: Getting Access to 300V source in Volt



ClarksonCote
09-06-2012, 09:00 AM
Has anyone done this successfully? I've heard stories of people trying, and inadvertently shorting shields to the high voltage. Has anyone found a place to tie into the high voltage battery for a larger backup generator-type installation?

Note: I don't plan to do this myself, and I also know it would void the warranty... Just curious more than anything.

Raymondjram
09-06-2012, 09:56 AM
As the saying goes: "Curiosity killed the cat". This type of curiosity can kill you! 300 Volts DC is extremely mortal, much more than with AC because DC will hold all your muscles fixed (you can't move) and will stop your heart and lungs. There are special tools, instruments and protection needed to handle and service high voltages, but they are expensive and no layperson has them. So I strongly recommend never attempt any test or access to the Volt's high voltage circuits. Leave that to well trained electricians, who really know what to do, are well protected, and have the correct equipment rated for high voltages and the correct insulated tools.

I know because I am an EE, and I worked with 120 VDC circuits that were used in telegraphic communications between 1974 and 1981. I did get a few shocks and they are more painful than the common 110-120 VAC circuits in homes. I have also worked with vacuum tubes in TV and radios, which use high DC voltages (but very low currents), and they really scare you when you accidentally touch any live wiring. And some here will tell of their experience working with normal ignition cables in a running gasoline engine. That shock is at thousands of volts but very low current and short duration. My last experience felt like if I was kicked by a horse on my arm, and I definitely won't try it again!

For the sake of your own life, don't ever try to violate GM protection in that 300 VDC vehicle. GM designed and protected it well that even water or a casual contact will not conduct any of its energy. Just enjoy the Volt as it was designed for.

Fulgerite
09-06-2012, 10:20 AM
Short answer: No. Bad idea.

kns
09-06-2012, 10:22 AM
The National Fire Protection Association (NFPA) and manufacturers have been spending a lot of time and money to ensure that first responders are able to avoid contact with high voltages present in EVs. See for example the following page

http://www.evsafetytraining.org/Training

This should help you to restrain your curiosity.

KNS

ClarksonCote
09-06-2012, 10:23 AM
Short answer: No. Bad idea.
I appreciate everyone's words of caution, and agree with them to a large extent.

Personally, I've worked with 300V DC electronics in my career, designed a high-power DC-DC converter board that took in 270VDC and output 12VDC, among other things. I recognize it's dangerous.

I completely recognize it's bad for the do-it-yourself person to try this, but if there's any engineers that have tinkered, I'd be interested in hearing more about their approach, either on here, or in private messages if preferred. It's more of a curiosity in learning more about the intricacies of the Volt than anything else.

Thanks! :)

DCFusor
09-06-2012, 10:23 AM
Well, danger is relative to skill in a lot of cases, but batteries lack this off switch thing - except the Volt, which does have one in the console. Trouble is, then you have to get it "rebooted" at a dealer or get whatever tool they use.

I begged GM to sign an NDA with me to do just that - but it's not simply a question of getting to the HV (that's easy = if you have to ask, you shouldn't). It's a question of keeping their battery health monitor/TMS system in operation so you don't screw that up - you want whatever else they have designed into the battery system to be working right for this use as well. They simply would not consider doing a deal with me on that. Many solar inverters could run directly off the 360v with little or no modifications, in theory.

I have extensive experience in high power switching/conversion design - decades. But GM engineers think they are the only ones who could do this, evidently. Hate to tell you guys - you're not the first on this street corner by a very long shot.
At the moment, I build multi kilovolt/kilowatt supplies for my fusion operation...my own designs. I'm still alive, and so are nearly all my semiconductors. Those use a 500v, 20a H bridge to drive the HV parts. Same turf, but much more tricky since the HV can store a lotta fast joules of its own and reflect back into the LV stuff through the transformer in an arc situation.

As an EE, a physicist, and solar guy, yup, there's some risk involved in high voltages, especially things like solar panels and normal batteries that don't have an "off" switch. This isn't that case if you do your homework. We DO have an off switch. The Volts HV battery is fully isolated from ground, which could help or hinder depending on what your application is.

