Power inverter installation/options

[cr08]

Looks like I'll potentially have a need coming up to run a higher wattage power inverter, more than the stock one will provide. I also would like to future proof for potential future uses especially considering we've had two long-ish term power outages this summer alone here due to the storm frequency and severity we've dealt with. Doing some further research I have the following notes to go on here:

 

• Per the official Ford workshop manual, the DC-DC converter is capable of 'up to' 145 amps to the 12v systems/battery.
• Under ideal operating conditions w/ a fully charged 12v battery, sitting idle in EV mode but 'Ready to Drive', and Daytime Running Lights active, the base 12v load as indicated by the DC-DC converter appears to be between 30-40 amps, usually hovering around 30 at least on my '13 Energi.

 

With the above noted, the theoretical max capacity inverter one would want to use is 1000 watts (continuous rating) max. This would be a 100 amp load on the 12v side, not counting for any conversion inefficiencies. Ideally you probably want to aim for 800 watts to account for headroom and those aforementioned inefficiencies. There are TECHNICALLY some ways you can get around this including adding a beefier aux battery to the mix as a sort of buffer if you need the higher wattage for only brief periods. But for a 100% stock and unmodified vehicle, the 800w-1kw inverter ratings are the theoretical max you'd want to go with 1kw being used continuously likely completely maxing out the load on the DC-DC converter so keep that in mind.

 

Most higher capacity inverters seem to expect to be hardwired and do not include cables with clamps on them but eyelets to bolt down instead. A handy Volt owner has a thread over on reddit with what I believe is a nice baseline setup to accomplish this and what I will likely base my own setup from to make it a handy quick disconnect system: My DIY inverter wiring setup : volt (reddit.com)

 

 

The main takeaway with our vehicles and any kind of hardwiring in this case is connecting to the vehicle wiring in the appropriate spots. There is a battery monitoring sensor on the negative post of the 12v battery which is key in that it provides the vehicle useful data on how much current is being drawn or supplied to the 12v battery and allows the DC-DC converter the information it needs to output the right amount of power to supply all loads. So a third party load like this should be AFTER this sensor electrically. The positive side of the battery does not seem to have this same issue and -should- be able to be attached to normally.

 

I will be doing more physical research and will start getting the items together to work on this. I'll document this process as I go.

[David McC]

You would probably be better off with a stand-alone portable storage unit. They seem to be all over the 'net at the moment. Some have solar charging options.

[cr08]

On 7/25/2022 at 8:26 AM, David McC said:

You would probably be better off with a stand-alone portable storage unit. They seem to be all over the 'net at the moment. Some have solar charging options.

 

A number of reasons for not going down this route: A lot of those portable storage units/battery packs have limited power output. If you aim for the <$500 budget range, most only put out 200-300w. If you want up near 1kw, plan to spend over $1k. Also with infrequent use being in play here, all being lithium based I am wary of spending the money and having it sit and likely self-degrading as a result. Generators are also out for similar reasons. And more importantly they are just noisy and in the end likely run a lot less efficient than using the C-Max as a generator itself.

 

All in all going down this route I'm probably looking at $200-$250 all in for the inverter and all the extra bits and this will get me an 800w-1kw continuous power feed that the car should be able to handle just fine. And I can safely and quickly disconnect it and pack away the inverter when not in use and hook it back up just as easily when needed. This definitely isn't an unusual setup especially in the hybrid/plug-in communities. This is just the first time a personal need for this has come up and finding a very good setup to base off of.

[cr08]

Got around to doing the most tasking part of this: Getting the actual vehicle-side wiring done. My original plan was to do a 'belt and suspenders' setup with a 150 amp fuse (included with the inverter I purchased) right off the battery and then a smaller 100 amp circuit breaker in an accessible location behind the rear fuse panel on the driver side as both protection and an easy to access switch to turn on/off power as needed. However I had a heck of a time trying to sort out how to mount the CB back there even though there are two bolt holes in the body (one is being used as a grounding point for some circuit).

 

I changed it up to make it a little easier to get wired and I'm just running the 100 amp CB right off the battery. SLIGHTLY more difficult to access but not by much. It can still be accessed via the small plastic panel covering the battery (on the Energi this is the one that holds the fuel funnel) so just need to empty out the cubby to get to it. No tools needed or bolts/screws removed. I've attached photos of the wiring and routing below.

 

Grounding point was easy. Factory, Ford has a big beefy (looks to be about 4awg based on my own wiring which is also 4awg) ground cable going from the battery to the body. This is also the ONLY ground connection from the battery to the rest of the vehicle it looks like. I ran the ground for my inverter circuit here and placed the lug on TOP of the existing factory lug just to ensure it still maintains solid contact to the body.

