What kind of batteries are you charging. If they're not lead acid with internal resistance that list the charge rate, you can over heat the alternator. I saw another video from another guy that had a system on his boat with Lithium phosphate batteries. The batteries had the ability to take charge amperage rtes in excess of what the alternator is normally designed for with lead acid batteries. Effectively the alternator the batteries will take everything and anything that alternator will put out beyond its rating because there's no limiting factors to regulate the amperage flow. You'll have to limit the alternators speed to keep it within its engineered limits of amperage output either by engine RPM or by changing pully size. if your wanting to exceed the alternators normal max amperage rating your going to need some serious cooling or it'll burn up. Change the pulley sizes to give more torque at the alternator and limit the alternators speed to keep its output close to its max output. Get a higher rated output alternator if need be and make efforts to increase the cooling to the internal windings if you want to exceed the ratred output for any alternator. look around for that vise I mentioned. I don't have it off hand at the moment
My batteries are lithium and I am aware of how much they will take from the alternator, I don't intend to run the system for more than a couple of minutes at a time. I will restrict the power output if I run for longer than a few minutes. Thank you for your comments I appreciate them Richard.
Hi. Very nice movie. The alternator is probably a poor solution. You can use some BLDC motor. For example, an alternator from a hybrid car. Alternator from Hyundai Kona Phev. You will get much more power. You will need a 3 phase rectifier bridge and an MPPT regulator. You have to be careful as the voltages are much higher.
please explain how a variable field alternator, that comes with its own three phase rectifier, and can be controlled to deliver a constant voltage at a constant current form a constant RPM, is inferior to "some BLDC motor", with fixed magnetic fields that cant be altered and can only deliver a given voltage at a specific RPM, when loaded to just the right current, and will give different currents and voltages anytime the RPM is altered?
Hello. I have some solar but I am looking for a way to charge the batteries on sunless days. My question is would it be better to build something like you did, or buy a generator and battery charger?
Hi, this is not a cheaper way to charge batteries it would be far cheaper to use the grid if you have grid power available that is. If you don't have grid power then this is a good way to charge batteries. To charge batteries with a generator and a battery charger you will find battery chargers don't have a very high output, so this is a good way to charge.
If its a 48 volt system, Its better to use a generator and 48DC 100 Amp charger. The gear ratio this guy is running is wrong. Alternators only need 1200 to 1400 Rpms to max out Amperage.
Hi, I believe the ratio is 2.6 to 1 I know 1 to 1 would be much better but it's a case of getting getting the pulley at the right price. This is all about testing to find out the best way to go.
Thats his problem. You only need like 1500 rpm on the Alt. It can literally be 2 to 1 on pulley ratio. I'm already building one. Also, the pulleys should be wider for more grip. I'm going to do 3" on the engine and 6" on the alternator. Then run the engine at 3600 RPMs for my 1800 RPM at the Alternator. Turn that engine into a 30 hp engine.
There is no way you can stall that engine with a 150A alternator. You have to be over volting the stator and in effect creating a mechanical brake. If this is a self reg alternator and you are over riding the regulator, you may well over charge the batteries. the charge needs to be tapered down over 80% Charge. If you blow full power into them you will damage them by over gassing which may distort the plates and over heating. Don't try to get the alt to put out all the power all the time. With lead acid batteries of this type you want to limit the max charge to about 40% AH capacity. In other words, 200AH capacity total, 80A max input. when they are above 80% Charge, then that drops down to 10%. Don't over cook the batteries.
Hi, sorry I didn't make it very clear, the battery's are not lead acid, they are lithium lifepo4 batteries 24-volt 280ah x2 and each one can be charged at a maximum of 200 amps. So basically they can take every thing that the alternator can put out. Yes maybe I need to adjust the voltage being fed to the rota. I will be doing some more testing in the next few weeks. Thank you for your interest shown.