What I DID do is put an inverter on the 12v system (http://www.coultersmithing.com/forums/viewtopic.php?f=48&t=553&sid=f653e2a58362d8f062a65e710596e3e6), which is enough to trickle charge my solar house batteries (car "on" in the driveway, engine cycles as required in MM). I limit draw from this to under 1kw, which is more than plenty to keep up with an average off-grid-battery solar home - the house batteries handle all the peaks. I haven't managed to fry the APM yet doing this, but I haven't had to do it much. My other reason for that inverter is to run an 800w ceramic element heater in the winter, which should heat the car far quicker and better than the 5kw+ one that is built in to heat the out of doors with your precious battery energy and has a ridiculous time lag doing it.

You should be careful drawing too much power out of the APM 12v system when the car might move, as it also powers things like the accessories, hydraulic pumps and such that would normally be engine driven. It has 175 amp rating - but they didn't plan on your load on top of theirs, so take it easy on that one, I have no idea if it gracefully current limits or just goes up in smoke if overloaded.
Obviously you're not going to pull a kw out of that tiny agm battery for very long at all (seconds, tops). So you're really looking at what the APM has left over in a Volt parked in the driveway (no one turning wheels, running HVAC, or pushing brakes).

Bob G
09-06-2012, 10:25 AM
As the saying goes: "Curiosity killed the cat". This type of curiosity can kill you! 300 Volts DC is extremely mortal, much more than with AC because DC will hold all your muscles fixed (you can't move) and will stop your heart and lungs. There are special tools, instruments and protection needed to handle and service high voltages, but they are expensive and no layperson has them. So I strongly recommend never attempt any test or access to the Volt's high voltage circuits. Leave that to well trained electricians, who really know what to do, are well protected, and have the correct equipment rated for high voltages and the correct insulated tools.

I know because I am an EE, and I worked with 120 VDC circuits that were used in telegraphic communications between 1974 and 1981. I did get a few shocks and they are more painful than the common 110-120 VAC circuits in homes. I have also worked with vacuum tubes in TV and radios, which use high DC voltages (but very low currents), and they really scare you when you accidentally touch any live wiring. And some here will tell of their experience working with normal ignition cables in a running gasoline engine. That shock is at thousands of volts but very low current and short duration. My last experience felt like if I was kicked by a horse on my arm, and I definitely won't try it again!

For the sake of your own life, don't ever try to violate GM protection in that 300 VDC vehicle. GM designed and protected it well that even water or a casual contact will not conduct any of its energy. Just enjoy the Volt as it was designed for.

The OP didn't ask for a sermon about safety; he asked if anyone has done it. I too would like to know.

PatsVolt
09-06-2012, 10:40 AM
If you did access the main battery voltage system, you voided your warranty... a very expensive proposition and risk.

ClarksonCote
09-06-2012, 10:41 AM
Well, danger is relative to skill in a lot of cases, but batteries lack this off switch thing - except the Volt, which does have one in the console. Trouble is, then you have to get it "rebooted" at a dealer or get whatever tool they use.

...

Exactly. I know of places that one can access the physical voltage without too much difficulty, but it's all the soft monitoring and faults that may trip depending on where it's accessed.

I was hoping you'd chime in here DCFusor, but perhaps with more success in getting GM to sign an NDA.

The 12V inverter option you mentioned is one that I think many people could use, even though it would only provide a kW or so, still good in an emergency keep-my-fridge-and-a-couple-lights powered scenario. Many have done that with success. I'm tempted to sell a kit for others to do it with less difficulty.


If you did access the main battery voltage system, you voided your warranty... a very expensive proposition and risk.

Yes, I mentioned that in my original post. Like I said, I'm curious and intrigued, but not planning to void my high voltage battery's warranty.

bonaire
09-06-2012, 10:58 AM
Actually - it's interesting to know why you'd be interested. What's the goal anyway? Run a high-Voltage inverter (like DC's stated PV inverter?) Those MPPT inverters might not know what is going on when they see the type of voltage coming off the volt. The amperage available from the 360V battery pack is very high - much higher than a normally sized solar string.

