Using the 480V DC port to directly charge from a solar array

[RandDP]

Does anyone have information on using the 480V DC port to charge the LEAF directly from Solar?

One could use a DC to DC converter to generate the correct charging voltage from a lower voltage solar array.

I am new to this forum having just purchased a used Leaf with 45,000 miles on it with a battery that is down 3 bars. I would like to charge through the 480V DC port with a fairly low current, perhaps only 2 amps, using an efficient DC to DC converter and avoid going through an inverter and rectifier. My sun exposure is very limited so I can only get a few KW per day which would be sufficient for my very limited range needs. I can design the converter and decode the protocol of the 480V port.

 

[KillaWhat]

Oh my.
You are talking about juggling a whole bunch of balls at once..
Could you theoretically do this?
Probably.
Do you really want to?
No.
Having messed with this HV system quite a bit, I'm telling you that what you want to do just isn't worth this trouble.

If you REALLY have your heart set on HV charging, then you can circumvent the DCQC protocols, and charge the pack directly.
Not safe, but doable.

Why not take the easy, off the shelf component path, and hook up a PV array to some 12vdc cells and a "made for this purpose" solar inverter, and charge 120vac level 1 when your production allows.
If you don't produce much, then use the 12vdc battery cells as an "accumulator" and then charge.

No offense, but I'm not going to take the time it would take to discuss the problems you would face trying to ChadeMo charge "directly" from solar.

Be careful.

 

[HighDesertDriver]

This question has been raised several times in the past couple of years without any starts. Garygid is successfully working a mini QC with several talented folks, but the project has huge challenges. The first is determining the charging protocol without paying reportedly huge license fees. Like the other poster, I'll leave the research to you. If you can solve the direct PV to QC challenge, you'll be a hero to this community.

 

[Boomer23]

I suggest you read the mini QC thread to get an idea of the complexities of using the DC charge port. The protocol has built into it some very demanding requirements for the power being supplied to the vehicle. Not least among the problems you would face, solar power of inherently variable wattage would not likely meet the requirements of the protocol.

 

[planet4ever]

Does anyone have information on using the 480V DC port to charge the LEAF directly from Solar?

Just to debunk a few misconceptions, it is not a 480v port. It is a variable voltage port topping out a bit over 400v. The car will refuse to accept any electricity until voltage/amperage has been negotiated between the car's battery computer and the external charger's computer. Even after that negotiation, during charging, the car will make varying amperage demands on the external device, which must vary the voltage to satisfy those demands. The circuit with the car must be completely isolated from the source power circuit.

There is a reason that DC/QC chargers are as big as refrigerators and cost $15K to $40K. Feeding a LEAF DC port directly from a solar array is so ludicrous as to be downright funny.

Ray

 

[RandDP]

OK, Your information is very useful! I was unaware the the DC port was so demanding. The information I had so far seemed like it was very flexible and a Nissan employee thought it would be a reasonable project.

So going with plan B: I have a 24 Volt solar charged battery system with deep cycle batteries with about 7KWH capacity. Also a 1500 Watt (With 3KW peak capacity) sine wave inverter. The Leaf 120 volt (12A) level 1 supplied "charger" will not operate from this inverter.

Before I purchase the next size larger inverter does anyone have experience as to what size inverter will work with the 120 Volt charge option? Also, would a sine approximation (stairstep "sine") or even a square wave inverter be adequate? I would think that a square wave inverter would be the best option since the output will just be stepped up and rectified anyway; no need for sine wave unless the transformer needs that kind of signal.

Does the 120 Volt level 1 charger reduce the current required as the batteries approach full charge?

Thanks for your comments they are really valuable information to me.

 

[UBUYGAS]

Sorry to go off-topic here but I was looking at your profile and it say delivery date of 3/24/2011.

It seems like we need to add some additional lines there, Like; Did you purchase your LEAF new or used. When did you purchase it.

Joined: Thu Dec 26, 2013 7:45 pm
Posts: 2
Delivery Date: 24 Mar 2011
Leaf Number: 000605

Unless the OP should be putting his purchase date in delivery date?

I really don't know but it seems like people would want to know if you bought the LEAF new or used.

Sal

 

[RandDP]

Sorry about profile. I can't figure out how to edit it. It was not clear what information was asked for.

