2nd alternator, 12V

yagenrok636

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Well, I ended up getting one of these for my head unit and speakers. It had good enough reviews to try for $40, and I don't need a second alternator or battery.

I would like to do the 2nd alternator and third battery, because its more reliable, but I guess not until I have more accessories to run. I'll let you guys know how it installs and runs.

http://www.amazon.com/Pyle-PSWNV720...d=1413559578&sr=8-1&keywords=pyle+24v+to+12+v
 

Wildchild467

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I have the second alternator and the only thing I power with it are 4 LED work lights. I also have a redi-line generator I can run off it if i choose to, and that draws a lot of current. I wanted the alternator also because of its reliability. I could have done a 1 wire delco alternator, but I went with the 3 wire due to its availability. If I ever needed another, I can get one anywhere. I also can plug in jumper cables and jump start another vehicle without the worry of damaging my 12 volt system. My 12 volt alternator charges the 3 deep cycle batteries I have on board. That is what beautiful... I can power things a long time and if my batteries die, no worries at all. Just start the truck back up and charge them. Easy peasy.
 

Lieutenant Dan

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Yup wildchild nailed it! 2nd alternator is the way to go. I don't regret it one bit. All my accessories are ran off of it. I have my federal signal light bar whidraws about 40 amp when all lit up and all my led work lights too. I run a power invertor off of it when camping as well. Plus my 600 watt stereo system, cb, and other goodies. I would like to add another one or two deep cycles under the bed in the frame rails for camping and put a solar panel on top of the cover to keep them topped off.

http://youtu.be/nyZUi3K52Pg

http://youtu.be/kLxwsEtEUlI
 

m715mike

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Well, I ended up getting one of these for my head unit and speakers. It had good enough reviews to try for $40, and I don't need a second alternator or battery.

I would like to do the 2nd alternator and third battery, because its more reliable, but I guess not until I have more accessories to run. I'll let you guys know how it installs and runs.

http://www.amazon.com/Pyle-PSWNV720...d=1413559578&sr=8-1&keywords=pyle+24v+to+12+v


I would like to have the second alternator as well. But I took baby steps and went with the Pyle converter first.


Here is some more information on my install:
http://www.steelsoldiers.com/showthread.php?120966-My-12-Volt-DC-Accessory-Kit-Installation



One of these days I'll step-up to the second alternator....
 

yagenrok636

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I have a dumb question. I've got two 12v batteries like everyone else in my Deuce. When I hook my multimeter up to the ground and check my battery terminals, I get 12-13 volts between the two batteries. Nothing at the ground obviously and 26-30 off the terminal that the starter is hooked up to.

Why do I even need a second alternator or a converter? Can't I just draw 12~ volts from the first battery and ground my light bar to the frame?
 

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Lieutenant Dan

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No cause as soon as to go from any terminal on the batter to ground you get 24v. It must be off one battery and only light loads. It causes uneven draw from one battery and will damage it over time.
 

ralph3162

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Well, I ended up getting one of these for my head unit and speakers. It had good enough reviews to try for $40, and I don't need a second alternator or battery.

I would like to do the 2nd alternator and third battery, because its more reliable, but I guess not until I have more accessories to run. I'll let you guys know how it installs and runs.

http://www.amazon.com/Pyle-PSWNV720...d=1413559578&sr=8-1&keywords=pyle+24v+to+12+v
I got that exact same one and installed it in my deuce it lasted three days before it gave up the ghost so I went with dual alternators instead much better choice I believe.
 

red

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No cause as soon as to go from any terminal on the batter to ground you get 24v. It must be off one battery and only light loads. It causes uneven draw from one battery and will damage it over time.
To piggyback off the question what about running a set of wires in parallel from the batteries to provide the separate 12 volt system?
 

yagenrok636

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No cause as soon as to go from any terminal on the batter to ground you get 24v. It must be off one battery and only light loads. It causes uneven draw from one battery and will damage it over time.
Ok that's what I always thought but now that I think about it, how do you get 24v off the first battery? I used my multi-meter and grounded it to the frame and then touched the positive terminal on the first battery and got 13 volts...

But according to what you just said, i should be getting 24 volts on all the different terminals. I can understand getting 24 volts off the positive on the second battery because 12 + 12 is 24...but the current doesn't flow backwards from the starter back into the batteries and into the first battery right?


So lost.
 

eagle4g63

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The problem you guys are missing when you pull 12 volts off one of the batteries is the fact that the stock 24 volt alternator is putting out 24 volts.....the ONLY way it can charge the batteries the same is IF both batteries are being drawn from the same.....just in case anyone asks......YES BOTH batteries should be the same, by that I do mean they should both be the same CCA and the same draw rate...if not they will charge different, one battery will inevitably get charged more than the other one.....that is where you end up "killing" one battery, it will either be the one that never gets charged enough, or the one that is always being over charged.

You WON'T get 24 volts from all terminals....only the first and last terminal in the series....If you measure from the first battery than yes you are correct and will get a 12 volt reading(13)

Again the best way to get 12 volt is one of 2 ways....ONLY.....a second 12 volt system or a voltage step down....I don't like the term "converter" as in this case it is miss used, it doesn't "convert" anything it reduces the voltage....a converter is what you use to "convert" from ac to dc and vice versus.