If you want to provide 240V or 120V home current, is the 12V battery enough to do that for what you might want?

There are better options than an EV for running home appliances during an outage. (see thousands of threads on generators and such we've had :) ) If folks can afford a Volt, they can afford a pretty good generator type of a solution.

ClarksonCote
09-06-2012, 03:19 PM
Actually - it's interesting to know why you'd be interested. What's the goal anyway? Run a high-Voltage inverter (like DC's stated PV inverter?) Those MPPT inverters might not know what is going on when they see the type of voltage coming off the volt. The amperage available from the 360V battery pack is very high - much higher than a normally sized solar string.

If you want to provide 240V or 120V home current, is the 12V battery enough to do that for what you might want?

There are better options than an EV for running home appliances during an outage. (see thousands of threads on generators and such we've had :) ) If folks can afford a Volt, they can afford a pretty good generator type of a solution.

I'm an engineer, I like to think outside the box. ;)

Actually, the Volt is one of THE best options for a whole house generator, if the functionality were already built in. And once it has V2G capability, that functionality will be built in. You essentially have the equivalent of a $12,000 whole-house generator, right in your car, for FREE. The thought of not tapping into that, like VIA motors did, is a bit perplexing. I can see why not on the first model year, but subsequent model years would've made another awesome selling feature.

Ladogaboy
09-06-2012, 03:49 PM
The only reason I could see to do this is if you bought a battery separately and wanted to use it to power your own EV project or something similar. But you'd have to be building a new electrical system from scratch at that point (or at the very least, Frankenstein one together.

adric22
09-06-2012, 03:57 PM
The Toyota Prius is relatively easy to get to the high voltage terminals. The sad part is a Prius actually costs less money than an equivalent power diesel generator. The generator (MG1) in a current Prius model is about 33Kw. That should be enough to run an entire home. I'm surprised more of these vehicles haven't been modified for use like this. In fact, I'm surprised the hybrid manufacturers themselves haven't pushed that technology offering a built-in inverter than runs off of the high voltage system, making the car useful as a portable generator.

ClarksonCote
09-06-2012, 04:12 PM
The Toyota Prius is relatively easy to get to the high voltage terminals. The sad part is a Prius actually costs less money than an equivalent power diesel generator. The generator (MG1) in a current Prius model is about 33Kw. That should be enough to run an entire home. I'm surprised more of these vehicles haven't been modified for use like this. In fact, I'm surprised the hybrid manufacturers themselves haven't pushed that technology offering a built-in inverter than runs off of the high voltage system, making the car useful as a portable generator.

You hit the nail on the head here. VIA Motors does it with their EREVs. And the motor generators are very efficient. Once the Volt was out of battery energy, it would simply cycle it's engine on and off to generate electricity to provide power longer. Too bad they don't include that as a built in feature like VIA Motors does.

To add insult to injury, if/when these cars are Vehicle to Grid (V2G) capable, they'll already have the inverter built in too. It'll really be ridiculous if there's no emergency power at that point. Even as it stands today, a lot of the hardware already exists, just not quite in the right setup to provide 240V 2-phase back to a home.

WopOnTour
09-06-2012, 04:31 PM
Keep in mind ALL of the easily accessible HV DC points of interest will only be hot when the car is "ON" (due to the contactor system within the battery assembly) and again, assuming all high voltage safety protocols are adhered to..

I think for what you are doing, the easist most convenient access would probably be to simply removing and then lifting the lid on the Auxillary Power Module (APM) , "tap" off the high voltage rails internally and constructing your own isolated point of exit pretty easily adding it to the APM lid or chassis. Alternatively you could "Y" connect by using the APM connector itself which "pigtails" through the rear floor to a typical HVIC protected high-voltage connector under the RH rear of the car.

