Using your Mach-e to Power electric devices for 'Glamping' or Home Emergency Battery Backup

[dtbaker61]

I used to have a '66 Sunbeam Tiger.... headers, big cam, dual point ignition, etc.... damn thing ran HOT, but in the old days the top of the motor was uncluttered, and you could fit a good sized baking dish right on top between the carburator the radiator expansion tank such that it wouldn't slide around even while driving 'hard' thru the mountains. The club had a great recipe book and timed tours to cook various dishes; and we'd all meet and potluck wonderful hot meals from under the hood... without a Frunk.

This of course is leading up to what we can cook (or refrigerate) with our Mach-e with the lovely big batteries on board.....

Turns out that if you disable your 'auto-off' setting, and leave the MME 'on', you can extract about 1500 watts of power from the LV (12v) connection points which is backed up by your large main (HV) battery. Plenty to run a little refrigerator, teapot, or even an inductive cook-top. Perfect for 'flameless' camp cooking as well as running lights, CPAP machines, recharging cordless tools at job sites, etc.

Or.... running critical electric appliances like your refrigerator, computer, phones and little loads like that at home in Emergency situations....

The basic steps/components needed are:

- gain access to your LV connection points... easy with a 1-7/8" hole saw, or removing the 'beauty covers'.​

​

- 1500 watt pure sine inverter, buffer battery, charge controller, cables.... and it's possible to package everything into a carry-on bag for truly portable power! Cost less than $200​

https://www.amazon.com/dp/B078MW96M4?​

There are commercial power packs available, but they cost significantly more for less battery capacity and probably less power. If you shop for portable power packs, make sure the inverter is 'pure sine', and 1500watts. I have found that there are several brands of Lithium battery you can get for under $400 for a full 100ah capacity yeilding about 1 kWhr of useful energy. The battery can be charged with an inexpensive charge controller via a little solar panel, or direct from a running vehicle.

You can hook up with jumper cables for quickest/cheapest solution, or package a few more bits into a 'portable power pack' that you can charge with your MME.

I thought I'd post a couple pix just to give people ideas.... and if you want plans or a few pre-fab parts/cables to help you build you own, we can work something out for an instruction book or video or something....

 

[Scott Miller]

Love the setup and glad to see people are accessing the HV battery capacity via the LV battery for juicing up induction cookers, teapots, tools, etc.! I plan on putting something like this together in the near future. That said, aren't the charge controller and 1 kWh battery a bit redundant, if you have 91 kWh usable capacity right in the car? Am I missing something about the usefulness of the separate charge controller and battery? Happy cooking!

 

[dtbaker61]

Love the setup and glad to see people are accessing the HV battery capacity via the LV battery for juicing up induction cookers, teapots, tools, etc.! I plan on putting something like this together in the near future. That said, aren't the charge controller and 1 kWh battery a bit redundant, if you have 91 kWh usable capacity right in the car? Am I missing something about the usefulness of the separate charge controller and battery? Happy cooking!

the 'carry-on portable power pack' is designed to be re-charged either via solar, or (any) vehicle 12v. In the mach-e I COULD wire directly to the 12v connection, but this a more generic solution which allows using the power pack 'away from the vehicle', and charging from whatever source is handy.

I didn't want to limit the use of the inverter to 'at the vehicle' only. I often need to have a bit of power a couple hundred yards from where I can park.

 

[mkhuffman]

Dan, this is a relevant topic now with the hurricane hitting FL. So bumping it up, but also I have a question.

Did you turn your MME on while using it to cook, or did you just rely on the typical maint the car provides when off? Seems like turning it on would be a lot better for the LVB.

Edit: I reread your OP more carefully and see you left the car on. Sorry I missed that the first time.

 

[Garbone]

Ok, has my attention. So the question is what is the amperage that the internal 12v system can sustain and was is designed for continuouse use, say 48 hours with temperatures above 80 degrees.

 

[emichnov]

Dan, very creative! I did something similar with my Volt; just haven't got around to doing this with my Mach-E yet.

If your inverter is extracting about 1500 watts of power from the LV (12v) connection points, isn't that about 1500 watts / 12 volts = 125 amps? And, for safety purposes, we should size up 20%, so a planned 12 volt load of 150 amps? Wouldn't a 150 amp circuit require a 0 AWG (aka 1/0-size) copper wire? It looks like your application uses something like a 12 gauge wire? Does the external battery pack buffer the amps enough that you are not pulling all the amperage from the LV battery?

How hot does that wire from the LV connection points to the inverter get when the teapot is heating water?

 

[Logal727]

I feel like the wires connecting to the 12v points should be a lot thicker?

 

[dtbaker61]

Dan, this is a relevant topic now with the hurricane hitting FL. So bumping it up, but also I have a question.

Did you turn your MME on while using it to cook, or did you just rely on the typical maint the car provides when off? Seems like turning it on would be a lot better for the LVB.

