Sorry for my inconsiderate post. That 140 amp alternator will only assist the batteries.

 

At one time back when cars first started using alternators you could buy an adapter that replaced the regulator, regulators were not built into the alternator back then. This allowed the alternator to make 120VAC so you could use power tools, tools had universal motors back then too. So to my way of thinking you should by modifying a modern alternators regulator, be able to get what ever voltage up too 120V out of one.

The voltage to the rotor in a car alternator is only around 5V not the full voltage of the battery. This rotor voltage is what is done by the voltage regulator, so the rotor voltage is what needs to be changed to get the higher output voltage.

 

As mentioned before, I used the LM311 comparitor, it replicates the earlier type of regulator that replaced the electro-mechanical version, these were later replaced with PWM types due to radio interference of the first type.
Max.

 

What is your goal? Do you realize that you loose efficiency when you convert mechanical energy to electric energy? Also you loose efficiency when you convert mechanical energy to electrical energy to charge batteries and then you loose more energy when you convert battery energy back to mechanical energy with the electric motor.

 

At one time back when cars first started using alternators you could buy an adapter that replaced the regulator, regulators were not built into the alternator back then. This allowed the alternator to make 120VAC so you could use power tools, tools had universal motors back then too. So to my way of thinking you should by modifying a modern alternators regulator, be able to get what ever voltage up too 120V out of one.

The voltage to the rotor in a car alternator is only around 5V not the full voltage of the battery. This rotor voltage is what is done by the voltage regulator, so the rotor voltage is what needs to be changed to get the higher output voltage.

i already can do that. the alternator I have has a pass though so I just put 12v to the field and regulate the voltage with the rpm's. you can also regulate the Amps as if you keep the voltage close to 60v you will get no amps, but as you go to 74 you get full amps. The problem is the alternator is going to be limited in amps @ 74 volts.

 

What is your goal? Do you realize that you loose efficiency when you convert mechanical energy to electric energy? Also you loose efficiency when you convert mechanical energy to electrical energy to charge batteries and then you loose more energy when you convert battery energy back to mechanical energy with the electric motor.

Here is my goal; I have a sailboat that has a 60v battery bank and a 12 volt battery. I have a regular frig and a few other things 110v because it is easier and cheaper to use than going 12v. Since it is a sailboat I do not have to use the motor to travel unless I absolutely have to. So I have access to a 500 ah battery bank. The 60v bank feeds a converter to 12v the 12v feeds a inverter. I also have 300 watts of solar. So typically you will go a week before the batteries may or may not get down to 50%. At this point you have to charge them up fully. So I need a charging system that can do this rather quickly or I am running an ICE to long. I am at anchor so I cannot just plug in. A battery will take around 100 amps between 50% and 80%. after that the solar can finish it up. Then also if I have to run the motor if I have enough amps I can run the ICE charger to run that and charge the batteries. So in a better world every 1 hour of running the motor I could shut the ICE off until the batteries were back down to 50%. Most people use a 25 to 50 hp motor to run their boat a big waste of fuel as it could also be charging batteries then running on an electric motor in peace and quiet, but they do not have an electric motor. I may waste some energy in transfer but I am still way ahead in savings. Not to mention totally self sufficient but for a few gallons of diesel per month.

 

A battery will take around 100 amps between 50% and 80%.

I think you have used that number a few times now, where do you get that number from? I have never seen that high of an amperage associated with battery charging. Not saying you're wrong, just wanting to understand how you came to that number.

 

I think you have used that number a few times now, where do you get that number from? I have never seen that high of an amperage associated with battery charging. Not saying you're wrong, just wanting to understand how you came to that number.

A battery will take as much amps as you can give it. The closer it is to full the less it will accept. So a starting battery usually takes very little amps because they never are less than about 90%. But if you notice some times on your charger when a battery is close to dead the amp meter will show as much as the charger can give. So on a 6 amp charger it will show 6 amps, on a 10 amp 10 amps, on a 60 amps or 100 amp it will show ... As the battery gets charged the amps will start to go down no matter what setting you have it on. You can also see this when you jump a car that had a dead battery. After it starts run it around the block and it will usually start back up, because the alternator was putting 100 amps or so into it. That's an explanation on why. It all depends on the type of battery and follow the recommendations of the battery manufacturer. But as long as the battery does not heat up or boil over you are generally good to go. And again I am not putting 50 amps to a fully charged battery, only between 50% and 80% which does not take that much time to get to.

 

I would think that pushing 100 amps into any battery has to take a bit of voltage to do. Batteries do not like to be taken over 15 volts and high amperage surely does damage to the cells, in particulat the plates. The heat produced in there would be fairly high and deep cycle or not, would not take that kind of punishment for long. Best battery charging practices are low and slow for long life.

 

I would think that pushing 100 amps into any battery has to take a bit of voltage to do. Batteries do not like to be taken over 15 volts and high amperage surely does damage to the cells, in particulat the plates. The heat produced in there would be fairly high and deep cycle or not, would not take that kind of punishment for long. Best battery charging practices are low and slow for long life.

If the battery is at 50% the voltage will not be that high. The batteries will have a temp sensor so heat is not a problem. Not all batteries like low and slow. Most batteries like low and slow after they get to 80% at which time they cannot accept as many amps. Batteries have to absorb the last bit of amps to the inner part of the plate which takes time. But before 80% you are not going there. If you have a battery at 50% or less putting 2 amps into it is not a good thing it takes too long. Lead crystal batteries do not like low and slow they need to be worked. To rejuvenate a battery that is what you do is put 15 volts to it and watch the temp and electrolyte. This is done once a month or when a smart charger senses it needs it. My charging system is not automatic it is very manual. 100 amps goes to the motor and battery, 50 amps runs the motor and the rest goes to the battery. When the battery is at 80% or the temp sensor goes off the ICE gets shut down. To limit the amps going to the battery all I have to do is lower the voltage from the alternator. Once the voltage is low enough all the amps will go to the motor. Or I could just turn up the motor and suck up more amps.

 

I have an update!

I just found a nice generator that has a 10 hp diesel motor (Just rebuilt) with a 5500 watt single phase generator head.
I know form past reading that this generator head does not work well with battery chargers because it is single phase AC. My plan is to remove the head and replace it with my alternator, but before I do is there anything I can do to the single phase head to rewire it to 3 phase. can I just use a rectifier bridge to convert the single phase to DC and just use it like that? I would still need to regulate the voltage but just wondering if the head will produce the correct current to charge 60v DC using a rectifier bridge.

 

You can use a rectifier to convert the 1ph to DC, but not practical to rewire to 3phase.
Max.