Hello everyone first off I'd I not a mechanic but a hobest. I have a 1965 Chevy that has a 250 straight 6 in a 1965 longbed c10. I want to install a second alternator, I am thinking of putting a box in the bed with a small one horse pull start gas engine. This will allow me to use a good size inverter to run a few things and if I kill the bat I start up the little guy to get going again. My quetion is when I put the second one in can I simply run the four wires off the first alternator to the second? or does this require a second voltage reg as well, anyone done it? Also does anyway know if they have a carb to fit that engine with a fuel return line? I am putting a tank in wiht one.THank you to anyone who responds.
eeeh!! stop... invest in a better quality battery if you have a costco card.. go there.. or install a second battery.. with either a mechanical switch.. or a specialty relay.. there are about half dozen different ways to perform this..you could have a cranking only battery... a small engine with a generator is not the proper way to fix this system.. i have a guy i know.. used two of the cable type spare tire hoists to lift a second battery in its box with cables already attached up under an open area under his truck.. the box lifts up till the studs go thru and nuts can be installed..i have another friend who uses on of the circle track mini batteries to crank his engine.. its like 4 inches deep x 10 inches wide and 10 inches tall..
I think I found a solution I will list but first thank you for your response, two batteries would not work because it still would kill the first battery then I would have to drain the second as well. The truck does not have any problems related to this post. However I did figure it out I will install a toggle switch and up will not allow the chevy engine to start or run but will allow the little guy to run and vise versa. I believe it should work if both alternators are connected to the same reg because they can't run at the same time literally. I am going to talk to a mechanic first to make sure I don't need to install relays to cut one off for to run the other. My worry is the current from one might damage the one that is not being used if so I will have to go with the relays. I was over thinking it just a tad but I think this will work.
two batteries would not work because it still would kill the first battery then I would have to drain the second as well.well... a decision to drain the second battery instead of using it to start your engine.. well..swap to internally regulated alternators. including the version on the small gasoline engine...pickup a self energizing voltage regulator for the delco units or ford units..even motorola units..with only one horsepower to turn the alternator.. you need to find a rebuilder and have him assemble you one with a tiny rotor coil so the voltage regulator cannot generate as large as a rotating magnetic field to create a LOT of current output.. which will overload your small engine.. lug it down.. check out just one of several articles on duel battery installation and isolation..http://www.fourwheeler.com/how-to/0704-4wd-2001-jeep-tj-battery-isolator/http://www.streetrodderweb.com/tech/1112sr_gms_sure_start_smart_battery_system/this one has a video to go with it...please don't try to extend the voltage regulator wiring to a remote alternator..you are not going to get it to to work properlythe voltage regulators control the current output of the alternator by changing the size of the rotating magnetic field created.. but because of the way the charging system works..when the field wire is not sending power or ground to the Field circuit .. the regulator switches it to the other polairty.. to dampen the size of the magnetic field.. without that function.. you have a run away charging system.. i will be glad to continue this conversation.. just would be nice to know why you are having battery drain issues.. unless you are running something like a catering truck.you can get built in battery chargers... and 600 watt or slightly larger AC generator sets.. to power the 120 V AC input of the charger.. just as long at the AC output of the generator is about 1/2 to 1/3 more than the input of the battery charger so you don't overwork the generator set.. there are battery isolators that are 3 post and that are 4 post so you can run dual charging systems.. without one battery discharging into the other..you will need probably one of these special constant duty solenoids..Bargman - Battery Isolator Battery Solenoid 3 TerminalPart # : 54-98-002 | Line: BGMBargman - Battery Isolator Battery Solenoid 4 TerminalPart # : 54-98-004the difference between these is on the 3 terminal version.. the coil winding inside it has one end grounded to the mounting bracket of the unit.. so if you supply 12 volts to the small stud.. you get the solenoid to turn on...on the 4 terminal version.. the coil is isolated from ground.. you have to supply ground on one terminal and positive on the other... this allows you to switch the negative side as thats safer to switch with just one wire..
I am going to talk to a mechanic first to make sure I don't need to install relays to cut one off for to run the other. My worry is the current from one might damage the one that is not being used if so I will have to go with the relays. I was over thinking it just a tad but I think this will work. i really need more info on exactly what you are doing.. i used to work on catering truck wiring.. so i am familar with a lot of issues where one battery gets partially discharged... i also spend 22 years on weekends and a few weeks each years working on my friends wooden power boat.. it had 3 generator sets built in.. a 6 cylinder perkins turning a 35KW 3 phase gen set..a 4 cylinder ford layman turning a 25KW 3 phase gen seta 4 cyl benz diesel turning a 5 KW night generator set.. plus some gas powered back up generator sets that we always had on board so we could run power tools or pumps when the mains were shut down.. why i am trying to help.. is that i don't want your truck to have an electrical fire.
