Clarity as a back-up power source? (DC-DC converter size, idle behavior)

[Landshark]

At the point near where the power enters your house inside your breaker box. Not what I expected either.

Anyone able to explain it in a couple of sentences ground neutral bonding?

The short answer is so that the circuit breakers operate properly (immediately). A short to ground to neutral will trip the breaker. A short to ground often becomes a steady-state ground fault that will not trip the breaker.

 

[craze1cars]

Really? At what point is this bonding occurring? Certainly not what I have come to expect.

Yes. Inside the breaker box. Take your main service entrance cover panel off and take a look. You'll see white neutral wires and bare ground wires all share the same bus bars within all properly wired residential service panels. Even if they happen to be on separate bus bars for neat appearances, I assure you they're bonded together by a solid bar and it should be visible if you look closely...so they're all shared.

I underlined main service entrance for good reason.

Because this is not true for distribution panels (often known as sub panels). Neutrals and grounds need to be separated from each other in sub panels.

This is one of the biggest rookie mistakes when DIY/homeowners, and some electricians wire a residential sub-panel in a garage or basement or whatever for a remodel, or to add more circuits. The installer duplicates what he/she sees on the main panel by combining neutrals and grounds, and does it wrong. They MUST be isolated in sub panels, but bonded in service panels. Funny thing is even if they don't do this right, everything tests correctly and works, so they think it's done correctly. It's still wrong and dangerous. I even had to fix this in my own home after a "licensed electrician" put a sub-panel in my basement, after a first "electrician" came and overloaded several circuits and violated the NEC in multiple ways, resulting in a parent company firing one guy after acknowledging the errors, and then sending me "their best guy" to fix the problems caused by the first guy. Guy #2 did a MUCH better job, but after the fact I learned he screwed up by bonding neutrals and grounds in sub panel itself. The whole incident actually inspired me to do some studying to become an electrician for my second career. I learned electricians make mistakes like other humans do, TWICE on the same project even. And it kinda annoyed me. So now I trust only ME with the electrical in my home.

@The Gadgeteer as for why: Here are two links. First is a clear and detailed explanation for main panel being neutral and ground bonded: https://www.esgroundingsolutions.co...eutral-and-the-ground-wire-in-the-main-panel/ and here is a clear and detailed explanation for subpanel grounds and neutrals needing to be isolated: https://www.esgroundingsolutions.co...ound-bar-from-the-neutral-bar-in-a-sub-panel/

 

[craze1cars]

Every car has that, but with our plug in cars we have massive amounts of HV voltage. Why isn't the discussion about bypassing the limitations of the ubiquitous 12volt system and tieing into the real batteries and the charger that keeps them topped off?

Cost prohibitive.

 

[craze1cars]

I've been using a 1500 watt pure sine wave inverter as backup power, and for camping, for a decade now. My truck is set up to accept it, so I just idle my truck when I need to use it. Protected by a 125 amp fuse, set up with 1 gauge marine wire with crimped and soldered lugs, direct bolted connections to battery, and a 175 amp quick disconnect plug. This wiring to connect the wire to the truck cost me almost as much as the inverter itself. Agree wholeheartedly this is where people make huge mistakes with inverter installations...they don't properly understand the amperage these things can move thru a cable. A LOT.

Anyway I've only used it once at home during a prolonged outage. Couple extension cords to refrigerator and deep freezer and TV and a couple lights kept things rolling. But I use it annually when camping and fishing on lakes that are electric trolling motor only. I use it there to recharge up to a half dozen 12V deep cycle batteries at a time after long days of fishing. It's nice and quiet to just idle the pickup truck at the campsite instead of purchasing and maintaining and listening to a running standalone generator. Silverado has a 145 amp alternator and oversized battery, so I know for a fact it can handle the load. I've also learned when my 2015 truck's computer senses a big electrical load it cranks up the idle speed of the truck automatically to spin the alternator faster to generate more power. Works pretty slick as a system.

So the concept is sound. Unfortunately I have no knowledge of how the Clarity would compensate for such a load, and I see no reason to subject the miniature battery and unknown 12V charging capacity of the Clarity to this sort of treatment...plus Clarity doesn't tow my boat to the camping/fishing grounds anyway. While I don't doubt the Clarity can certainly handle some electrical load, I don't know how much. So I have no desire to make my car the canary in the coal mine to find out how much. A few gallons of gas idling the pickup truck works very well, for the 1 time per year I need a quiet generator...

