Permanent 12volt supply in cabin

[12v4U]

Hi all,

Here is a quick description of how I got 12v permanently in the rear of my Outlander PHEV.
The main motivation is to run a fridge in the boot, although I have used it successfully to pull 1kWh from the traction battery at mains voltage through a sine wave inverter.
My aim was to have 240vAC (low wattage) and 12v available permanently to draw on anytime.

The main gear I used was; 50Amp and 15 Amp cable, a Projector 100Amp Battery isolator; a 6 inch project box with two 16 screw voltage rails installed, and inline master switch, five 9aHr 12v SLA UPS batteries, and a digital 12v battery SOC meter, a 12v fused outlet, and a 240v Sine wave inverter (1000W)

The three design features of the PHEV that make this installation possible are;
1. the installation of the 12v Battery in the rear boot,
2. frequent recharging of the 12v battery. The 12v Battery is charged when driving, when charging from mains and at 2:00 every day by the onboard computer, and
3. space under the cargo tray for a battery isolator, and a small auxiliary battery pack.

Firstly, I installed the Projector 100A battery isolator in the cavity for the charge cable under the boot tray. The isolator is secured with velcro ties.
I ran cables to the 12v Battery under the boot molding. Access to this was easy by removing 6 screws which hold the tray in place. Cables run through a removable cap which exposes the groud terminal of the factory installed 12v Battery. Interestingly the factory 12v battery vents through a hose out to under the chassis. The SLA UPS batteries are fine to run indoors.

Secondly, I installed the voltage rails inside the project box and drilled holes in the box for leads to the isolator, the 5 UPS batteries, the SOC indicator, and the fused 12v outlet. These were wired up. The batteries were installed in parallel, providing 45aH @ 12V, with a capacity of about 0.5kWh. UPS batteries were used due to their modular size fitting easily under the cargo tray. There is room for up to 15 batteries, but this is unnecessary for what I want.

Finally, I secured the batteries with velcro ties, and connected the fridge and the 240V inverter. The fridge is secured to the infant seat mounting points in the boot.

So far, the system has continuously run a small (35W) compressor fridge for a week during touring, with the state of charge indicator rarely showing a state below 100%.
The PHEV supplies charge to the 12v Factory battery whenever the isolator indicates the UPS batteries are below full charge. This happens daily at 2:00, when driving, when charging. Impact on the traction battery not been measurable. In a test run, I have drawn 1kWh @ 240v over 12 hours with a power draw of 200W. I do not intend to do this for any practical purpose.

[Edit: removed incorrect reference to 12v factory battery charging occurring when the vehicle is in ACC mode.]
[Edit: Typos]

 

[HHL]

Hi all,


2. frequent recharging of the 12v battery. The 12v Battery is charged when driving or accessories, when charging from mains and at 2:00 every day by the onboard computer, and
e.

Hi,

Are you sure that the 12V aux is charged from the drive battery in accessory mode?
It does not in mine.

 

[12v4U]

Just checked and can confirm that HHL is correct.
No charging occurs when vehicle is in ACC mode.
Correction has been made in the original post.
Thanks.

 

[Sunder]

Here is a quick description of how I got 12v permanently in the rear of my Outlander PHEV.
The main motivation is to run a fridge in the boot, although I have used it successfully to pull 1kWh from the traction battery at mains voltage through a sine wave inverter.

Just curious, did you pull 1KW, or 1KWh from the traction battery? I'm about to hook up an inverter as well, and I had heard some people say you can only get 10A (120w), from the traction battery, while others say you can get 100A (1.2kw).

I'd love it if it was 100A. Could run almost anything on that.

 

[12v4U]

To clarify, I pulled 1kWh at around 200W (16 amps at 12v) through my small grid tie inverter- it took all night! The traction battery was the source of energy, topping up my auxiliary battery when needed.

