Converting to dual alternators

[rat4spd]

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

That whole magic thing bothers me. Magic smoke, magic boxes....next you know, Harry Potter really exists, and no one has control of anything anymore.

 

[tm america]

That whole magic thing bothers me. Magic smoke, magic boxes....next you know, Harry Potter really exists, and no one has control of anything anymore.

now this is a funny post..

 

[plym49]

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...

(Military) trains, planes and automobiles...............

.............it's all about power. Alternators produce current (amps) at a voltage and that equals power (watts). The engines in a vehicle produces power (HP). One HP equals 746 watts. Power is power.

No one has a problem with hanging multiple loads (power absorbers) off of an electrical system. But, in this discussion, there seems to be some discomfort with the notion of hanging multiple alternators (power producers) onto one electrical system.

Electrically, it doesn't matter. Power in equals power out. There is no rule that there be only one alternator any more than there is a rule that there be only one power user (circuit or device).

 

[FireFighterHill]

My question is What will that 12v alt do when it sense's 24v on the line. By adding 24v from one alt and 12 from the other wouldn't that be essentially 36v? My expierence with AC current is that if you take 110 and 110 from 2 different power sources and put them together you get 220, does the same rules apply to DC?

 

[tm america]

ok im gonna show you how power is not power ...ok if the load is across the 24 volt side and the 12 volt alt turns on before the 24 volt alt does it will charge the first battery more than the second gets charged..then when the 24 volt alt would have turned on it wont..the 24 volt alt looks for 24 volts across both batteries it doesnt know if one is 10 and the other is 14...trust me when i say a little bit off here makes for a bad day alot quicker than you think ...electicity does care ....two of the same alts will turn on and off at different voltages..now imagine what two different alts will do..Go to autozone have them grab two of the same alts throw them on the tester and watch the results it won't take you but about ten minutes to know you are wrong...alts are built with a range not an exact turn on -off voltage..good is anything above 13.2 to 14.6 if the the turn on voltage is different you will have big problems..there are way to many veriable in the system to even dream that two different alts running to two different batteries will turn off or on at the same voltage as the regulaters and draw will be different.

 

[FireFighterHill]

From my research that running more then one alt on a single combined circuit takes some planning and caution If you put them in series, you risk exceeding their current rating. If you put them in parallel, you risk exceeding their reverse voltage limits. If they are not sized correct for amperage it would result in cascading failures starting with the diodes and ending with burned coils. I have also read that you should NOT combine alternators of different voltage on the same system in either series or parallel. I'm trying to find an explanation as to WHY you shouldn't.

 

[tm america]

This is exactly what happens when you draw from the front battery to get 12volts....it discharges the front battery and overcharges the second..now you are gonna draw from the first and hope the alt charges it exactly when and at the same rate as it is being taken from the first battery befor the 24 volt alt sees a discharge..seriously think about it...what will happen is the front battery will discharge to the turn on point for which ever alt has the lowest turn on point..if it is the 24 volt it will undercharge the first and overcharge the second..if it is the 12 volt it can over charge the first and make the 24 volt not turn on when it should...either way you are counting on the regulaters to be in perfect sync and that might happen if you get lucky but 9 out of ten times good alts being within spec will turn on and off at different voltages..

 

[tm america]

plym49 do you have a truck with that type of electrical system ?have you ever tested multiple alt of the same or different part number?do you know how the 24 volt alt charges the two 12 volt batteries wired in series?ac and dc electric work totally different ..If you know anything about automotive electrical systems you would know there is a very good reason there is no manufacturers running the type of system you are saying works?Facts are facts noone here cares about a therory when you have to buy a battery or get towed home they only care about what works and has been proven to work for 50 yrs ..Not what you think could work but hasn't been proven in real work tests and apps.You buy it,build it ,test it,and prove it and you can compare it to trains planes and automobiles,chickens water and air what ever you want when you can bring the real world data to prove it works..till then how about we stick with what has been on the market working for 50 yrs or more ok

 

[FireFighterHill]

TM, from what ive read its not the problem with running multiple alts its more with the alts not being identical in there output of both voltage and amperage. Another thing to consider is RPM, at what RPM are these alternators producing voltage and amperage and how much at any given RPM. I read its best to mach alternators for a dual alt system like you flow match injectors.

