bradleydavidgood777
Posts: 222
Joined: Tue Aug 29, 2017 11:55 am
Location: Media, PA

Always on lighter/12v port - Charging battery banks

Wed Jun 12, 2019 10:43 am

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
Last edited by bradleydavidgood777 on Thu Jun 13, 2019 5:40 am, edited 1 time in total.
2017 I-Miev

Aerowhatt
Gold Member
Posts: 444
Joined: Wed Jan 28, 2015 1:52 pm

Re: Always on lighter/12v port

Wed Jun 12, 2019 12:59 pm

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
(July) 2014 cool silver ES, acquired new 4/2015 (40.9ah at ~34K miles)
(Aug) 2014 Labrador Black Pearl ES, acquired new 3/2016 (39.7ah at ~20k miles)

bradleydavidgood777
Posts: 222
Joined: Tue Aug 29, 2017 11:55 am
Location: Media, PA

Re: Always on lighter/12v port

Thu Jun 13, 2019 5:24 am

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.
2017 I-Miev

bradleydavidgood777
Posts: 222
Joined: Tue Aug 29, 2017 11:55 am
Location: Media, PA

Always on lighter/12v port - Charging battery banks

Thu Jun 13, 2019 5:39 am

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
2017 I-Miev

Aerowhatt
Gold Member
Posts: 444
Joined: Wed Jan 28, 2015 1:52 pm

Re: Always on lighter/12v port

Thu Jun 13, 2019 11:15 am

bradleydavidgood777 wrote:
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
(July) 2014 cool silver ES, acquired new 4/2015 (40.9ah at ~34K miles)
(Aug) 2014 Labrador Black Pearl ES, acquired new 3/2016 (39.7ah at ~20k miles)

bradleydavidgood777
Posts: 222
Joined: Tue Aug 29, 2017 11:55 am
Location: Media, PA

Re: Always on lighter/12v port - Charging battery banks

Thu Jun 13, 2019 1:23 pm

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.
2017 I-Miev

Don
Site Moderator
Posts: 2899
Joined: Thu May 10, 2012 3:55 pm
Location: Biloxi MS

Re: Always on lighter/12v port - Charging battery banks

Thu Jun 13, 2019 2:32 pm

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
2012 iMiEV SE Premium, White
2012 iMiEV SE, White
2017 Chevy Volt Premier
2014 Ford Transit Connect XLT SWB wagon, 14,000 miles
1979 Honda CBX six into six


Don
Site Moderator
Posts: 2899
Joined: Thu May 10, 2012 3:55 pm
Location: Biloxi MS

Re: Always on lighter/12v port - Charging battery banks

Fri Jun 14, 2019 9:29 am

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
2012 iMiEV SE Premium, White
2012 iMiEV SE, White
2017 Chevy Volt Premier
2014 Ford Transit Connect XLT SWB wagon, 14,000 miles
1979 Honda CBX six into six

bradleydavidgood777
Posts: 222
Joined: Tue Aug 29, 2017 11:55 am
Location: Media, PA

Re: Always on lighter/12v port - Charging battery banks

Fri Jun 14, 2019 12:18 pm

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.
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