Ham Radio battery connection

DBoondocker

Hi,
I have replaced the battery that cam with my 2022 320S with a 100amp LiPo4 battery. 

I am a ham radio operator and would like to “plug in” my radio to the battery. It required 20 amp power.
are the wires that enter the Tab powerful enough to handle 20 amps? Can I use one of the fuse imputes on the panel? Is there another way that I can connect a wire to be able to run my radio.
How are the wires routed into the Tab? Can I pull wires from the battery box to the under seat electrical connections?
I hope I made myself clear.

pthomas745

20 amps?  How big is this radio?  What type of circuit do you plug it in at home?  The trailer is capable of 30 amps on shore power, but none of the 12V  circuits are close to 30 amps, except for the battery protection/charging fuses.

DBoondocker

It is a 100 watt ham radio. I am trying to find out the wire gauge that was used from the battery to the fuse panel and where I might tap into those wires for a 20 amp circuit. I can use a 120v power supply but 12v is the way to go for portable use. I currently use it with a 20a LiPo4 battery but, since I have this nice big battery in the rv, I would like to use that and leave the 20amp at home.

pthomas745

100 watts is doable with an inverter plugged into a 12V port, and the radio plugged into the inverter.  If that would give you stable enough power.  There are threads that describe the basic wiring that runs into the converter from the front of the trailer.  If you look under the driver's side bench you should be able to see the wires back there. I'm not the person to give advice on this, however.  There are general threads that talk about the wiring that goes into the converter, so this one might help, at least give you places to inspect.

https://tab-rv.vanillacommunity.com/discussion/10049/converter-power-supply/p1

Grumpy_G

Ham radios are typically designed around 12V power so no point in using a inverter to generate 120V just to then convert it back via an external power supply. 
In most newer T@bs there is at least one fuse of 20A or higher in the fuse box so if there's a open fuse slot that might be the ticket. It might be worthwhile checking the wire gauge from the battery if it can carry the combined load of the fridge and the radio. A 100W radio will likely draw somewhere 10-12 amps, not close to the rating of the recommended fuse. 

DBoondocker

Grumpy, you are correct, I want to operate the radio on 12v. There are no empty fuse slots. When transmitting, the radio can draw up to 20 amps. I’m thinking I might need to connect 12 gauge wire right to the battery but not sure how to get it back into the rv. Drilling holes is what would scare me.

BridgerSunset

I'm contemplating the same scenario with 100 watt ham radio, but in a 400.  Tying into the main battery/batteries is easy with the 400's location; but I worry about RF interference from all the T@B functions.  Like you, I have an independent 20 amp Li, but in the tow vehicle, which I prefer to totally isolate it from the truck's system.  If you don't want to tote around or install the 20 amp Li inside the 320, or drill holes, I wonder if it's viable to  tie your transceiver (fusing it for 15 amps or whatever the Victron is rated for) right into the Victron solar charge controller 12V output ports, assuming the Victron is inside and if you have consistent sun while operating?

hamrx

I am an amateur radio operator KA4FJV.  I had the same issue and decided to run my ICOM 7300 off a seperate LIFEPO4 20 amp battery for POTA and Field day activity,  I even run my 705 off the internal or 20 amp battery.  Actually the 7300  draws 22 amps on full power.  hope this helps.  73

pthomas745

Now I'm curious:  I asked about how much power the radios need, and wondered about the 20 amps usage.  Is this just for the transmitter to get up to power before transmitting?  Or during an entire transmission?

DBoondocker

Ham Radios only draw that much power while transmitting. When they are just receiving, they only draw a few amps. Nice to know there are other hams with NuCamp RVs.
KK4JOW

pthomas745

Thank you very much on the transmitter lesson. 

KK1L

A typical transmitter amplifier is about 60% efficient. So 100W out at "12V" (usually really 13.4V ish) is about 14A plus the idle current of the radio. This maximum will really only occur on AM transmissions or CW "keydown". Voice communications would draw on average much less (40% ish).

@DBoondocker I seriously doubt the wiring to the cigar plugs is up to 20A service, but you will be averaging well less than this. The real issue to the radio is the IR drop on the power line. A good option for you would be to get a Victron Orion (or similar buck-boost converter) and wire it to the T@B battery (fused) and use it in power supply mode to feed your radio. You can set a low voltage cut off, so the battery does not discharge too far. And it will keep the radio side voltage constant.

I would not worry about RFI on the power feed. If you are going to get any it would come from the antenna or more likely the feedline if not well choked. There is a reasonable amount of aluminum to keep the radiated RF out