Those are all great questions
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Originally Posted by chrisp68
Ben,
A few more questions...
1. Why the expensive batteries? ($160 EACH for 4 Optima yellow top 55AH batteries) Will a standard 12V car battery not work?
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The batteries are where I splurged. They are spill-proof and can pull a lot of power very quickly. Great for acceleration.
12V car batteries would be a poor choice, they are designed for high power, but only briefly. They are not designed to be drained mostly empty repeated times. Another alternative would be either AGMs (absorbed glass matt) which the Optimas are basically just a fancy version of, or deep cycle boat batteries, which are cheap and hold a fair amount of power, but require watering and could spill.
Quote:
Originally Posted by chrisp68
2. On the ALLTRAX AXE - PM wire diagram, what is the purpose of the Main Contactor?
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The main contactor interrupts the high power circuit of the batteries, motor, and controller. It is usually used as a security feature - you need the ignition key to make the contactor go - and as a safety feature. If there is ever a bad situation where the controller freaks out into the "full on" mode, you can turn off the contactor to kill power to the motor. Since many electric motorcycles have a direct link between the motor and rear wheel, you need the contactor as an electrical disconnect.
The earlier version of my motorcycle didn't have a contactor on it, just a cut-off key. It worked fine like that.
Quote:
Originally Posted by chrisp68
3. Also on the diagram, where would the DC to DC converter be placed?
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Wire up the DC/DC converter so that it turns on when you put your key to the accessory position. This will be a totally seperate circuit using smaller, lower power wires than the motor and main batteries use.
Connect the DC/DC converter to either end of the main battery pack. If you batteries have two sets of posts (one set on top, other on the side, etc) hook up the main power cables to the big posts and the DC/DC converter, charger, or anything else that goes on there to the other set of posts.
Quote:
Originally Posted by chrisp68
4. Would it be possible to salvage old parts from a golf car? (Example: the throttle mechanism)
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Yep, an electric motorcycle is very much golf cart technology. In fact, a decent place to order parts from would be an electric golf cart place.
Quote:
Originally Posted by chrisp68
5. What is the current draw for the 48Volts battery pack when charging? I want to size my solar panels properly for charging purposes.
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Using a KILLAWATT, the power usage at the wall is about 110 watts. How many watts are used depends on the power of the charger. Higher amperage chargers charge faster, but also cost more.
A typical rule of thumb is to charge at a rate no faster than 1/10th the total amp-hours of the battery. Since my batteries are 55 amphours, I shouldn't use a charger faster than about 5 amps. Optimas are actually better that way that they CAN take a faster charge, but lets not get to crazy here. When I put a 6 amp/12volt charger onto a single yellow-top, it does get slightly warm while charging.
Quote:
Originally Posted by chrisp68
Sorry for simple questions... I have a better mechanical background than electrical.
Thanks,
Chris
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That's OK, I have no idea what I got myself into doing a project like this.
So far, this project has inspired or spawned at LEAST three other people to convert cycles to electric.
Take care,
-Ben