit is 1800w 15a 120v. This transfer switch can be used on circuits that have a 15a breaker. Some microwave ovens and air conditioners will be on 20A circuits.

This particular inline transfer switch plugs into the inverter. Most inverters have two outlets.

You can guess at the high amp alternator output amps:
150A x maybe 13V = 1950W 150A x 14V = 2100W
160A x maybe 13V = 2080W 160A x 14V = 2240W
170A x maybe 13v = 2210W 170A x 14V = 2380W

[wincrasher]

Understood. On my van, my interest would be to power the air conditioner and the water heater only. Battery charging is already taking place with the existing alternator.

[mojoman]

After I bought my Promaster I looked under the hood to see how much room there was to put in a second alternator, couldn't see a way to put one in without major mods, ordered a Onan2800. I'd like to see a picture of one installed.

[avanti]

Having just doubled my AGM battery capacity to 440 amps, I am very close to pressing the button on the Nations Alternators 270 amp second alternator kit for my Sprinter:

Sprinter Dual Alternator Kit with 270XP Amp Alternator - 2014 and Up Sprinter Vans with 2.1L

Looks like a turnkey solution when purchased with the accompanying Balmar regulator/charger. Anybody think this is a bad ideal, or know a better alternative?

[gerrym51]

Originally Posted by avanti

Having just doubled my AGM battery capacity to 440 amps, I am very close to pressing the button on the Nations Alternators 270 amp second alternator kit for my Sprinter:

Sprinter Dual Alternator Kit with 270XP Amp Alternator - 2014 and Up Sprinter Vans with 2.1L

Looks like a turnkey solution when purchased with the accompanying Balmar regulator/charger. Anybody think this is a bad ideal, or know a better alternative?

this is what sportsmobile does-sounds good to me

[booster]

Originally Posted by avanti

Having just doubled my AGM battery capacity to 440 amps, I am very close to pressing the button on the Nations Alternators 270 amp second alternator kit for my Sprinter:

Sprinter Dual Alternator Kit with 270XP Amp Alternator - 2014 and Up Sprinter Vans with 2.1L

Looks like a turnkey solution when purchased with the accompanying Balmar regulator/charger. Anybody think this is a bad ideal, or know a better alternative?

I think the alternator is a DC Power unit, which is a very good one. You do need a regulator of some sort, or the DC Power alternate internal regulator is they will do it for you, to get the right voltage.

The Balmar may be an issue, though. An aquaintance has one on a 270 amp alternator add on in a Chevy, and found that the Balmar needs to have a load of at least 4 amps on it to regulate properly. His ran very high voltage without the load. He had to add a resistor bank to get load on it all the time, which is just not a good thing IMO.

You may want to do a little calling to Balmar about that issue, as that is where he got his information about the necessity of a load on the system to make it work. It would do fine as a vehicle alternator setup, as the engine would always pull enough power, but not as a stand alone.

[tbirdman]

Too bad with the Travato you can't delete the Onan generator and have the Nations dual alternator installed. Seems expensive for what you get. They are selling a high output alternator. It appears the kit part cost ~$1000. They need some competition to get the price down.

[booster]

Avanti has mentioned in the past about using a separator cutoff to prevent overcharging of the coach batteries, so this setup might be appropriate for him. It would not require the cutoff, and would go to float based on return amps to the batteries. I ran across this a while ago, and have no experience with it, but it sounds like a very nice setup for accurate charging, in an engine generator setup. It should be much more accurate than a standard timer/algorithm smart regulator.

Best ways to control big engine generators? - Class B Forums

[avanti]

Originally Posted by tbirdman

Too bad with the Travato you can't delete the Onan generator and have the Nations dual alternator installed. Seems expensive for what you get. They are selling a high output alternator. It appears the kit part cost ~$1000. They need some competition to get the price down.

Yeah, a little pricy. But they apparently use genuine MB parts for the alternator mount (which I am told is difficult to source in the US), and it it kind of nice to have a known turnkey solution and (presumably) tech support from a single source.

As for the Balmar load issue: My configuration would be hard-wired to four large AGM batteries and also my Outback 2800 watt inverter, so I would imagine it would be OK. I guess I should double-check with Balmar, though. Thanks!

[booster]

Originally Posted by avanti

Yeah, a little pricy. But they apparently use genuine MB parts for the alternator mount (which I am told is difficult to source in the US), and it it kind of nice to have a known turnkey solution and (presumably) tech support from a single source.

As for the Balmar load issue: My configuration would be hard-wired to four large AGM batteries and also my Outback 2800 watt inverter, so I would imagine it would be OK. I guess I should double-check with Balmar, though. Thanks!

The system that had the issue was the 270 amp alternator, Balmar regulator, 300ah of AGM and tied to a Xantrex 100/2000 inverter/charger, for reference.