I have a 6.5hp electric start clone and added a second charging coil so there are 2 under the flywheel now. This engine came with a small diode and the coil I took from a honda 9hp had a small rectifier. Should I keep both independent of each other and then splice them together after their diode/rectifier or could I splice the 2 coils (ac voltage) together and then run them both through the honda rectifier and leave the tiny diode out of the picture.
If you want double the Voltage, with the Amps of just one coil, connect the two coils in series (end-to-end) then pass the output through a rectifier or Voltage regulator. Note that the two coils must be magnetically out of phase with each other, for this to work.
If you want double the Amps, with the Voltage of one coil, connect the coils in parallel then pass through a rectifier or Voltage regulator. Note the two coils must be magnetically in phase for this to work.
If you want double the Amps, with the Voltage of one coil, connect the coils in parallel then pass through a rectifier or Voltage regulator. Note the two coils must be magnetically in phase for this to work.
I want to double the amperage. How do I know if the coil are magnetically in phase, these coils are made for these engines. Right now I have it so each coil goes to it's own rectifier then directly to the battery. Is there any problem with this. I got rid of the key switch and used a double throw spring return to center toggle switch up to engage the starter and down to ground the ignition coil. I am only showing 12.4 -12.5 volts at the battery with engine on, I was expecting high 13s to low 14's. Engine off is 12.3
Jon, I know you've done a lot of work and research into this.
Isn't it true that attaining 180 out phase relationship is going to be impossible with this set up? Using a common rectifier, input is going to be the algebraic sum of both sources. What a member here found was that one coil began the negative cycle while the other was going positive- thus the AC voltage sum going in to the rectifier was low.
Using a battery, I'd opt for separate AC and rectifiers to a common regulator. If that is feasible, I suppose a diode would need to be used to isolate both pulsating DC inputs?
Mark, it is quite possible that your regulator is limiting the voltage to 12.5 VDC. I knew InventorPardue would comment on this, as he has a lot of experience and knowledge on these systems.
Isn't it true that attaining 180 out phase relationship is going to be impossible with this set up? Using a common rectifier, input is going to be the algebraic sum of both sources. What a member here found was that one coil began the negative cycle while the other was going positive- thus the AC voltage sum going in to the rectifier was low.
Using a battery, I'd opt for separate AC and rectifiers to a common regulator. If that is feasible, I suppose a diode would need to be used to isolate both pulsating DC inputs?
Mark, it is quite possible that your regulator is limiting the voltage to 12.5 VDC. I knew InventorPardue would comment on this, as he has a lot of experience and knowledge on these systems.
I don't have a regulator and I don't think any of the honda/clone electric start model do either. Here is a diagram I found online . I was told by a local small engine repairman that the battery acts as the regulator since there is fairly little current. I tried putting this pic here but can't figure out how to do it, here is a link to the diagram.
http://www.engineman.co.uk/ekmps/shops/engineman/resources/Design/elecrtic-start-wiring-diagram.bmp
http://www.engineman.co.uk/ekmps/shops/engineman/resources/Design/elecrtic-start-wiring-diagram.bmp
OK, sorry to get off the track here. It's common to use a battery as a VR. Question is does the voltage increase as you rev the engine? If not, you're got a bad rectifier leg, bad charge coil, (I doubt it) or wiring problem.
Next question is how to hook both coils together. As Pardue states, you have two options, parallel or series. My question to him was; is it possible to parallel two AC sources? I ask that, because I see of no way for you to ensure your charge coils are 180 degrees out of phase with each other.
That experiment was done on a Tecumseh system and it didn't work. You generally can not parallel AC sources. However, you can parallel DC (rectified AC) to a common voltage regulator.
I don't think you can run your AC outputs in series, and if you ran your DC in series, you are looking at way more voltage than you want to charge your battery with. Could be as much as 40 VDC. That's why I asked the question of Pardue. (and why you'd need a VR)
I see Honda offers an extra coil as an option. I cant find a schematic for it though.
Next question is how to hook both coils together. As Pardue states, you have two options, parallel or series. My question to him was; is it possible to parallel two AC sources? I ask that, because I see of no way for you to ensure your charge coils are 180 degrees out of phase with each other.
That experiment was done on a Tecumseh system and it didn't work. You generally can not parallel AC sources. However, you can parallel DC (rectified AC) to a common voltage regulator.
I don't think you can run your AC outputs in series, and if you ran your DC in series, you are looking at way more voltage than you want to charge your battery with. Could be as much as 40 VDC. That's why I asked the question of Pardue. (and why you'd need a VR)
I see Honda offers an extra coil as an option. I cant find a schematic for it though.
I was thinking about trying to use two charging coils. Use one to run lights and the other to charge battery. You would have two separate systems but you would have to rectify both charge coils separately . A 3 amp charge coil will output up to 35 watts , use leds for lights but not sure how well the other coil will charge battery . gonna experiment on this though.
Dave has it right. Now with the schematic in hand, you must run two separate rectifiers... which you are doing. This doubles the Amps, and eliminates magnetic phasing and parallel AC coupling issues. Looking at the diagram, the coils are grounded on one end. My earlier answers depended on no coil ground connections, so please ignore the "double Volts" part.
The fact you have only 12.5 Volts DC at the battery is a bit of a disappointment, but there may be some reasons for that. Can the battery be charged above that 12.3 Volts DC with a charger? A 6 cell lead acid battery is no good if it only charges to 12.3 Volts. The 12.5 Volts running tells you its charging, or trying to.
With no battery connected to the rectifier(s) what kind of DC Voltage is present at the rectifiers? What rectifiers are you using?
3 Amps will slow charge a car battery, but will boil a small motorcycle battery.
Jon
The fact you have only 12.5 Volts DC at the battery is a bit of a disappointment, but there may be some reasons for that. Can the battery be charged above that 12.3 Volts DC with a charger? A 6 cell lead acid battery is no good if it only charges to 12.3 Volts. The 12.5 Volts running tells you its charging, or trying to.
With no battery connected to the rectifier(s) what kind of DC Voltage is present at the rectifiers? What rectifiers are you using?
3 Amps will slow charge a car battery, but will boil a small motorcycle battery.
Jon
I just did some testing. Engine off 12.2 volts, idling and revving up only 12.39 volts. Then I disconnected the charging system from the battery and it reads 12.4 up to 70 volts dc when I rev it up. Then just to get a feel for the amperage output I connected the charging wire to an automotive 1157 bulb, one filament lights up nicely while the other one is fairly dim (these bulbs are 8 and 26 watts), they get brighter with increase in engine rpm. Then I connected a 55 watt H4 bulb and it doesn't light up at all at idle and glow a faint orange when revved up. I also found out that there are special flywheels for the GX series with 4 internal magnets, with 2 coils is supposed to produce 88 watts, mine only has 2 internal magnets. I think this will keep the battery charged and allow intermittent use of the heated grips and light. I wish I could find a replacement led bulb but there doesn't seem to be anything available. OEM bulb is GE645J
