High Output Alternator Recommendations

[Oz]

I'm considering installing a higher output alternator in order to recharge the batteries and provide additional power for using on-board electronics while driving.

Any recommendations as to what's available and how to determine what size is needed?

[bhostinsky]

Autozone has a 100amp Duralast alternator for older Dodge vehicles.  When I went to Autozone earlier today they said it would work, but I didn't want to buy it yet because I remembered something about the pulley size.

How much are you looking to power? 

I remember a thread from the old MSN boards about needing a wide pulley alternator?  Anyone remember anything special about these high output alternators? 

[Oz]

My Air Conditioner or Microwave oven. I have 5 gel batteries and a 4,500 watt inverter.

[bhostinsky]

We've actually looked into this, but are not ready to do it yet.  You'd need a 175 to 200 amp alternator min.  I'd probably go with a 250 just so you're not running it close to max load for long periods of time.

You wouldn't be able to take full advantage of a 4500 watt inverter, but you'd have a good 2500 watts available to you above the normal engine needs.

Here's a link to a site I had bookmarked for power reference.  http://www.hayesequipment.com/honda_generator_wattage_guide.htm

For the air conditioner or microwave you'd need some large capacitors to handle the startup surge, but it could be done.  I haven'[t found one yet with the same bolt pattern as our old rigs, but they might be out there.  There are several universal mounting brackets though.

We're pretty much in the same boat.  Looking to put in atleast a 100 amp so that we can run the fridge and a few other items as well as charging our 4 deep cycle batteries while going down the road.

Edit:
I checked through some bookmarks on another computer and found these:
http://www.alternatorparts.com/Extreme%20Duty%20Dual%20Rectifier%20CS-144%20type.htm
and:
http://www.alternatorparts.com/Alternator_brackets_1.htm

They would probably be worth contacting.

[DaveVA78Chieftain]

Mark,
For reference:
13,500 btu rv air conditioner example
Starting Watts = 2750 (Battery bank can act as a buffer)
Running Watts = 1250
Your 4500 Watt Inverter should handle that but ....
1250 watts is 104 DC Amps (1250/12=104)
Given that inverter efficiency is typically only 80%, the actual running amps is 125 (104*1.2=124.8)
Now, since you should never run an alternator for sustained periods greater than 80% of rated output, that drives the alternator value up to 150 amps (125*1.2=150) for the AC alone.  Now there is the other stuff, like normal battery recharge (5-35 amps or more for all them nice gel cells plus the engine battery), headlights (15 amps), GPS, stereo, etc and your up to needing a 200 amp alternator.
Now, that little fan belt up there for the stock alternator is only designed to handle a 75-80 amp alternator.  Even a 1/2" belt only supports 100-110 amp alternators.  So your into a multiple belt marine or serpentine belt ($3000) setup.
Now many of the alternators you can get have a built in regulator.  Sadly, automotive regulators are actually designed for just the starter battery.   Those nice gell cells only get about 80% charge from the alternator.  So, it's best to get a real 3 stage regulator.  Option is, do what you can with the stock Mopar system then use a good 3 stage 110VAC charger (or maybe you have a inverter/charger) to top off the gel cells.
Most everything I just posted came from the book:
Managing  12 Volts, by Harold Barre; $19.95

Look over that http://www.alternatorparts.com site closely.  Lots of goodies there.

Dave

[povertycoach]

Mark,
I just put a Chrysler 114amp alternator (NAPA #66006) and a new voltage regulator.  It is a monster.  I had to modify the mounting bushing a little, but it fit using factory brackets, and overall was very easy.  I wired it directly to the battteries using 6 ga wire to take the load away from the volt (amp) gauge.  It is working like a champ.

p-coach

[ibdilbert01]

Mark, I think if memory serves me right you have the same model AC unit that I have, its a courrior 13.5.   

I've been running both AC and my fridge on inverter power while traveling, I have a second Ford 250amp 3g alternator that I use to run off the water pump pulley with one belt.


I had issues keeping the belt tight and ended up relocating the alternator to the bottom side of the engine and driving the alternator with two pulleys coming off the crank.  I had to find a 4 groove pulley to accommodate the new configuration, but I have had no issues with belts even after a trip to Indiana and back.  Had it not held up, I would of went to the junkyard to find parts to do a serpentine conversion.


