We now have a completed electric motorcycle.
That's great for practical local transportation, but what about the 22 hours a day that the motorcycle is just parked there!? Isn't an electric vehicle just a big battery pack with wheels? Wouldn't it be great to in some other way make use of that?
A lot of very clever people think so. They are working on something called "The Smart Grid",
in which electric vehicles only charge up at a time that little power is being used, and the EV PROVIDES it to everyone else when too much power is being used. It's just theory right now, and requires a lot of standardization of components, fancy computer controls, and vehicle owners agreeing that everyone else can "borrow" their power. It's a really neat concept, but I don't think it will happen anytime soon.
Could some of those same ideas be used on a personal level?The Poorman's Smart-Grid
One use that would be fantastic for an electric vehicle is for home blackout protection. Instead of purchasing a gasoline or diesel generator for use in a power-outage, just run your house off your electric motorcycle!UPS delivers for you
You might be familiar with a UPS (Uninterruptable Power Supply.) People often have their computer at work plugged into one. In a brief blackout, the UPS switches power over to an internal battery, allowing you to finish what you are doing and save your work. When the power comes back on, the UPS switches seamlessly back to regular wall power and recharges the internal battery.
While most basic UPSs are 12V, larger ones, such as for computer server rooms, often run on 48V. Hmmmm - that's the same voltage as the electric motorcycle. I spoke with a local computer recycler and asked if he ever gets 48V UPSs coming through his facility. He said that he did, but I wouldn't want it, as the batteries are always bad. I told him that not having batteries was no problem! It wasn't long until I got a call saying that a salvaged 48V UPS was in. I was able to get the salvaged UPS at no cost to me.
I mounted the UPS in a cabinet in my garage. It had been a while since my cheap, imported onboard battery charger had quit working, and I was using a basic off-board charger since then. Because of that I already had an Anderson quick connection on the motorcycle. I wired the UPS connection that would normally go to internal batteries to instead go to a matching Anderson connector. That way, I could quickly connect and disconnect the cycle from the UPS.
Keep in mind that a UPS is actually two things, a battery charger
, AND a high-quality power inverter
. By simply plugging the UPS into the cycle, it begins to recharge, and acts as a typical 48V battery charger.
If AC wall power is cut off from the UPS (such as happens in a blackout) it stops charging the batteries, and instead takes DC power from them and converts it to 120V AC power as is typical in American homes and businesses. The back of the UPS has several 15 and 20-amp outlets. That would be fine if I only wanted to power a few items directly plugged into the UPS. What if I wanted to run the whole garage off it, or my entire house!?
To do that, I first added an additional 20-amp circuit to my garage circuit breaker box. (The garage is separate from the house and has its own dedicated 100-amp, 240V breaker panel.) Connected to that circuit, I added what would become a power "inlet". Instead of electricity going OUT from the breaker box there, it would input to the breaker box there. This is called a "load-side connection".
(If you have specific electrical codes, or are required to use only licensed and certified electricians, don't mess around in your breaker box. High-voltage AC power is potentially fatal. Don't screw around if you don't know what you are doing!)
The new power inlet is a "twist-lock" connector. It is physically different than anything else in my garage, so a person can't plug anything else in there by accident. It is also labeled as UPS POWER INLET on the connector and in the breaker panel.
I built a custom cable with two male ends. One is a 20-amp plug (one blade is turned 90 degrees from a typical 15 amp plug) and the other is the twist-lock connector, which is rated for up to 30 amps.
I connected the cable from the UPS to the twist lock wall "inlet". On the breaker box, the mains circuit breaker is manually turned off, and the 20-amp breaker for the UPS blackout protection is turned on. That allows power from the motorcycle batteries to go through the UPS, get converted to AC power, and feed all the other circuits in the breaker box. My garage is now "off-grid"! I've run the radio, garage door opener, lights, and shop vac, and other power tools from the UPS. The UPS is rated for 2200 watts, enough to run any heavy corded drill or other shop tool.
The UPS only outputs 120V power, NOT 240V power. I do not have any 240V appliances (such as an electric oven or water heater) in the garage or the house. The garage only has two circuits, and both of those are on the same "leg" as the UPS.
If I wanted to run power to the house from the garage. I would turn off the main power to the house from the grid, and turn the circuit breaker (100 amp, 240V) from the garage to the house back on. It is illegal and dangerous to provide power to your house with it connected to the grid when grid power is down. Solar "grid-tie" connections have "anti-islanding" features, and generators use an "automatic transfer switch" to disconnect a residence from the power grid during a blackout. This manual system could be upgraded in the future with an automatic transfer switch or an appropriately designed system of relays.
So far, I have tested the system many times, both charging the motorcycle with the UPS and running my entire garage on just battery power. I haven't yet optimized my house circuits to put all the critical circuits (furnace, well pump, refridgerator, main living space lights) onto just one power leg, but we haven't had any blackouts yet either!
An IDEAL Poorman's Smart Grid would also have PV (photovoltaic) solar panels, a solar charge controller, an AC grid-tie, and device to switch from charging the 48V batteries, to running power back into the grid when the batteries are fully charged. 48V is a common voltage for many solar panels and solar charge controllers. With an electric vehicle connected to a garage power hub, the solar panels will charge the batteries, and the UPS will be available for household power backup. All of this could be done for only several hundred dollars in off-the-shelf parts.
PS: For more on this, I did produce an Instructable just on this aspect of the projectPoor-Man's Smart-Grid