C-Max as a UPS

[darrelld]

Has anyone considered using the traction battery on their C-Max to power an inverter for emergency power. The Prius guys are doing it.

 

http://hiwaay.net/~bzwilson/prius/priups.html

[MikeB]

Yea, given the recent power outages due to severe storms, I'd really like to see a way to power my house from the Energi I'll own shortly. The big 7kWh battery would easily be enough to cook dinner on an electric stove, or I could be more reasonable and run just critical electronics and lights for a week. Of course, that needs a pretty hefty inverter, both in terms of input voltage and amperage. But if you're going to spend money on a generator, you might end up gettiing a big inverter and a small generator and being just as happy.

 

Actually, there is already a small inverter installed in between the front seats, but I don't think it's driven from the traction battery. Especially for the Energi, it might be interesting to be able to use that at any time, rather than just when the car is on. Wonder how it's wired?

Edited November 3, 2012 by MikeB

[darrelld]

Yea, given the recent power outages due to severe storms, I'd really like to see a way to power my house from the Energi I'll own shortly. The big 7kWh battery would easily be enough to cook dinner on an electric stove, or I could be more reasonable and run just critical electronics and lights for a week. Of course, that needs a pretty hefty inverter, both in terms of input voltage and amperage. But if you're going to spend money on a generator, you might end up gettiing a big inverter and a small generator and being just as happy.

 

Actually, there is already a small inverter installed in between the front seats, but I don't think it's driven from the traction battery. Especially for the Energi, it might be interesting to be able to use that at any time, rather than just when the car is on. Wonder how it's wired?

 

Consumer Reports tested using a car powered inverter during a power outage with good results.

 

http://www.consumerreports.org/cro/2012/02/can-a-pint-sized-power-inverter-replace-a-generator/index.htm

[jmckinley]

I read the Prius report. This guy really did a careful, complete analysis. The only problem I saw was he mounted the inverter in the car permanently. If I did this I would keep the inverter out of the car so I wouldn't have to drag around its substantial weight all the time. Also it would cool better outside of the car. Quick disconnects could handle the battery cable issue.

 

I'm wondering, however, if the C Max would work the same as the Prius regarding the engine firing up as needed to keep the battery charged. Someone who actually has their C Max needs to run a quick experiment using the built in inverter. Plug some small load into it (I think it's only 150 watt capacity), leave the key on and see if the engine fires up from time to time to replenish the battery. If it does, then we're good to go hooking up a bigger inverter.

[jmckinley]

Another thought. The C Max car battery is fairly small. If you were really serious about this, it might make sense to hook up a larger battery next to the inverter (again, not mounted in the car) and charge it from the C Max. This might reduce the run cycles on the C Max engine, which would be more efficient. It should run less often, but longer each time it runs.

[darrelld]

Another thought. The C Max car battery is fairly small. If you were really serious about this, it might make sense to hook up a larger battery next to the inverter (again, not mounted in the car) and charge it from the C Max. This might reduce the run cycles on the C Max engine, which would be more efficient. It should run less often, but longer each time it runs.

 

I thought about getting a deep cycle marine battery and using it as a power buffer as you suggest. i also agree with free air mounting the inverter for cooling, a garage wall is what I am considerting. The technical obstacle is how to safely (large current draw) mounting a 12v tap point inside the C-Max to connect to the inverter.

Found these docs about the battery;

https://skydrive.liv...AKZCTpCF0iZ2ya8

Edited November 3, 2012 by darrelld

[jmckinley]

I was also thinking about a garage wall mount, keeping in mind that the car will need to be outside to prevent Carbon Monoxide problems. One possibility is just plain old jumper cables, but I haven't seen the car battery location so don't know what might be possible regarding clamps. I think there are some high current quick connectors available, but this will take further research.

[darrelld]

I was also thinking about a garage wall mount, keeping in mind that the car will need to be outside to prevent Carbon Monoxide problems. One possibility is just plain old jumper cables, but I haven't seen the car battery location so don't know what might be possible regarding clamps. I think there are some high current quick connectors available, but this will take further research.

 

A way to T into the quick connect would be perfect, no vehicle mods required.

[jmckinley]

That was easy. Here's a connector with 175A capacity for $10. http://www.parts-express.com/cat/high-current-dc-power-connectors/1569.

These are made for the car audio guys who use tons of current to power their aggravating zillion watt stereo systems.

[darrelld]

Sent an email to the company about this product;

 

https://converdant.pinnaclecart.com/plug-out/

 

http://green.autoblog.com/2013/01/30/these-kits-turn-your-prius-into-an-emergency-generator/

 

If there is enough interest they might put engineering resources into a product.