My inverter is a fairly cheap Vector, but it is a 3000 watt continuous.   It seems to handle the AC load rather well.   So I would imagine your 4500 will toy with the load.  As for the alternator, it was just an Ebay purchase I scored online.   My brother use to rebuild alternators where he worked and he told me the classes he had attended told him never to run an alternator for long periods of time over 50% of their rating, that is why I went with a 250amp. 

I ran some "heavy" cable from alternator to the batteries, then back to the inverter.   I think it was 1/0 or 2/0  welding cable, its about the size of your thumb, and even with that heavy of a cable, it still will start to get warm when pulling heavy loads.   The 3g alternator has a tiny lug, I ran a 3 foot leader of smaller cable from it to the larger cable.   

As for cost, I think I paid about 200 dollars on ebay for the alternator.  The inverter was about $280, and the welding cable was 60 dollars.  The 4 groove pulley was 5 bucks from the junkyard.   All the mounting hardware was just scrap laying around the garage.

If you worried about your gel cells, there are some aftermarket companies making regulators for such a task. 

http://www.emarineinc.com/products/alternators/aqualine.html
http://www.xantrex.com/web/id/107/p/1/pt/7/product.asp

Keep in mind, the 3g alternators have a built on regulator, there are some aftermarket regulators, but I have not seen one for Gels, but I also have not been looking.  Also keep in mind with one alternator, you might need to try to find a dual regulator capable of charging both your gels and your engine battery. 

[DaveVA78Chieftain]

p-coach,
While this is a Winnebago version, do you have the 3 gauge dash set similar to this?  (your enclosure will look different but the gauge set itself is from Dodge)

If so, then the dash amp gauge is a shunt type.  Actually it's a voltmeter that measures the voltage drop across a very small resistance which is why the circuit only uses 18 gauge wire.  Dodge changed to that type in 74 for safety.  This way the full supply/charging current is not routed up to the dash like it was in 73 and earlier.
Your description indicates you wired B+ from the alternator directly to the battery.  Did you install a fuse, circuit breaker or fusible link in the line at the battery?  You need one for safety.
Was the only wiring mod you made to the B+ wire?  If so, then because the regulator sense is based on the main solder junction (best engineering practice) then you may overcharge your battery.  Because the Alternator B+ has to travel from the alternator, to the battery then back to the starter relay to the ignition switch to the main junction then to the regulator, there will be a voltage drop along that path.  As such, the regulator will drive the output voltage higher
as seen at the battery which could create overcharging problems.  As you turn lights, heater, windshield wiper, etc stuff ON, the voltage will be even higher.  It's best to keep the Dodge wiring scheme even if you may have to beef the wiring up some.   These higher voltages can kill a Gell cell battery.

Dave

[Oz]

Excellent replies, all of you!  This isn't as daunting an upgrade as one would  expect it to be.  I have looked into regulators and converter options and there are some very "smart" systems out there, able to read voltage input, demand sources and low voltage in both the chassis and coach batteries, drawing current to ensure the chassis battery is charged first, then the coach batteries and effectively manage the electrical system in general.

Based on the excellent information provided by Dave as to how to determine demand requirements and the practical application of an actual dual alternator set-up by Tim, as well as all the addtional, relevant info provided by the rest of you, it's obvious this is very feasible for me or anyone to do!

Cost effectiveness is always an issue as well as the intended purpose of upgrades such as this.  If a "shopping list" was made for the variations of this upgrade, it would prove to be a relatively expensive project, mostly considering purchasing quality batteries capable of storing a substantial charge.  Obvioulsy, the ideal way to accomplish providing the required power to run the air conditioner and all accessories while driving is to have a generator.  But, there's plenty of reasons one might not want to use that option.  The same can be said while dry camping.  Personally, I would prefer not to have a generator running while dry camping.  The noise, primarily, and using more fuel.  I've also become very accustomed to having the generator compartment available for storage.

[povertycoach]

My logic (this could get scary) was that the VR senses voltage drop from the harness, which is supplied by the battery, so I reasoned that if I put the B+ right to the battery, all I have done was by-pass the wiring to the dash...
 
My gauge cluster looks the same as the Winni, and I believed that since the B+ ultimately goes through the volt gauge it was really just an amp meter.

If I was to restore the Dodge wiring path for the new B+, what type of mods do you think I would have to do to the existing wiring...the crispy, crunchy, existing wiring.

...and no I did not put a fuse in the B+ circuit I created.  A 10ga fusible link sounds like a good idea.


