We have a caboose with a 12V Safety generator and regulator system and we're working to get it going again. We're wanting to use it to charge an automotive battery to run the lighting with LED bulbs. The regulator isn't picking up and rather than trying to horse around with the springs, weights and linkage adjustments without a manual, I was wondering if anyone has used an automotive generator regulator in place of the monster-sized Safety regulator. If you have, what did you use and what, if anything, should we watch out for?

Generator is a Safety Car Heating & Lighting Co. model AA1500 - 15V, 67A. The brush holder is a rocking type polarity changer that flops back & forth 90 degrees depending on the direction of travel so the output is always the same polarity. The generator has been flashed and does work.

Regulator is also made by the Safety but has no ID plate on it so we don't know what model it is. It has the usual voltage and current mechanical regulators and a cut-out relay.

Caboose is ex-EJ&E #5XX series built by International Car, one of the ones that were sold to the B&LE who removed the original propane system including the generator and installed the Safety generator with Spicer drive and regulator.

Thanks

Well, they do still make mechanical (relay type) DC generator voltage regulators for old automobiles. But they are about 10 amps max; operate the headlights, some running lights and maybe an AM radio. They work with a sort of "pulse frequency modulation" scheme where they connect the generator to the battery "every so often" (about 200 Hertz) to flow current into the battery to keep the battery voltage "up" to a set value.

Maybe an "industrial" unit for a truck, tractor or bulldozer might work.

Here's one I found after a short search (30 amp capacity);

https://www.rareelectrical.com/i-269055 ... 02191.html

I bet if you give those folks a call they can find you one that can handle 67 amps.

Or two of those 30 amp units in parallel with a couple of low value resistors between the output of each regulator to the battery positive terminal may work. The series resistors (1-10 ohms) allow the voltage output of each regulator to be just a little bit different but still flow charging current to the battery.

Warning, you may still need to adjust the regulator "arms" by bending them a "wee bit" to get close to the charging voltage you want (normally 13.5 volts or so). But brand new units should have instructions on how to accomplish that adjustment (hopefully).

And, if you find a replacement unit it may have 3 terminals (using the metal chassis as a de-facto electrical ground) or 4 terminals (with a dedicated ground terminal). Be sure you have a good electrical ground that does not go through corroded/painted metal chassis/frame components. But you probably already knew that.

And the ampacity question is mostly about how many batteries you want to keep charged. While your generator can output 67 amps (per the nameplate) it may take 10 batteries to "suck up" all those amps. So, if your "load" (one or two automobile batteries) can only accept 10 amps then the fact that your generator can "make" 57 amps you can't "accept" does not mean anything. The battery will accept all the amps it wants to and then the battery voltage will "top off" and the regulator (if it is working properly) will stop sending charge to the battery.

With LED lighting and one or two 12 volt batteries (like a nominal automobile battery with say 400 amp hr capacity) I bet that 30 amp voltage regulator for $65 will likely work just fine.

For the sake of safety just put a 30 amp fuse in the circuit. Use wire rated at over 30 amps with an inline fuse receptacle and install a 30 amp fuse. That way everything is protected and the worst thing that can happen is you have to buy some more fuses until you get it figured out....

If you have a bank of a dozen "normal" 12v car batteries that you want to keep "fully charged" then you probably need a higher ampacity voltage regulator (or multiple regulators in parallel).

Lectricy; Everybody's been studying it for years, nobody really knows how the heck it works...

Good luck, Kevin BSEE, MSEE

Use 6-volt trolling or golf cart batteries connected in series. Using auto batteries will cost you much more as they do not handle multiple discharges and will fail quickly.

If every light is on, the max current draw with LED bulbs should only be 4.7 amps so one run of the mill car battery will suffice, two would be better if sitting still all day but that’s an unlikely scenario. I haven’t figured the charge current needed yet but I’d figure enough capacity for two depleted batteries. We’ll use either fuses or breakers and an isolation switch for protection.

The generator has three wires: one roughly 12 ga. marked as +F which is the field and two roughly 8 ga. marked as +G and -G which I assume is battery and ground respectively. Someone tell me if I’m assuming wrong.

That’s a good suggestion.

If you want a more modern and higher capacity 12V charging system perhaps there is some way to use a GM alternator of the type used on Chevy Suburbans and pickup trucks with 6.2 diesel engines (and other applications) back in the 1980s. These had the voltage regulator inside the alternator. They are commonly called a "one-wire" alternator. Unfortunately though, some alternators are designed to turn one way, which presents an obvious application problem. I am not sure whether the GM one-wire types are designed to produce output in both directions.

Added: I see a listing where an aftermarket outfit produces bi-directional cooling fans for GM alternators.


PC

While I hesitate to go 'counter' to a known source of wisdom, I changed the alternator on my 1994 6.5TD precisely away from the 'internal' voltage regulator to external, for a reason that may likely be significant here.

