Big alternators benefits

[booster]

As I have been getting the parts ordered for our charging and inverter upgrade on the 07 Roadtrek C190P, I have also been reading whatever I can find about what other people have and how it works. We have the factory 145 amp Delco alternator in the van and there is #4 wiring through 80 amp breakers to the battery charger/inverter. I don't ever recall having seen any indication that the 80 amp breaker was tripped from charging the batteries, even when they were quite low, so I would guess we are always charging at less than 80 amps. We have 375AH worth of Trojan wet cells, so we have considerably more battery capacity than stock. From this, I would have to say there would be no reason to have more alternator to charge the batteries, at least for us. Perhaps AGMs would be able to accept more amps and could change that.

The other reason to go bigger, and the reasoning I think for the big engine generators like Roadtrek uses, would be to run stuff of a huge inverter. By adding another #4 wire to the batteries, we would be able to get 120+ amps, which is plenty to go through a 1500 watt inverter for the microwave. All that is left is the air conditioning, and there is no way we would run the van to have the AC on.

Is there some other reason that folks would want, or need, more engine generated power? I know Campskunk has the engine generator, but no air conditioning, and I think less battery than we have, so I wonder when he finds the generator necessary. You would still have 120amps available to feed AGMs, which is quite a bit, with the stock alternator.

To me, it appears unless you have an electric cooktop, toaster oven, electric water heater, or other high draw appliance, the only reason to have the huge generator would be for air conditioning. Very few of us have those items.

Any input or ideas on this?

[gordonhks]

I checked the specs on our Sprinter and it came equipped with a 200amp alternator. Is that big as compared to standard alternators?

[booster]

Originally Posted by gordonhks

I checked the specs on our Sprinter and it came equipped with a 200amp alternator. Is that big as compared to standard alternators?

That should easily run a 2000-2500 watt inverter which will power pretty much everything but the AC, I would think.

[markopolo]

I basically reached the same conclusion for my van. This post http://www.classbforum.com/phpBB2/vi...p=17368#p17243 explains why.

Your alternator is newer than the old CS144 model for my van and presumably better but you can see how the output of these alternators doesn't reach its peak until the engine RPM's get up there. Being able to control the engine rpms at idle gives an advantage.

I had hoped to run two alternators as a fun project but can't find one needed bracket - GM part # 10244209. I can source everything else; bolts, pulley, belt etc.. A guy offered to mail a paper template of the part to me but it hasn't shown up. With two alternators I'd use the second one for coach purposes. It would be a "1 wire" type installation that would require that you momentarily rev the engine from idle rpms to excite the second alternator.

That's basically what Roadtrek instructs you to do - so the second alternator they use is probably a 1 wire type installation. (just a guess)

From the current as of today E-trek FAQS:

Once you start your vehicle bring the rpm up to 2500 briefly and release, to initiate charging cycle.

Anyway, back to the single large alternator. You really have to research the specs of the particular alternator you are looking at to make sure that, at the engine rpm you are comfortable with, the alternator output is what you need or want. Some high amp output alternator only deliver the max amps at highway speed type rpms.

[markopolo]

Booster - you might have the AD244 alternator in your Chevy.

I found this in a current GM publication for municipal fleets:



The listed amps were for the Express van but with a Duramax diesel in one publication. I haven't been able to find a full performance chart for the AD244.

[booster]

Originally Posted by markopolo

Booster - you might have the AD244 alternator in your Chevy.

I found this in a current GM publication for municipal fleets:



The listed amps were for the Express van but with a Duramax diesel in one publication. I haven't been able to find a full performance chart for the AD244.

I think you are right on the part number, or it may be a variant of it. I found lots of similar numbers when I was searching for regulators. I haven't searched out a curve for it at this point, but from past GM stuff I have seen, they seem to like to set them up to run 65-70% output at idle. Newer stuff may be a bit higher because of all the high use electronic stuff in the fancy cars now. I need about 100 amps to start the microwave, and less than that to run (according to Samlex), so I don't think it would take much rpm bump. I would guess 1000 rpm would get plenty for everything. I have also seen 200 amp alternators for the case size I have.

[booster]

These guys show a bunch of high output alternators for our 07 with the 6.0 engine. All but the stock 110 amp do over 100 amps at idle, but they don't define idle speed. They claim to go to 400 amps? Yikes.

http://www.qualitypowerauto.com/catalog.php?item=9

Found this, but know nothing about them, and no costs on the site, but they seem to make high idle switches for about everything.

http://www.offroadengineering.com/index.html

[markopolo]

Good links. I wonder how much the fast switch costs? Too bad GM didn't offer a PTO option on the gas engines. You've probably seen the "2008 Fast Idle Upgrade for 6.0L Gas engines" idle control instructions here: http://www.classbforum.com/phpBB2/vi...&t=2295#p12231

Another thing to consider for an inexpensive amp boost at idle would be to replace the stock alternator pulley with an overdrive pulley.

I'm pretty sure I have a 7.5" crankshaft pulley. I was looking around for an overdrive alternator pulley and found one with a diameter 1.7".

So 7.5" divided by 1.7" = 4.41 ratio

624 engine rpm x 4.41 ratio = 2752 alternator shaft rpm
1070 engine rpm x 4.41 ratio = 4719 alternator shaft rpm

624 engine rpm or 2752 alternator shaft rpm would output approx 115 amps (ACDelco CS144)
1070 engine rpm or 4719 alternator shaft rpm would output approx 135 amps (ACDelco CS144)

You have to make sure you don't exceed the max rpm the alternator was designed for though. With the low rpms on the diesel I'd be well under the maximum.

I found a bit more info on the AD244 on http://www.acdelcotechconnect.com