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Stranded and trying to charge with generator

Posted: Thu Jun 01, 2017 12:03 pm
by Browndog
So, I had my first 'pull over now' moment, which I tried to ignore since I was only 1mi away from home and juice. Made it safely off the road and into a driveway. Hooked up my standard 120 charger to a small generator (2200 running watts) and I can't get it to register 1mi of battery to get me home. The light on the charger is solid on the vehicle side and the light ring on the charger port is sometimes flashing and sometimes dark. Dash display says it's charging. What gives? No reason this shouldn't work but maybe I'm just not realizing how long I need to leave it hooked up?

Re: Stranded and trying to charge with generator

Posted: Thu Jun 01, 2017 12:43 pm
by davideos
The fact that you say that the ring is sometimes flashing and sometimes not makes me think that your 120V charger or car is not happy with the generator's power. There is more to the equation than just raw power. Could be that the voltage drops when under load and the car and charger might not like it and shut down. When it does, it goes back to a no-load situation and the voltage increases back to an acceptable level. What does the generator sound like? Does it sound like it is under heavy load?

Hard to tell you exactly why without actually making measurements, but that would be my guess.

Re: Stranded and trying to charge with generator

Posted: Thu Jun 01, 2017 1:02 pm
by triangles
if it's a 2200W constant load and not peak rating for the generator it should be no problem. No matter what EVSE you have, at 120V the car will pull no more 12A (1440W) Maximum which is about 4 miles per hour of charge. So you should have no problem. Sounds like your EVSE doesn't like the power from your generator maybe?

Running on propane my 240V generator is rated at 6600W continuous. The current meter on my EVSE says it's pulling 29A (6960W) and the generator sounded like it was struggling. I backed my EVSE down to 24A (5760W) and the generator sounded much happier. It charged just fine in about 3 hours from a not quite dead battery. I've only done this once as test in case I ever run out close enough to home and don't want to wait for a tow.

Re: Stranded and trying to charge with generator

Posted: Thu Jun 01, 2017 1:39 pm
by Browndog
As suggested, the charger/car didn't like the power for whatever reason. It was 15amp and 2200 watt continuous. Hooked it up to a larger 7000 watt generator and it's doing fine. Thanks!

Re: Stranded and trying to charge with generator

Posted: Thu Jun 01, 2017 4:23 pm
by Pearl
I think THIS would be the perfect Generator to charge the FFE.

http://www.homedepot.com/p/Ford-4-050-W ... /207111961

Re: Stranded and trying to charge with generator

Posted: Fri Jun 02, 2017 7:05 am
by triangles
:lol: never knew Ford had branded generators. It would be funny to see one mounted on a trailer hitch on the back of a FFE. Holy $@*t! 5.5 gal/hour fuel consumption!?!? That can't be right. that would be 5.5gal/3kWh=1.83gallons per kWh!!!!! Must be a typo. It CAN'T be that inefficient! Maybe they meant 0.55 gal/hr and it's .183ga per kWh?

Re: Stranded and trying to charge with generator

Posted: Tue Aug 01, 2017 6:51 am
by FiSh
They messed description.
It's 5.5 hours running time under full load. Tank is 4 gallons, so it's 0.73 gal/hour

Re: Stranded and trying to charge with generator

Posted: Tue Aug 01, 2017 7:08 am
by spirilis
This is a good question I'm (not too seriously) considering, do we need to use an inverter generator (and/or is it a generally "safe" option or is an "inverter" still no guarantee)? What 240V options are out there?

Re: Stranded and trying to charge with generator

Posted: Tue Aug 01, 2017 8:17 am
by spirilis
Ok from the little bit of reading I've done, a few issues with generators:

1. Neutral and GND should be tied together via resistor, if the generator doesn't already do it. This is a common problem with L1. You can build or buy an adapter that does this. The EVSE will check that GND is actually connected (there should be a voltage potential between hot and GND) and fault if not.

2. Inverter generators preferred but, I've yet to see any solid tests demonstrating this beyond your typical forum conjecture & tall tales. Makes sense in theory, just not sure yet. Concern seems to range from changes in AC frequency (not sure that the charger's AC-DC converter would care) to spikes in voltage (depending on the frequency of these spikes, that could trick up the internal DC boosting circuit, at worst possibly cause erratic charging of the battery cells). True sinewave inverters tend to run on the small side, so Level 1 only, and 240V probably needs a traditional generator with a double-conversion UPS which is heavy and several thousand $$ for a 4+kW unit. I'm imagining what it would take to outfit a towing service with an on-the-fly EV charging solution, since they'd be the only ones to afford such a rig.

However, I'd guess #2 isn't as big an issue as people make it look.

3. EVSE would tell the car to pull full current during charging, but the genset might need some time to "ramp up". Not sure how the Ford actually deals with this, I'd imagine it "ramps up" the power draw over a minute or so but it would be nice to have a special "ramping" EVSE that could enforce this via the J1772 square wave's pulse width (stepping from 5A to 12A over 3 minutes or so). Teslas don't have this problem 'cause the charge rate can be manually set from the dashboard tablet UI.

Re: Stranded and trying to charge with generator

Posted: Tue Aug 01, 2017 1:07 pm
by jmueller065
spirilis wrote:3. EVSE would tell the car to pull full current during charging, but the genset might need some time to "ramp up". Not sure how the Ford actually deals with this, I'd imagine it "ramps up" the power draw over a minute or so but it would be nice to have a special "ramping" EVSE that could enforce this via the J1772 square wave's pulse width (stepping from 5A to 12A over 3 minutes or so). Teslas don't have this problem 'cause the charge rate can be manually set from the dashboard tablet UI.
The Focus (and the C-Max) ramp the current up.

I know this by watching the display on my JuiceBox. It takes a few minutes to get up to full current.