More Alternator woes

Topic: More Alternator woes (Read 2009 times) previous topic - next topic

Re: More Alternator woes

Reply #25 – August 11, 2019, 11:02:15 am

The Delco bulletin is confusing. The diagrams on the 2nd page are showing how plug style connections were done with older alternators with analog regulator. I believe you could use an older alternator as you suggest, but Jerry has the 28SI with digital regulator that requires 12v on the B+ to start up per the 1st page and 3rd page.

Re: More Alternator woes

Reply #26 – August 11, 2019, 11:25:51 am

So why wouldn't the old excite wire work on the B+ post on the 28si? Then also use the old sense wire on the S post.

That way I could take my time and mount the Sterling in a much nicer way and muck around under the bus in a bit cooler weather. Right now I'm just trying to get this thing running/charging

Re: More Alternator woes

Reply #27 – August 11, 2019, 11:32:03 am

Don't do that, once the alternator starts charging, charge current will flow back on the excite wire and you will fry the excite wire (or blow a fuse).

Re: More Alternator woes

Reply #28 – August 11, 2019, 11:39:27 am

I won't. So it has to be temp 12V signal and the Sterling Ign post does that?

Kind wish I would have just bought a replacement Lecee-Neville.

Re: More Alternator woes

Reply #29 – August 11, 2019, 11:43:07 am

Correct, either the Sterling, or diode isolator with ignition post.

As myself and others will attest, the new Delcos - 28SI, 40SI (brushless) are a superior alternator, but you need to also change the isolator to use one.

Re: More Alternator woes

Reply #30 – August 11, 2019, 01:34:17 pm

Sorry about the silly question. I have been taken aback that I actually needed a new iso. How would the average person even know that a question needs to be asked.

Starting to understand that the ign post on the sterling just de-islolates the alt in and pushes 12V into the B+.

Re: More Alternator woes

Reply #31 – August 11, 2019, 01:45:09 pm

Both the Sterling and diode isolators use a diode in the excite circuit to allow current to flow to the B+ post at startup, but then block it from flowing the other way when the alternator starts charging.

Re: More Alternator woes

Reply #32 – August 11, 2019, 04:05:51 pm

If you're comfortable doing this, a diode can be manually wired in to use a Delco 28SI/40SI with a standard diode isolator. Wire the diode in series with the excite wire to the Delco B+ post. To make sure you have it wired the right way, turn ignition on but don't start, there should be 12v on the alt B+ post, with ign off the voltage should return to zero. If no voltage with key on, turn the diode around and try the test again. Once you're sure it's wired correctly, start the engine, the Delco should now start charging. Remove the diode and connect the excite wire to the Sterling when you switch isolators.

O'Reilly universal diode

Re: More Alternator woes

Reply #33 – August 11, 2019, 04:26:42 pm

I know little and want to know less about alternators myself.

I replaced my rebuilt LN Duvac with another new duplicate unit.

We were going out of town so I took the coach into the Cummins shop and had them swap the good rebuilt for a new duplicate unit.

Supposedly has a new solid state VR.

Here's the LN

Applications
Popular RV Motorhome Alternator
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DAIMLER TRUCKS NORTH AMERICA LN 2824LC
GILLIG CORP 51-00179-008
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MACK TRUCKS INC 2742 5034-2824LC,
Monaco A001090772, A0012824LC, A0012825LC
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OSHKOSH CORPORATION 6HA518
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SPARTAN MOTORS INC 0499-GG1
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Series number: 2500JB, 2600JB, 2700JB, and 2800JB.
MODELS: 2524JB, 2624JB, 2724JB 2824JB AND 2829JB

NOTE: INCLUDES STANDARD 8 GROOVE PULLEY

OEM(s): Leece Neville
System voltage: 12
Output: 160 AMPS
Rectifier location: Internal
Excitation type: Ignition Excite
Regulator Location: Internal
Mounting style: J-180
Fan Location: External
Rotation: BI-DIRECTIONAL
Mounting bolt size: 1/2-13 UNC
Positive stud: 5/16-18 UNC
Negative stud: 5/16-18 UNC

