Appears I have a 3G alternator in my 2005 E350 V10.

I need to replace it (low output).
With the three batteries aboard, I need at least 150amps to charge them properly. (according to the webz & crappy math skillz)

I've been told buy one person that the stock 3G alternator is best putting out 220amps, anything less has been crippled to a lower amount.
Any truth to that?

Sure I'd like more power... but the cost starts going up real quick after 160amps.

Please learn me some about the Ford alternators, thanks.

 

I thought the 3G was good for 130 amps(some where only good for 95).

I also am questioning the need for 150amps. If you charge most batteries at too high a rate, you end up ruining the batteries. Batteries are better served by charging at a slower rate. I am curious what you are actually trying to do , and what your loads are. 12v systems do have their limitations.

 

while there would be a long and interesting conversation about what I'm doing with all the power, I'm just in need a simple answer to the statement I was told today.
Sorry to be blunt, but before I go and order something that is not cheap I'd like to be informed to the most I can be. (educated shopper)

I'm turning my van into a camper, refridge, water heater, heater, house batteries, raising the roof and hopefully going 4WD, etc...
But I need to lay down all the wiring and power items first.
This will be a slow process over a long time frame.
"do it right or don't do it at all"

 

I am willing to wade through this if you are, the actual use is pretty important to the overall system design. And there are others that pass through this forum who know a lot about RV type systems. If you don't want to mess with it, that's fine too, but you you said you wanted to be well informed.

I do not know if you are familiar with solar/water/wind systems, but none of them have a large enough generator/alternator to supply the loads, it would be too expensive. That's because in most households(which is what your RV is also) a lot of power is used in short bursts. You usually use a lot of power when you get up in the morning to take a shower and eat breakfast, but after that you hardly use any.

What they have in those systems are large banks of batteries. The solar panels/wind generators slowly generate enough power through the day to charge the batteries, so the batteries will be ready for you to drain them at a high rate when you need the power. So if you use will be similiar to this, you may not need such a large alternator.

Another point to consider is practicality. A large alternator like that can be bought, but they are usually modified stock units, and would be hard to get on the road at the local store if it failed. You might be better off to research if your model had a dual alternator option(a lot of vans and trucks did) and or see if you can retro fit another stock alternator along with the trucks's original alternator. This would give you a dedicated standard alternator for your RV, and if it broke it could easily be found on the road and replaced.

 

I've done some research on the dual Alts, rather expensive both parts and labor... even with junk yard parts- that would be very hard to come by.
I completely understand that most of my power would be short bursts while camping, but with 2 house batteries (AGM later) and one starter battery I should have plenty of stored power.
Most of the van campers have very LARGE single alts (200amps+) and not one complaint from those owners on any of it.

With my plans being close to the camper vans, but with one exception I also work from it and need to have plenty of 110 power on a constant supply, Sometime with the van off.

I do appreciate the ideas and comments, I'd like to hear more.

 

I am curious and would like to see the camper vans with the 200+ alternators. Most of the large RV's I have seen that need a lot of power have a Onan or some other brand gas generator stored in the basement of the rv, and can be pulled out and used during some large power eating event. These are much more efficient on fuel rather than running the large main engine that moves the vehicle, just to turn the alternator. A gas generator can also use smaller wiring, since it's already generating at 120/240v. Even 200 amps, because it's at 12v, is not as much power as you would think.

 

Sir,

I have way too much time on my hands. So, to keep from going crazy, I am currently researching large alternator systems on Ford Trucks. In no way am I an expert, but I can get you up to speed on the basics.

I have built a 130 amp 3G setup on my old '72, and it works great. I used the E-350 Ambulance unit, with the best OEM parts. Currently, I'm beating a dead horse, and you will see our comments in a while in the electrical section. The issue is if there is a need/solution for the white delay-and-soft-start regulators for very large alternators which have only single or dual-belt systems to turn them. Don't use a single v-belt. Great fun.
Back to your issue now.

My summarized results from research:

The first limitation is the kind of belt you run. Serpentine belts are by far the best. Hopefully you have the wider setup already. There are catalogs with different sizes and width options available. http://www.balmar.net/pulleys.html The pulley at the crankshaft may be the limiting factor.