What kind of batteries are you charging. If they're not lead acid with internal resistance that list the charge rate, you can over heat the alternator. I saw another video from another guy that had a system on his boat with Lithium phosphate batteries. The batteries had the ability to take charge amperage rtes in excess of what the alternator is normally designed for with lead acid batteries. Effectively the alternator the batteries will take everything and anything that alternator will put out beyond its rating because there's no limiting factors to regulate the amperage flow. You'll have to limit the alternators speed to keep it within its engineered limits of amperage output either by engine RPM or by changing pully size. if your wanting to exceed the alternators normal max amperage rating your going to need some serious cooling or it'll burn up. Change the pulley sizes to give more torque at the alternator and limit the alternators speed to keep its output close to its max output. Get a higher rated output alternator if need be and make efforts to increase the cooling to the internal windings if you want to exceed the ratred output for any alternator. look around for that vise I mentioned. I don't have it off hand at the moment
My batteries are lithium and I am aware of how much they will take from the alternator, I don't intend to run the system for more than a couple of minutes at a time. I will restrict the power output if I run for longer than a few minutes. Thank you for your comments I appreciate them Richard.
Hi. Very nice movie. The alternator is probably a poor solution. You can use some BLDC motor. For example, an alternator from a hybrid car. Alternator from Hyundai Kona Phev. You will get much more power. You will need a 3 phase rectifier bridge and an MPPT regulator. You have to be careful as the voltages are much higher.
please explain how a variable field alternator, that comes with its own three phase rectifier, and can be controlled to deliver a constant voltage at a constant current form a constant RPM, is inferior to "some BLDC motor", with fixed magnetic fields that cant be altered and can only deliver a given voltage at a specific RPM, when loaded to just the right current, and will give different currents and voltages anytime the RPM is altered?
Hello. I have some solar but I am looking for a way to charge the batteries on sunless days. My question is would it be better to build something like you did, or buy a generator and battery charger?
Hi, this is not a cheaper way to charge batteries it would be far cheaper to use the grid if you have grid power available that is.
If you don't have grid power then this is a good way to charge batteries. To charge batteries with a generator and a battery charger you will find battery chargers don't have a very high output, so this is a good way to charge.
If its a 48 volt system, Its better to use a generator and 48DC 100 Amp charger. The gear ratio this guy is running is wrong. Alternators only need 1200 to 1400 Rpms to max out Amperage.
Dude!! Its going to keep happening until you change the gear ratio. That gear ratio looks to be 8 engine 1 alternator.
Hi, I believe the ratio is 2.6 to 1
I know 1 to 1 would be much better but it's a case of getting getting the pulley at the right price. This is all about testing to find out the best way to go.
8 inch pulley for engine
Hi, not sure what you mean, an 8" pulley would put even more load on the engine.
Thats his problem. You only need like 1500 rpm on the Alt. It can literally be 2 to 1 on pulley ratio. I'm already building one. Also, the pulleys should be wider for more grip.
I'm going to do 3" on the engine and 6" on the alternator. Then run the engine at 3600 RPMs for my 1800 RPM at the Alternator. Turn that engine into a 30 hp engine.
There is no way you can stall that engine with a 150A alternator. You have to be over volting the stator and in effect creating a mechanical brake. If this is a self reg alternator and you are over riding the regulator, you may well over charge the batteries.
the charge needs to be tapered down over 80% Charge. If you blow full power into them you will damage them by over gassing which may distort the plates and over heating.
Don't try to get the alt to put out all the power all the time. With lead acid batteries of this type you want to limit the max charge to about 40% AH capacity. In other words, 200AH capacity total, 80A max input. when they are above 80% Charge, then that drops down to 10%.
Don't over cook the batteries.
Hi, sorry I didn't make it very clear, the battery's are not lead acid, they are lithium lifepo4 batteries 24-volt 280ah x2 and each one can be charged at a maximum of 200 amps. So basically they can take every thing that the alternator can put out.
Yes maybe I need to adjust the voltage being fed to the rota.
I will be doing some more testing in the next few weeks.
Thank you for your interest shown.