Always on lighter/12v port - Charging battery banks

[bradleydavidgood777]

Hi,

I've been thinking of wiring an always on lighter port from the battery terminals (or positive battery terminal and vehicle ground nearby), to the center console area. I would then be able to charge some kind of battery that accepts 12v input. Also, I can use the lighter when the car is off, or charge a phone while the car is off.
Also, when the car is in Ready mode, I still like the idea of being directly connected to the battery with my chosen thickness of cable - like if I were to run something larger - and maybe run something 120v that is plugged into the battery bank while the battery bank is being charged by the 12v lighter socket to the 12v battery in the front of the car. This puts a cheap piece of equipment between a load and the car battery that would have it's own breaker and such.

I realize that I would have to be careful not to drain the 12v battery. I would probably hook up some kind of timer...have to think about that one.

Question: If the car is plugged in charging, and I'm trickling the 12v battery directly, I'm under the impression that the car will not top off the 12v battery until the car is in Ready mode. Correct?

I really would love if it did. That way I could charge the car and the portable battery bank for free at my spot.

Even if it can't, I like the idea of charging the portable battery bank during the day and leaving work with a full car and full battery bank that I can take home and run stuff on at night for free.

Thoughts on this?

Also, does anyone have suggestions for the route of the cable from the battery area through the "firewall"?

Thanks

 

[Aerowhatt]

The car does charge the 12v while charging. It uses the DC to DC converter which always puts out 14.4V. Which is a cycle charging voltage for a 12 volt battery. Float or trickle would be around 13.6 volts. 14.4V is exactly the same voltage charging when in READY mode too. Once the car stops charging though, you are back to the isolated 12v battery for power only.

Depending on how much power (amps x volts) you are wanting to draw through this power socket. You should be able to pick up + power at the fuse box under the dash on the drivers side and not need to go through the firewall at all. If you wish to pull more than 10 amps you need a better plug in than a lighter port. They will run nice and warm at 10 amps. More than that it would be a fire hazard.

Aerowhatt

 

[bradleydavidgood777]

Awesome, thanks aerowhatt!

That will work out perfectly. I'll check the draw on potential power bricks I'm considering. I go out to my car every day around the time that it is done charging, so it won't be on the 12V for long after charging is complete. Maybe 30-60 minutes.

Wait, I have not checked if the stock lighter is active while plugged in. I assumed it was not. That would make it even easier...but then I wouldn't have my aux lighter port when not charging...which is useful for lighting things.

 

[bradleydavidgood777]

Here are the two battery banks I am considering. One for the car and one for the house. Although I may sometimes take the larger one on the road while camping without electricity nearby.

Small one says 13-22V/2A max input from solar panel. I'm assuming it's about the same for the lighter.

https://www.amazon.com/gp/product/B07GJR5M6L/ref=ask_ql_qh_dp_hza


The larger one says:
Three 120V household AC outlets
Two USB ports - 3A of combined power
One 12V DC port (240W max)
Expansion Port: 200A Fuse
Charging AC Input (90W)
Solar Input (200W Max)
Wind Input (300W Max)

Sounds like it will be way under the limit. I did send the maker a question about it.

https://naturesgenerator.com/collections/featured-systems/products/natures-generator-gold-we-system

 

[Aerowhatt]

Wait, I have not checked if the stock lighter is active while plugged in. I assumed it was not. That would make it even easier...but then I wouldn't have my aux lighter port when not charging...which is useful for lighting things.

The stock socket only works with the key on, unless a 2017 is different.

You need to be careful selecting an auxiliary battery to charge from a car. Best case is it has a port just for that. Solar panels "12V" actually put out more like 17V to 21V. Most of the AUX battery units are using lithium batteries so the voltages don't match up with the 12V car system. If your AUX portable battery is running a 16.8 volt (at 100%) storage you will be in trouble trying to get it full with the cars output. So it is best to have a system where there is an input for charging specifically from a car lighter socket. That way the unit will limit the amperage to a safe level from the cars port and also convert the voltage, as needed, to fully charge the portable units storage battery. Read specs and fine print to avoid any issues with how you wish to use the unit.

