Converting to dual alternators

[73m819]

a common DC ground is used a lot in welding, so I would not think there would be a problem with a vehicle

 

[rat4spd]

I just want to see the post count get to 100.

 

[plym49]

I understand the beauty of redundancy and of a back-up to the back-up to the back-up. So, adding a third battery as the OP did is understandable and, if those are your needs, desirable.

However, Jason S's statements of fact are - - - fact. It does not mean that that is the way you should run, it is only that electrically it is a perfectly acceptable way of doing it. If your 12 volt demands are modest (stereo and an accessory or two) then this saves the cost and space and weight of the third battery.

For those wondering about how the 24v and 12v alternator/regulators will 'duke it out' (how they each decide how much current to put out), the answer is "whatever they want". It is all handled automatically and know one knows from moment to moment how much of the load is being handled by either alternator unless you had them instrumented to see it.

Think of it this way. Say you had a train with two locomotives. Let's pretend that one locomotive is 1000 hp and the other is 2000 hp, and that the train needs 2500 hp to move. How much power does each locomotive deliver? Answer is that is does not matter, it is driven by the throttle settings of each engine, and the engines themselves never know that the train is requiring more power than each engine can produce by itself.

Power is power.

 

[FireFighterHill]

I agree with what others have said. If you tried to run both a 24v and 12v system together you would still run into the problem of draining more power from the battery that is hooked up for 12v then the others. This would cause over charging of the other battery.

Is it possible to have 3 batteries, 2 ran in series for 24 then a 3rd that sat behind a battery isolator for 12v?

 

[tm america]

Guys rather than hijack a great thread with the obivously highly debated subject of weather you can or can't charge two batteries with two alts.?Maybe it would be best to start another thread in the electrical forum and do some real world tests on what you are proposing..

 

[tm america]

if you have a metal battery box three batteries fit in the just fine.. plastic battery box may be a different issue..i will try it on my truck i have both types of boxes on hand here

 

[militarysteel]

i like my duce the way it its. Bone stock and Proud!, people that spend all this crazy money, are just spending money.

i suppose you can mod anything, but then its just not as cool as it was before.

 

[FireFighterHill]

http://www.steelsoldiers.com/electrical/61876-discussion-combining-24-12-volt-systems.html

 

[DUG]

i like my duce the way it its. Bone stock and Proud!, people that spend all this crazy money, are just spending money.

i suppose you can mod anything, but then its just not as cool as it was before.

I like the word deuce spelled the way it's supposed to be - d e u c e and proud.

Your deuce has plenty of mods on it. Unless it's a virgin M35. The only difference is some depot, motor pool or Army mech did them for you.

 

[plym49]

If you could add a 12 volt alt to one battery and still have the 24 volt alt charging both batteries( in series) and have it( the 24 volt alt) charge correctly, you wouldn't need the 12 volt alt in the first place. You could load the first battery with your accessories and it would charge as JasonS said it would(with unequal battery states) , but it won't. Those of us that have "been there and done that" know this. Your Advanced degree ain't worth the paper it's printed on. Electricity is NOT basic math.

WRONG WRONG WRONG...

Now I'm done, Sorry Dug.

I believe the point of his original suggestion was if the total "12 volt" load was exceeded the capacity of the normal 12 volt system - IOW, if you are drawing more amps from the 12 v (first) battery than from the second (24 v).

Actually, electricity is basic math, at least it is in DC circuits. Ohm's Law.

The math for AC circuits is more complex as they get funkadelic, especially as the frequencies increase.

I think JasonS stated that he generates power for a living. The type of load-balancing that goes on with multiple power plants simultaneously connected to a distribution network is a more complex example of what we are talking about here. If it did not work, we would all have to do with only one power plant.

Just as you can have more than one electric motor (or other load) simultaneously connected, you can have more than one generator (alternator) simultaneously connected, as well. The math (and the electrons) work the same in both directions.

Also as a person who has been here and done that, I understand that you can run into problems if you do not connect things right. I also understnad that this is a scenario that few of us might ever need. But, to paraphrase Galileo, 'it still works'.

 

[jwaller]

My point is that you CAN connect a 12V alternator to the midpoint of the batterys and it WILL work. I don't care about any other ancillary points.

I have to agree with this point, to me it's the same as using a std vehicle to jump a deuce. You simply connect the jumper cables from your POV to each battery separately. even when the deuce cracks up and runs and you still have the POV connected nothing special happens, it works perfectly fine.

Even the M809 series trucks have a 12V load going to only 1 battery, I know it's small and gets used about as often as we launch the space shuttle but it's there and the designers didn't think it would hurt.

 

[rat4spd]

Think of it this way. Say you had a train with two locomotives. Let's pretend that one locomotive is 1000 hp and the other is 2000 hp, and that the train needs 2500 hp to move. How much power does each locomotive deliver? Answer is that is does not matter, it is driven by the throttle settings of each engine, and the engines themselves never know that the train is requiring more power than each engine can produce by itself.