The setup is going to “allow me to use a good size inverter to run a few things and if I kill the bat I start up the little guy to get going again.”, that was in the first post I should add I could run the invertor off the second alternator while running these things such as tv, saw, etc. This would allow the bat to stay charged run the radio/lights for a while and not have to worry about anything at the end other than a switch. I do appreciate the help and concern and I understand about the fires that is why I am doing a lot of research. As a commercial driver I spend a lot of time on the road and see a lot of stuff and when I have a place card on what I am driving it makes me all the more cautious, that makes me really cautious at all time now. I still don't understand why there would be a problem if the pully(on the 2nd alternator) running off the witch can be larger than a 1 horse (I can investigate that but I did not think it would have to be much larger) small engine turned at the same rate as the one running off the 250 at idle. I do want to look into duel batteries as well but I want to figure this out first. I am looking at the page below. http://brianesser.com/technical-information/alternator-wiring-diagrams-and-information/In this diagram the alternator has 3 wires and a ground, 4 wires in all. If safest bet would be to cut the first one out of the system when running the second then that can easly be done with 4 relays per alternator or per regulator(2 alternators, 2 regulators). Flip a switch the truck changes alternators and the alternator produces the same as if it where idling with a fraction of the fuel, I could run lights and a stereo for 8 hours without switching bats or running the truck.I am going to talk to my mechanic he goods at “outside the box” stuff, It seems simple as a worst case 2 regulators, 2 alternators and 8 or more relays( I cant think of the name but other devices exist that like if or statements in computer programming I can look into as well that's a different person to talk to tho, ex electrical engineer). One thing we learn from tesla is anything is possible so we will see. THanks again I'll update this post if I ever make it happen.
while i am thinking about this...you might want to find a BIG RIG ELECTRICAL shop.. they are more hip than i am..if there is a big rig junk yard around.. about 5 or 7 years ago.. when fuel was even higher than it is now.. there are side of the frame mounted gen sets.. like a fuel tank... that run the cab power with 12volts and 120 volts AC.. also ran the heating and AC for the cabs and sleepers while the big engine is shut down.. perhaps one of these small diesel units could be purchased for a reasonable price..i think the burn rate was less than a quart an hour.. lets look at the Delco 10DN charging system...F short for FIELD goes to a brush that connects the rotor winding coil 2/R is connected to one end of the 3 field windings and has Half the output voltage in AC only when the alternator is charging.. 3 is Battery positive voltage...4 is complicated.. its goes to either a resistor or an indicator lamp.. and the other side of that is hooked to switched positive voltage.. ###############theory of how it all works..a coil of wire wrapped around a steel or iron core when you swing it past a magnetic field.. the lines of the magnetic field passing thru the coil create electrons.. the reverse is possible..the same coil of wire wrapped around an iron or steel core. if you run voltage into that.. you create an electro magnet.. ~~~~~~~~~~~~~~~~~~~~now... how it kinda works.. when the system is charging.. the voltage regulator is moving a contact between BAT + and BAT - inside the regulator on the F terminal.. this controls the size of the magnetic field in the spinning rotor... the magnetic field looks like this/\/\/\/\/\/\/\/\/\/ as it passes thru the over wrapped triple windings..you can see those the R and F in the image...they are wrapped like this..xyz, xyz, xyz, /// /// /// /// /// ///one end of these stator windings are attached to the R terminal.. where it will send alternator speed and half the DC output voltage as AC voltage to the #2 terminal...the other end of each of the X Y Z stator windings is attached to 2 diodes.. you can see those staring below the red ring output terminal at 10 o clock... the first one is positive. then the next thats pressed into the rear half of the housing is negative.. then another positive and another negative.. another positive and negative..because the rotor has a magnetic field rotating inside the stator.. there are eletrons being created. in the 3 windings..any electrons above ZERO volts AC go to THRU the positive diodes and to the red ringed output stud and electrons below ZERO volts AC go thru the Negative diodes and to the housing of the alternator where they pass thru the case, mounting brackets, engine block. battery negative cable to the negative battery..~~~~~~~~~~~~~~~~~~~~~~now.. the voltage regulator uses the voltage and the pulse rate from the R terminal to the #2 to vibrate the contacts to match the alternator speed.. this keeps the on off time of the contacts the same in proportion to the speed.. so the regulator does not go crazy as the engine changes speed.. creates a stable output voltage..this is were you are going to run into problem if you attempt to operate 2 alternators with ONE regulator.. they will not be in phase .. so you are more than likely going to get some smoke out of the wires at someplace.. .. the #3 terminal usually has constant battery positive on it.. the #4 terminal is the turn on circuit. when the key is turned on.. battery voltage goes to the alt lamp.. a small fraction passes thru that but thats enough to signal the regulator to wake up.. once the alternator starts charging.. the voltage inside the regulator on the #4 terminal comes up to match the #3 terminal.. and any light goes out.. because there are equal amounts of voltage on either side of the light turning out the light as the electrons are not moving...and why. they use a light.. if the voltage is higher or lower on either side of the light bulb.. the light will glow.. there are NEWER 10SI delco alternators that come in the same case.. but have internal voltage regulators.. these have bolt in components and are easily rebuilt in the field.. no soldering required.. spare parts are cheep to get if you know where to shop.. if you select the proper parts... they are almost industrictable..
this is the back of a 10SI alternator... they can be had from 37 amps to right around 85 amps..the next size up an 12SI can be had up to 94 or 108 amps.. think versions of the 7127 alternator... i like to use the 7145 as the unthreaded mounting ear is farther away from the side of the case.. and has more material to drill and carve away.. if you wanted to install an internal voltage regulated delco on your engine.. you could use this wiring...so now you kinda know a little more about charging systems...i think i need a nap..
lastly.. DO NOT EVER pull a battery cable or use a battery disconnect while the engine is running...what happens.. if the alternator is putting out current.. and you disconnect the battery .. there is no place for the electrons to go to.. so they build up..this build up becomes voltage.. the charging system can go over 100 volts in a split second.. this cooks the diodes.. as it is above their rated forward voltage.. in the 10SI.. the standard diodes are rated at 25AMPS at 100 Volts Peak inverse voltage.. the heavy duty diodes are rated at 50 amps at 200 PIV... so they don't burn out or short any where near as easily...