Aerowhatt

 

[bradleydavidgood777]

OK cool, good to know. I also will try charging the smaller battery bank in the car with the solar panel that comes with the home kit and compare the charging speed with the lighter port and see which one works better. I want to explore all options and try them - you never know how you can get a charge and if you will need to know these things. My goal also is to always be ready to grab some free energy and be doing it every day as part of my life. I could even add a second panel and bank on the balcony at work which would be fun.

 

[Don]

The stock socket is fed with a tiny wire - 18 gauge I would guess. Not good for any sort of current

There are quality cigarette lighter type sockets rated for 15 amps and would probably handle up to 20 amps with correct sized wire - 10 gauge or 8 gauge if it's more than just a few feet long. They're fairly expensive, but worth it. The matching plug goes in with a twist and stays put until you untwist it to remove. Google Blue Sea Systems to find quality electrical components. They have the plugs and sockets in both black and white

Don

 

[bradleydavidgood777]

Thanks Don!

This one is cool!
https://www.amazon.com/gp/product/B074FH81GQ/ref=ox_sc_act_title_1?smid=ATVPDKIKX0DER&psc=1

What would you use for wire? I don't see blue sea wire.

Here is a 12 gauge:

https://www.amazon.com/GS-Power-Alu...ords=12v+wire&qid=1560526143&s=gateway&sr=8-4

 

[Don]

Good price, but you probably don't need 100 feet of wire ;-)

Lowes, Home Depot, West Marine and many other places sell duplex wire in most gauges by the foot, so you can just buy what you need. 12 gauge would be fine for 10 amps or so if it's just a short piece. If you want a more robust installation though, I would go up one size to 10 gauge

Don

 

[bradleydavidgood777]

Yes, I do want robust. And I can use some of the extra wire for an outdoor sound system. Thanks for the suggestion, I'll get the 10 gauge.

 

[bradleydavidgood777]

I made some progress on this project. I did the hard part - wiring and cutting.

Now I need to decide where to connect the wires. Ideas please!

Do I use an open fuse (never did that before) or do I use an inline fuse on the red side? I want this to always have power, key on or off.

Thanks!


Some pics:

The new rear 12v panel installed in the rear compartment door:

Picture 1

Picture 2

Picture 3

Picture 4

Wire routing:

Picture 5

Picture 6

Picture 7

Picture 8

Fuse box area:

Picture 9

Picture 10

Existing ground connection near fuse box

Picture 11

Other connections near fuse box

Picture 12

 

[bradleydavidgood777]

Parts used:

https://www.amazon.com/gp/product/B01C7O8166/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

https://www.amazon.com/gp/product/B074FH81GQ/ref=ppx_od_dt_b_asin_title_s00?ie=UTF8&psc=1

 

[Aerowhatt]

I had the need for 12 Volt on all the time also, mine for a 300 watt sine wave inverter. I picked up the ground behind the panel that you show your set up mounted into. The always hot positive is available at the front side of the On Board Charger under the rear deck. I just removed one of the child seat restraint attachment points and ran the positive through a plastic grommet through the bolt hole left behind. Sealed and supported on each side by a good dollop of 50 year silicone caulk, #10 wire and a 30 amp wet location inline fuse very close to the positive post on the OBC. It's worked very well for 3 years now and was easy to remove and re-run for a warranty trip to the dealer. Never know any of it was there unless the cover is popped and the inverter behind it is in use.

Aerowhatt

 

[kiev]

Aero's suggestion is better than mine, but since you have the wires already laid from the rear to the front:

i think the large diameter red wire coming in to the relay panel shown in pictures 10 and 12 of your set has 12V directly from the battery. There is also the 30A fuse #24 underneath the white plastic panel that could be another option.

An inline fuse could be added to your red wire right at the tap that you pick at the junction box and a slightly smaller one also added behind the panel where it feeds your outlets and meter (where it would be easier to replace if needed).

 

[bradleydavidgood777]

Thank you Aerowhatt and Kiev, great ideas.

The pictures are now numbered in the previous post.

I like the idea of tapping in at the rear because it is closer, but I want to do a permanent install and not have to remove anything for dealer visits. I also don't want mechanics later blaming something on tapping in somewhere that is not approved. And since I am a novice electrician, and still can't figure out the numbers, and since I already have the wires run to the front, I think I like the 30A #24 fuse idea the best. It isolates everything to that one fuse. Plus I would like to know how to do that. I see an icon of a battery on that fuse. Is this fuse open/extra? Is that what that means? How do I connect something to it, do I remove that silver bolt into the white plastic below the fuse box panel [picture 9] to access the rear of the fuse box?

