luckyFool wrote: The terrain I will be using this on will be mostly flat. I don’t need to go fast at all nor do I need a fast pickup speed but it would be nice if it cold go 10-20 miles at least. I will be stopping and starting a lot probably.
Under those conditions and weight, you're probably looking at power usages similar to my trike while I'm hauilng the trailer, with a Saint Bernard on the trike and another on the trailer.
Hard to say since you won't say what speed you need it to go (makes a significant difference the faster you need to go, especially above about 15mph where wind resistance starts to make a real impact).
For me, at the ~20MPH cruise speed I use, that's something like 60-80wh/mile or more.
At 10mph or less, that'd probably be 25% less, but most of the power is used to get started from a stop because of the weight, with frequent stops/starts.
Less stops/starts and then wind resistance gets more important, so slower speeds start making more of a difference to the power usage.
So let's say you need 80wh/mile, for 20 miles, means you need a pack with at least 1600kwh.
If it's a "48v" pack, then that's about 34Ah.
Keep in mind that if it gets windy, you'll need more power, and for any slopes (even very small ones! with that weight) you'll need more power, so your requirements might easily grow quickly with those conditions.
The roads here are pretty flat, but even what looks completely flat to me, and feels that way on a regular bicycle back when I could pedal those easily, is definitely not on my trike even without a load. Keeping the throttle input steady, I can watch my speed drop or raise by more than 1mph just from those slight changes, even with zero wind, while power usage rises or drops by more than a couple hundred watts.
I see anythign from 800w to 1200w as a reasonably steady power usage, so you'd need a battery that can keep outputting that kind of power level without straining it (nowhere near it's max ratings). If it's a "48v" pack, that's about 25A continous, down to about 16A.
If you dont care how long the battery lasts, like if this is for a one-shot (burning man-type) project, then you can abuse it but if you want it to last a long time you need to use the battery at as low a level as you can, for most of the stuff out there.
Also want to add lights and sound but I have a 2000 w generator for that. Which makes me wonder: Could I use that generator to power the electric motor?
Probably not directly, but you could use it to keep the batteries charged, for whatever range your gas tank gets you.
I'd guess that your sound will have to be really loud, though, to cover the noise of the generator. Except for some of the Honda ones, I've never heard a quiet one.
My budget for everything is 3k max. I am pretty good at making things, and I have a friend in welding shop, so the DIY capabilities are there.
The battery will probably be the most expensive single part. If you have a lot of time to do this, you can read up here on ES on all the different DIY battery options and build one yourself, but it is a LOT of reading, to be sure you know enough to decide what to do and then to do it. (weeks, probably months). There are hundreds (at least) of "what battery do I use?" type threads, and at least that many more DIY battery threads, and at least that many more threads discussing various battery types and methods of construction, charging, etc.
It's a lot easier to just buy one, but you'd still want to look around to find out what kinds and vendors to avoid, so you get one that's able to actually do what you want at the power levels you need.
I want gears up front for the guy pedaling but I also want to be able to stir it form the backseat (I have seen designs like that on recumbent bikes).
See my SB Cruiser for a way to do the gearing without derailers. You'[l need to work out the gearing range you need for hte speed range you expect. If it's a narrow range you can do what I did with the 3-speed IGH and a single crank gear. I can get up to about 4-5mph out of it at highest gear, IIRC (though I myself can't pedal it very far at that, and have to shift to the lowest 1mph gear for the most part).
see my CrazyBike2 for the remote steering. Keep in mind that if *both* people can steer, you'll need coordination you might not be able to get with the timing you'd like, so your best bet is to just make the front a stoker, and have the rear be captain (tandem terminology).