I did buy the Leaf used on Dec 5, 2013. It had 45,000 mi on it and is in beautiful condition. The battery is down 3 bars probably because it was charged through the QC port a lot. It was driven by a Nissan manager who lived far from work. The dealership has the QC charger. 95% of my driving is short range so the Leaf is perfect for me. I am a retired EE and love to work on difficult engineering tasks. I love the Leaf. My first electric car was in the late 1970's and was a VERY poor design; it was a modified golf cart that could go 25 mph on the flat - an accelerator pedal that had 3 positions, low, med, & high. I am not very familiar with these discussion groups as you can tell.

-Richard

 

[cwerdna]

OK, Your information is very useful! I was unaware the the DC port was so demanding. The information I had so far seemed like it was very flexible and a Nissan employee thought it would be a reasonable project.

So going with plan B: I have a 24 Volt solar charged battery system with deep cycle batteries with about 7KWH capacity. Also a 1500 Watt (With 3KW peak capacity) sine wave inverter. The Leaf 120 volt (12A) level 1 supplied "charger" will not operate from this inverter.
...

Does the 120 Volt level 1 charger reduce the current required as the batteries approach full charge?

For level 1 and 2 AC charging, the charger is on-board the car. See http://www.mynissanleaf.com/viewtopic.php?p=262630#p262630" onclick="window.open(this.href);return false;. The brick w/J1772 handle and 120 volt plug is just an EVSE, NOT a charger.

For '11 and '12 Leafs, the OBC is under the hump in the back. See http://www.mynissanleaf.com/viewtopic.php?p=69224" onclick="window.open(this.href);return false;.

As for "Nissan employee", is it someone who works for Nissan, the company and in a technical role or is it some employee at a dealer? In the US, due to franchise laws, automakers basically can't own dealerships. Google for tesla franchise laws dealers, if you want to read about that.

If you want to read high-level info about CHAdeMO, see http://www.chademo.com/wp/technology/details/" onclick="window.open(this.href);return false; and the links on the left.

I did buy the Leaf used on Dec 5, 2013. It had 45,000 mi on it and is in beautiful condition. The battery is down 3 bars probably because it was charged through the QC port a lot.

I doubt that's the cause. I'm guessing you live/the car lived in a hot climate and the battery wasn't well cared for either, coupled w/the relatively high mileage. See http://www.mynissanleaf.com/viewtopic.php?f=27&t=14271" onclick="window.open(this.href);return false;.

Can you update your location info via User Control Panel (near top) > Profile (left side)? That way, we don't need to ask in future posts/threads or do sleuthing to deduce it.

 

[planet4ever]

Sorry about profile. I can't figure out how to edit it. It was not clear what information was asked for.

It's not difficult. Click on 'User Control Panel' on the top right corner of any page. Click Profile in the left pane. Change the date to the date you got the car. Also, please provide some location information. This really helps when we try to determine what climate you are in, and what your charging opportunities are.

Then click 'Edit Signature' in the left pane of the Edit profile page. Here is where you can say that in 2013 you bought a used 2011 SL with QC, 45K miles, down 3 capacity bars. All of those things will be helpful as we respond to future posts.

Ray

 

[wwhitney]

So going with plan B: I have a 24 Volt solar charged battery system with deep cycle batteries with about 7KWH capacity. Also a 1500 Watt (With 3KW peak capacity) sine wave inverter. The Leaf 120 volt (12A) level 1 supplied "charger" will not operate from this inverter.

I'm not that familiar with inverters--does the output of the inverter have the ground bonded to the neutral, or is it left floating? The L1 EVSE supplied with the LEAF does a ground integrity test, which will fail if your ground is floating.

Cheers, Wayne

 

[RandDP]

Thanks Wayne, That was it! The inverter output is floating. So just tying the common to ground makes it work. My only complaint now about using the inverter is that from the solar battery to the car battery the efficiency is only about 50%. 70A at 24 Volts solar battery seems to supply about 2 A at 390 V at the car battery. Does anyone know if a square wave inverter would work more efficiently with the charger in the car (using the 120 Volt L1 connection) than a sine wave inverter?

Another bit of information is that my current battery condition of 3 bars down at full charge has about 67.6% capacity of a new battery.

Regards, Richard

 

[TomT]

Most electronics do not like square waves...

Does anyone know if a square wave inverter would work more efficiently with the charger in the car (using the 120 Volt L1 connection) than a sine wave inverter?

 

[brettcgb]

So going with plan B: I have a 24 Volt solar charged battery system with deep cycle batteries with about 7KWH capacity. Also a 1500 Watt (With 3KW peak capacity) sine wave inverter. The Leaf 120 volt (12A) level 1 supplied "charger" will not operate from this inverter.

