Solar charging - what size/type inverter, etc?

[SirCaptainAhab]

I've owned my i-MiEV since May 17, 2012. I've driven over 37,000 gas free miles and love it!

I've build my own off-grid solar system at home, with solar panels I've made myself, hooked up with a charge controller, inverter, and batteries. My inverter is only a 650 watt modified sine wave inverter, which I now know isn't what I need to do what I want to do.

I want to be able to get the right off-grid inverter to be able to plug my i-miev into the standard 110 outlet on the inverter so I can charge it right from my solar panels.

1. Is this even possible?
2. If so, what size/range of inverter do I need?

I've just been told as of yesterday that I need a pure sine wave inverter. And that I may need to send my portable charge cord in for an upgrade whereby it will have a lower amperage possible for trickle charging at lower amps.

Can anyone provide suggestions or ideas on how I can make this work? I'd be interested in being able to make the off-grid system portable in the back of the car, to take it with me, as I drive 31 miles one way to work. But during the winter time, I don't have enough charge to get home and can't currently plug in at work.

Any ideas, suggestions, etc would be most helpful. I want to make this happen!

Thanks!

Captain

 

[PV1]

You'll need a 1,000 watt (1,200 watt preferably) pure sine wave inverter. The stock (US) EVSE is set to pull 8 amps, though the car actually only pulls about 7.5 amps. This works out to be around 910 watts.l, and is just shy of 1 bar per hour of charge.

Also, check out the thread Range Extender as I had the same thought as you even before I bought my i-MiEV.

 

[SirCaptainAhab]

Thanks PV1,

It looks as if I should do the upgrade as offered on: http://evseupgrade.com/?main_page=product_info&cPath=3&products_id=8 . It says its adjustable from 6-12 amps. So since the trickle charge would be coming through the inverter that's hooked to the batteries, I'd want a lower amperage that this upgrade would provide, correct?

It sounds as if the only 2 things I need to do is 1) this upgrade of the portable plug in, and a 1200+ watt pure sine wave inverter!!!

That's what I shall work on!

Thanks!

Captain ;-)

 

[FiddlerJohn]

... I want to be able to get the right off-grid inverter to be able to plug my i-miev into the standard 110 outlet on the inverter so I can charge it right from my solar panels.

1. Is this even possible?
2. If so, what size/range of inverter do I need? ...

You don't need to upgrade your EVSE for 110VAC 8A charging. You don't need a pure sine wave inverter.

http://myimiev.com/forum/viewtopic.php?f=24&p=17607#p17607

The i-MiEV charger first filters the AC, then converts the AC back to DC to charge the car. I tried to build an EVSE to charge directly from DC, but the on-board charger went to a fault condition. You just need 110VAC at 8A to use your stock EVSE. Please let us know how it works.

 

[jray3]

So why would it need to be a sine wave? Since it's getting rectified into DC, wouldn't even the most basic 'square wave' inverter suffice, and quite possibly be more efficient (no RMS, just 'alternating DC').

I've got the gear to try if a square wave is approved. I've already charged off of a sinewave inverter that is a salvaged uninterruptible power supply fed from a 48 VDC battery bank.

I've recently acquired a new old stock Outback PS1, which is a grid-tie inverter that'll also handle standalone and emergency backup duty, also running off of a 48V battery, but unlike the UPS, it was designed to be fed by a solar array, complete with a MPPT charge controller. I plan to mount it and it's array on my 16' enclosed car hauler, yielding a mobile solar power station/EVSE that spends most of it's time feeding into the grid.

http://www.altestore.com/store/Inverters/Off-Grid-Inverters-Capable-of-Grid-Tie/Outback-PS1-2500-Grid-tie-Solar-wBattery-BU/p2482/

 

[SirCaptainAhab]

So...if the type of inverter is moot....perhaps its the wattage size that just needs changed. As I originally mentioned, I only have a 650 watt inverter. So perhaps if I get a 2000/4000 watt inverter, that would be more than plenty, I would think. Looking for an affordable one now.

Maybe I'll do that step first, before worrying about upgrading the EVSE.