Heat dissipation from the alternator is the next issue. A dual alternator system cools better, and for very large current demands, is probably the overall cheapest and most long-lived solution. There is a wide variety of components inside the alternators, and they go from junk quality to the highest heat resistance and dissipation standards. Quality rebuilders and suppliers can order the good stuff, but it is pricey.

Very large heat-capacity alternators for over-the-road rigs are REALLY expensive, and may not be as good at the price point as above options. They tend to have better mounting, connections, bearing load surfaces, and the large case diameters can produce much more juice down at low RPMs, where you will find much of your charging is done. When they are hot, the amperage is not de-rated nearly as much. http://www.zena.net/htdocs/alternators/alt_inf2.shtml

Very large alternators may be set up with the regulator, and even the DIODE ARRAY mounted outside the body of the alternator.
http://www.alternatorparts.com/quick...rectifier.html This gets the most sensitive parts out in the cool air flow. Marine units are the best-built systems for this sort of thing. External parts can have better heat sinks, more room for adjustable features, computer supervised charging curves, and additional attachments for other batteries, and differential support for different kinds of batteries. It looks expensive, until you get into the long-term costs.

You will end up using a different battery type for the deep-discharge side of the house, vs the engine starter battery. But you know that... The charging curve differences will begin knocking on your wallet door in short order. Marine battery bank internet information will help you reduce the substantial cost of your investment. http://www.balmar.net/regulators.html

The cautions you have received about charging batteries too fast, even AGM style, are true. You can boil the batteries, and ruin them very easily. If the batteries are in a shrouded area, as usual, temperature monitoring is a big deal. The cost of fancy monitoring electronics is cheap, compared to replacing batteries, having failures, and dealing with battery acid all over the place. (Real simple systems might even have fire issues.)

If you drive everyday, you will have the engine at higher RPMs, and will charge the batteries easier. Overcharging may be your gremlin. Sitting still idling, your HP requirements will only be 5-20 HP, to run the big alternator you mentioned.

Having the vehicle engine doing this is a huge waste of fuel, is likely to damage your engine/catalytic converter, and create a bunch of pollution. Plus it will stink and be expensive. Your neighbors will hate you. An engine management system may be needed to rev the engine from time-to-time to avoid the problems above. http://www.zena.net/htdocs/welders/acc_inf.shtml#Speed (donwn the page a ways) Check out the stories in your favorite "living in an RV blog/site/magazine" for details. From what I gather, doing it wrong will be 2-4 times as expensive, as estimated by RV home-owners.

Take a closer look at that requirement for AC power. If it is for southern Air Conditioning, you are going to need an external AC generator, there is no cost-effective way around it. (unless you are very wealthy) And you may need to control that item too. http://www.neon-john.net/RV/Electric...gen_delay.html

A fridge is usually the really big power sink. Read up: Small, super-insulated, chest-style, open it only occasionally....

Many other devices may be AC or DC. Your computer may only need a DC power supply or cord/converter. DC-AC-DC is a wasteful way to go.

Protect and insulate that heavy cable, while resisting the urge to undersize it. BIG currents are going through this stuff.
http://www.lentun.com/index.php?page...emart&Itemid=1

Most manufacturers barely supply a system that works. In a year or two, it is a disaster. I'd get the heavy wiring, more batteries, computer monitored, deluxe deluxe setup. From what I see, it will be cheaper in about four years, not including the fuel costs, and defending yourself from angry mobs.

Forward whatever you learn. I want to do the same thing. My long-term interest is in mobile emergency support computer facilities.

Experts in electrical engineering are welcome to Flame away.

...and that is all i have to say about that...

 

If it were easy, everyone would be doing it correct?

 

Hey Bbasso, I've designed and repaired lots of systems for RV and work vehicles over the years. If you you are a common sense electrical kind of guy (which from reading your posts, I think you are) let me give you some guide lines for designing a very simple, relatively inexpensive system. This is also a design that offers longer life expectancy than hi amp alternators with battery isolators (which are only for ambulance and limousine drivers with no common automotive education) You need:

1. heavy duty A,B, BOTH battery selector switch
2. 2 voltmeters
3. 130 a 3g alternator (stock hi amp) look me up if you need a rebuild kit and how to video
4. Heavy duty (not gell cell) lead acid battery
5. Heavy duty deep cycle battery or group of batteries
6. On board trickle or 5 amp charger

Hook the vehicle battery to "A"and one of the voltmeters. Hook the "B" to the deep cycle battery(s) and the other voltmeter. When you're sitting still, switch the battery selector switch to "B". If you sit there all night and can't plug in the charger, you can still switch over to "A", start the vehicle and let the alternator charge the deep cycle batteries by switching to "BOTH". But from my camping experience: 2 6v deep cycle batteries will just about run an army all night.