The 'stock' alternator is designed to provide normal working load at relatively high average engine rpm, as if in normal driving. Those using trucks for purposes where large amp draw is combined with low rpm, as with ambulance or police operation, run rewound alternators that can provide significant ampacity at low shaft rpm (e.g. PTO idle at ~1800rpm), combined with special external regulation (that can usually be adjusted for different excitation depending on duty cycle). There have been all sorts of threads in diesel-truck forums about this over the hears: here is one with some plausible options described:

https://www.thedieselstop.com/threads/ambulance-alternator.258898/

I'd suspect that a Spicer-driven generator in a typical 'preservation' operation might not get to considerable road speed very often, and hence one of these external 'ambulance regulators' might be just the ticket for adjusting output -- they work 'out of the box' for dual-alternator conversions (where the AC compressor location on the 6.5TD as installed has a second alternator installed instead ... electric air being put in if 'necessary' ;-}

No few modern 'luxury' automobiles are now built with nominal 130A or higher alternators, and the 'regulator' part of the rectified output would surely be sufficient ... if it can be easily extracted or 'bridged to' with adequate cooling, which is really a primary concern here. As a further option, if you look at some of the fringe-community experimenters with "HHO" promotion in diesel engines, you will find installations where a Spicer-style driveshaft has been provided with multiple pulleys and Weller tensioners or spring mounts for multiple alternators to provide the current to generate the 'promoters' that make enhanced combustion possible. This would surely work as a means of 'retrofitting' at least one high-output "car" alternator for operating battery-charging purposes, as Mr. Cook has suggested, ... BUT BE SURE YOU KEEP THEM COOLED.

It looks like the supply current of your generator is past what a regular car battery will tolerate. If you stick with a car battery maybe an old school automotive regulator will work. Lots of improved solid state versions for the classic car market are around. Put a fuse to the battery at the high nominal charge current. Then monitor the battery voltage and current and see what happens. If it works fine, if not try a few ohm series resistor. If all that fails your only out a few bucks.

As noted the 'supply current' of the generator will be what the connected load demands; presumably this application will use specific lead-acid or AGM charging and float and not just stick excited 12V across the battery terminals when the generator is 'on'.

One of the point Mr. Cook may have been making is that many high-amperage automobile alternators are intended to carry the electrical load of the vehicle with the engine running -- lights, fans, radio, perhaps suspension or horn compressors -- and this is managed through one or more of the 'computers' in the vehicle. This would have to be simulated if a 'voltage regulator' is not built into the alternator itself. Is it expected that the generator take some of the car load directly in operation, or just keep the batter charged and floated?

Ideally for this application, the voltage regulation should mirror what a good 80/20 float charger puts across whatever battery banks are installed . That probably involves periodic conditioning of the cells, and perhaps some diagnostics.

This is probably configured so you use can connect it for a "positive ground" (common in some old buses and trucks) or a "negative ground" like a normal automobile.

Check for continuity between both +G and -G to the frame of the generator. If there is no continuity then it is multi-polarity. Old auto generators only had the +G terminal since they connected the -G terminal to the generator chassis (ground) internally. These could only be used for a "negative ground" system.

So for a "negative ground" + 12V system I would;

Connect Generator terminal -G to ground at the regulator, either a good rust free connection to the metal frame of the regulator or to a dedicated ground terminal if the regulator has one.

Connect Generator terminal +G to the regulator input through a fuse & cutout switch or a circuit breaker (make sure it is a DC rated circuit breaker, easy to find for 12V)

Connect the regulator field terminal to the Generator F terminal

Connect the regulator output to the battery

Connect the battery minus terminal through to the same ground at the regulator with a smaller gauge wire (avoid using the heavy gauge wire that is part of the starter circuit)

Have fun, don't trip over the ground loops and watch out for the sparks...

Scratch that bit, I was thinking you had a generator in an IC engine. Just make a good ground between the battery, generator and regulator with wire that exceeds the expected ampacity (10 gauge for 30 amps is more than enough, 8 gauge if you want to splurge).

Also, two more things...

If you go with one of those old school mechanical voltage regulators make sure you install/maintain the gasket between the base and the cover... You'd be SHOCKED how many electrical systems fail because a spider decided to take a stroll through the inside "bits" of electrical parts and got stuck in the contacts and FUBAR'd things.

And, I would install a "trickle" charger onto the Caboose that uses 120 Vac to maintain the battery voltage between trips. Plug your cabin car (aka a Crummy/Hack) into "Shore Power" at the end of the day, unplug it the next morning and you should have lots of Lectricty to keep those LED's burning bright through your trips. A 120 Vac socket hidden discretely under the steps of the Caboose and a regular extension cord plugged into a 120 Vac outlet at your yard/station and you are good to go each day.

And this only on 12V. Effects like this can apply on much higher voltage...

I had a property with an outside timer switch that did not conduct. Looked carefully at the mechanism, could see nothing wrong -- upon careful inspection of the contacts, found a tiny part of ant exoskeleton effectively blocking 120VAC. Contacts looked fully closed to 'casual' view, and only a Sherlock-Holmes style deduction that something had to be in there resulted in finding it.

My "Dad in Law" had a very fancy Lincoln Town car that was presented to him after 50 years of service to his company. He had trouble adding gasoline into the "tank"...

Turns out that a few very busy spiders had blocked the "vent" tube and no gas would flow into the "tank" because no air could flow out of the tank....

I have a beautiful Weber (TM) propane gas grill that has a prominent temperature gauge right on the front of the grill cover, one spider decided to immolate himself right in center stage of that thermometer.... Dang spider is still there all dried out and deader than a doornail,,,

Dang those spiders....

I looked at the specs for that DC generator voltage regulator I suggested;

https://www.rareelectrical.com/i-269055 ... 02191.html

It has three distinct terminals and a de-facto ground (using the metal case of the regulator).

They call out; "TERMINAL ID: BATTERY-ARMATURE-FIELD"

So, Battery is the output, Field goes back to the generator field, and "ARMATURE" would connect to the "+G" output from your generator (assuming a negative ground system).

Just make good corrosion free electrical connections and you should be good to go. Easy Peasy...

I think that regulator would meet your needs just fine (assuming one, two or maybe three "regular" automobile batteries). And the price is attractive ($65).

Good Luck,