Captain

 

[FiddlerJohn]

So why would it need to be a sine wave? Since it's getting rectified into DC, wouldn't even the most basic 'square wave' inverter suffice, and quite possibly be more efficient (no RMS, just 'alternating DC').

I've got the gear to try if a square wave is approved. ...

I'm sure the i-Miev Charger will work on a square wave. The 2012 QEM EVSE uses a 120VAC to 12VAC transformer, a rectifier and a 7812 regulator for the 12VDC in the EVSE to drive the relay and the J1772 protocol. A square wave will heat this transformer a little more, but 110V square wave should work just fine.

... I only have a 650 watt inverter. So perhaps if I get a 2000/4000 watt inverter, that would be more than plenty, I would think. Looking for an affordable one now.

Maybe I'll do that step first, before worrying about upgrading the EVSE. ...

The rule for inverters is to use them at less than their power ratings. If the fuse doesn't blow they may start a fire. However, if it were mine I would try it for a few minutes. But don't trust it. You're playing with fire.

Your 650 watt inverter might even work if you can keep it cool, but keep an eye on it. The inverter will either shut down nicely or blow it's fuse. The fuse will blown because something else in the inverter got hot and blew, but you are planning on buying a new 2000 watt inverter anyway.

The EVSE upgrade is only good if you are using 240VAC or want more than 8a. You don't need either. I say get your car to charge using the OEM EVSE first at 110VAC @7.5A and then decide if the upgrade is worth it.

 

[DonDakin]

Hey Guys,

I realize that you are trying to get to the technical aspect of charging the imiev from solar, But Is it really worth it to charge on solar with L1 ? If you charge the imiev at 8 amps from solar you may get 4-6 hours of charging at best from a 1-2 KW array. That's not much in terms of driving range maybe 40 Km a day. Would it not be better to charge at L2 with a larger array to at least be able to fill her up within a days sunlight ?

Don....

 

[SirCaptainAhab]

Hi Don,

Thanks for the msg. I'd be happy with just a couple extra kW added back to the battery. But I'm looking at being able to load this off-grid system in the back of my i-miev and bring it with me, set the panel out and let it trickle charge the car up, while I'm at work all day...since I can't plug in right now.

Those extra couple of kW added would make all the difference in whether or not I make it home at the end of the day, given that I drive 31 miles one way to get to work.

I just need to be able to find the right, correct sized inverter to be able to plug the EVSE into so that it will kick on and charge my car. Right now, all that happens is the green light just blinks - it doesn't switch the orange charging light on.

Captain

 

[FiddlerJohn]

... Right now, all that happens is the green light just blinks - it doesn't switch the orange charging light on...

If the green light blinks there is a problem. The green light should be lighted solid on with no blinks. The blinking might indicate a ground fault or open connection. Please check me on this. When you plug your EVSE in a wall outlet does the green READY light stay on with no blinking?

 

[PV1]

Yeah, blinking green light means no ground. The EVSE has this issue on cheaper inverters and generators, as well as outlets with dirty or bad connections. To save on cost, lower power mod-sine inverters don't have a true +120 volt and neutral/ground. Instead, they put +60 volts on one terminal and -60 volts on the other (alternating, of course) so that the plugged in device sees 120 volts. Because of this, there is no connection in the ground terminal of the outlet.

Fortunately, there is a way to "trick" the EVSE so that it sees a ground. They discussed this over on the My Nissan LEAF forum, linked here: http://www.mynissanleaf.com/viewtopic.php?f=26&t=5792&start=38
Only perform this if you are comfortable and knowledgeable about high voltage.

I've successfully charged my i-MiEV from two separate pure sine wave inverters. These are high power quality inverters that have a true 120 volt "Hot" and neutral/ground.

 

[SirCaptainAhab]

Yes, when I plug it in to a regular grid-tied connected outlet, it works and charges just fine.

It's only when I plug it into my current 650 watt inverter, is when it just blinks and does nothing else.

Which makes me think the inverter is not powerful enough to allow for the peak in wattage needed to get it going at first.

Captain

 

[PV1]

You're correct in that your current inverter isn't powerful enough, but the blinking light is a failed ground check (no ground). The EVSE itself only takes a few watts to power up.

