To Ground or Not to ground that is the,,,,,,,,,

[Super60]

Hello Guys and Gals. Got a question. I have setup my truck mobile system. I didn't want a 8 gauge wire from my battery and have to run it or upgrade the battery so anyway I made a powerbox for it. I use it to power my smiled on President Mckinley to a RM Italy KL503 NON HD to a Sirio Performer 5000 mag mount antenna. The power supply is a box I made housing a Lithium Iron Phosphate 50 AH battery. It works really well for me and I have a car charger for LIFEpo4 batteries as well as a 120 volt charger. Swr is 1.1 on 40 and 1.2 on channel 1 so I am happy. The question is simply since the whole mobile unit is isolated from the chassis of the truck should I ground any of this to the truck? I would be much more concerned if the swr's were high etc but everything seems happy and I am really getting out with it., also thanks to Mother Nature too of course and I get very good reports on signal and modulation etc. Any thoughts would be great. Thanks for your time and 73's from 505 Western Massachusetts mobile.

[Windwalker]

Greetings...
In my opinion the more ground the merrier. You still use the vehicle around the magnet mount for a ground plane so to speak. I personally would ground the outside of the coax connector PL259 off the radio and maybe the radio chassis to the battery and frame. I would also ground the battery straight to the frame and or vehicle body panels.
It cant hurt and shouldnt bother your excellent swr.
Just a note !!
In a 12 volt DC system the electricity flows from negative to positive. Thats why it is called a negative ground system...
Back in my younger day I had a Messenger 250 amp. I could never get any DX and I also had a good swr. I added a body ground to the amp and BAM !! I was talking DX Worldwide.

JMHO

WW1

[Super60]

Interesting and thank you for the reply. I will certainly try some if not all your suggestions. Is it really ok to ground the negative of my Lifepo4 battery to a car ground? I'm sure you speak the truth it just seems somehow counterintuitive to a electronically challenged person like me lol.
Fascinating stuff and thanks again for the reply.

[Windwalker]

In all honesty you can run that linear right from the battery. It seem costly to have a seperate 12 volt system for that amp. It should be easy to run off the vehicle battery even if you dont upgrade the battery. It just dosent pull that much current.
So Im not telling you to connect that battery to ground at all. I dont know what would happen using an independent charger.
Further there are other ways to isolate the system for the linear that would allow you to charge the battery with the vehicle alternator when you want to.
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[Super60]

Thanks Windwalker and for the link ,I appreciate it. I am running both my President Mckinley and the RM Italy 503 from my Lifepo4 50 ah battery. I built it for RC charging at the field and found it to work really well with my mobile station and not have to wire my truck for it.

[Windwalker]

Personally I would run the radio from the vehicle lighter plug. That way you can remove it easy. Further an added benefit of using the vehicle battery is that when you start the vehicle the voltage goes up. It still will be within specs for that linear but an extra volt or two is a good percentage of 12 volts. If your battery does 12 volts and when the car is running you get 13.8 that is about 15% more voltage. And again it is still within specs but it might just give you a few more whiskeys. Plus higher voltage equals lower amps or current making the box run cooler and better.
I would definately run it off the vehicle battery and your ground issue turns into easy peasy.

WW1

[Super60]

Good info thank you

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Post Merge Complete

Added 3 days 23 hours 59 minutes 21 seconds after previous.
I tried to run the KL 503 from the lighter socket and it blew. According to my amp meter hooked to the lifepo4 battery it pulls between 15 to 25 amps when keyed down in SSB. I used to run my McKinley and a small kl 203 on different lighter plug sockets no problem .

[Windwalker]

The 503 is too big for the lighter socket. I ( suggested ) run the radio from the lighter and linear from the existing vehicle battery.

[Super60]

Ahh I see ,interesting thought. Thanks ,I will give it a try.