BE CAREFUL!
WOT

PS. I`ve been wondering if there were any way of adapting the Leaf to Home power supply (http://www.nissan-global.com/EN/TECHNOLOGY/OVERVIEW/leaf_to_home.html) that Nissan offers to the Volt. Anyone have detailed techncial specs on it...

ahaer
09-06-2012, 04:32 PM
It seems like the "trick" for powering a house from the volt main battery would be to tap into the MOTOR (AC) side of the inverter and figure out the proper throttle position to get the desired AC output. I'm not sure how much of a problem the 3-phase output would be. I'm sure you would also have to fake some sensor data, such as wheel speed, in order to trick the car into thinking that it is moving as well.

It *seems* that if you could unplug the motor and plug in a 3-phase ac load and unplug the sensor(s) and plug in a "sensor simulator" you would be able to get the inverter to output any thing that you wanted...

Actually now that I think about I don't know if the motor controller changes the ac voltage, the frequency or both...
maybe it wouldn't work as well as I thought...

techtom
09-06-2012, 05:27 PM
It seems like the "trick" for powering a house from the volt main battery would be to tap into the MOTOR (AC) side of the inverter and figure out the proper throttle position to get the desired AC output. I'm not sure how much of a problem the 3-phase output would be. I'm sure you would also have to fake some sensor data, such as wheel speed, in order to trick the car into thinking that it is moving as well.

It *seems* that if you could unplug the motor and plug in a 3-phase ac load and unplug the sensor(s) and plug in a "sensor simulator" you would be able to get the inverter to output any thing that you wanted...

Actually now that I think about I don't know if the motor controller changes the ac voltage, the frequency or both...
maybe it wouldn't work as well as I thought...

With the size, weight, and power-output of the Volts motor/gen set.... I have a feeling it is running something a lot higher than 60Hz. Higher frequency requires less magnetic core weight needed. That's the reason aircraft run 400Hz power. You could probably find 60Hz if it's a variable frequency drive, but the generator may not be rated to run 60Hz for extended periods.

focher
09-06-2012, 05:45 PM
I'm tempted to sell a kit for others to do it with less difficulty.I, for one, would be very interested in buying such a thing.

Fulgerite
09-06-2012, 07:33 PM
So... Let's say you DO tap the 360 volt battery successfully. (Without killing your self.) Where do you get a 360 volt DC to 120 VAC inverter to run your home? Anybody make a commercial product like that?

ronmerkord
09-06-2012, 08:28 PM
Many of the solar inverters are designed for 300-450 volts DC input. For example, my SMA grid tied inverters on my 15 KW solar system have 390 VDC input at up to 40 amps ! Just right for the Volt battery.

Ron

ClarksonCote
09-06-2012, 08:29 PM
I, for one, would be very interested in buying such a thing.

As GM would say, "Stay Tuned" :)


So... Let's say you DO tap the 360 volt battery successfully. (Without killing your self.) Where do you get a 360 volt DC to 120 VAC inverter to run your home? Anybody make a commercial product like that?

Yes, you can find inverters that convert nominally from 300VDC. But the real ideal solution here is for GM to sell the car with this feature. It's got most of the hardware built in already. Having your vehicle be the equivalent of a whole house $12,000 generator is a pretty nice perk when considering the sticker price. VIA Motors has this for their EREV line; they call it their "Power Export" option.


Keep in mind ALL of the easily accessible HV DC points of interest will only be hot when the car is "ON" (due to the contactor system within the battery assembly) and again, assuming all high voltage safety protocols are adhered to..

I think for what you are doing, the easist most convenient access would probably be to simply removing and then lifting the lid on the Auxillary Power Module (APM)

Thanks for chiming in WOT, now my two favorite engineers on here have contributed (the other being DCFusor).

This is quite literally exactly what I had thought best too, that one could theoretically tap into it from inside the APM, and make an exit point for the wiring. However, I was concerned about software/safety monitoring. That is to say, if the firmware detects more current being supplied through the APM line than expected, will it cut power and fault? Or, if there's a high voltage fuse somewhere there, might it get blown?