Power is power.

The first locomotive runs the show. The rest are slaved to the master. One brain.

 

[plym49]

The first locomotive runs the show. The rest are slaved to the master. One brain.

Yes, but that is not the point. Each locomotive does not know that there are other locomotives. That's the same as multiple alternators. The train does not know how many locomotives there are. That's the same as the load in an electrical circuit.

To round out your analogy, in the old days there was no 'brain'. There was an engineer in each engine and they would coordinate throttle activity. At any moment in time, #1 might be doing more work than #2, and vice versa.

I was once on a double-header steam train where the engineers got crossed up. #1 engineer was throttling back and #2 opened it up. #2 pushed #1's tender up enough to cause it to derail. That was on the side of a mountain in the winter and it was not the most pleasant evening.

 

[DUG]

Yes, but that is not the point. Each locomotive does not know that there are other locomotives. That's the same as multiple alternators. The train does not know how many locomotives there are. That's the same as the load in an electrical circuit.

To round out your analogy, in the old days there was no 'brain'. There was an engineer in each engine and they would coordinate throttle activity. At any moment in time, #1 might be doing more work than #2, and vice versa.

I was once on a double-header steam train where the engineers got crossed up. #1 engineer was throttling back and #2 opened it up. #2 pushed #1's tender up enough to cause it to derail. That was on the side of a mountain in the winter and it was not the most pleasant evening.

Rat4spd and I know a couple things about trains. Working for the railroad was the ONLY job our dad ever had, well except for those two years in Korea.

When I was 10 or 11 I "drove" a train with three engines, 19 cars and for some reason 2 cabooses. All of my brothers and sister got to drive at some time in our childhood.

 

[plym49]

Rat4spd and I know a couple things about trains. Working for the railroad was the ONLY job our dad ever had, well except for those two years in Korea.

When I was 10 or 11 I "drove" a train with three engines, 19 cars and for some reason 2 cabooses. All of my brothers and sister got to drive at some time in our childhood.

That's very cool.

Nowadays that would be treated as a major offense with a bunch of federal agencies involved.

 

[rat4spd]

Yes, but that is not the point.

It's entirely the point. Two alternators equal two voltage regulators trying to regulate voltage on the same battery, except one is also charging the other battery.Which regulator wins?

In your steam example, you have two locomotives in manual. That requires babysitting, which I do relatively frequently at the plant....but is doable. Call me a control freak, but in situations that have multiple brains, you should only have one in auto. More than one boiler in a power plant.......one in auto, the rest in manual......grid power production......big boys control voltage, little guys run speed droop(not voltage regulate)...

An example of chaos with two things in auto: My former Silverado with dual climate control......my wife liked it hot, I liked it cool. In the end, mine was all the way cold, hers was all the way hot.....it sucked for the both of us.

I don't wish to argue ohms law. It will work, I understand that. Will it work well? I dont believe so...or at least no better than pulling 12V of the first battery with one alternator. If two alternators paralleled can't keep both batteries relatively optimized, why bother?

 

[tm america]

When did two alts become two trains...Do any of the guys that drive trains have a vehicle with two different voltage alts charging two 12 volt batteries in series?If not you are guessing at what it would do based off of a therory.Trains and electrical systems are two very very different things..Two engines vs two alts are like comparing apples to water...

 

[plym49]

It's entirely the point. Two alternators equal two voltage regulators trying to regulate voltage on the same battery, except one is also charging the other battery.Which regulator wins?

Whichever one wants to. They work it out for themselves, automagically, moment by moment.

In your steam example, you have two locomotives in manual. That requires babysitting, which I do relatively frequently at the plant....but is doable. Call me a control freak, but in situations that have multiple brains, you should only have one in auto. More than one boiler in a power plant.......one in auto, the rest in manual......grid power production......big boys control voltage, little guys run speed droop(not voltage regulate)...

An example of chaos with two things in auto: My former Silverado with dual climate control......my wife liked it hot, I liked it cool. In the end, mine was all the way cold, hers was all the way hot.....it sucked for the both of us.

I can relate to that LOL. But in that we have hot and cold fighting each other. A closer example might be if you had two engines, each water cooled and plumbed to the same heater core. Which engine is heating the vehicle? It doesn't matter.

I don't wish to argue ohms law. It will work, I understand that. Will it work well? I dont believe so...or at least no better than pulling 12V of the first battery with one alternator. If two alternators paralleled can't keep both batteries relatively optimized, why bother?[/QUOTE]

I understand your last point.. It all seems to boil down to the amount of power required by your 12v circuits. The borttom line might be that if your circumstances or desires preclude use of a separate battery, this technique can be used to supplement the load on your 24 v alternator and first battery.

 

[DUG]

I think the trains were added to help grant Rat4spds goal of 100 posts.

 

[tm america]

oh ok well lets at lest keep it mv..Can we substitute planes or tanks in place of trains?