Direct wiring to vehicle battery

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John Chin

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Dec 19, 2021, 8:58:48 AM12/19/21
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I am looking for ideas.

When hooking up your radio directly to the car battery what is needed?  

The radio would be either a FTM-400XDR (max 12 A) or a IC-7100 (max 22 A).  I am thinking may be could operate a  IC-7100 out of the car for POTA.  Maybe a Lifepo battery would be better for POTA. 

I am thinking the negative will be attached to the body of the car. Fuses will be put on both wires.

I am using a mag mount for my Hyundai Santa Fe.  I am not looking at drilling a hole for a NMO mount, yet.  My reason, my cargo box extends beyond the centre of the vehicle.  It would cover the NMO whenever, it is installed.

I looked, other that a small area at the bottom of the hatch, there is no where else I have a single/thin sheet metal to attach a lip mount.  I cannot locate a metal bracket that I can use to attach the antenna to the car either.  I can find them for trucks and Jeeps, but not for my SUV.  Is this even an good idea?

73,
John VA3BOF, VE3JCC

Chris McGaffey

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Dec 19, 2021, 10:10:51 AM12/19/21
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Hi John, my suggestion would be to size the wire based on your maximum anticipated load and acceptable voltage drop.  If that is 22A, I would suggest 10 AWG minimum with a 30A fuse. Depending on the length and how much of a voltage drop you deem acceptable, you may want to use 8AWG. You will be able to find a voltage drop calculators online. 

Chris
VA3DXZ

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John Leonardelli

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Dec 19, 2021, 10:38:12 AM12/19/21
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I have a number 6 jumper cable I use for higher power or 22ah current drain to minimize the voltage drop

Otherwise at 20w to 50w on HF or even 2m Fm the cigarette lighter works

I only use the Anderson one from Rick at Amertron power. He sold em for I think $20 at what was known as hamfests in our history books

John VE3IPS

John Leonardelli

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Dec 19, 2021, 10:43:07 AM12/19/21
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Most of or lately all of my POTA ops is with a Bioenno battery stack

No car battery required

John VE3IPS

So I won't be stranded with a dead car battery that won't crank

John Chin

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Dec 19, 2021, 12:13:24 PM12/19/21
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I found using low to medium power seems to work fine with the cigarette lighter socket.  I have been happy with this solution.  Now, I could just make sure that my power draw is always on low or medium.

On Friday I accidently had the radio on high power in the car.  That is a 12 A maximum draw.  Now that I read the vehicle manual again, it says the maximum attachment should not draw more than 10 A.  I am surprised that the vehicle fuse did not blow.  I originally thought the manual said my maximum draw on the accessory socket was 15 A.  I misread it.  The maximum draw on my cigarette lighter plug is 20 A.  It comes with a 15A fuse installed.  I do not want to do any damage to the vehicle's wiring.  I will swap it to a 10 A fuse.

When I accidently touched the glass fuse holders they were super hot. Just before that I was receiving reports that there was a lot of static on my transmissions.  I was also receiving a lot of static.  The wire remained cool.  When I changed the power to low, my static problem disappeared.  I could change the cigarette lighter plug to a lower fuse.  I use the default one (15 A).

So now I think I never had a problem with my SBB-2 antenna.  I am still happy with my SBB-5 antenna.  Now I can freely swap as needed.

A LifePo battery will likely be my final solution for POTA.  Nice to know that in a pinch the accessory socket will work for the times when I forget the battery at home.  I also have an inverter generator.  It is okay, if I am operating close to the car.  Otherwise, it is a bit heavy to lug around.

73,

John VA3BOF, VE3JCC



VA3MA - Dan Howard

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Dec 19, 2021, 4:27:08 PM12/19/21
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Hi,

 I have an icom 7100 in the car. I have a lithium battery that sits next to the main unit of the 7100. I have it such that I can just grab it and bring it in when it needs to be charged.
I find it's much better as I don't have to worry about running the car.
73, Dan, VA3MA



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Steve VE1OR

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Dec 19, 2021, 5:19:38 PM12/19/21
to York Region Amateur Radio Club, Chris McGaffey

I agree with Chris and would use #8 as a minimum...  but should do that load - distance - loss calculations.

I have more than once gone under the vehicle - from the engine compartment - following the brake lines - then into the cab or trunk of the vehicle through a grommet...

One additional suggestion is that you fuse it at the battery AND at the radio.


John Chin

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Dec 19, 2021, 8:48:51 PM12/19/21
to York Region Amateur Radio Club, Chris McGaffey
Thanks all.

Which type of wires should I use for the wire run?  Cross Linked wire? Primary wire?  Where would you find 6 or 8 AWG wire (or thicker wire) in the GTA?

