View Full Version : Repost - gasfreeearth - Best Electric Motorcycle and Electricity Grid Relationship?

08 September 2010, 1942
Ok, so we all here either have or are in the process of building an electric motorcycle right?

Also we all use grid electricity in our house, and to charge our bikes.

How can we best take advantage of this relationsip is the question I'm raising.

Since I got into the Time of Use rate from my power company, I realize it's talked about everywhere recently.

UCF is building a giant water tank to chill water at night when power is cheaper and use the cool water to cool buildings during the day.
(Great short informative link btw ----->) http://www.energy.ucf.edu/?q=node/88

Last night on "dirty jobs" with Mike Rowe, a steel recycling plant has switched it's shift to nighttime to cut costs as the electrodes used to melt the scrap steel use 150 Megawatts and it has cut their biggest cost in half.

Energy experts from Secretary Chu to former CIA director James Woolsey to Amory Lovins from the RMI all say in a decade we all will have plug in electric vehicles that feed power to the grid during peak demand times and charge at night.

All this stuff makes perfect sense. But most of us have EV's already. Can we take advantage of it now?


This post is to raise the question, and feasibility and how to make it work for us.

Discuss amongst yourselves...

08 September 2010, 1943
gasfreeearth - Ok, let me start by raising the issues I'm having, so others can see the problems and brainstorm most effectively.

First hand I can tell you that the Time of Use rate works. There is no catch or fine print you need to read. You get charged less off peak and more on peak. If you are at work during peak hours, then of course you don't need a house battery pack. Since most of us have at least a 2-3 kwh battery pack in our electric motorcycles, could we use this?

The problem I am running into is figuring out the least expensive way to connect the two.

Main problem: Electric motorcycle pack is not 12V. 120V inverter for house power accepts only 12V.

It's not as simple as just using a DC/DC converter either as I'm seeing. First of all, to just take power out, I need a DC/DC converter that can handle 4500 watts, which the inverter puts out. And remember, the goal is to keep the cost down.

Second, (and this problem only applies if you are using solar to recharge) but how do you charge the bike back up? DC/DC converters are only one way right? So you would need a second one and a separate connection.

Or you could charge during sunlight hours using your regular charger powered from 120V from the inverter, but then you have a loop, and will be wasting energy in 3 places as heat. Inverter, converter, and batteries.

You could make a really hefty series / parallel switch for your electric motorcycle that recables the bike from 72V to 12V with the throw of a 6 pole 6 throw switch, but that would be a lot of high amp cable and material.

Plus 12V DC doesn't like to travel far without losses, so your bike needs to be close to your inverter. But your solar panels need to be close to your inverter too as they also don't travel far without losses.

As we talked about in chat this morning, I'm sure others out there have done an EV to grid tie system already, but we could not find a simple inexpensive way to do it.

And I'm sure there is a most efficient way, I just need some fresh ideas from others. I'm stuck thinking inside the box and can't seem to get out. Help!!!

(sorry for the over caffeinated post. The coffee was overly strong this morning as those in chat were aware of)