I know the battery itself can handle way more current than a back-up generator type project would ever need, but I don't know the ins and outs of how much subsystem-level safety protocols were put in place. Any insight?


PS. I`ve been wondering if there were any way of adapting the Leaf to Home power supply (http://www.nissan-global.com/EN/TECHNOLOGY/OVERVIEW/leaf_to_home.html) that Nissan offers to the Volt. Anyone have detailed techncial specs on it...

Regarding the Leaf option, I looked into it a bit. They use their CHAdeMO port, which I'm sure allows access to the high voltage through there, with the right command sequence. Now, if the current SAE Level 2 spec had a command that allowed access of the HV battery through its port, you could have something similar. My hope is that when the revised specs come out with the combined Level 2/3 plug, it will include a protocol for accessing the high voltage through that port, for V2G or V2H. I don't believe such an option exists on the current SAE Level 1/2 connector spec from what I've read, but I also didn't pay for the full text of the standard either. ;)

I briefly considered that a person might be able to design a connector to simply wire up a Volt to one of those Leaf power systems, but my guess is that there's some safety/security built in there to prevent power from being generated without the right command ack's from their CHAdeMO port.

WopOnTour
09-25-2012, 11:30 PM
Thanks for chiming in WOT, now my two favorite engineers on here have contributed (the other being DCFusor).

This is quite literally exactly what I had thought best too, that one could theoretically tap into it from inside the APM, and make an exit point for the wiring. However, I was concerned about software/safety monitoring. That is to say, if the firmware detects more current being supplied through the APM line than expected, will it cut power and fault? Or, if there's a high voltage fuse somewhere there, might it get blown?

I know the battery itself can handle way more current than a back-up generator type project would ever need, but I don't know the ins and outs of how much subsystem-level safety protocols were put in place. Any insight?Thanks for the kind words CC. I have a lot of respect for you and DCFusor as well </big group hug> lol

OK there IS a 20A "in-line" fuse in the 360V output to the APM (ie maximum 7200 watts) But it IS accessible on the front of the battery pack (battery removal NOT required) and I don’t see any reason why it couldn’t be increased a bit to say 30A? (10.8kW? that enough?)
I believe the HV cabling is ALL the same size/gage so I don’t see why is couldn’t handle it up to the APM. I'll verify that though, but what are your input power requirements? DCFusor was talking about ~10Kw through his H-bridge- that enough??

I have spent a significant amount of time researching the applicable diagnostics, and I don't believe there is ANY way this relatively small amount of additional current would/could be detected and flagged as fault by the BMS/VITM. But you wouldn’t really know for certain until you tried. So I would probably just tap your inverter into a "jumped" connection down at the APM connector under the car (after up-rating the fuse if need be) load it up, and see what she does!
Regarding the Leaf option, I looked into it a bit. They use their CHAdeMO port, which I'm sure allows access to the high voltage through there, with the right command sequence. Now, if the current SAE Level 2 spec had a command that allowed access of the HV battery through its port, you could have something similar. My hope is that when the revised specs come out with the combined Level 2/3 plug, it will include a protocol for accessing the high voltage through that port, for V2G or V2H. I don't believe such an option exists on the current SAE Level 1/2 connector spec from what I've read, but I also didn't pay for the full text of the standard either. ;)

I briefly considered that a person might be able to design a connector to simply wire up a Volt to one of those Leaf power systems, but my guess is that there's some safety/security built in there to prevent power from being generated without the right command ack's from their CHAdeMO port. Didn’t know it was CHAdeMO. Didn’t think they would do that considering not all Leafs have a CHAdeMO port. That will of course complicate things if it's only to be implemented as V2G/V2H but there still might be a work-around... If you have any data on the Leaf kit you can share, please shoot it to wopontour@gmail.com ;)
WOT

DCFusor
09-26-2012, 01:46 AM
Thanks for the group hug WOT - I appreciate it. You too, Carson.

