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

Thanks for giving us the amp numbers. That’s another good data point about the Clarity.
I am lead to believe from other posters on this forum and from common sense that everything but the motor and starter generator (and of course the HV batts/converters/inverters) are on the 12v bus.
The question I would ask is if you load the 12v bus up a lot more than normal for the DC to DC converter, will that in and of itself trigger the ICE sooner than it normally would otherwise? Or will it act like normal and not trigger the ICE until it depletes it’s usable SOC?
 
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I have a 1000w continuos output inverter that I bought on amazon for $65 specifically for use with my Clarity. I used it successfully after our hurricane this fall to power our large fridge, chest freezer and a few lights. I think a 5000 watt inverter is too much to power from the Clarity battery.
 
briano said:
hello all, new to this thread, and site, I ID'd an ideal inverter (link below) for $600 that could be plugged into 12V side of battery and power up to 50 AMPs of stuff, which is quite a hefty amount of power (6kw). Just curious if anyone has tried this yet, before I shell out some $$ for a 12VDC / 120VAC inverter. Thanks,

https://www.powerinverters.com/products/royal-6000-watt-power-inverter-12-dc-to-110-ac-volt

BPL
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If the info from @Garry2 is accurate, the inverter you linked to is way too large. I’m leery of the inverter info on that site too. 50A from a standard outlet is crazy and could lead to a fire, but it claims it can do that. And, it mentions wiring to your fuse panel but supplies no transfer switch. That’s deadly. Skip that one, IMHO.
 
briano said:
hello all, new to this thread, and site, I ID'd an ideal inverter (link below) for $600 that could be plugged into 12V side of battery and power up to 50 AMPs of stuff, which is quite a hefty amount of power (6kw). Just curious if anyone has tried this yet, before I shell out some $$ for a 12VDC / 120VAC inverter.
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As noted by others, that inverter is not the right device. As Garry2 mentions above, Clarity's 12V DC-DC converter apparently maxes out at 2.3kW (about 190A at 12VDC), so when you factor in parasitics on the 12V bus and the fact that you probably don't want to be pushing the DC-DC converter to its limit if you don't have to, you really don't want anything over 2kW max. Personally, I would be wary of putting a steady load above the 500-1000W range on it (very ballpark guesstimating that as the sort of 12V load the climate stuff in the car might draw for an extended period and therefore be confidently what the system is designed to handle long-term; one could measure this for a better number).

Not to mention that at 500A you would need huge cables to feed the thing off a 12V bus without it hitting the 10.5V undervoltage shutdown (that's if the Clarity's battery could even manage 10.5V at the terminals under 500A load, which I doubt), and it's going to run very inefficiently down at the power levels you can realistically use it.

Even if it were suitable, though, it's a modified sine wave inverter, which generally are cheap (and I personally wouldn't trust expensive appliances or electronics to), it's not a major brand, and it doesn't even seem to be UL listed. If you don't mind modified sine for your stuff, get something cheap; if you're going to spend that much money, you might as well get a true sine inverter. For example, something like this:

http://www.xantrex.com/power-products/power-inverters/freedom-xi.aspx

That inverter is by a long-time off-grid inverter manufacturer Xantrex (which is now owned by major conglomerate Schneider, along with major UPS manufacturer APC), is true sine, is sized correctly for the Clarity, and the 2000W version retails for around $600 so is about the same price.

Or this model by the same manufacturer, which is also true sine but has a few less features and isn't marine rated, but is half the price:

http://www.xantrex.com/power-products/power-inverters/prowatt-sw.aspx

Sandroad said:
I’m leery of the inverter info on that site too. 50A from a standard outlet is crazy and could lead to a fire, but it claims it can do that.
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Indeed, it says specifically the outlets have no individual protection and each can supply the full load, which is nuts. No wonder it's not UL listed. It's probably targeted at "The bigger the number the better!" idiots who really just want to run a drill or something, will never actually plug 6000W into it, and if they did would be seriously disappointed when it either set their cable on fire or shut down on DC bus undervoltage because they didn't have three parallel 2/0 cables feeding the DC side.