Many will argue that you can just tap off and get a perfectly usable 12 volts....you will get a useable 12 volts.....however you ARE doing harm to your battery bank if you do this.....however small, it will lead to a shorter than useable life of a battery.......is the trade off worth it to you for what you are going to do with your truck? that is for you to decide....but I can tell you, the day you happen to have one of the batteries DIE and leave you with a 7 ton paper weight at the most in-opportune time is a total kill joy...plus you are back to the buying 2 batteries again, not just the one you killed....the damage to the second battery WILL lead to another shorter than designed life of the new battery....
 

rustystud

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The only way to use just one battery for 12 volts is to use a "Vanner" style battery equalizer. We use this style on our busses since we use both 12 volts and 24 volts. If you do not use a battery equalizer you will destroy your batteries.. The problem is battery equalizers like the Vanner cost a lot of money. Our 80 amp units cost over $500.00 . I have heard some have found good deals on eBay, but with anything bought there your taking a chance on it's quality.
 

yagenrok636

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The problem you guys are missing when you pull 12 volts off one of the batteries is the fact that the stock 24 volt alternator is putting out 24 volts.....the ONLY way it can charge the batteries the same is IF both batteries are being drawn from the same.....just in case anyone asks......YES BOTH batteries should be the same, by that I do mean they should both be the same CCA and the same draw rate...if not they will charge different, one battery will inevitably get charged more than the other one.....that is where you end up "killing" one battery, it will either be the one that never gets charged enough, or the one that is always being over charged.

You WON'T get 24 volts from all terminals....only the first and last terminal in the series....If you measure from the first battery than yes you are correct and will get a 12 volt reading(13)

Again the best way to get 12 volt is one of 2 ways....ONLY.....a second 12 volt system or a voltage step down....I don't like the term "converter" as in this case it is miss used, it doesn't "convert" anything it reduces the voltage....a converter is what you use to "convert" from ac to dc and vice versus.

Many will argue that you can just tap off and get a perfectly usable 12 volts....you will get a useable 12 volts.....however you ARE doing harm to your battery bank if you do this.....however small, it will lead to a shorter than useable life of a battery.......is the trade off worth it to you for what you are going to do with your truck? that is for you to decide....but I can tell you, the day you happen to have one of the batteries DIE and leave you with a 7 ton paper weight at the most in-opportune time is a total kill joy...plus you are back to the buying 2 batteries again, not just the one you killed....the damage to the second battery WILL lead to another shorter than designed life of the new battery....
Excellent points.

I guess I'll try my hand at fabricating a second alternator bracket. I've got the Pyle 24v reducer installed and my gauges work great, but like someone else said, I'm not sure how long it will last. Then I'll be stuck driving somewhere without a pyrometer.
 

74M35A2

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The only way to use just one battery for 12 volts is to use a "Vanner" style battery equalizer. We use this style on our busses since we use both 12 volts and 24 volts. If you do not use a battery equalizer you will destroy your batteries.. The problem is battery equalizers like the Vanner cost a lot of money. Our 80 amp units cost over $500.00 . I have heard some have found good deals on eBay, but with anything bought there your taking a chance on it's quality.
False. The military pulls 12V from 1/2 the battery bank on M939 series vehicles which only have a single 24v alternator.
 

74M35A2

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You're fine, I'm not out to get you. Just happened to notice recent activity regarding a 12v topic.

At the same time, it is important to set the record straight that it has been done this way, per military design intent, on approximately 32,000 vehicles. The batteries in my M939 series were 7 years old when I received it, and all still in great working condition with plenty of reserve capacity left.
 

Stalwart

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Bull poopie, the military typically uses a dual voltage alternator that is a huge beast of a thing. How do I know this, have a new one on the shelf, not in the HEMTT yet. They might allow tapping the grounded battery for teeny, tiny loads but even that will come with an eventual cost of reliability and battery failure.
 

74M35A2

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No poopies about it. It has been done, in production, by the military. Any M939 wiring diagram will show it, and the dash battery switch even has a dedicated pole for it to control its connectivity same as the 24v line simultaneously. People get all bent out of shape and become mostly silent when this is brought to light, but, it is fact, having nothing to do with anybody's opinions.

Your Scorpion is cool.
 

daytonatrbo

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No poopies about it. It has been done, in production, by the military. Any M939 wiring diagram will show it, and the dash battery switch even has a dedicated pole for it to control its connectivity same as the 24v line simultaneously. People get all bent out of shape and become mostly silent when this is brought to light, but, it is fact, having nothing to do with anybody's opinions.

Your Scorpion is cool.
One thing that I don't see discussed on here is balancing the loads between the 12V batteries. Obviously its only a golden unicorn option, should you happen to have suitable loads that are used at the same frequency.


The other thing I never see, that I may use on my own truck, is putting 12V resistive loads in series. I wouldn't do it for headlights, but for auxiliary lighting you can run 2 12V bulbs in series on 24V. Yes, you run the risk of blowing out one bulb and losing the output of both (think christmas lights) but it can be a budget friendly way to add offroad and auxiliary lighting. The bulbs MUST be matched wattage though.
 
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