 

The positive wire I had to figure out how I wanted to run this and hopefully keep the rest of the vehicle happy. One of my main concerns after reviewing wiring diagrams is there's a 150 amp maxi-fuse that sits between the battery positive and the leads to not only the DC-DC converter but the rest of the vehicle electronics. In the one picture below, this is buried inside the big red plastic cover on the battery. Since I already essentially have fused protection with the CB, I connected it before the factory 150a fuse so it is able to pull surge power if it needs to straight from the battery without risking blowing the factory fuse (which seems to be hard to find and not sure if it is a standard off the shelf fuse type). Same as the ground lug, I kept this above the existing mating surfaces so the factory mating and thus current handling capability should be maintained.

 

This is all ran via 4awg wire over to the driver side and up in the cavity where the rear fuse panel is located. Wired into a beefy Anderson style quick disconnect (which comes with a cover that is tethered to it to keep things safe when not in use).

 

Right now the CB is just floating there and not secured, though I'm probably going to find some heavy duty velcro and just secure it to the top of the battery. I tried and spent probably a good hour or two trying to locate a more secure mounting solution that still remained accessible but had no luck.

 

There's ample room behind all of the plastic trim panels. None of the wiring is interfering or has a chance of being pinched or rubbing through other parts. Even the cavity behind the driver side trim panel with the rear fuse box has lots of space. The picture showing that looks messy but that was a rough 'shove it in there to button up the car' deal but I can easily slide the QD and wires out of the way of the fuse box.

 

I do plan to get some corrugated wire conduit like Ford already uses on much of the wires back here for extra physical protection.

 

Next up is to wire the other side of the QD to the inverter and test. I'll report back when I get to that stage.

Edited August 20, 2022 by cr08

[cr08]

One caveat I will note is when attempting to use the big negative lug on the frame, you should still disconnect the negative right at the battery. The bolt used to go into the frame is very snug and long and relying on this to be your main method of a battery disconnect will lead to intermittent connections and sparking as you try to unbolt it (as I stupidly attempted to do the first time around). Disconnecting right at the neg battery post is cleaner and quicker. THEN you can unbolt frame lug. It was tempting to go that route especially being an Energi with all the ducts in the way. Even with those removed per Ford's workshop manual, the bolt on the neg terminal was still a pain to get to but was doable with an open ended wrench.

Edited August 20, 2022 by cr08

[cr08]

And here's the inverter side of things and the final hookup. All working smoothly. Couldn't test at its full rated power as I didn't have anything handy that could pull that amount. But tested with my gaming laptop and a crockpot pulling about 480-500w total and no issues. DC-DC converter was showing about a 50-60A load on the LV side and only around 3-4A from the HVB. Didn't even look like the 'Other' gauge on the IPC moved much.

Also the voltage drop must be just about nonexistent which is a good sign. Inverter was reading the same voltage as what I read at the battery posts around 14.8v at the time. Cables remained cool under an extended test with the above half load.

 

All in all a very clean setup and easy to store away keeping cables out of sight when not in use which is especially nice with cargo space at a premium already with the Energi.

 

The original 'potential' use for this is coming up this weekend. Will need to see if the park we're going to and setting up at has working outlets. If not, it'll be this setup's time to shine and I'll definitely report back how that went.

 

(Also realized the backwards posts on the inverter. The actual wires are correct, I was just dumb and put the plastic covers on backwards. It's since been fixed.)

Edited August 26, 2022 by cr08

[SnowStorm]

Nice.  Hybrid cars have the potential to make an incredible back-up and portable power source.

[joshg678]

This is great information. 
I’ve been considering something like this as a backup for my small power wall at home. I would use something like a Victron Orion DC-DC charger to charge my 24V system with the C-Max 12V. 
I’m assuming the Hybrid and Energi have the same DC-DC converter, anyone able to confirm?

[cr08]

On 10/4/2022 at 12:41 AM, joshg678 said:

This is great information. 
I’ve been considering something like this as a backup for my small power wall at home. I would use something like a Victron Orion DC-DC charger to charge my 24V system with the C-Max 12V. 
I’m assuming the Hybrid and Energi have the same DC-DC converter, anyone able to confirm?

 

As best I can tell, they share the same DC-DC converter. Nothing in their workshop manual seems to make a differentiation between the hybrid and Energi models when it comes to DC-DC converter/12v charging systems. Both are still rated for 'up to' 145 amps.

Edited October 4, 2022 by cr08