Get rid of your battery - if you have a kick starter

[mrkprsn]

I've had to drop out of the last 2 motogiros because my bike died due to the battery dying due to over charging. Blaat (Jim) is also facing the same problem although I think he may have a stator problem now.

(1962 Ducati 200GT) I have been been having an "overcharging" issue since I replace my weak original 2 wire / 2 stator, flywheel and (doesn't exist) RR with a modern ones. I've tried two different RRs with the same result, four blown batteries over the past year. I bought some diodes (rectifiers) and was trying to lower the voltage from the RR before it gets to the battery. I was also going to use a small capacitor to smooth the voltage. I was hoping that those two techniques would result in a lower smoother voltage which would be better for the battery.

I found one 4 diode rectifier bridge and wired that between the RR and battery. (https://octopart.com/datasheet/vbo40-08no6-ixys-4006460) It dropped the voltage but rectifier got very hot. I didn't trust is to hold up. So I decided to get rid of the battery and I installed a 15V 10K uF capacitor. I bought this one because it had a spring mount. https://www.hughshandbuilt.com/product/ ... capacitor/ You can find cheaper ones but I recommend getting a name brand with screw in posts. https://www.electronicsurplus.com/mallo ... 00uf-15vdc

Today with just the capacitor it started on the first kick. I just got back from a 56 mile ride and everything works as it should. The voltage is 7.4 with lights off and 6.9 with lights on. My batteries would blow up at around 30 miles so I hope this is the fix for my motogiro woes.

[Jordan]

That's good news.
Hopefully the lights don't burn out.

By the way, adding a capacitor to a pulsating rectified voltage increases the average voltage.

[JimF]

I use a large capacitor (housed in a hollow battery box) as well.

[mrkprsn]

Jim, What stator, flywheel and other electrical components are you using? What size capacitor? Also what bike is this on? Thanks...Mark

[ecurbruce]

Hi Jim, how's it going?
I would also like to know that same?
Thanks,
Bruce

[DesmoDog]

I have a 250 Monza powered bitsa that I would like to set up to run with no battery. Is there a website or thread that explains what I need to do? I have some experience with electrickery but am not at a point I can figure it out on my own.

No other part of the electrical system exists at this point. I don't have any form of regulator or rectifier to use yet. LED lights are planned with the idea I could end up running total loss on those if needed. I'd prefer not to but whatever. Since I didn't have an electrical system worked out yet I ordered AC/DC LED bulbs... I'll have them in both 6 and 12 volts since I'm working on two bikes right now. (There other has a more modern 12 volt ignition/charging system).

[Jordan]

I'm sure a battery-less system can be arranged for your bike, but it gets a bit involved.
My own single has self-powered CDI for ignition, so that side is catered for. Other loads are managed with a bridge rectifier, capacitor, Lucas type 12V zener diode regulator, plus some wire mods. A garden tractor 20 amp rec-reg is another gadget worth trying, as they are neat, cheap and easier to find than the Lucas thing. For example, Onan part: https://www.ebay.com.au/itm/145625133750

With no CDI, something else could be done to provide sparks and lights etc - with luck - experimentation required!
I have done it on Lucas alternator equipped 12V British bikes.
In fact, it was a standard feature on Norton Commandos, as a "get you home" method in case of battery failure. It also helped start a bike with a flat battery.
It wasn't perfect though, because although it all sort of worked, if engine revs were not kept high enough, turning on a light could rob the engine of sparks and stop it, because everything drew power from the same alternator output. Not great for full-time batteryless motorcycling.
I worked out a way around that, by modifying the alternator wiring and doubling up on some components.

Start with an alternator that isn't enclosed in the cursed potting mixture. Happily, many alternators fitted to Ducati singles have no stupid "encapsulation". So, you can fetch your wire cutters and soldering iron and modify your stator coils!
The idea is to divide the alternator coils into two separate groups, with 2 wires coming out for each group - 4 wires total.
If you have a 6 coil stator, you could divide it "3 plus 3", so ignition and other loads can each have half the current output. On my BSA 441, I use 2 for ignition, 4 for for lights horn etc. Then there's plenty of power for sparks, and using the horn or lights had zero effect on the ignition.
However, I haven't done this on a Ducati, which is designed as a 6V system. So, I don't know of a high current regulator such as is easily found for 12V machines. You could rewire the coil bobbins with more turns of thinner wire to boost the alternators output, but you'd have to be keen.
As said, it's experimental.
I just remembered, some bikes of the 1960-70s had no regulator as such, but their alternators used the split output method.
The headlight switch also selected the required number of stator coils- crude but effective enough to avoid battery over-charging.
Some were 6V.