Hypothetically they might be talking about a transfer panel for that "wire it direct to your fuse box" bit (who the heck even has fuses in a panel in this day and age?), but somehow I suspect if they're willing to let it output 50A from a 15A outlet they just expect someone to use a double-male extension cord to plug into an outlet, backfeed the house, and kill whatever lineman is up on a pole fixing your neighborhood's power because you forgot to open the main breaker.
 
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MNSteve said:
This is the part of the whole thread that bothers me the most. Please do not unknowingly put the linemens' lives at risk.
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Given what the topic of this thread is it does indeed bear noting:

If you are planning to use your Clarity as a back-up power source, either hook the inverter up to the generator side of a properly-installed, inspected transfer panel, or just plug your loads directly into the inverter using an extension cord and power strip. Do not ever scab it into an electric panel not designed specifically for this, by any means or method, even if you think you know what your'e doing.

A) It's illegal in most places for a very good reason, B) It runs a non-zero risk of causing an electrical problem and damaging stuff, C) If you screw up at best when the power comes back on your inverter will explode, possibly damage your Clarity, and maybe start a fire when the hookup wires melt, and at worst it will backfeed the pole through the transformer and kill somebody.
 
M.M. said:
Given what the topic of this thread is it does indeed bear noting:

If you are planning to use your Clarity as a back-up power source, either hook the inverter up to the generator side of a properly-installed, inspected transfer panel, or just plug your loads directly into the inverter using an extension cord and power strip. Do not ever scab it into an electric panel not designed specifically for this, by any means or method, even if you think you know what your'e doing.
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This was a really interesting discussion that seems to have ended with appropriate warnings about the real danger of linking inverter directly into an electric panel and caution about using the right sized inverters.

That said, I was wondering if you decided to give this a try and what inverter and cables you selected. I searched for other examples using inverters for backup power. This confirmed that the Honda Power 9000 and ConVerdant options are likely unavailable, but did turn up a different option.
https://cargenerator.com/us-store/
https://cargenerator.com/product-specs/

They packaged a 1000W, pure sine wave inverter with matched cables for the purpose of using a 12V car battery (ICE or EV) for backup power. Clearly not an established company, but they at least claim that their components work for this purpose. At $400 for the basic package, the markup doesn't seem too bad. ($700 for the version with a waterproof case is another story).

Opinions?
 
As I mentioned earlier on this thread, I bought a 1kw inverter on amazon for $65. I used it successfully to power our big fridge, chest freezer and a few lights when we lost power.
 
Just got back from vacation
mhb said:
I searched for other examples using inverters for backup power. This confirmed that the Honda Power 9000 and ConVerdant options are likely unavailable, but did turn up a different option.
https://cargenerator.com/us-store/
https://cargenerator.com/product-specs/

They packaged a 1000W, pure sine wave inverter with matched cables for the purpose of using a 12V car battery (ICE or EV) for backup power. Clearly not an established company, but they at least claim that their components work for this purpose. At $400 for the basic package, the markup doesn't seem too bad. ($700 for the version with a waterproof case is another story).

Opinions?
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In broad terms, I like what that company is doing--they’re offering the DIY parts to do what I hooked up.

In terms of specifics, it comes down to how much you trust that they picked a good device to rebrand, how much you trust that they’ll be around long enough to honor their warranty, and how much markup is acceptable to you for the service they’re offering.

I couldn’t find an obvious device that looked like the photos with which to guess where they’re getting the dry inverter, but a Xantrex should cost around $300, and recognizable brand (Mean Well, although I only know their power supplies not inverters) is similar. Off-brand 1000W true sine inverters (or at least ones that claim to be) tend to cost around half that, which is what you’re almost certainly going to be getting here.

A good one might actually do what it says; a bad one is totally lying about the power output, would overheat rapidly if actually run at anywhere near 1000W, and will shut down at a fraction of that on low DC voltage due to cable resistance. (Note, also, that the alligator clamps used to connect this to the battery are probably going to have significant contact resistance in real-world use; screw-on lugs will do way better.)