 

[tm america]

Yes like i said there are way to many veriables to think it could be a practical setup..most systems using two alts to charge the same batteries use issolators and use one as the primary and the other only when the load demands it reguardless of what the regulater is doing on the secondary alt.But that is on two alt same voltage systems not you are talking about taking and adding voltage in the middle of the ciruit that is being sensed by the 24 volt alt...And everyone with all the knowledge and degrees noone mentions that they might not turn on or off at the same voltage?noone considers the pulley size?the voltage drop over the lenght of wire .what happens when you use different grade or sizes of copper wire?the way the lead acid battery works and how number of load cycles effect the batteries abilty to hold a charge..and the effects of charging two batteries in series that have different load cycles?There are way to many therories and not enough hard facts for certain people to be taken seriously..

 

[plym49]

plym49 do you have a truck with that type of electrical system ?have you ever tested multiple alt of the same or different part number?do you know how the 24 volt alt charges the two 12 volt batteries wired in series?ac and dc electric work totally different ..If you know anything about automotive electrical systems you would know there is a very good reason there is no manufacturers running the type of system you are saying works?Facts are facts noone here cares about a therory when you have to buy a battery or get towed home they only care about what works and has been proven to work for 50 yrs ..Not what you think could work but hasn't been proven in real work tests and apps.You buy it,build it ,test it,and prove it and you can compare it to trains planes and automobiles,chickens water and air what ever you want when you can bring the real world data to prove it works..till then how about we stick with what has been on the market working for 50 yrs or more ok

Wow, this issue can get the juices flowing - no pun intended.

Actually, I have had experience with dual voltage, except 6/12 instead of 12/24.

I completely agree that anything slim shadied is not going to work, or for long. I have seen many many cars, truck, motorcycles, you name it with completely rigged electrical systems. Poor splices, frayed wires, corroded terminals, wires going thru steel panels without grommets, you name it. I'm sure you have, too.

There is no doubt that a dual alternator system would need more careful implementation, and it would be easier to muck something up.

I didn''t think the issue had to do with whether this approach was cost-effective or 'best' for any particular situation, or that it is a panacea. JasonS pointed out that it is possible. It is.

BTW, Detroit is going the dual voltage route. You will be seeing dual voltage vehicles - 48 volts and 12 volts. The reason is that there are now so many electrical accessories that the current requirements are getting out of hand (larger wire = more copper = higher cost and weight). Four times the voltage means one fourth the current. But not all of the accessories will be 48v; there will still be 12v components. Not exactly like Detroit's move from 6 to 12 volts, since when that happened everything in the vehicle went to 12 volts.

Commercial dual-alternator units? They will always be few and far between, because manufacturers like to keep the parts count low, and there are fewer parasitic losses driving one alt than two (even of the overall power output is the same).

 

[tm america]

i agree it can work in a perfect setup ...with the proper control of the voltage regulators..but not with off the shelf alts and this means it is not practical..this is why they make battery equalizers they have the voltage sensing circuitry needed to make it practical..and they eliminate the variables...we are already seeing hybrid cars in our shop dual voltage systems and various ways of charging the battery packs but the alts and charging systems are all computer controlled.Not controled by two separate regulaters ...And as for cost of those systems most cant even afford the test equiptment needed to work on them let alone trying to come up with a system that could be added to a mv..not to mention the way they do this is very dangerous or even deadly when you don't use the proper technics to work on them..gotta love technology

 

[DUG]

So back here in the real world-

I have three ATVs to load in the back of my deuce. I have a cheap 3000 pound winch to pull each one up a set of 11 foot ramps. It's dark because I stayed at DIRTBAG too long (probably to sober up for the drive home) so I have a couple 12 volt lights on. I might even have a back up camera system to help me get hooked back up to the M105 camper I brought and lived in for 4 days. My iPhone is plugged in and charging so it's useful when I get a signal leaving the dez.