I hope there are some clues there.
Maybe some commercial bike electronics company could do something along these lines?

[JimF]

I am a little late in replying to questions about my battery-less electrical system.

I used the biggest capacitor I could find that would fit in the battery box so as to have the most capacitance I could get. In this case it turned out to be 54,000uF (microfarads). The voltage rating was the only thing I was a little concerned about, so I made sure it was over 12 VDC (volts DC).

msCapacitor in battery box.jpeg

msCapacitor.jpeg

A friend gave me a Podtronics 12-volt "single phase" rectifier-regulator. The important thing about the single-phase is that it only has two yellow wires for AC (alternating current) input and I only had two wires coming off my stator. This makes my electrical system 12-volts DC.

msPodtronics.jpeg

s-l1600.jpg

So the two stator wires connect to the two yellow wires of the Podtronics. The black wire of the Podtronics connects to the capacitor negative (-) terminal and the red wire to the capacitor positive (+) terminal.

I added another black wire to the capacitor negative terminal (-) and connected that to the frame.
Another red wire comes off the positive capacitor terminal (+) and leads to the spark coil.

At this point I can kick start the bike and it runs fine, but it won't stop running. So I took one of the little Ducati push-button horn switches and ran another red wire from the coil red wire to the switch and connected the other side of the switch to the metal handlebar (grounding it to the frame). Now I have an engine kill switch.

I ran another red wire to the headlight bucket where I use a high-power white triple LED as a headlight. It's not bright enough for night driving but I only ever drive in the day and it's bright enough to let oncoming drivers know I'm there. It consumes about 6-watts (about 0.5 amps).

I ran another red wire to the taillight (another high-power LED) that consumes about 2-watts. To finish the whole thing off a red wire goes to the brake switch and the other side of the brake switch goes to the brake light. When the brake is lit the tail and brake light together use only 12-watts.

I have no turn signals (not that I couldn't ad them) and no horn (likewise).

I have no keyed ignition switch whatsoever. I just walk up to it and start it. I ride with high security "leg irons" attached to the frame, and when I stop, I use the leg irons to chain the bike to whatever is nearby. (I use them as my bicycle lock too.) I figure an ignition switch won't stop theft as half the population where I live (Texas) drive pickup trucks, and two guys could get a 250-pound motorcycle into the bed of a pickup truck and be gone in under a minute.

OIP.jpg

If you choose to lock your bike with leg irons, get the ones with real lock cylinders and not the ones that use a simple handcuff key as they can be defeated in 10 seconds with a paper clip.

[DesmoDog]

Thanks for the info, I think I have enough of an idea to venture off on my own with this now. I ordered a regulator and will need to find a capacitor. Unfortunately the caps I have around here for guitar amps aren't big enough...

[JimF]

Keep in mind that in my case I did no math on how much capacitance would be needed because I wouldn't know where or how to begin. I just picked one to fit the battery box and made sure the voltage rating (referred to as WVDC) was more than my rectifier/regulator would be kicking out (greater than 12-volts). For all I know, a capacitor with half the storage (27,000uF) or even less would work. Maybe it would work without any capacitor.

I used to think that the first few times I kicked the engine over and the engine failed to start I was in effect adding electrical energy into the capacitor that would be present for the next kick-over attempt. If the engine didn't fire up, I was at least adding charge to the capacitor for the next kick.
However, I realized I have no headlight or taillight switch. They are both hard-wired along with the capacitor to the output of the regulator. What that means is any power I manage to put into the capacitor on a failed kick-over attempt is immediately drained out of the capacitor by a very short-lived illumination of the headlight and taillight.

This makes me wonder if I need a capacitor at all. The capacitor will smooth out the DC power (what engineers refer to as pulsating DC) though there should be some smaller capacitors inside the Podtronics unit doing that. At the end of the day what I have works great, and I don't want to pull the capacitor out just for the sake of trying it without one.