Idea for charging an electric car portably w/o relying on electricity infrastructure

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reikiman
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Joined: 11/19/2006
Points: 8454

A guy that lives down the street from me has a three-wheeler electric motorcycle, looks like it came out of Mad Max The Road Warrior, and it has a canopy that has solar panels. He charges it anywhere just by parking in the sun. He's also built a trailer with more solar panels that can make for a higher charge rate.

Problems are: $$$'s to set up, and it's got horrible aerodynamics ..

Has me thinking - my Karmann Ghia conversion - could conceivably tow a small trailer - has a 50 mile range

What's the best way to get longer total driving range, and maybe do a long range trip with the car? The immediate question is I have a couple weekends coming up soon where I'll be driving to Laguna Seca Raceway, 88 miles from the house, goes through several mountain ranges to get there, and the location is remote enough that charging stations are few and far between. However, FWIW, I just heard of a charging station opening up in Watsonville, which will help.

Anyway..

Could be solar panels on a trailer, but more $$'s than I can afford, and bad aerodynamics.

Next thought - a generator. Apparently the Honda EU3000 as a high enough output to handle the charger on my car. It would mean burning gasoline to drive an electric car.

Over on the Nissan Leaf forum someone calculated that for a Honda EU2000i, 2000watts @ 120 volts, runs 4 hours on 1.1 gallons of gasoline, and figured this is good for 27 miles, or 24 miles/gallon efficiency.

Someone else noted that if you want to trade gasoline for miles on an electric vehicle, GM already has this neatly packaged in a car - the Chevy Volt - gives 37MPG on gasoline.

One option I'm considering is to skip the conversion to AC and the charger, and do a direct DC connection to the battery pack. This would be more efficient. The trick is to ensure the DC voltage on output is in the correct range for your battery pack, but I'm not certain of how to calculate this. I suspect that it would be best for the DC voltage to be slightly less than the fully charged pack voltage. On my car that's 166 volts or so, and therefore a 158 volt DC output would bring the pack up pretty high without risking overcharging. The question would be, how to find a gasoline or diesel(biodiesel) charger that outputs DC?

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- David Herron, Green Transportation Examiner, Green Transportation Info, The Long Tail Pipe, Electric Race News, davidherron.com, 7gen.com, What is Reiki
- Charger bike (rebuilt), Electrified Electra Townie, 1971 Karmann Ghia

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IBScootn
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Joined: 01/03/2011
Points: 232
Re: Idea for charging an electric car portably w/o relying ...

Hmm interesting idea. I was thinking of doing the same but for my 87v pack. Charge just to 82-84VDC. Antiscab suggested the following modification to a standard gas generator:

"The Alternator of a cheap inverter generator will put out ~120vac 3 phase, independant of engine rpm.
that rectifies out to 170vdc.

The output voltage can be changed by removing the governor, and powering the alternators field magnets to lower the output voltage to ~82Vdc @ 5000rpm
The current that has to be put through the electromagents would have to be found trial and error.
having a lab powersupply on hand makes this much easier.

Theres no need for any current limiting resistor, the system will find equilibrium by itself.
A 2200W rated generator will probably result in 30A charge current @ 82Vdc.

If you want less current, put more amps through the field windings, this will raise the output voltage causing the motor to slow down."

So sounds like you could drop the voltage down to what you need. I never tried this as J1772 stations started popping up, and I started to look for suitable 240V chargers instead.

Another approach might be just make your oun generator with a engine and a windmill servo motor/generator. I looked at a 3KW gas generator and it had a 212cc, 6.5HP engine. At HF you can buy a 212cc engine for $120.

Good luck,

IBS

__________________

Motorcycles:
2011 ZEV Trail 7100, 84V, 60AH, 75+mph, Cycle Analyst, TNC throttle, modified charger. 800 miles so far.
2010 ZEV 6100, 72V, 40AH, 60+mph; Cycle Analyst, LED head lights, 3 Cell Log interfaces, TNC throttle and faster charger added. 8100 miles so far.

Big EV Grin. :)

Ampy
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Joined: 03/27/2014
Points: 52
Making petrol range extender

I have an Aixam Mega powered by 4x 12v batteries in series (it started with 4s2p but I removed 4 batts)

I want to make a petrol range extender, with 12v dc going to each of the 4 batteries

Is there a way of doing this using just one Alternator (not 4)?

The problem with taking 4 pairs of wires off one alternator, is that if the batts are connected also in series - it will short.

Is there a way to isolate the 4 sets of 12v from a single alternator, using diodes or something?
(i.e. the alternator is 100amps max, so that would give 25 amps to each battery). I only do short journeys with lots of stops so I worked out with 25amps running into the batts continuously that would be enough for me)
But it would be easier if I could use one alternator, not 4 separate smaller ones????

IBScootn
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Joined: 01/03/2011
Points: 232
Re: Idea for charging an electric car portably w/o relying ...

Ampy,

As long as you don't want to charge while driving, there is a way to do this. Many folks charge by configuring the batteries in parallel, then when they want to drive they configure the batteries in series. You can do this by bringing the 8 leads from your 4 batteries all to one connection block. Some folks use power pole connectors permanently glued together into a block of connectors. Then they make two mating blocks for plugging into this battery connection block. One of those blocks configures the batteries in parallel to allow charging from one standard battery charger or in your case an alternator. Another mating connection block configures the battery block into series mode so you can run the vehicle.

Instead of using power pole connectors, you could use a switch to make the swap between parallel and series connections.

Hopes this makes sense,

__________________

Motorcycles:
2011 ZEV Trail 7100, 84V, 60AH, 75+mph, Cycle Analyst, TNC throttle, modified charger. 800 miles so far.
2010 ZEV 6100, 72V, 40AH, 60+mph; Cycle Analyst, LED head lights, 3 Cell Log interfaces, TNC throttle and faster charger added. 8100 miles so far.

Big EV Grin. :)

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