I acquired a used Lifan flathead (side valve) engine, which I have installed on a bicycle (I know, not a minibike, but not sure where else to ask, figured you guys would know). I downloaded a doodlebug manual so I would know what type of oil to use and a couple other things. The manual shows a picture of a minbike with lights. That made me curious, do the doodlebugs have batteries and a charging circuit? Some important info: I disconnected the low oil sensor and stock killswitch, and connected a killswitch from my handlebars, but its wired the same, one wire to ignition, the other to ground. Also, the batteries that power my lights are 7.2v nicads wired in series to produce 14.4v. Is there some way to build a charging circuit, perhaps by connecting a wire to where the low oil sensor used to be connected to the ignition? Also while I am here, does anyone know if this engine has a 6v or 12v ignition? Thanks in advance guys.
Charging circuit for 98cc Lifan flathead?
Even though no one has commented on this thread, I still thought I would give a bit of an update. I did not figure out a way to get juice directly from the engine for charging the batteries. I do know now that the only way to do this is to use a coil with a lighting wire, which I do not know where to find one. But I have figured out a way to make a charging circuit. A member of another forum has offered me an old school tire-driven generator and mini-charger (essentially a small black box with a circuit built into it and an led indicator light which tells you its working). The value of these parts is over $70, and he is sending them to me free of charge. My wife's brother-in-law also gave me a power distribution terminal, which I will be able to connect the generator and both lights and batteries to. This way, when the generator is running, the lights will be powered by the generator and the batteries. When the generator is not running, the lights will be powered solely by the batteries. The batteries should never go dead unless the bike is sitting for a couple weeks or more, and in that case I can still bring the batteries in the house and charge them via the wall charger I currently use to charge them. I hope to have the entire charging system installed on Tuesday, and will probably post another update then.
Well today I installed the generator and the charger. It was pretty much a diy type of thing since the person who gave me the generator did not include any of the mounting hardware for it. So I had to come up with my own mounts for that, which I eventually did. My multimeter confirms ac voltage from the generator and dc voltage from the charger. I still need to replace a blown fuse that was sent with the charger, but everything is installed and connected, including the generator, charger and power distributor. I was able to go down from two batteries to one, which is nice. The fuse will get replaced later this evening.
I replaced the fuse and the charger system is producing voltage. The problem is that the nicad batteries are higher capacity than what the charging system produces, so it is actually draining the battery. I ordered a 12v 1.2Ah sla battery on ebay that will be much more suited to the charging system I've designed.
Ok then it didnt happen. You do realize that this is a doodlebug engine on a bicycle, right? Nothing particularly special about mounting a bicycle tire dynamo on a bicycle, really. Besides, I'm not here to prove anything to any naysayers. Just here to share what I've done with my bike. Take it or leave it.
I would hardly say that I got bent out of shape. I didn't realize that comment was a "request". If he had said, could we see some pics, that would have been recognized as a request. Saying "pics or it didn't happen" to me comes off as a challenge. I only visit one other forum besides this one, but no one there ever says "pics or it didnt happen". I didnt realize it was a commonly used expression, and to me it seemed rude. Either way, I'll get some pics one of these days.
Seems to me using a 6volt generator to charge a 12 volt battery is futile, those spindle drive friction generators are 6 volts to the best of my knowledge. Your thread is titled "charging circuit fir Lifan 98cc" and you end up using a bicycle generator that is driven by tire friction. It's been done before on minibikes to run 6 volt lights, nothing new or interesting about that. Turning 6 volts into 12 is interesting, I'm perplexed as to how you got that accomplished and seriously doubt it really did. Best to go to a motorized bicycle forum and dazzle them guys with your brilliance.:laugh:
There are 12 volt spindle generators for bicycles as it turns out. Your choice of engines is questionable at best though. They are poor performing engines at best, too light for a boat anchor and not worth half a buck in scrap metal. That and this is a vintage minibike site, move along if you cannot take the ridicule.
They perform poorly on minibikes because the gearing (including wheel size) is all wrong for this engine's powerband. I geared my bike to redline at 32mph with 26" wheels, and overall I'm quite happy with this engines performance. I do wish that it climbed hills better, but lowering my pedal gearing will make pedal assisting easier. I've already bought a smaller chainring, but have yet to install it. But I can take off from a stop pretty easy, and my cruising speeds are perfect. I built this bike to be a reliable cruiser/commuter, not a race bike. If I wanted crazy performance, I'd have bought a Predator engine, but I just wanted reliability. So far, the only problems I've had with this bike/engine were due to my own mistakes. It does exactly what I built it to do, and its my bike so I built it the way I wanted. Plus, a buddy offered me the engine for $50. You can't get a Predator or any other 4 stroke of equal displacement for that cheap unless you get it used (the Lifan was used, but still cheap). I'm not sure what you think this being a vintage minibike site has to do with allowing people to ridicule me, and I don't really care. I don't take crap. If you dont like it, I'll kindly invite you to refrain from commenting in my threads. Just like momma used to tell me, if you aint got nothing nice to say.........
I forgot what else I wanted to say. I started this thread because my engine originally came from a minibike. So I figured if anyone knew anything about charging circuits for these engines, it would be you guys. I did actually attempt to google it beforehand, but either my search terms were too staggered or there isnt any info available. The manual I downloaded had a wiring diagram, but it wasn't very detailed. So I came here. No one commented, so I assumed that no one had any info to provide. After awhile, I did learn that the only way to get juice off the engine is to have a coil with a secondary output. I updated this thread because I always update my threads when I have new info, whether anybody else cares or not. That way, when someone comes along looking for the same info, they will know what answers I found. Or even if anyone is just curious when they read this thread months from now and wonder if I ever came up with anything. On the other forum I visit, they always appreciate when people update their threads. So I updated my thread out of courtesy.
And we appreciate updates. Especially ones with pics. If you think my comment was a challenge, so be it. It wasn't meant that way. BTW, if you peruse many other threads here, you will find that same comment used by many people here. We post lots of pics here so everyone can see what you did, and maybe they will want to do it also.
I took one of those DB engines and put it in a Schwinn Stingray. Maybe I wanted to see how you did the generator so I could use that on my conversion.
Here is the Schwinn:
I took one of those DB engines and put it in a Schwinn Stingray. Maybe I wanted to see how you did the generator so I could use that on my conversion.
Here is the Schwinn:
Stangrcr, I completely forgot you were the one with the stingray. I accept your explanation of what you meant, and I apologize for misunderstanding you. I did take a picture, just haven't uploaded it yet. I will upload it in a bit. Right now I need to walk my dogs and a couple other things, so some time later this evening I'll get that pic up. I'm just not used to that comment. No one uses it on the other forum I visit. But now I know for future reference that if someone uses it here, its not being rude. Again, I apologize.