Bear in mind for component longevity these facts. A car voltage regulator doesn't like to charge deep cycle batteries, but when it's charging deep cycle in parallel with a normal lead acid battery, it doesn't seem to care. That's why you use "BOTH" if you need to charge up with the alternator.
Real deep cycle batteries (not to be confused with marine batteries) perform better by being deeply discharged before charging back up again. So when you're at home and want to re charge (but they're not all the way down yet) put the selector switch to "B" and drain them down with the parking lights.

 

I am not sure I agree with the above statement. I have never heard that before in any of the electric vehicle/rv/home power system designs. Deep cycle batteries "can be" discharged more deeply than a regular battery and hold up better under this use, but I do not think they should be purposely discharged completely on a regular basis. It's my understanding any battery type will have a longer life if it has a easy life with less deep discharges.

But I am open to any new info you might have to back this up.

 

Yes, you are correct.Sort of. But my personal observations are this. and I've never done any net research on the subject. Some of the guys who work at the Crown Battery distributor helped me and I've successfully recommended this technique to other people:Mostly trolling motor bass freaks, but same thing. It all started when I had complaints to my sales person. This was their advise I'll be damned if changing up the routine a little, didn't make a world of difference!
You wouldn't want to constantly run down the things every weekend or every cycle like a dry cell. But the deal is batteries (especially deep cycle 6v in series) don't reach full amp hour capacity for about 20 cycles. During that break in period: it's a make or break time for the AH performance of the battery's life. They even make an electronic machine for wet cell rejuvenation called BDU's. Battery Discharge Unit. I don't have one, but I think some of the electric golf cart oriented communities would have to. What they do exactly as far as the discharge/charge cycles, IDK but it rebuilds the battery and tests it. It would be great to sit there and watch the thing but I never had time to. Most of 'em go for a couple hours or so.
Anyway, I've always had great luck running the things down a couple times. Not completely, just down really really low, so the charger can start from the bottom and work it's way up. Technically I've always used a car charger, which is wrong. Maybe they would function more normally if people had deep cycle chargers, but they don't, and they're not easy to find. Gotta get to work now.

 

I looked up Battery Discharge unit, and from what I can gather, this equipment is designed to check the health of the batteries by monitoring their performance while they are under load. Check page 2 of this link.

http://www.lesterelectrical.com/search/pdf/01510_E.pdf

 

i nave a '95 E350 w/ a 460 in it. i run two 200A 3G alternators. the stock serpentine belt will only support a 180A load. i run this as a split system with no connection between the two. that requires an additional relay to do the turn on that the ign switch does for the stock system. i have a separate voltmeter for the second system that i modified to fit an idiot lite. that must be an incandescent bulb bypassed (in parallel) with a 50 ohm resister. all OEM functions run off the original system as does the aftermarket alarm since it interfaces directly with, and runs off of, the stock system. all audio and video and other accessories live off a pair of deep cycle batteries mounted to the frame rail in back.

 

FYI I did go with the 130 amp alt and it's not enough to keep the volts steady when I turn on the factory rear a/c. Nothing is wrong with the van, the rear a/c unit has a huge fan that draws. dips to 12.6

I knew I was right in needing at least 150amp. Sucks for me when I'll need more power later.
thanks.

 

I am assuming this van has a lot of non-stock stuff added to it? If so, I am also assuming you know you just can't stick a 150 or 200 amp alternator in place of the 130 and everything will be alright. You may get by with it, but the more amps you are demanding, the larger the wiring has to be. You will need to upgrade the charge wire, and also need some additional power distribution(aux fuse box) to drive all this extra stuff.

You never know, that might be part of the problem right now if you took the 12.6 vot reading downstream somewhere far away from the alternator's output.