Sorry for the thread jack Mark

Frank

[DaveVA78Chieftain]

Tim,
Do you recall what engine/vehicle you found the crankshaft pulley on?  Finding alternator pulleys is easy.  Crankshaft is another story.  Having a base to start from helps.
Can you provide some more information about the alternator mounting bracket you used?
Did you retain the battery isolator relay (DUAL-BOTH-MOM) in your circuit?

Dave

[DaveVA78Chieftain]

p-coach,
The only wiring you have to beef up is the section that goes from the alternator B+ to the battery.  That is the A20, A20A, A20B, and S1 wires (with the fusible link) to the starter relay.  As I said before, in 74 they changed the amp meter circuit design (your new dash style).  It is a shunt style amp meter which measures the voltage drop across a very small resistance.  By small resistance I mean, the section of A20A-10BK wire between where the B1-18RE wire solders to it and the A1-18BK wire solders to it is  the resistance being measured (yes, just the wire itself is the resistance).   The size of the 18 gauge wires (A1 and B1 circuit) going to the dash amp meter tells you this is a shunt style meter.
As far as the field side wiring, you need to know if the field current draw of the new alternator increased to the point that the existing wiring cannot handle the current.  If it did, then that is more complicated because many things are impacted (ignition switch, plugs, wiring, etc) from the starter relay to the alternator.
This is the difference between upgrading the existing system vs adding a new system like Tim did.

Dave

[ibdilbert01]

Dave,

The mounting bracket was made out of scrap metal laying around the garage.  And your right about the 4 groove pulley, it was a tough one to find, but we found one on an early 80s Dodge Ramcharger at a junkyard.   One other thing to note, I downsized the alternator pulley to gain some RPMs on the alternator at idle.

I kept the house electrical system entirely isolated from the chassis system, with the exception of a Caterpillar Master Key switch located in the battery compartment.  Keeping the original isolator relay might have been a better option for convenience.  I also have two volt meters on the dash, one monitors the chassis system, the other monitors the house batteries.   

[bhostinsky]

Nice alternator setup you've got there.  That's exactly what we hope to put in next year.  Our current alternator and regulator needs replaced so am just going to put in something a bit larger to run just the fridge.

How does running the roof AC work out for you?  I've read differing views all over the place of the effectiveness.

Thanks for the pics and the info.  Was wondering about the pulley configuration.

[ibdilbert01]

"How does running the roof AC work out for you?"

Not as good as I expected. It helps for the back of the rig, but the front of the rig still stays warm on hot days.  I pulled the factory AC parts off of another dodge a week ago and am toying with the idea of installing dash AC on the winnie.   

[DaveVA78Chieftain]

Note

The following was in response to a request for a upgrade that had already been performed.  I will provide more expanded detail for other charging system issues at a later date.

P-Coach,
First let me say:

CAUTION

The Dodge A-727 Loadflite transmission was not designed to be operated in Park for extended periods (i.e. Battery Charging).  Damage to the transmission can be incurred if the engine is left running while in Park for extended periods.  When the transmission is in Park, the location of the manual valve (inside the valve body) allows fluid to leak by a land off the valve thereby creating a line pressure drop. This low pressure in park keeps the converter from completely filling and loading the engine unnecessarily. This also means components inside of the transmission are not being continuously lubricated nor cooled (oil heat transfer).  In neutral, the converter is filled and there are no "controlled leaks," as in park. This is the reason you should always check the fluid level only in neutral. If you check the level in park, the level checks higher than it really is.  Reference http://www.allpar.com/mopar/transmissions/torqueflite-tom-hand.html

Here is a diagram of the stock 74 up charging  circuit (new style dash):

The red wire section from the Alternator B+ terminal to the Starter Relay B+ terminal is the portion that you should beef up when upgrading to a larger alternator.   Disturbing the battery cable from the Battery to the Starter relay is not required.  Here are some points of information that help to understand the needs of this upgrade:

• The 1970's era Dodge Motorhome Chassis used a standard automotive charging system.  As shown in the graph below, it is designed to support needs of the starting battery and normal automotive loads of that era and uses a linear (tapered) charging process.  This  type of charging system will quickly restore a starting battery back to 80% of it's rating and support all the remaining chassis requirements will doing so.  Because this design sharply drops the current provided, it requires several hours to bring a battery charge back up to 100%.  Upgrading to a larger alternator will reduce the time to obtain an 80% battery charge level however, the design of a standard automotive regulator is such that it will still take the same amount of time as a smaller alternator to complete the last 20% of battery charge.  The only way to change this limitation is to use an aftermarket regulator that is designed for a 3 stage charging process (OK, there are a few other ways but they are normally beyound the normal RV users desire/ability).
  