For my needs, running a small inverter off the APM (http://www.coultersmithing.com/forums/viewtopic.php?f=48&t=553) (car on, in MM in the driveway, in park) suffices for a huge majority of the time. The engine cycles as needed, and you're not cycling the main battery much, just that window's worth (0.4kWH?). I have not yet tried running my 800w ceramic heater off this while driving, but I probably will soon - the fear is that the extra 800w (66 amps or so, at 12v) might run the APM into a limit if something else needs huge APM power during a drive. Or not do that AGM battery much good, at any rate. Having lived many decades with all flavors of lead-acid batteries, I can certainly say they don't like C/1 types of discharge rates! If the APM shuts off, and no one is in the car to see the display for the error...you can see what is going to happen to that little guy. The inverter I chose does shut down at 10.5v or so, but...That's not very friendly to an AGM battery.

Sure, there are times I could use more, but since I already have 3 chained 4kw inverters to run my campus - and plenty of submarine batteries (well, Rolls-Surrette, huge 2v cells, a big truckload worth), well...all I really have to do is keep up with my average load, and if I know I'm running on gasoline, I cut that down considerably - from a level already so low most non-off-grid-solar people couldn't comprehend how I can live on it...most of the time I look at my net wattmeter at night and see, dunno, about 240w total, eg, this computer and 1-2 led lamps - no AC, a dorm-room-class refrigerator, that kind of thing. I only turn on my big loads (like charging the Volt itself, water distillation, hot water for showers) when there's power to spare - some big solid state relays run off info in my solar system handle that automatically and only allow large loads on a couple special circuits when I have the power "falling on the ground" anyway - house batteries (24kWH+) already full and the solar charge controllers in "float" type mode and just not using the full PV panel output anyway. That's when the welders, milling machines, lathes and so on get used as well.

In fact, the 650w 24v DC charger I run off the inverter hack I've already put in is more than I need and I can actually gain charge, not just keep up, with that alone. Works fine, but these days I need it very rarely - the other hot-spare generators need some runtime to keep fit for service themselves. The big winner with the Volt is just that it uses around half the gasoline per delivered kWH.

I do worry a bit about people not used to running on limited power. You just know someone's going to fire up the electric hot water heater (or not realize how to prevent that, or confuse need with want), the electric stove, Jacuzzi, pool pumps - AC, whatever, and really put a heavy duty load on this - possibly shortening the main battery life (costing GM money on warranty replacements), and definitely running the thing out of gasoline in short order - that's not so large a gas tank for the tens of kW class output. What would they do then?

Remember the Volt can only drive itself to get more gas if you've not run it down already and run it out of gasoline too.

Or worse, the power company's nightmare - forgetting to install a proper transfer switch and thus sending power out to the grid - to perhaps injure a person trying to repair it (and also frying your inverter because you can't run the whole world).

Damn, I'm starting to sound like the too-boxed-in little-old-ladies here who think that everything not mandatory is forbidden. That's a bit out of character for this cowboy engineer, but with a wide readership, you have to be a little careful about what you say.

Unfortunately, a grid-tie inverter needs a grid - a reference frequency and voltage to sync up with, and faced with no sync, will simply turn itself off, if I understand those data sheets correctly - again, this is safety for the power company and your system. So they are not a solution in and of themselves.

I may try a half-h bridge on the APM input power for grins (for 120v AC, pwm'd at some higher frequency and filtered to get a sine) or a full H for 240, it's not that hard (I've done a lot of high power switching designs - think kilowatts at many kilovolts for my fusor).
I'm guessing you'd need an isolation transformer to prevent the Volt from thinking it had a ground fault, though - if I understand right, you can't ground either end of its battery.

In my own case, there's actually no need - All I need to do is put power into my house batteries, and the rest of the system functions just fine as is (and has a lot of redundancy already) - so a straight buck-type switcher to 24v nominal gets me there...much easier in some ways, but making that good an inductor or step down transformer...that's going to be some fun! It doesn't even have to ride around in the car for that - it'd better be placed at my house batteries and run the HV to it there - less wire loss that way.
I might even find a really nice huge 24-28v switcher around that would work directly for that. I know Lambda made some huge ones for big solid state radio transmitters.