How many batteries do I want for this situation?

I could care less if two, three or eight alts can be hooked up. I want a dedicated 12 volt only battery because if I kill it loading the ATVs with the truck off and those lights on with the phone charging the truck is still going to start. I'm still going home.

A second alt hooked up to a dead battery isn't going to charge anything if the truck doesn't start.

My way, with Georges kit is the best way - for me.

 

[DUG]

Double post - must be a glitch with too many things hooked up.

 

[plym49]

So back here in the real world-

I have three ATVs to load in the back of my deuce. I have a cheap 3000 pound winch to pull each one up a set of 11 foot ramps. It's dark because I stayed at DIRTBAG too long (probably to sober up for the drive home) so I have a couple 12 volt lights on. I might even have a back up camera system to help me get hooked back up to the M105 camper I brought and lived in for 4 days. My iPhone is plugged in and charging so it's useful when I get a signal leaving the dez.

How many batteries do I want for this situation?

I could care less if two, three or eight alts can be hooked up. I want a dedicated 12 volt only battery because if I kill it loading the ATVs with the truck off and those lights on with the phone charging the truck is still going to start. I'm still going home.

A second alt hooked up to a dead battery isn't going to charge anything if the truck doesn't start.

My way, with Georges kit is the best way - for me.

In the scenario you described, I personally would go with a separate/redundant system. Not because electrical theory says it can't work that other way (since Harry Potter has been mentioned, "that way that should not be mentioned"), but because I am a redundancy freak. Keep work separate from play. If the play system dies, you still have the 24v system. If the work system dies, you have an extra 12v battery. Others have already pointed this out.

I even have on hand a tiny, el cheapo 2 cycle 12 volt 350 watt genset on hand. It is tiny and light. It takes no space. I keep it because, sometimes, every battery is dead just when you need it/them. This way I can always get a battery charged.

 

[DUG]

In the scenario you described, I personally would go with a separate/redundant system. Not because electrical theory says it can't work that other way (since Harry Potter has been mentioned, "that way that should not be mentioned"), but because I am a redundancy freak. Keep work separate from play. If the play system dies, you still have the 24v system. If the work system dies, you have an extra 12v battery. Others have already pointed this out.

I even have on hand a tiny, el cheapo 2 cycle 12 volt 350 watt genset on hand. It is tiny and light. It takes no space. I keep it because, sometimes, every battery is dead just when you need it/them. This way I can always get a battery charged.

I have the 800 watt harbor freight genset that I picked up for 79 dollars. The blender for margaritas will get run no matter what. Because I bring this genset along, one of the four Jerry cans on my deuce is mix gas. Hope the thieves guess correctly or they might have trouble.

 

[tm america]

Dug another thing you can do when you have a separate 12 volt system with its own dedicated battery..Is you can use one of those cheap 12 volt solar chargers so you can go longer times before you even need to start the truck to charge the acc battery..Having a separate 12 system allows you to run things like dual power fridges.,and any other item you would find in an rv.

 

[rat4spd]

I have the 800 watt harbor freight genset that I picked up for 79 dollars. The blender for margaritas will get run no matter what. Because I bring this genset along, one of the four Jerry cans on my deuce is mix gas. Hope the thieves guess correctly or they might have trouble.

Sheet, if you'd gotten a MEP003 like myself, you could light up all of dirtbag, an we wouldn't be pushing 125 posts talking magic smoke, Harry Potter, an yer alternator set up. Got 'lectricity?

 

[doghead]

Double post - must be a glitch with too many things hooked up.

Dug, did they post in series or parallel? The math says it could happen either way.

 

[DUG]

Dug, did they post in series or parallel? The math says it could happen either way.

They posted in series, but I place 82.4% of the blame on the iPad and 9.3% of the blame on the pain meds I'm taking for my back. The rest of the blame falls directly on the guy driving the train - Harry Potter.