Before I purchase the next size larger inverter does anyone have experience as to what size inverter will work with the 120 Volt charge option? Also, would a sine approximation (stairstep "sine") or even a square wave inverter be adequate? I would think that a square wave inverter would be the best option since the output will just be stepped up and rectified anyway; no need for sine wave unless the transformer needs that kind of signal.

Does the 120 Volt level 1 charger reduce the current required as the batteries approach full charge?

Thanks for your comments they are really valuable information to me.

Since you're looking at getting a new inverter anyway, consider a 240V, 4kW inverter. It should be a "true sine wave" type (electronic devices don't get along well with power pulse generators AKA "modified sine wave" inverters), and a relatively high efficiency model.

I have a 300W 12VDC > 120VAC true sine wave inverter that seems to have an efficiency of about 85% (measured), comparable efficiency to another 400W "modified sine wave" inverter, but at about 5x the cost.

120V vs 240V? With 240V, the vehicle charges more than twice as fast as when using 120V. I'm guessing that electrical losses in the on-board charger are essentially fixed regardless of the input voltage. Assuming 100W of fixed losses, charging at 120V for 21 hours means 2.1kWHr lost energy vs 240V for 6 hours for 0.6kWHr lost energy. (The fixed losses are likely much greater than 100W.)

Based on the data I download from Blink from my home charger, the vehicle draws 3.6kW (240V) continuously until it reaches end of charge, at which time it simply shuts off. I see no reason to expect anything different at 120V.

With a 7kWHr battery bank, you wouldn't be able to fully charge the Leaf from zero in anything less than 3 very deep discharges. Hmm....

You may already have your optimum charging system if you dedicate the 120V inverter to charging the Leaf, and very little else. Whether this is good enough depends on how much driving you do. (The likely limit is probably close to 15 miles/day, i.e. 7 mile range.)

To significantly improve your charging situation, you are looking at spending considerable $$$ on a 240V inverter, a modified "trickle" EVSE (accepts 240V), AND doubling (tripling?) your battery bank and solar array size. The size of the solar system and battery bank is the limiting constraint.

You should have evaluated your solar system with an eye towards charging your Leaf BEFORE you purchased the Leaf.

 

[smkettner]

Before I purchase the next size larger inverter does anyone have experience as to what size inverter will work with the 120 Volt charge option?

Does the 120 Volt level 1 charger reduce the current required as the batteries approach full charge?

I have charged my LEAF with a Xantrex Prosine 1800. Inverter is mounted in a smallish compartment in my RV trailer and complains of heat in about ten minutes. If I ramp down power with the evseupgrade.com modified brick it will run at seven amps continuous. Driven with 4x GC2 batteries and 600w of solar. I tested to investigate possibilities. However I don't use this system to charge. I only recommend sine wave inverters.

The on board charger (OBC) controls the charge voltage and current to Nissan specifications using L1 same as charging at home from a regular outlet.

Upgrade your L1 brick and there might be nothing to buy. Just ramp down the charge to 10 amps and you should be fine.

Just add more batteries and solar as needed.

 

[brettcgb]

Before I purchase the next size larger inverter does anyone have experience as to what size inverter will work with the 120 Volt charge option?
Does the 120 Volt level 1 charger reduce the current required as the batteries approach full charge?

Among other things, the EVSE indicates to the vehicle how much current the OBC can draw from the utility (your stock L1 brick indicates 12 Amps from NEMA 5-15 outlet). The OBC converts that power to something appropriate for battery charging.

I have charged my LEAF with a Xantrex Prosine 1800. Inverter is mounted in a smallish compartment in my RV trailer and complains of heat in about ten minutes. If I ramp down power with the evseupgrade.com modified brick it will run at seven amps continuous.

That sounds like a fan blowing into the small compartment might have helped. Did it?

I tested to investigate possibilities. However I don't use this system to charge. I only recommend sine wave inverters.

The on board charger (OBC) controls the charge voltage and current to Nissan specifications using L1 same as charging at home from a regular outlet.

Upgrade your L1 brick and there might be nothing to buy. Just ramp down the charge to 10 amps and you should be fine.

Just add more batteries and solar as needed.

+1

 

[RandDP]

Thanks for the information. I have very limited sun due to neighbors trees. However my driving is usually very limited so the solar that I have now does re-charge the LEAF most of the time which was my goal. I do have a 240 V connection as well so that can be used if needed. As a temporary work around until I get the larger inverter I was able to use a variac to reduce the needed current a bit so my current inverter does handle the charging load (L1). It is very close to not working so a slightly larger inverter (than 1500W) running at it's optimum efficiency would be a solid solution.