OK, to answer the 100A draw question - I just went and tested the max continuous current draw from the user installed aux 45Ah 12V battery pack when supported by the traction battery.
I connected my 1000W 240V Inverter and used a hairdryer with different fan and heat settings as my test load.
Using a power meter, I found that in the 240v side I could easily sustain about 570Watts without the system overheating. The power was coming from the traction battery, as the isolator was indicating the 12v factory installed battery as full all the time, and the S.O.C .meter on the aux battery pack was continuously reading 100%. This means the PHEV was holding the 12V battery supply at 14.4 volts, and supplying all of the current.
However, the inverter shutdown for power settings over 1100 watts, so I can't confirm any higher power draw at the moment.
570W would easily run a domestic fridge.

TL;DR
50A draw at 12v tested for about 15 minutes with no apparent problem.
100A needs more testing. I'll get back to you.

**Update
After upgrading some 50A cables from to 115A I ran another test, this time using a 240v vacuum cleaner, which gives a continuous range of wattages.
Turns out the maximum wattage supported is 760W (63A @12v); the inverter shuts down not due to low voltage, but insufficient current.
I suspect that the PHEV inverter limits current to the starter battery to around 75 amps (considering 240v inverter losses), so as not to damage it with too high a charging current.
Anyway, the system could sustain 760W although the cables did become worryingly warm, and the connectors on the Projecta isolator where hot to touch - not good.
The 100A isolator is rated at 12V 75A continuous draw; so I think it was running above capacity if there was 63A on the 240v side, since efficiency is probably lower than 15%.

I left the system running @ 500W for about 2 hours until the power meter indicated 1kWh was drawn. The traction battery meter on the dash had dropped a bar.

In summary;
500W @ 240V draw is sustainable. (estimated 50A @12V). Lights, fridge, charging electronics could be done indefinitely.
760W @ 240V runs the system hot; PHEV appears to shut off supply to starter battery above this wattage. (estimated 75A @12V).

Upgrading the isolator to 150A and all the DC cables to 115A would probably allow continuous 760W draw.

Hope this helps.

 

[MartinH]

Interesting.
I have one question, as i work in the forrest also using a battery chain saw, Husqvarna 536, The best ever chainsaw for trees/branches up to 25cm, to charge the batteries the charger consumes app 425W. What i have read is that this should be possible to draing from the 12V battery in the Booth.
My question is if i need to have the "Ignition"(you know what i mean) on, or will the battery be supplied from the main battery without Power up the car?
Beacuse i leave the car, and it would be nice for it to be locked and quiet when charging in the boot.

Last week with -15´C, the car runned all day only on EV(short jurneys about 15km total) but the Husqvarna battery did not want to work(stored in the car over night), i had to warm it up inside for some time before it started to give the saw the Power it neede.

 

[jaapv]

The 12V battery is not charged in ACC mode. You'll flatten it.

 

[HHL]

However, the inverter shutdown for power settings over 1100 watts, so I can't confirm any higher power draw at the moment.
570W would easily run a domestic fridge.

TL;DR
50A draw at 12v tested for about 15 minutes with no apparent problem.
100A needs more testing. I'll get back to you.

**Update
After upgrading some 50A cables from to 115A I ran another test, this time using a 240v vacuum cleaner, which gives a continuous range of wattages.
Turns out the maximum wattage supported is 760W (63A @12v); the inverter shuts down not due to low voltage, but insufficient current.
I suspect that the PHEV inverter limits current to the starter battery to around 75 amps (considering 240v inverter losses), so as not to damage it with too high a charging current.
Anyway, the system could sustain 760W although the cables did become worryingly warm, and the connectors on the Projecta isolator where hot to touch - not good.
The 100A isolator is rated at 12V 75A continuous draw; so I think it was running above capacity if there was 63A on the 240v side, since efficiency is probably lower than 15%.

I left the system running @ 500W for about 2 hours until the power meter indicated 1kWh was drawn. The traction battery meter on the dash had dropped a bar.