 

Edited January 31, 2013 by darrelld

[plus 3 golfer]

Sent an email to the company about this product;

 

https://converdant.pinnaclecart.com/plug-out/

 

http://green.autoblog.com/2013/01/30/these-kits-turn-your-prius-into-an-emergency-generator/

 

If there is enough interest they might put engineering resources into a product.

 

Spending extra $$$ for "pure sine wave" inverters is not needed.   A basic kit with chopped sine wave is perfectly fine.  If the 12 V battery charging current is limited to 100 A on the C-Max (like supposedly the Prius), then I suspect that one could buy an inverter of around 1 kW sustained power output and tap the 12 V posts in the engine bay. But, I'd still like to see the electrical specs and a wiring diagram for then entire car.  It may be feasible to supply X times the (100 A * !2 V) = 1200 W

 

I would think that the average load on the 12 V system at any time could be well in excess of 1200 W (audio system, cooling fans, blower motor, windshield wipers, electric heated seats, electric window defroster, charging 12 V battery, and so forth).  

 

Also, do we know if the C-Max computers have the capability to continually cycle the engine on / off when stopped indefinitely. 

[darrelld]

Spending extra $$$ for "pure sine wave" inverters is not needed.   A basic kit with chopped sine wave is perfectly fine.  If the 12 V battery charging current is limited to 100 A on the C-Max (like supposedly the Prius), then I suspect that one could buy an inverter of around 1 kW sustained power output and tap the 12 V posts in the engine bay. But, I'd still like to see the electrical specs and a wiring diagram for then entire car.  It may be feasible to supply X times the (100 A * !2 V) = 1200 W

 

I would think that the average load on the 12 V system at any time could be well in excess of 1200 W (audio system, cooling fans, blower motor, windshield wipers, electric heated seats, electric window defroster, charging 12 V battery, and so forth).  

 

Also, do we know if the C-Max computers have the capability to continually cycle the engine on / off when stopped indefinitely. 

 

I am not sure that much current is available on the small scale battery posts used to power up the electronics. Some of the earlier research I did on the Prius indicated they tapped the high voltage side to do UPS functions.

 

I can't find the reference now but another poster here mentioned stop/start idling for about an hour with the heat on.

[plus 3 golfer]

When I look at the + Battery post in the engine bay and the wiring to it from the inverter and the wiring to the 12 V battery, the wiring looks of sufficient size to handle several 100 A.   The + battery post also appears to be connected to the fuse box adjacent to it which houses high capacity fuses.  It really wouldn't surprise me if one couldn't get 3 kW of 12 V power from that post.  But I'd like to see the wiring diagrams and the specs on the C-max inverter.  It would be easy to connect (when needed) #4 - #8 AWG wire to the post and a ground point in the engine bay and run the two wires to a terminal block on a wall that supplies a 1 - 3 kW inverter mounted near the terminal block.  You'd want to keep the wire runs as short as possible to reduce voltage drop.  Otherwise, one might want to increase the wire size.

 

The basic 1 kW inverter being sold by that company connects to the 12 V battery of the Prius via jumpers.  The larger inverters appear to have wiring way too small for 12 V and thus almost certainly connect to the HV battery.  The advantage of connecting the UPS to the HV battery directly is one eliminates the car's inverter from the UPS and thus its energy losses.  But the price of one HV / 120 Vac inverter is likely significantly more than several 12V /120 Vac which are readily available.

[darrelld]

I already have these items but would to like to see the wiring diagram before doing a load test.

Edited February 1, 2013 by darrelld

[PWBarrett]

I would figure that any non-reversible tap into the HV connections would void the warranty at least for all the hybrid components.

I'd only do it if I could come up with the same connectors that Ford used and not have to cut a wire anywhere.

[darrelld]

Reading through the manual it says you can jump another car off those battery posts so an inverter should be no strain. I originally intended to hook the inverter up to my TDI but with the C-Max you get the advantage of ICE only when needed instead of continually idling.

 

With all the reports of dead batteries I have placed this project on hold until something definitive is determined from Ford.

 

I still suspect a problem with the DC/DC converter circuit or whatever senses the charging threshold.

Edited February 1, 2013 by darrelld

[zhackwyatt]

I'm assuming this is all because the built-in inverter doesn't have enough capacity for the needs you guys want?

 

The 110 outlet in the car is, what, 100watts max I think?

[MikeB]

Yea, the built-in inverter has enough to power a laptop, or a portable DVD player for backseat passengers, but not much more than that. 100watts sounds right, or maybe 110?

 

But it would be interesting to find out how long you can draw off the built in inverter, charging phones and running laptops in an emergency would still be useful.

[mvenergi]

On the Energi, the 110V has 150W rating.

 

It seems that it would be much better to connect directly to the 12V battery - access in trunk.