Their transfer switch (a 4-circuit one they’re charging $399 for), for what it’s worth, looks to be a rebranded Reliance Controls Pro/Tran2 R104B, which usually retails for about half that. I like that company’s stuff--I used a Pro/Tran 2 306A for my own hookup (very similar, but has 6 circuits, analog meters, and a 30A split-phase plug rather than 20A single-phase like that one).

A 100% markup isn’t unreasonable if the company is selling you good rebranded parts and offers good after-sales support, you just have to weigh whether you think that’s going to be the case and, if so, if that markup is acceptable to you.

I have not actually bothered to buy a larger inverter yet, just a little 300W doodad that can be plugged into the 12V console port, in part because I got a PV inverter with a 120VAC outlet for use when the power is out, so the potential utility is decreased.
 
M.M. said:
Just got back from vacationIn broad terms, I like what that company is doing--they’re offering the DIY parts to do what I hooked up.

In terms of specifics, it comes down to how much you trust that they picked a good device to rebrand, how much you trust that they’ll be around long enough to honor their warranty, and how much markup is acceptable to you for the service they’re offering.

I couldn’t find an obvious device that looked like the photos with which to guess where they’re getting the dry inverter, but a Xantrex should cost around $300, and recognizable brand (Mean Well, although I only know their power supplies not inverters) is similar. Off-brand 1000W true sine inverters (or at least ones that claim to be) tend to cost around half that, which is what you’re almost certainly going to be getting here.

A good one might actually do what it says; a bad one is totally lying about the power output, would overheat rapidly if actually run at anywhere near 1000W, and will shut down at a fraction of that on low DC voltage due to cable resistance. (Note, also, that the alligator clamps used to connect this to the battery are probably going to have significant contact resistance in real-world use; screw-on lugs will do way better.)

Their transfer switch (a 4-circuit one they’re charging $399 for), for what it’s worth, looks to be a rebranded Reliance Controls Pro/Tran2 R104B, which usually retails for about half that. I like that company’s stuff--I used a Pro/Tran 2 306A for my own hookup (very similar, but has 6 circuits, analog meters, and a 30A split-phase plug rather than 20A single-phase like that one).

A 100% markup isn’t unreasonable if the company is selling you good rebranded parts and offers good after-sales support, you just have to weigh whether you think that’s going to be the case and, if so, if that markup is acceptable to you.

I have not actually bothered to buy a larger inverter yet, just a little 300W doodad that can be plugged into the 12V console port, in part because I got a PV inverter with a 120VAC outlet for use when the power is out, so the potential utility is decreased.
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Thanks for the feedback! Especially about the cables - I was specifically wondering about the merits of a screw-on versus clamp type connection.
 
Someday EV / PHEV manufacturers will give us direct access by a high voltage connector to the traction battery, with related relatively small gauge cables (much lower current at 350V for the same power) compatible inverters. These systems are definitely on the horizon. Part of the attraction to the utility companies, beyond our desire for emergency power, is the ability to use the EV battery to supplement grid power during peak times.

Until then, IMHO it is of limited value to convert from 12V DC back up to 120V AC. A small gas generator in that 2 or 3 kW class is a generally a more practical way to go.

You can either do the formal transfer panel thing for your critical loads, even for a small 2kW emergency generator (or inverter), or just unplug stuff from the home system and plug into extension cords (no kludging home boxes or wiring for the reasons above, it's unsafe).

I installed a formal transfer switch for <2 kW worth of loads, especially picking up the blower motor for my gas furnace. But, abandoned my Xantrex 12V inverter with very heavy cables to my Chevy Volt, for a Honda 2 KW generator. The small generator is much easier to use overall, plus with no risk of damaging a $30k+ car, or the $1k - $2k DC-DC inverter (called an auxiliary power module "APM" in the Volt). Plus the little Honda generator turned out to be quieter than the Volt engine providing the same power.
 
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Interesting idea, but I went with two 2000 watt inverter generators connected to a 10 circuit transfer switch. Enough power to run the fridge, freezer, all interior lights and even a 7500 btu window A/C unit if I get a power outage in the heat of summer. Inverter generators can be paired together to double their output.
 