  
  
  
  
• To prevent overheating and burning out the alternator, the size chosen for a given application is typically 2-3 times what the maximum expected current load.  This ensures that the alternator does not burn out when charging for extended periods.  Alternators designed for higher amperage applications typically have temperature sensors built in that are monitored by voltage regulators designed to support those alternators.  Those type of regulators will reduce the output from the alternator if the temperature gets to high.
• Ammeters are actually volt meters (milliamp) that are used to measure the voltage drop across a resistive shunt.  Ammeters like the ones used in the 1973 and earlier Dodge Motorhome chassis  (old style dash) as well as the aftermarket analog style meters sold at autosupply houses, have the resistive shunt built into them.  The 1974 and later Dodge Motorhome chassis (new style dash) use a section of wiring (approx 1ft long) as the resistive shunt (circled in the drawing above).   This approach is much safer in that it does not require high current wires to be routed from the alternator to the starter relay/battery via the dashboard.   Only 2 small gauge wires are needed to provide a signal measurement path to the meter (atually a milivolt meter calibrated to read amps) Aftermarket solar setups, charge controlers, battery monitors, etc, also use the remote resistive shunt approach to measure current flow to and from the house batteries.

Here is a diagram of the modifications needed to the 74 up charging  circuit when upgrading to a 100amp Alternator (new style dash):

This modification uses one of the meter/shut kits available on ebay for around $40.  (http://shop.ebay.com/?_from=R40&_trksid=p3907.m38.l1313&_nkw=shunt+ammeter&_sacat=See-All-Categories)  It is modified such that the original dash ammeter is retained as well as adding the digital Volt/Amp meters.  Please note that I did not have any documentation concerning the original dash meter (measurement size).  Far as I know it will work but I do not know if it's size is acutually 100 millivolts.  If you do not want to use the aftermarket meters, then you only need to procure the 100amp, 75mv shunt and connect the dash ammeter across it as shown in the diagram.  The selection of a 80 amp fuse was to prevent an excessive load (safety issue) to be applied to the 100 amp alternator.  The original 10 gauge wiring between the alternator and the starter relay (A20-10BK, A20A-10BK, and S-10RE) is replaced with 6 gauge wiring.  The soldered attachement points for the ammeter wires (A1-18BK and B1-18RE) as well as the main power feed wire (A20-10BK) are hidden within the wiring harness (between alternator and starter relay).  I have never looked for where the splices are located so your on your own to find them.  This design moves the 14 gauge fusible link from the starter relay to the alternator side of the 100 amp shunt.  The main power wire connects to it.  I moved it there because the fusible link is not designed to handle the increased capacity of the 100 amp alternator.  The 3 amp in line fuses (attached to the shunt) are for safety in case the wires get chaffed and shorted (they go to the meters in the people compartment).  Original design, the fusible link was the protection for them.

Please note that the Digital ammeter/voltmeter 100amp; 75mv Shunt kits can also be used to monitor the house battery.  The shunt would be mounted to the house battery and all loads would be connected to the shunt output.  Meters would be installed where convienient but be sure to include a power on/off switch so the meters do not drain the house battery when the rig is not in use.

Parts:
Digital ammeter/voltmeter 100 Amp; 75mv Shunt kit: http://shop.ebay.com/?_from=R40&_trksid=p3907.m38.l1313&_nkw=shunt+ammeter&_sacat=See-All-Categories  Either get just a digital ammeter or a digital ammeter/voltmeter kit.  Most, myself included, feel a voltmeter tells you more than a ammeter.  For the price both, are best.   The meters may require some configuration.  I do not have the manuals that come with them so I do not know what all may need to be done.  Mount the shunt as close as possible to the starter relay so you can keep the wiring between the 80 amp fuse (mounted to starter relay and the shunt) as short as possible

80 Amp MIDI bolt on fuse (slo-blo):  Littlefuse P/N MID80 - Attach directly to B+ terminal of starter relay.  The cable from the shunt will connect to the other end of the fuse.

