Running 2 batteries

[azuogu1]

Have any of you ever been able to run 2 batteries in parallel on a RSTD? I have been thinking that it may help make sure that i always have power, but I am not sure how the increase in amps will affect the bike. Any ideas?

[dingy]

Have any of you ever been able to run 2 batteries in parallel on a RSTD? I have been thinking that it may help make sure that i always have power, but I am not sure how the increase in amps will affect the bike. Any ideas?

 

 

There will be no increase in amps in a sense. You will have more amp/hour capacity though.

Amperage is a function of voltage supplied divided by circuit resistance. You could have a million amp hour battery (rated at 12v, really over 13v) and the current pulled from this huge supposed battery would be the same as in your battery now. But, you would be able to pull that current for a longer time before battery discharged.

Flip side of this is you also then have a longer charge time, as the R/R & stator output has a max limit. This being said, it is the R/R in combination with the stator output capacity that limits your avaliable amp/hour capacity, not the battery itself. Think of the battery as a sponge. It supplies needed power to start bike, which squeezes water from sponge. Then once motor is running, the R/R & stator start putting that drained water back in sponge for next start. The excess going back into sponge (battrey) is what is left over from the needs of the systems operating while bike is being operated. The higher the RPM, to a point, the more current put back into the system. If motor is idleing, there will still be a drain on battery as R/R & stator do not supply enough power at low RPM's to run lights, TCI, etc.

Gary

[saddlebum]

There is also the risk of overtaxing the stater depending on the total currant draw of the entire electrical system

[frankd]

No, the stator always operates at 100% no matter what load is on the electrical system. The rotor is a permanent magnet, so it always has the same strength. The regulator is what is called a "shunt regulator". All the extra energy that's produced by the stator is dissipated as heat. When you put a higher load on the electrical system, the regulator shunts less energy to ground.

 

Frank D.

[MiCarl]

Motorcycles use pretty small capacity batteries. If you're drawing more power than the alternator can produce the battery won't last long. Adding another won't make much difference to that.

[dacheedah]

I would say you need a setup like a boat where you need an isolator that charges the primary battery until full then sends the charge to the aux battery. If the aux is dead you can still start and run as normal. The second battery would have to be capable of taking the discharges

[dingy]

No, the stator always operates at 100% no matter what load is on the electrical system. The rotor is a permanent magnet, so it always has the same strength. The regulator is what is called a "shunt regulator". All the extra energy that's produced by the stator is dissipated as heat. When you put a higher load on the electrical system, the regulator shunts less energy to ground.

 

Frank D.

Kinda correct, sort of wrong.

 

The stator output is RPM dependent. The higher the RPM's, the faster the magnets on the rotor move past the coils in the stator and more energy is produced.

 

On a 1st gen, vicinity of 2,500 RPM's will give maximum usable output based on Regulator/Rectifier rating of 26 amps. Anything past that is shunted to ground.

 

Gary