# Help matching engine/alternator/motor for hybrid trike/charging trailer generator?



## nwohater (Jun 11, 2011)

Tell me how far my thinking is off here or where to start with this idea please.

I want to build a long range gas/electric trike that can double for city commuting and weekend fun, but is not limited to battery life or battery range. I think an electric trike with optional generator trailer is the way to go.

I'm having some trouble though coming up with specifics like what batteries and controller setup can work and charge at the same time, if any, and at what rate they can charge to make it work (hopefully) non stop. Do any dc 48v+controllers do regen braking?

To start with I have a couple nearly new 6.5hp briggs lawnmower engines I'd like to get some use out of, and a couple dead small motorcycles. a 150cc scooter and 250cc rebel to grab parts from, both are like new but have no engines. I'd like to get some use out of those briggs lawnower motors even though they aren't ideal partly because I have them already, and partly because they're so cheap to replace and or fix. 

From what I can tell a 6.5hp briggs motor should be able to crank around 3-3.5kw of electric each, and I figure each can turn a pair of 110a or so permanent magnet car alternators and could be on a trailer that I ditch for day to day use, but pull with me for long trips. They could either be wired one alternator per battery directly or series 48v? Not sure. I know I could have the gas engines could work as a pusher trailer and kick in at high speeds, drive the electric drive motor(s) in part regen mode and thus cut out the weight of a bunch of alternators. That may be lighter and more efficient but probably not so safe, plus I like the idea of a pair of mobile camping generators with the alternators anyway. That would always be handy to have a trailer like that.

I know it will be heavy either way, especially with two gas engines and 4 alternators and batteries and drive motor(s) and guaranteed not fast, but even 45mph or so tops would be ok. 6kw on flat land might get me 55-60mph though from what I've seen of 6kw scooters on youtube. Or can I have it switch from charging batteries with gas engines to boosting my 48v higher with one or two engines adding voltage, and get over 55mph running electric and gas together to climb hills or such?

Is any of this possible and how, and with what combination of budget parts for drive engine(s) and controller? I was looking at 48v dc with hopefully SLA batteries but am not sure if they'll take the fast charging or work the way I want or whatever.

What can I expect from a heavy pile of junk parts like this, what drive motor(s) would I need to get the speeds I want at 48v, and how would you wire it up or set it up to make it work best?

Basically this concept scaled up without using a charger and using dc generators rather than a/c:
http://www.youtube.com/watch?v=http://www.youtube.com/watch?v=PJDNWcnYlFo[URL="http://www.youtube.com/watch?v=PJDNWcnYlFo"]PJDNWcnYlFo[/URL]

I might want a reverse trike though with shell to reduce air drag and aerodynamic trailer so I can get the speeds I want on just 6-7kw.
http://www.youtube.com/watch?v=http://www.youtube.com/watch?v=JUxThE20jRw[URL="http://www.youtube.com/watch?v=JUxThE20jRw&feature=related"]JUxThE20jRw[/URL]

I know enough electronics to wire blocking diodes in so current only goes one way from the alternators, I think I can have a manual switch to bypass the diodes to use the alternators as starters for the engines while driving, and I can probably wire up something to prevent overcharging if I just find out what is needed to sense full batteries regardless of engines running and open the charge circuit or kill the engines automatically. 

What I don't know though is dc controllers and how they will repond to voltage changes wiring things like this in, or dc motors and if a 48v+ motor exists that can pull all this weight at the speeds I'm looking for, or batteries suitable for the draw and charge rate and how fast I'd kill them with a setup like this. I weigh 180lbs and might want to pull an added 50lbs of camping gear on the trailer. Getting up mountains may be a real problem without figuring a way of getting boost from the generators and batteries in series. I would want to add camping gear to the trailer but not too much. I weigh 180lbs and would only want to add maybe 50lbs of camping stuff in addition to the bike and genset trailer. Am I way out of line on my expectations? Some mountains in my way for camping excursions are long and steep so overheating the motors at speed may be a serious issue.

It's either the above or two trikes, one electric for daily use and one straight gas leightweight trike like this for distance:
http://www.youtube.com/watch?v=[URL="http://www.youtube.com/watch?V=jvM7cSPZhec&feature=related"]jvM7cSPZhec[/URL]


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