6 gauge wire as needed (alternator to shunt; shunt to starter relay) - Many people will be tempted to just add a 2nd 10 gauge or larger wire to the existing circuit.  This is not a godd solution because:

• For safety, each wire would need a 40 amp fuse so if it is damage it is protected.
• The stock ammeter wiring is still connected to the original wire.  Dash gauge will to providea proper reading.
• Main power lead is still connected to original wire.
• Last but by far not the least, the 14 gauge fusible link is not designed for the addition amperage of the 100 amp alternator.

crimp style lugs and insulators as required

Liquid insulator to help keep things sealed up noice and tight.  Lots of current in this area. 

Dave

[ibdilbert01]

"Damage to the transmission can be incurred if the engine is left running while in Park or Neutral for extended periods."

I'm fairly sure the fluid pumps in Neutral.  However at one time there was some information on modifying the Valve Body to pump in Park too.  Stanley Steamer use to mod their trannys so they wouldn't burn up while running their van installed steamers. 

[DaveVA78Chieftain]

ibdilbert01,
After doing a lot of web searching, I finally found the information about the Park vs Neutral issue.  You are correct about being able to idle the engine in Neutral.  I have updated my post and provided the reference source for the information about the differences between Park and Neutral.  I have also seen references that the Transgo TF-2 kit may accomplish the modification to the valve body.  Still looking for a solid source for that information.

Thanks for you input,
Dave

[RV Mech Tech]

just some info for members regarding any engine modifications such as on this post, the automotive and truck high-performance industry as well as marine parts suppliers will usually have items that are not available through the regular parts channels- for ex: - in one of the above posts Dave mentioned about crankshaft pulleys and the difficulty in finding them - a good source is the Mopar high performance suppliers - one source is www.bouchillonperformance.com  (also www.BPEMopar.com and www.BPEUSA.com) an excellent source for engine parts for Chryslers-  I usually find what I need in doing searches in these areas as well as heavy-duty applications such as service trucks for example that my have custom installations and have parts sources for them.   Y!

[vacuumbed]

Does anyone know if a Ford 3G alternator will bolt on in place of the old Chrysler alternator?

[ibdilbert01]

Actually I installed a 3g as a second alternator, not a direct replacement.   But going through my spare parts I was able to come up with the shell of a 3G (Swing Mount, Small Case) and an older Chrysler to compare.   Here are the pics.   (Chrysler on the right)

[smg id=2259]
[smg id=2258]
[smg id=2257]

The 3G in this pic is the small case and is smaller in diameter than the Chrysler, but a few inches deeper.   The 3G Large Case is actually not that much larger, and probably would still have a smaller if not the same diameter as the Chrysler. 

On the 3g, the thickness of the pivot bolt area is thinner than the Chrysler by 1/4". You could use washers as a spacer and I wouldn't be a bit surprised if the adjuster arm lined up perfectly.    (For the small blocks at least, I don't have a big block).

The 3g can be wired as a one wire alternator so you could and should ditch the old Chrysler regulator and keep the wiring simple.

[vacuumbed]

ibdilbert01,
Thanks for taking the time to take those pictures, those are very helpful. If I decide to do this mod, I will post my results.

[jkilbert]

one other alternator to look into is the leece-neville alternators used in most emergency vehicles. alot of times they can be found on old ambulances and fire trucks. i had one on my '83 suburban that i bought from the volunteer fd that i was a member of. it was 165 amp output with an adjustable voltage regulator

[jkilbert]

i did a quick google search and found the leece-neville alternators putting out up to 320amps @14v. that should run just about anything

[Wantawinnie]

Hi guys,

I am to the point of hooking the alternator up on my diesel swap. It is a 120 amp alternator that came factory with the '89 Dodge diesel donor. I also have the older style '73 and down Dodge dash setup that doesn't have a shunt for the ammeter. It seems a lot of the concern about these older Dodge automotive wiring systems came from the firewall bulkhead connection corroding and heating up (don't think we have those with the RV Chassis) Hm?  and the full power going through the factory ammeter.

It is the Custom dash setup so it has two ammeter guages(main and aux) and a voltmeter gauge with a two way switch for monitoring both banks. These gauges are made by Teleflex and seem to be of good quality for the day. Probably superior to the factory gauge but that is not known.



I'd like to retain the original gauge arrangement so do I just run the larger wire from the alternator to the starter relay, relay (fusible link and wire) to the dash, rewire all gauges heavier, and then head back to the battery again with the same heavier wire? Basically eliminate the original charging circuit altogether. I have the wiring from the diesel truck and haven't figured out the gauge size yet. It does appear to be about twice that of the original.

Thanks