GerryAZ
Gold Member
Posts: 1488
Joined: Mon Nov 22, 2010 6:47 pm
Delivery Date: 12 Jun 2011
Location: Phoenix, AZ

Re: Can you limit charge current to 1kW for emergency charging with a generator?

Sun Oct 22, 2017 8:27 am

jjeff wrote:
GerryAZ wrote:The J1772 standard goes down to 6 amperes at anywhere between 120 and 240 volts (probably down to 100 volts, but I don't have the standard in front of me). The later versions of EVSE Upgrade units are adjustable down to 6 amperes at any voltage. You could use a 1.5 kVA transformer to drop the voltage from 220 to 110 and use an EVSE Upgrade unit set at 6 amperes to charge with your generator. I actually do the opposite. I have a 3 kVA transformer that I use with my 3 kW Honda generator which operates at 120 volts to charge the car at 12 amperes and 240 volts with my EVSE Upgrade unit in emergencies (or to run the generator periodically under load).

Not that you'd probably want to spend more money, but you could also just get an EVSE that would output full amps(27.5) @ 120v :)
I have several EVSEs that will do that, allowing me to fully utilize up to a 120v 3300w continuous generator. In your case with a 3000w generator you should be able to charge at ~24a @ 120v with your generator, avoiding the losses of your transformer(and also having to lug around what I'd have to believe might be a heavy?? transformer.
One scenario where I could see your transformer being handy would be with one of the old(pre '13) Leafs that maxed out at 12a @ 120v and I'm thinking the post '12 S Leafs without the charger package may also have the 12a 120v limitation, but I'm not sure of that. With those you should be able to almost double your charge rate with your transformer.


I bought the transformer when I had the 2011 which would draw a maximum of 12 amperes at 120 volts regardless of EVSE pilot signal so it did double the charging rate on generator for that car. The transformer is heavy (probably about 50 pounds), but it has a 3-wire 120/240-volt output so I can use it for a lot more than just charging the car. I would have purchased a 120/240-volt generator if an inverter model with lots of sound insulation had been available back when I bought my Honda EU3000is.
Gerry
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015

LMF5000
Posts: 3
Joined: Fri Oct 20, 2017 9:19 am
Delivery Date: 20 Oct 2017

Re: Can you limit charge current to 1kW for emergency charging with a generator?

Mon Oct 23, 2017 3:49 am

Hi All,

Thank you for the replies so far. I'm already learning a lot!

I looked at the EVSE upgrade cable and I find it a bit disappointing that on a €300 product I would have to short two pins with a paperclip and repeatedly press the handle to set the charging current. There are DC-DC converters for sale on eBay with buttons and displays for less than €5 including shipping, how much would it have cost to add a decent user interface to the EVSE?

Regarding converting from one voltage to another, the instant you mentioned it I immediately thought of weight. You need lots of iron to do power conversion at a low frequency of 50Hz (which is why aircraft electrical systems for example operate at 400Hz AC and inverters, power supplies and other electronically-controlled power conversion devices operate their transformers at some 25kHz).

Sure enough, a 1kVA 240 to 120V transformer weighs 15kg and costs €268 (I'm looking at the Mouser 530-DU-1). For reference, my 1kVA inverter generator cost €220 and weighs around 15kg too. At those prices and specs it actually makes more sense for me to sell my generator and buy a 2kW generator. Or look at different electric car options :lol:

jjeff
Posts: 1486
Joined: Wed Jan 13, 2016 9:10 am
Delivery Date: 13 Jul 2014
Leaf Number: 422121
Location: MSP MN

Re: Can you limit charge current to 1kW for emergency charging with a generator?

Mon Oct 23, 2017 3:33 pm

LMF5000 wrote:
I looked at the EVSE upgrade cable and I find it a bit disappointing that on a €300 product I would have to short two pins with a paperclip and repeatedly press the handle to set the charging current. There are DC-DC converters for sale on eBay with buttons and displays for less than €5 including shipping, how much would it have cost to add a decent user interface to the EVSE?

I agree it seems, and maybe is a bit hokey but I believe the designer wanted to change the case as little as possible, possibly thinking of people turning their EVSE in at the end of a lease. It was probably also done for weather tightness, an upgraded EVSE is just as weatherproof as an OEM EVSE. That said I'd probably agree that there are now other ways of adjusting current that don't require buttons. My older Zencar EVSE uses a shaking method, each hard shake of the EVSE increments to the next highest setting. This works OK for my Zencar EVSE that only has 3 amp settings but would be kind of a pain for the EVSE upgrade that has 15 possible amperage settings. The new Zencar EVSEs use a proximity card to increment the amp settings, one to increment amps and one to lower amps(I believe it works this way) that would be the best way to adjust without buttons IMO. Another cool option is what my old Juicebox uses, a small RF remote with + and - buttons to adjust output, of course, the new Juiceboxes use your smartphone to adjust but the downside is I believe you need WiFi and the internet to do it.
The paperclip method is quite ingenious though and quite easy to adjust.
2012 SL purchased used 2/'16
2013 S w/QC purchased new
Juicebox Premium 60a L1/L2 EVSE, Ebusbar 16a L1/L2 EVSE
'12 EVSEupgrade'd 20a L1/L2 EVSE, '13 EVSEupgrade'd adjustable 6-20a L2, 6-13a L1 EVSE
Zencar 13, 20, 30a L1/L2 portable EVSE
GE Durastation 30a

smkettner
Posts: 7019
Joined: Mon Aug 09, 2010 10:13 pm
Delivery Date: 26 Feb 2014
Location: Orange County, CA

Re: Can you limit charge current to 1kW for emergency charging with a generator?

Mon Oct 23, 2017 5:33 pm

LMF5000 wrote:I thought of buying a cheap used leaf in the UK and driving it down to Malta, but my calculations show it will need recharging a minimum of 17 times over the distance of the trip. That's why I need some sort of backup in case I find charging stations broken or occupied. Course I could have it shipped to Malta directly for €950 like I did with my last car, but where's the fun in that? :D
Yea I think for everything involved either figure out the charging or have it shipped.
Only other option might be to rent a larger generator that can power the included OEM cord.
1 bar lost at 21,451 miles, 16 months.
2 bar lost at 35,339 miles, 25 months.
LEAF traded at 45,400 miles for a RAV4-EV

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