The solar charging of the LEAF is a perk. Using Standard Utility power is still a good option - in my case it is 11 cents a KWH and comes from wind and solar. So the whole system is fairly "green." My LEAF has reduced range due to the previous owner's use in a hot climate and frequent use of the QC option (Charging at 1.5 C is tough on the batteries in my opinion) which is fine with me as I don't need the full range. I was able to purchase this very clean LEAF at a good price partly because of the (< 70% of new) compromised battery.

I appreciate all of your comments on these issues.

Regards, Richard

 

[cwerdna]

Based on the data I download from Blink from my home charger, the vehicle draws 3.6kW (240V) continuously until it reaches end of charge, at which time it simply shuts off. I see no reason to expect anything different at 120V.

That doesn't sound right, unless you're only charging to 80%. It should ramp down as it nears 100%. My '13 Leaf does that at 208 volts (by looking at the 5 minute interval graph on Chargepoint's site). But, charging to 80% results in no ramp down, it goes from ~6 kW at 1 interval to 0 kW, the next.

I've also charged other pre-'13 Leafs (identified by the side marker lights mine doesn't have) on the same EVSEs and also observed the ramp down. (Charging is free at my work and sometimes I plug in other cars and start sessions for them.)

http://www.mynissanleaf.com/viewtopic.php?f=30&t=15009&&p=338038#p338038" onclick="window.open(this.href);return false; has a link to the graph for the tapering and bumps in 1 minute resolution for the '13 and there's a graph earlier in the thread for a '12.

 

[brettcgb]

Based on the data I download from Blink from my home charger, the vehicle draws 3.6kW (240V) continuously until it reaches end of charge, at which time it simply shuts off. I see no reason to expect anything different at 120V.

That doesn't sound right, unless you're only charging to 80%. It should ramp down as it nears 100%. My '13 Leaf does that at 208 volts (by looking at the 5 minute interval graph on Chargepoint's site). But, charging to 80% results in no ramp down, it goes from ~6 kW at 1 interval to 0 kW, the next.

I've also charged other pre-'13 Leafs (identified by the side marker lights mine doesn't have) on the same EVSEs and also observed the ramp down. (Charging is free at my work and sometimes I plug in other cars and start sessions for them.)

http://www.mynissanleaf.com/viewtopic.php?f=30&t=15009&&p=338038#p338038" onclick="window.open(this.href);return false; has a link to the graph for the tapering and bumps in 1 minute resolution for the '13 and there's a graph earlier in the thread for a '12.

You apparently have a 6.6kW OBC in your 2013 car. It may perform slightly different near end of charge. (I wish I had the 6.6kW OBC... :mrgreen: )

The Blink data I see is accumulated over 15 minute periods. If tapering were happening, it would have to be very brief, occurring over less than a minute or two. Otherwise, I would be seeing two consecutive periods where both indicate less than maximum possible energy, and this would be happening at the end of every charge. I'm simply not seeing it. Not when charging to 80%. I don't think I've seen it at 100%, but routine charging to 100% was a recent change (started when I lost most of my regen for SoC > 30%, about a month ago). I have enough history that I might see tapering - I'll go back and look. Tomorrow.

Now that I've read through that thread....

As long as I've had the car, I've set the Leaf charge timers to end charging at a specific time (no specified start time).

A couple times a week, I see a couple of 15 minute periods where the car draws something like 300WHr, always following the bulk of the charging. I had thought these were the car waking up for something but didn't know why - I'm now thinking these are equalization charges.

I don't often reach LBW (2 a month?), and almost never VLBW (2-3 times a year). I really don't like hitting VLBW - I'm risking getting stranded. I'll stop at an L2 and grab a bite for an hour if I think I'm going to get close. When I hit LBW, I tend to manually start a 100% charge as soon as I get home.

 

[RandDP]

I just want to follow up on the need to charge the LEAF from a minimal solar array. I am looking at a few KWHrs of charge for a locally used LEAF. Because of a lot of neighbor trees my solar array has only partial solar exposure. The array charges a set of deep cycle batteries - a 24 Volt system. I want an efficient charge since there is so little energy available from this system. My batteries can provide up to 7KWHr of energy. I tried using a 1500W sine wave converter but the 120V LEAF charging system would not work with that unless I used a variable transformer to drop the load a bit - a pain to use! Anyhow I got a 2500 Watt sine approximation converter that is about 95% efficient (24V DC to 120V AC) that works great with the LEAF 120 V charger. Any inefficiency is in the LEAF on board charger at this point. So without building something to use the High Voltage DC charging port this is the best I can do.
Regards, RandDP