In summary;
500W @ 240V draw is sustainable. (estimated 50A @12V). Lights, fridge, charging electronics could be done indefinitely.
760W @ 240V runs the system hot; PHEV appears to shut off supply to starter battery above this wattage. (estimated 75A @12V).

Upgrading the isolator to 150A and all the DC cables to 115A would probably allow continuous 760W draw.

Hope this helps.

You're certainly a brave man to try this.....
There is actually a fuse shown in the technical manual, which may be located inside the charger/inverter and if you blow that one, it could be a real pain to replace.
It seems that it is possibly a 100A one and the inverter charger may be current limited to well below that.

Thanks for sharing this info. It will certainly make me more confident in running a bit of stuff off the aux battery. I have connected a cable with Anderson connectors to come out in the left compartment next to the battery. It is fused at 30A so obviously well within the safe zone according to your experiments.

 

[Sunder]

Hope this helps.

That really helps mate. I went to my dad's farm this weekend to pick up the inverter to try this, but now I don't even need to!

I am building a 50Ah 12v LiFePo4 battery to buffer high demand periods for this project. It can continuously discharge 1200w and discharge up to 2400w for 10 seconds - that's without the assistance of the car or the lead acid battery. Enough to start and run almost anything I can think of for at least 10 minutes.

We've had a lot of storms lately, and while we haven't had any power outages, there have been places as close as 3kms away that have had multiple outages in the last few months. I'm keen to have this as a backup.

 

[HHL]

Hope this helps.

We've had a lot of storms lately, and while we haven't had any power outages, there have been places as close as 3kms away that have had multiple outages in the last few months. I'm keen to have this as a backup.

I would not get too enthusiastic about drawing serious power from the aux battery/inverter system. It would be much safer to just buy a little petrol generator to do that job. I have heard somewhere that the jap version of the PHEV does have an inverter option to supply house current, however, that runs directly off the drive battery and does not involve the 12V circuit.

I can see no problem trying to run a small camping fridge off the system you envisage, but not much beyond that.

 

[Sunder]

I would not get too enthusiastic about drawing serious power from the aux battery/inverter system. It would be much safer to just buy a little petrol generator to do that job. I have heard somewhere that the jap version of the PHEV does have an inverter option to supply house current, however, that runs directly off the drive battery and does not involve the 12V circuit.

I can see no problem trying to run a small camping fridge off the system you envisage, but not much beyond that.

Sorry, didn't see this reply.

There's 600wh in the LiFe battery, which you can generally extract at around 80% efficiency. (3% battery loss, 15% inverter loss)

Should be about 300wh in the Aux battery, which I can probably get out at around 40-50% efficiency (Above + Peukert's effect)

And 10kwh in the traction battery, which I can probably get out at about 50-70% efficiency. (Inverter down loss, inverter back up loss, + a vague guess for using the Aux battery to smooth out power drain.)

All in all, I'd guess I'd get at least 5kwh usable out of it, and optimistically 8kwh, which would keep the fridge, computer and phone chargers going for a full day. Not had a chance to try it since we haven't had any black outs, but I might do it for fun one day when I have a bit of time to rig up a watt meter.

 

[Seeker407]

Have you found any way to improve on this system?

I see that this was done years ago, how is it working now? what is the efficiency?

What can you run vs what can't you run?

In the U.S., there are only 2 trims available, the SEL (lower trim) and GT (upper trim), the only thing I would want on the GT is built in 1500W inverter.. but two problems:

1. it isn't "always" on..

2. it costs an extra $7,000 for the GT

Can you provide an explanation as to how and when the original 12v battery is charged? What if you replaced the 12v battery with a "deep cycle" lithium ion 12v battery (that has much more aH than the standard 12v battery)?

Thanks

 

[esky]

Have you found any way to improve on this system?
.....
Can you provide an explanation as to how and when the original 12v battery is charged? What if you replaced the 12v battery with a "deep cycle" lithium ion 12v battery (that has much more aH than the standard 12v battery)?

...So, any answers....?

Thanks,