 

[jray3]

...since I can't plug in right now, given that I drive 31 miles one way to get to work.
Captain

Damn, what Satan signs your paycheck; Microsoft? (I watched a string of frustrated EV converters get denied at MS before the modern EV era)

When there were some objectors to my plugging in at work, I dragged in an aircooled genset on a trailer behind my car and left it running for four hours in a prime parking spot.

Executive-level authorization for my plugging into the building followed post haste!!!

:twisted:

 

[SirCaptainAhab]

PV1,

You mentioned in your previous post about MSW inverters splitting the charge to 60v on each plug in terminal. And that for it to be a true 120v, it needs to be a 120 "hot" and neutral ground wiring.

I've been looking on ebay to find an affordable inverter that is wired the way you indicated. Do you think this particular inverter is what I'm looking for?

http://www.ebay.com/itm/NEW-ADVANCED-PURE-SINE-WAVE-POWER-INVERTER-3000-6000-WATT-DC-TO-AC-12V-to-120V/391029279883?_trksid=p2047675.c100012.m1985&_trkparms=aid%3D444000%26algo%3DSOI.DEFAULT%26ao%3D1%26asc%3D27675%26meid%3Db0f3fbedb7e944d4a56652857fadfb9c%26pid%3D100012%26rk%3D3%26rkt%3D10%26sd%3D331446777197

In the specs, it says, " 4 - 110V AC Grounded 3-Prong Outlets" . Would this work, so that I don't need to learn how to modify the EVSE?

Captain

 

[SirCaptainAhab]

Jray,

I've had a similar situation here at work. Even though we have a Sustainability Plan, our old Executive Director of Facilities at my state-funded university, removed and covered 2 different plug in outlets, to keep me from plugging in and charging while I am at work. My coworkers in another building here on campus have overly complained that I'm "getting something for nothing", and find it unfair that I'm getting to plug in. I've been harassed by one of our on campus police offers and threatened with being charged for "theft of service".

The Parking Services says they are working on getting L2 charging stations installed on campus this summer, but I'll believe it when I see it, since I've been waiting 3 years for them.

Glad to see they worked swiftly to let you plug in!

Captain ;-)

 

[SirCaptainAhab]

Sorry to be messaging so much, but I did get some new info. PV1...the split 60/60 volts on the 2 plug in terminals is referred to as "Floating Neutral". I just found out that the Samlex PST pure sine wave inverters are the ones that are wired as 120v on the hot only. So this seems to be exactly what I need to get!

Now.. to come up with the funds to get the right sized inverter.

Captain

 

[PV1]

Great. Nice to also have the technical term for 60/60 volts, "floating neutral".

 

[SirCaptainAhab]

That information was provided by the staff at www.donrowe.com. They sell up to 9 different types of inverters. I just confirmed with them that at least the Samlex PST and SA Series Inverters, as well as the Xantrex Inverters do NOT have that 60v/60v "floating neutral " wiring configuration, and do have the "true 120v hot" to one terminal. The Xantrex inverters looks to be about 1/2 the cost of the Samlex ones.

This should eliminate any issue with the EVSE not recognizing it as being grounded, correct?

Captain

 

[PV1]

This should eliminate any issue with the EVSE not recognizing it as being grounded, correct?

As long as ground is bonded to neutral, yes. If the inverter is quality enough to have a true 120 volt "Hot", then this should already be done.

The first post in this thread confirms that Xantrex pure sine inverters are bonded internally, so this will pass the ground check and charge the i-MiEV.

http://www.fieldlines.com/index.php?topic=147824.0

To be able to bond neutral and ground, the inverter must be a true 120 volt hot, not a floating neutral. For a floating neutral inverter, the resistor trick mentioned in the LEAF forum is the fix. Measuring voltage from hot to neutral and from hot to ground will tell you if it is floating neutral or not. There should be 120 volts each for hot-neutral and hot-ground for a true 120 volt hot inverter, and 120 volts hot-neutral and either 60 volts or 0 volts hot-ground for a floating neutral.