For Duvac or Dual Battery Systems
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Weight: 24 lbs. / 10.91 kg

Includes Simple Hook-up Instructions

*PLEASE VERIFY YOU HAVE DUVAC TYPE SYSTEM BEFORE PURCHASE*

Re: More Alternator woes

Reply #34 – August 11, 2019, 04:56:46 pm

Quote from: prfleming – August 11, 2019, 04:05:51 pm

If you're comfortable doing this, a diode can be manually wired in to use a Delco 28SI/40SI with a standard diode isolator. Wire the diode in series with the excite wire to the Delco B+ post. To make sure you have it wired the right way, turn ignition on but don't start, there should be 12v on the alt B+ post, with ign off the voltage should return to zero. If no voltage with key on, turn the diode around and try the test again. Once you're sure it's wired correctly, start the engine, the Delco should now start charging. Remove the diode and connect the excite wire to the Sterling when you switch isolators.

O'Reilly universal diode

Just about finished. Will go back in the AM and button it up. Ran the new sense wire from the delco to the Sterling. Then taped into the existing exciter at the Alt position and ran it back to the sterling. Removed old ISO and mounted the sterling. Only thing left to do is put larger ring terminals on two existing wires for the larger sterling posts and install ring terminal for the sense/ign and ground wires at the sterling.

Also made notes on the factory wiring diagram.

But lunch was calling. A pulled Pork lunch no less. So off I went.

Re: More Alternator woes

Reply #35 – August 11, 2019, 10:59:41 pm

Went out and finished my project. Coach didn't blow up or turn to a pile of ashes. So I must have not mucked anything up. Charging just fine. High idle has 14.33V at the alt. and 40 Amps on the house panel.

Re: More Alternator woes

Reply #36 – August 11, 2019, 11:18:13 pm

Awesome, another Delco conversion

Re: More Alternator woes

Reply #37 – August 12, 2019, 01:46:14 am

Can you reduce the voltage to a set of fully charged batteries to 13.6 volts?

Re: More Alternator woes

Reply #38 – August 12, 2019, 04:59:23 am

Quote from: Caflashbob – August 12, 2019, 01:46:14 am

Can you reduce the voltage to a set of fully charged batteries to 13.6 volts?

Um, That's what a voltage regulator with a battery voltage sensing wire does.

The guys that design these alternators with internal digital regulators are pretty smart folk. So I'll leave electrical engineering stuff to the electrical engineers. So I'm not going to worry about it.

But as in all things. We humans often become overly pedantic about things and fret over minutia.

Re: More Alternator woes

Reply #39 – August 12, 2019, 08:48:53 am

Quote from: bigdog – August 12, 2019, 04:59:23 am

But as in all things. We humans often become overly pedantic about things and fret over minutia.

Congratulations on your success!
My Fiat has a generator.
And when the outside air temperature is 99° and the heat index is 110° there isn't much else to do.

FWIW my 1950 Chrysler was my summer transportation from 1976 until 2013. The way I figure it, this U225 and the '68 SIATA should take me to the end. Once I finish the SIATA.

Re: More Alternator woes

Reply #40 – August 12, 2019, 10:36:15 am

Quote from: Old Toolmaker – August 12, 2019, 08:48:53 am

FWIW my 1950 Chrysler was my summer transportation from 1976 until 2013. The way I figure it, this U225 and the '68 SIATA should take me to the end. Once I finish the SIATA.

I finally had to make my own heater valve as Fiat's failed time and time again. While very short, Fiat designed it with huge understeer so almost impossible to spin it even in the wet.

Pierce

Re: More Alternator woes

Reply #41 – August 12, 2019, 12:02:46 pm

Quote from: Pierce & Gaylie Stewart – August 12, 2019, 10:36:15 am

I finally had to make my own heater valve as Fiat's failed time and time again. While very short, Fiat designed it with huge understeer so almost impossible to spin it even in the wet.

Pierce

Don't get me started on Fiat's. I had a 1973 124 sport coupe. Good looking, fun to drive. Not many coupes around as everyone had the spyder. Driving sedately on my way to trade it for a pickup truck. The con-rod decided it wanted a bit of fresh air and made a big hole in the engine block. That was the end of my Fiat experience.