And about the fuse at the rear of the car just before the 12v Blue Sea panel....I thought that the Blue Sea unit had a 15A breaker and that is what the orange switch is for, to reset it in case of tripping over 15A....but it is unclear in the Amazon description. But the description does state the 15A thing and the side of that orange rocker switch is marked 15A....

So I'm not sure 30A at the front fuse box is a good fuse size - might need 15A at the fuse box???

Thanks

 

[Aerowhatt]

So I'm not sure 30A at the front fuse box is a good fuse size - might need 15A at the fuse box???

Thanks

I would fuse the front at 20 amps for two reasons. The set up in the back is breaker is 15 amps. I'm not sure what your wire size is, looks like it's 12 or 10 gauge which is good. By going slightly higher with the feed fuse you avoid nuisance fuse blows which could come at a bad time. The idea behind the fuse up front is to protect the long feed wire from starting a fire if it were damaged and shorted (of course). So there is no reason to go larger than needed. In a pinch type short situation a 30 amp will take longer to blow. Maybe enough longer to start that fire we wish to avoid.

I likely didn't need to pull my positive wire out for the trip to the dealer. I just know dealers all too well and any modification whatsoever can be cause for them to not honor warranty issues. Sure, with a fight you can usually get them to acquiesce and honor the warranty. Life has too many fights already. As a safety issue, the main power lead from the OBC to the 12 volt is fused at the battery (up front) which means that the DC to DC converter in the OBC is protected from over current situations internally. So it is safe to connect another reasonable load to it (50 amps or less). Like you seem to intend to, I only use my set up to charge/run other items while the car is charging. This pretty well insures that there will not be high 12 volt loads in other OEM systems of the car which could approach the limits of the OBC's ability to supply them when added to the auxiliary non OEM system added.

Aerowhatt

 

[bradleydavidgood777]

OK sounds good. It's 10 gauge wire.

Thanks for the additional info about the rear install and dealer.

I'm still leaning to the front connection....I guess at 20A since your reasoning makes sense, but wouldn't the 15A breaker trip from a load on that rear end before the wire melts?

And if I have 10 gauge wire then wouldn't it be relatively safe to have a 30A breaker in the front? Meaning, couldn't the 10 gauge handle the 30A? Because it would be nice to be on 30A if I could in case I want to do other things off that same rear wire later.

Thanks

 

[bradleydavidgood777]

Hi all,

I put this project aside for a while and didn't know what to do with it. I am afraid to tap into wires, especially the large red one - I don't have any wire taps that size and even if I did, I am afraid of damaging it by using slightly the wrong size or something.

I also looked into the 30Amp fuse someone suggested. I'm not sure how I'd tap into that. I watched a youtube on wire tap pigtails, but the 30amp fuse is a square kind and I don't see any like that for sale.

I think I'm giving up or considering getting a professional to wire it.

Would this be something the dealer would do? Or a car radio install place?

Or maybe you can convince me to try it.

Thanks

 

[Don]

Pretty sure you're already aware of this, but if it's hot 24/7 and there's no way to shut it off, the voltmeter on the Blue Sea panel will run your battery down over time - Not sure how much time it will take, but I have a dual USB panel with a voltmeter in my motor home and it ran the battery down in only 3 or 4 days and my battery is at least twice, if not 3 times the capacity of the little 12 volt battery in the iMiEV. I ended up having to put in a switch to turn it off anytime I'm not using it

Don

 

[bradleydavidgood777]

Hi Don,

Nope, didn't know that, so thanks! I think this is officially going under the category of abandoned projects. Looks good in the back of my car though!

I really don't care about it anymore at all. Glad to have another reason to not do anything more with it.

Sometimes you get onto things and are all into them and then you wonder why you did that. This was one of those. Funny too because I have since stopped taking on extra stuff like this in life and enjoy it much more. It was like this project was the last one like it.

So I learned some stuff about wiring and that I didn't want to do it, and I learned something about taking on extra projects that didn't have a reasonably big enough benefit. All good stuff.