There is an interesting new "class" of battery back-up inverters starting to enter the market based on power tool batteries, such as this ego:
https://www.homedepot.com/p/EGO-56-...ation-2-X-7-5Ah-Battery-Kit-PST3042/305092922

They are very pricey and don't store that many watt-hours (e.g. just under 2 kWhr with four of their largest 7.5A batteries), but interesting nonetheless, especially as more of us have 56V+ batteries laying around for electric lawnmowers. Another nice feature of this one is the ability to hot swap the 4 batteries. Yet, the ego batteries are still very expensive. OTOH, no fumes or CO, and you can run it in the kitchen or living room.

Also, even if this can do 1.7 kW for about an hour, the Honda 2kW generator runs for hours on a tank, and after that you just refill it.
 
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Hi.Ho.Silver said:
I have a 1000w continuos output inverter that I bought on amazon for $65 specifically for use with my Clarity. I used it successfully after our hurricane this fall to power our large fridge, chest freezer and a few lights. I think a 5000 watt inverter is too much to power from the Clarity battery.
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I was looking at setting something like this up but I'm curious if the Clarity is able to sustain this power load for a long time (many hours or even days) and, if so, if the car needed to be switched on in order to maintain the 12v battery, which from reading this thread seems to imply that the battery management system will maintain using the power stored in the lithium batteries. I was thinking of a 1500w pure sine wave inverter that could run my fridge, some lights and one or two electronic devices. Thoughts?
 
I’m no EE, but at full load:
A 1,500 W inverter is uses at least 1.5 kWh
So ~14 kW (usable part of the 17 kW) divided by 1.5 kW works out to
~ 9 hours or 18 hours at half load.

Then the ICE will have to come on and you'll have to deal with the deadly CO coming out of the tail pipe. Also, what if the ICE comes on before then for any of the various reasons on p 13 of the manual. I would not be comfortable trying this unless my car was safely parked outside. Then you’d also have to run a longer extension cord and size it properly to avoid voltage drop.

Safety first, foremost, and always!
Don’t let any ICE exhaust enter your house. Follow all codes and ordinances.
And don’t do anything that would back feed power into the grid which creates danger for the utility wireframes tesoring your power. (Like using suicide male to male ext cords from the inverter to an outlet or generators without transfer or lock out switches.)

So I guess it could be done safely, but IMHO I would only use it intermittently
to keep the fridge and freezer cold and not continuously.
You can’t really be sure unless you can measure how many Watts you’ll be using. My SolarEdge monitoring shows me I can get by with ~0.6 kWhrs just running a new efficient inverter fridge, lap top, and a few LED lights
So in that scenario, the traction battery would last me almost a day. So I would use it once every 4 hours for just long enough to keep temp.
But take all these figures as a little optimistic since they don’t take into account housekeeping loads of the turned on Clarity, and inverter and transformer losses.

People are always surprised that what seems like a huge battery can’t run their house very long at all. Even Tesla will tell you that you’ll need 2 to 3 PowerWalls to get by multiple days even with PV augmentation and that’s a hideously expensive proposition. IMHO, the only practical way to get through a protracted power outage is to have a portable or a standby generator and a transfer switch.
 
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Good to know.

This is to provide some emergency power at my vacation property where we sometimes have a day or two without power. You're probably correct and perhaps a 1500w inverter might be over kill. I'm heading back up to there in about six weeks and will do some checks using a power meter to see how much power I actually draw and then decide on whether it makes sense to use an inverter.
 
Funny that you're surprised that a "big" battery can only run your house for a day. What you should find surprising is that driving your car for one hour uses more energy than your house does in an entire day.

Although I agree with you about not doing anything stupid with the output connections, I don't really worry about leaving the car On and the potential ICE running. Pulling the car half out of the garage seems sufficient to dissipate the exhaust. I wouldn't leave it connected while I was asleep or away, though.

I'd rather have a fully emissions-compliant ICE running 1/4 to 1/2 of the time than run a generator full time, plus the maintenance and storage of another device. But, all this really depends on the power reliability where you live. We have less than 24 hours of outage in a year, so a minimal solution works for me. I would feel differently if I had experienced multiple 96-hour outages like some people. (But the Stoic in me still says you don't need to run your whole house while on generator. Just fridge, freezer, furnace, water pump, sump pump, and a few lights.)
 
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