One question I've not seen an answer to is - when and how much do other things need power from the APM? I'd guess most of them only run at turn-on (like filling a hydraulic accumulator for the brakes) or when actually moving (electric power steering), but could I accidentally be hitting some limits if something else comes on while I'm doing this? I really don't want to fry this great car!

I'm guessing the heat runs right off the HV, but I'd also guess the AC runs off the APM? Of course, I'd take care to have that off, but you never know - anyone can have an oops.

I'd like to see GM take a stab at this. I'd be really surprised if the Volt drive system isn't already up to the job itself - maybe only needs a low pass filter on the output and some safety stuff it might have already. It just about has to be the equivalent of a VFD - else it couldn't go slow when you wanted, and as we all know, it will. I would guess that the effective voltage is also reduced for low main motor RPMs since there's almost no back EMF then. It would just need some curve reprogramming and some contactors - one phase would surely be enough, I'd think - most people wouldn't need 100kw or even close. I guess some people would think they need 240v (for things you just shouldn't be running anyway when you're on gasoline, in my rarely humble opinion), but I got along fine without it for quite a long time myself.

Or one of the major inverter outfits. They've seen it all, and when I look inside any of the high quality ones (which would not include the harbor freight one I used), I'm pretty impressed with all the things they do for fault detection at every stage (LV and HV) and instant shutoff for a fault no matter what. A "simple" design might work for me personally, but the world at large...another story - you'd want that stuff. For example, dead-short one of my Xantrex inverters - you don't even get a respectable spark - it shuts down in under 1 millisecond - it doesn't wait for the half cycle to be over, even. Now, try that same trick with say, 50 feet of #16 wire - and the wire just goes poof. They are that good. One of the ones I have here has already lived nearly 30 years on that kind of abuse (peak loads from air compressors, shorted circular saw power cords and so forth)...no failures, infinite 9's.

solar_dave
09-26-2012, 01:35 PM
The APM trick is a great for limited emergency power. Most could get by with that setup in a pinch. I have looked at doing setups on both Volts to get some excess. I suspect that a freezer and refrigerator might be a bit much for a single inverter.

DCFusor
09-26-2012, 01:44 PM
Depends on how big and how old they are. Reefers (no, the type that make things cold) have improved a lot over the years. The big issue with most is the startup surge current, and most more-modern inverters have a lot of headroom for that, so you might be fine.
And yes, now you're thinking of what's really important, not can I have a luxurious hot tub while the grid is down.

FWIW, my top loader freezer is kept in a building in the woods, unheated, where even in summer it's cooler - it makes a fairly large difference in how many kWH a month it uses - and it uses almost nothing in winter that way.

Anecdotally, when the grid goes down here, the unprepared of my neighbors want to borrow freezer space first, then watch TV second(!). But the unprepared are fewer and fewer in number these days, it happens often enough that they eventually get wise.

But it goes in stages. Most let their backups sit and rust, therefore they don't work when they need them. A condensation-water hydro-locked engine is kinda hard to get started in bad weather, to say the least. I'd rather loan them freezer space than go out in bad weather to show them how to get their genset going again, frankly.

The Volt wins all that hands down, because you do run the engine some so it stays ready, and it's a high tech auto engine, not a briggs or equivalent...big difference in reliability on top of the huge efficiency gain.

frankydude
10-05-2012, 03:14 PM
So... Let's say you DO tap the 360 volt battery successfully. (Without killing your self.) Where do you get a 360 volt DC to 120 VAC inverter to run your home? Anybody make a commercial product like that?

Yope! It's called an Grid-Tied Inverter!
For one, I use an Fronius IG-5100 grid tie inverter, that could use up to 500VDC as input, and connect to 240V 60Hz AC on the output.
This output is connected to a 20Amps Breaker in my house electrical distribution box.

Hope this helps,

Francois
B2653
2.3kW Solar grid tied self installed.