Re: More Alternator woes

Reply #42 – August 12, 2019, 01:46:11 pm

Quote from: bigdog – August 12, 2019, 12:02:46 pm

Don't get me started on Fiat's. I had a 1973 124 sport coupe. Good looking, fun to drive. Not many coupes around as everyone had the spyder. Driving sedately on my way to trade it for a pickup truck. The con-rod decided it wanted a bit of fresh air and made a big hole in the engine block. That was the end of my Fiat experience.

We found that with the dog we needed a car and we wanted something easy to trailer. Our search took us past an XJ-12 that probably had heat issues and a any way you looked at it was run out, then back to the other extreme the Fiat 850 based Siata Spring. In the middle were any number of full size Chrysler products that blew the easy to trailer argument right out the window.

Is Yurre's rig supposed to have a pipe plug in the oil pan or was that something creative? I now own a 17mm hex key for an 850cc engine's cast aluminum oil pan's drain plug.

Re: More Alternator woes

Reply #43 – August 12, 2019, 05:52:07 pm

This guy has the best Fiat parts. Midwest Bayless.
Heres his car getting passed by my Red VW. @ Daytona ;
https://www.youtube.com/watch?v=c2HZk7QReTQ&t=95s

Re: More Alternator woes

Reply #44 – August 12, 2019, 06:08:03 pm

We (me included) are wondering off topic. Esp as it's in the tech forum.

Re: More Alternator woes

Reply #45 – August 12, 2019, 09:06:04 pm

We keep thinking your having more woes only to find where to buy Fiat parts.

Re: More Alternator woes

Reply #46 – August 12, 2019, 11:32:52 pm

My shop said if I installed a sense alternator I would get a constant 14.1 volts at the batteries.

Re: More Alternator woes

Reply #47 – August 13, 2019, 09:00:49 am

I loved my 1970 Fiat 124 Coupe until I leaned on the driver's side front fender and my elbow fell through. It turned out much of the body sheetmetal was being held together by the paint!

Re: More Alternator woes

Reply #48 – August 13, 2019, 10:46:29 am

My comment was to help nothing more.

14 volts at the batteries is quite a bit of overcharging both banks unless in zero degree weather.

Factory and Brett here both set the alternator at 13.6 volts at the battery.

The delco sense drawing shows 13.5 volts without the sense wire. 14 with.

I would remove the sense wire myself if possible.

If you have a Battery Temp compensating inverter with a remote panel you will see the battery charging voltages change with the batteries temp.

Most rv batteries "float" at 13.6 volts.

Yours will be permanently being overcharged, if full, at 14 volts.

50% decrease in battery life?

As you still seem to be having issues I am not sure if just removing the sense wire is as easy as it seems but killing $2000 worth of batteries quicker than necessary seems not a good thing.

What do your batteries "float" at at 77 degrees? Next to the motor the engine compartment batteries get much hotter.

Probably why Foretravel used optima red(or yellow in a few) top spiral wound AGM start batteries as they round cells dissipate heat better.

Lots of 10 to 12 year life redtop/mk gels reports here so the 13.6 at the battery volts is shown to work very well.

These are obviously not school busses and the rapid recharge rate at a higher voltage than "float" could shorten your batteries life considerably.

Just trying to help you and maybe others here with their coaches.

Old coaches had 14 volt battery boilers(chargers) only and I replaced every battery in every used coach I resold as they wore quickly. Especially in the desert southwest temps.

Hence the LN adjustable voltage regulator.

The smart inverters will start out at over 14 volts in moderate weather then reduce the volts as the batteries get charged then float.

Alternator does not know about float unless you have a temp compensating unit.

Those do not work well in a coach where the batteries are hot from the engine.

The charge volts can be close to 13 volts in those systems after a full charge in hot conditions at the battery.

The marine industry sometimes uses temp controlled alternator but the batteries are not normally that hot...

Re: More Alternator woes

Reply #49 – August 13, 2019, 11:07:39 am

Aren't all the automobiles charging at 14.2 volts under a hot hood. I get 6 to 7 years out of my Costco car batteries.

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