I do not think 6 or 8 AWG will fit onto an Anderson Power pole.  So I guess it needs to terminate at a bus bar or terminal strip or something like that?

73,
John VA3BOF, VE3JCC

SOrr

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Dec 20, 2021, 8:13:53 AM12/20/21
to yrarc...@yrarc.org, John Chin, Chris McGaffey

I would use simple stranded (more stands than less) - jacketed of course - copper wire.

I bought last time at a local electrical supply ... like Westburn or Nedco

So far as Anderson connectors - not everyone's favourite but I do use them and have had no issues - they are available up to several 100's of AMPs and wire sizes... bigger ones commonly used internal to a larger UPS to connect the battery banks top the charger / inverter.

In your case - current required and length - you should be fine with #8 ... this is what I most often run and common on high current commercial mobile radio installs.

Don't forget the fuses - 2 of them - on both ends - a video I have seen posted on Facebook does not appear to follow this practice**.  I would also run the GROUND wire back to the battery as well and not an intermediate chassis ground... these corrode over time and can become an issue.

In my case the main lead from the battery feeds a 12VDC distribution / breaker panel in the back and that in turn feeds the radios - cameras - GPS - Inverter - other accessories. All bolted to a rack/plywood floor that occupies the back seat of the truck - keeping the flying debris to a minimum in the event of a crash.... Like the video ... You may want to up size the wire if you are doing something like this.

If you want to get really fancy you can add a low voltage disconnect that will disconnect the panel / all connected from the vehicles battery if it gets too low so that you are still able to start the car. In my case this is connected to the "house" battery which is separate from the starting battery - the vehicle has two so I can set the disconnect threshold a little lower before it will disconnect... second battery always available for starting.


** I am also not a big fan of right angle backet mounting antennas to vehicles - future issues - but understand that many folks lease cars (ensuring that the dealers and car manufacturers make the bigger profits / higher margins) and prefer to drill holes and mount properly. Still stand by my experience that an antenna on the roof of a 10 year old car makes ZERO difference to the trade in value and dos not scratch the car up likke a mag mount.

Chris McGaffey

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Dec 20, 2021, 8:54:48 AM12/20/21
to SOrr, John Chin, yrarc...@yrarc.org
Hi John. Tinned wire is also a good option to consider. Tinned wire is commonly used in marine applications to limit corrosion. It maybe overkill, but it’s my first choice for power and signal wiring in outdoor or other applications with an uncontrolled environment. 

Chris
VA3DXZ

John Leonardelli

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Dec 20, 2021, 9:20:52 AM12/20/21
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I bought some jumper cables at Principessa Auto that I Anderson poled somehow

It clips onto the front battery allowing power to my trunk for High Current draw applications with very little voltage drop

I was lucky these chinese made jumpers had actual copper wire in them

I have added the Voltage Booster module to take 12v up to 13.8 (TG Electronics) and assorted West Mountain power accessories. 

see attached article from jan qst 2022  worth the cover price
John VE3IPS

Ham Radio is a life$$$tyle not a Hobby!
Take the radio outside and operate from the Field
Throw a wire in a tree and make a QSO




On Mon, Dec 20, 2021 at 8:13 AM SOrr <ve1or...@gmail.com> wrote:
QST Emcomm Power.pdf

SOrr

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Dec 20, 2021, 10:50:54 AM12/20/21
to Chris McGaffey, John Chin, yrarc...@yrarc.org

I can't afford anything that has "marine" - "sailing" - "yacht" or "boat" on the packaging... :-)

For the 12VDC breaker panel I used one meant for an RV ... MUCH more in line with HAM pricing...

John Leonardelli

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Dec 20, 2021, 12:01:57 PM12/20/21
to yrarc...@yrarc.org, Chris McGaffey, John Chin
Steve, the ones I got were open box , clearance with no return and looked like they were used several times and then return to the store

I cant afford new in box and its outside of my snack bracket

With food price increases I am now shopping at Bulk Barn and Dollarama and can only afford used ham gear now due to chip shortages and lack of a black friday sale at the candy store

To get 100 ft of coax for my 160m antenna I had to connect 5 odd length coax cables with adapters as the coax was out of stock and I cant afford the Infinite cables prices

I enjoy ramen noodles and small size Tuna in water (the ones packed in olive oil is too expensive) as its nutritious and cheap

I took the 'Elon Musk Challenge' and spent only $2 a day on food for a month — and it was easier than I expected



John VE3IPS

Ham Radio is a life$$$tyle not a Hobby!
Take the radio outside and operate from the Field
Throw a wire in a tree and make a QSO



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