Edit: I reread your OP more carefully and see you left the car on. Sorry I missed that the first time.

Turning MME on, and disabling auto-off setting are highly recommended. For relatively high-draw activities like a cooktop at 1200-1500watts, the voltage sag is too much for the LVB to take on it's own without the dc-dc support.

 

[dtbaker61]

Ok, has my attention. So the question is what is the amperage that the internal 12v system can sustain and was is designed for continuouse use, say 48 hours with temperatures above 80 degrees.

As far as I can tell, the 'thruput' of the dc-dc converter for Select level trim is 160amps to the vehicle's 12v system. That would be the aggregate TOTAL, and designed for 'continuous' use presumably enough to run eHeat or A/C and all systems on a long road trip for instance.

I would suggest not running eHeat, seat heaters, andrunning a cooktop all at the same time.

 

[dtbaker61]

Dan, very creative! I did something similar with my Volt; just haven't got around to doing this with my Mach-E yet.

If your inverter is extracting about 1500 watts of power from the LV (12v) connection points, isn't that about 1500 watts / 12 volts = 125 amps? And, for safety purposes, we should size up 20%, so a planned 12 volt load of 150 amps? Wouldn't a 150 amp circuit require a 0 AWG (aka 1/0-size) copper wire? It looks like your application uses something like a 12 gauge wire? Does the external battery pack buffer the amps enough that you are not pulling all the amperage from the LV battery?

How hot does that wire from the LV connection points to the inverter get when the teapot is heating water?

The 'direct draw' jumper cables from the connection points to Inverter really were just a test. The contact using alligator clips is not great, and jumper cables are maybe 4awg. So, 1500watts/12v = 125amps, but only for maybe a minute for a teapot. So, yes, not suitable for continuous use, but ok for a couple minutes.

For a more permanent install inverter, I'd probably go with at least 2AWG wire, and D-ring connectors for good contact, probably with a 150amp circuit breaker in the middle

For export to house backup, I buffer thru a much bigger battery in the middle, and the MME just acts as a charger.... current is naturally limited to about 35-40amps by the voltage difference between the MME at 14.4v, and the load-side battery sagging to 12 or so under heavy loads.

My house backgound loads hover around 200-300 watts... with only occasional spikes when appliances like the microwave or coffeemaker are used. So using the MME->battery buffer->inverter->house works pretty well with less average load than you might expect.

 

[dtbaker61]

I feel like the wires connecting to the 12v points should be a lot thicker?

when I am drawing power from my external power pack.... the buffer battery maximum sag under load is down to maybe 12v. When the MME system is at 14.4, the current is limited to less than 40amps by this voltage difference. So, the wires don't really need to be more than awg10, or awg8 perhaps if the system is 'heavily loaded' for a long time.

Usually, if my portable pack is depleted to about 12, and I jumper to MME for a quick charge, it's pretty much back up to 80% in 20 minutes.

 

[merrjoy]

This discussion is getting more informative. Thanks for the knowledge members.

 

[2021-MMEx-RT1]

I used to have a '66 Sunbeam Tiger.... headers, big cam, dual point ignition, etc.... damn thing ran HOT, but in the old days the top of the motor was uncluttered, and you could fit a good sized baking dish right on top between the carburator the radiator expansion tank such that it wouldn't slide around even while driving 'hard' thru the mountains. The club had a great recipe book and timed tours to cook various dishes; and we'd all meet and potluck wonderful hot meals from under the hood... without a Frunk.

Welp, that brought back memories! The only Ford I owned before the Mach E was a '62 F100 pickup (no, not new) and there was room a plenty under that hood. We'd go to the store put in steak and potatoes wrapped up in a few layers of aluminum foil and by the time we got home, it was a nice more than rare, less than medium rare... Good times.

Couldn't do that with my '72 Chevelle SS, the 454 was a bit too large and took up all the space!

 

[mkhuffman]

when I am drawing power from my external power pack.... the buffer battery maximum sag under load is down to maybe 12v. When the MME system is at 14.4, the current is limited to less than 40amps by this voltage difference. So, the wires don't really need to be more than awg10, or awg8 perhaps if the system is 'heavily loaded' for a long time.

Usually, if my portable pack is depleted to about 12, and I jumper to MME for a quick charge, it's pretty much back up to 80% in 20 minutes.

But it we connect a inverter directly to the MME without using the buffer battery you use, we would need to have wire that can support the full current load, right?

There are lots of 1500 Watt inverters available, and they are relatively inexpensive.

I think it would be really cool to get a 1500 Watt two phase 240V inverter, but they are much more expensive and harder to find. But then I could plug the car directly into the generator outlet I installed on my circuit breaker box.

 

[emichnov]

I think it would be really cool to get a 1500 Watt two phase 240V inverter

I agree! If you find one, let us know. The 1500 Watt, 120 VAC unit I have works pretty well, but it would be nice to have 240 V available.

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