 

[Cash Traylor]

@CyberDyneSystems ,So you can add an inverter to your Clarity's HV pack. I have come to embrace two statements that I finally, through experience, have found to be almost absolute truths. First, is that "...there is no monetary reason you cannot do that" and "I can build whatever you want as long as you draw me a picture on the back of a big enough check..." So, if you are willing to do the following you can absolutely attach a large inverter directly to your Clarity, not in any particular order of difficulty or expense:

1. Purchase and pay to import a Clarity PHEV equipped with a CHAdeMO connection from outside your country to here (import taxes, ferry, broker, customs, etc). Purchase Honda V2Home power adapter. This maintains vehicle warranty (if contract executed with Honda to that effect, as the license for use does not automatically follow the equipment and is geographically tied, so you need paper). @insightman
2. Purchase and install a CHAdeMO control unit in your current Clarity. This will likely void the warranty on both your HV pack and the electric interface section of the powertrain. Price is not published, likely not cheap but probably less than importing the car as in option #1. https://www.pues.co.jp/en/products/251.html also after that you can purchase this online http://setec-power.com/index.php?m=content&c=index&a=lists&catid=15 You cannot use the Honda version of this as it has proprietary protocols, but the CHAdemo E2Home will work.
3. Build your own relay HV tie in and use an off the shelf home PV based HV Inverter that accepts up to 400 volts, likely the cheapest option but also likely to kill anyone not skilled and trained as an electrician AND automotive technician. This is the the DIY funbag option that is the most likely to result in really cool fireworks - but can be done.

If my car was out of warranty, I would be willing to try option 2 or 3, as long as someone else was willing to pay for it.

Finally, the DC-DC converter rating (what charges and powers the Clarity 12 volt system) is now finally known at 2300 watts max (is fussed at 175 amps) so a sustained 13 volt draw down will likely blow the current limiter/regulator. We also know the real rating of the HV charger, it can only charge the battery at 6.6kW not 7.x. It is dissipating any additional current as heat and noise. See attached spec sheet from SAE Honda doc (no, I don't have a subscription, hence the watermark).

I will submit my answer for the ground bonding for ranking of shortest (@Landshark is current winner): mine = "Required by NFPA 70 - NEC."

Cheers,

Cash

 

[KentuckyKen]

Thanks @Cash Traylor . That validates what we’ve suspected as to the converter’s efficiency being about 92%. In that 6.6 kW / 7.2 kW (what my EVSE reports) = 92%. Thanks again for adding some more metrics to our understanding of the Clarity cause Honda sure ain’t helping.

 

[Cash Traylor]

Although this is not our charger. I have not confirmed manufacturer by removal and opening the case, and ours is liquid cooled with water blocks on top, this has pretty common industry numbers on it so just for info.

http://store.evtv.me/proddetail.php?prod=6.6kWCharger


Cash

 

[craze1cars]

Really? At what point is this bonding occurring? Certainly not what I have come to expect.

Also @The Gadgeteer may be interested. I know I beat this to death already, but I did another install today for a customer of a 6-50r receptacle in a garage (not for EV, but for a pottery kiln. Though if she or a future homeowner ever goes EV, this can also be used for L2 charging). Opportunity for a few clear photos of neutrals and grounds all mixed together on the bus bar, and also the bonding strip that connects these 2 bus bars. This is a correctly wired service panel.

This configuration would be INCORRECT for a sub-panel, however. Had this been a correctly wired sub panel instead of a main service panel, one bus bar would be all bare grounds, the 2nd bus bar would be all white neutrals, and the black bonding strip between the two bus bars would not be installed in the panel. This would isolate the grounds and neutrals from each other, as it should be in sub panels only.

Photo 1 just an overview of this very simple install. The outlet I installed today is immediately below the panel where I'm pointing, just for ease of wire fishing. Customer wanted least expensive location possible and this couldn't have been easier. In and out of the job in 1.5 hours start to finish, purchased $35 in materials including outlet, breaker, wire, box, faceplate, connectors, etc.

2nd 2 photos show mixed grounds and neutrals on both bus bars.

Last 2 photos show how the bonding strip connects the 2 bus bars together even though they're on opposite sides of the service panel from each other...making it one continuous bus bar (bonded).

 

[Landshark]

I will submit my answer for the ground bonding for ranking of shortest (@Landshark is current winner): mine = "Required by NFPA 70 - NEC."

Short indeed. It does, however, require interweb noodling for an explanation.

You have forced me to deploy my Mother’s standard answer, “Look it up.”

Your move.

 

[Cash Traylor]

I yield... as my mother's "Go ask your father!" is longer.

 

[CyberDyneSystems]

Thanks for the "clarity" all ,. now I feel a little silly

 

[sabasc]

Thanks for sharing the link @Garry2!
In addition to the electrical specs in the table on page 2 of that document, there's a lot of fascinating technical information in it. Well worth the $37.

I came across a technical puplication that lists the output of the DC-DC 12v converter at 2.3kw. it is cooled by the same loop as the battery and charger. That would mean pulling 2kw off the 12v battery would be no issue. Also interesting is that at AC charger is listed as outputing 750w of waste heat.
https://doi.org/10.4271/2018-01-1184

 

[sabasc]

And @Cash Traylor for including a screen shot of the table. https://www.insideevsforum.com/comm...ter-size-idle-behavior.1027/page-4#post-97798

Thanks for sharing the link @Garry2!
In addition to the electrical specs in the table on page 2 of that document, there's a lot of fascinating technical information in it. Well worth the $37.