Do you leave your mobile rig always powered?

[scanmanmi]

I'm wondering if anyone has experience with draining the car's battery. Of course it would depend on the battery, which I try to keep good ones. I'm thinking of setting up a crossband repeater in the car and using an HT in the house. The car is usually turned off so I would have to go outside to turn the rig on which wouldn't be a good setup.

 

[AJAT]

If you are going to that I would install one of these. PriorityStart! | Car Battery Protector | Battery Mart
I have one and they work great. If the battery voltage gets too low it disconnects the battery from the car, leaving enough juice to still start the car.
If your radio is on and not receiving or transmitting It would probably last all night, the more it transmit and receives the shorter it will last.

 

[RFI-EMI-GUY]

LIND sells a series of timers that can turn on a radio upon ignition sense or external trigger and run them for several hours.

At a minimum you need a low voltage disconnect or you will have no cranking current at some point.

But if you are wanting it to run 24/7/365 you will have quite a challenge. there are some radios and telemetry modules that have battery saver options that put the RX to sleep on a duty cycle, say 800 milliseconds off, and 20 milliseconds on until there is RX activity.

Then you may have challenges in cold weather keeping the equipment on frequency as it may be cold soaked.


Can you deploy a solar panel?

 

[popnokick]

I did this using the Cross-Band Repeat function on a TYT-TH9800. It ran down the vehicle battery in a few hours... and there wasn't that much activity on the TH-9800. The short life surprised me, and my vehicle battery wasn't so old as to be prone to rapid discharge.

 

[scanmanmi]

It ran down the vehicle battery in a few hours...

Wow I looked up the spec and it says the draw is 0.5 A squelched.

 

[jwt873]

If you're using the car repeater at home in your driveway, Using a battery charger would be the best bet. When away from a power outlet, then there isn't much you can do.. Other than increase your battery capacity.

I've got an IC-7000 in the Jeep. I have left it on for over 24 hrs and killed the battery.. But I discovered it has an auto power off function, so since then it's never happened again.

 

[RFI-EMI-GUY]

I have a bit of affinity for RITRON DTX-450 and DTX-150 telemetry modules. A pair of these can be cross connected as a low power (5 watt) crossband repeater. They each draw between 76 and 86 mA, so a pair will nominally draw 162 mA. They do have a battery saver mode that will put them in a sleep mode. The internal regulator can be bypassed so you can use a more efficient external regulator and perhaps save a few mA.

They are very small, so mounting in a vehicle should be simple. You can even plug in a cheap speaker mike like sold for FRS radios. Add a 2m/70CM Diplexer and dual band antenna, or go for a pair of 1/4 wave whips and be done with it.

These modules have a bunch of other clever options so you can operate CTCSS, DCS, Single Tone, or simply wire wideband mode and make a transparent repeater, perhaps passing DStar, P25 or Fusion with some signal/noise degradation. Two channel operation is as easy as a switch, 16 channel operation requires a resistor matrix (A/D translation).

http://www.repeater-builder.com/ritron/pdf/dtx-150-450-manual.pdf

 

[mmckenna]

I'm wondering if anyone has experience with draining the car's battery. Of course it would depend on the battery, which I try to keep good ones. I'm thinking of setting up a crossband repeater in the car and using an HT in the house. The car is usually turned off so I would have to go outside to turn the rig on which wouldn't be a good setup.

I think you are going to have a hard time with that setup without adding some sort of additional power source, unless you run the Lind timer and have it shut down after a set time.

I'm not running cross band repeat, but I have two mobiles in my work truck. Both are set up for ignition sense and will run for 30 minutes after ignition off. Even when off, they draw about 10ma each. That's not a lot, but it does add up after a while. I left my work truck for 3 weeks over Christmas/vacation and went to start it yesterday. It started, but barely. I have a small solar panel mounted on the service body that trickles a bit into the battery, but unfortunately the truck is often in the shade.

Cross band repeat is at the mercy of everyone else on that frequency, so if it's on a repeater, you might get a few long winded hams (aren't they all?) that will run your battery down for you in short order.
Plugging in a charger to keep the battery up might be an option, but it's a hassle.

@RFI-EMI-GUY idea using the small data radios might be a good solution. Just keep that at your home. You can often find those radios pretty cheap if you keep your eyes open. I thought about doing something similar with them years ago but never did. Looks like a useful solution.

 

[N4GIX]

If you are going to that I would install one of these. PriorityStart! | Car Battery Protector | Battery Mart
I have one and they work great. If the battery voltage gets too low it disconnects the battery from the car, leaving enough juice to still start the car.
If your radio is on and not receiving or transmitting It would probably last all night, the more it transmit and receives the shorter it will last.

Yikes! That is expensive! I have had this unit installed for several years and it works just fine. $25.00 from Amazon and will handle 30 amp draw easily!

You can select the cutoff voltage to suit your particular situation. I have mine set for 11.3 vdc.

CZH-LABS LVD Low Voltage Disconnect Module. (12V / 30Amp): Amazon.com: Industrial & Scientific

 

[KB4MSZ]

I do the same thing you are describing with a cross-band repeat radio. I have a Yaesu FT-8900 which I cross-band between my HT and a local group of linked repeaters which have a traffic net every night that I join in on. In my case the whole arrangement is automatic because the 8900 has a menu setting to turn the radio off after X number of hours of non-use. I have it set for 5.5 hours, this works for the time spread between when I get home until the net is over.

 

[AJAT]

Yikes! That is expensive! I have had this unit installed for several years and it works just fine. $25.00 from Amazon and will handle 30 amp draw easily!

You can select the cutoff voltage to suit your particular situation. I have mine set for 11.3 vdc.

CZH-LABS LVD Low Voltage Disconnect Module. (12V / 30Amp): Amazon.com: Industrial & Scientific

That device will protect a few loads. The priority start protects all your vehicle electronics from draining your battery. If you leave your headlights on, use a winch, have auxiliary lighting leave on your FM radio….. The priority start disconnects the battery from your entire vehicle not just a radio. For the OP yes the low voltage shut off will be less expensive and do the trick.
I like the low voltage shut off for some other set ups that I have, I might pick one up.

 

[n4dbm]

Agreed with the suggestion of the low-voltage disconnect. I have this model for my vehicle console. If you need more current switching capability, you can install a relay to switch the load available at any auto parts store. The model from Amazon wasn't available when I got this 15 years ago.

APO3: Automatic Power Off 3 - APRS World, LLC

 

[a417]

I spec this, for always on loads in vehicles.

It might be a bit of an overkill for a hammy radio in a personal vehicle, but this device takes shoreline power and powers loads (this model to 20a @ 12v) completely from shoreline, and reverts to alternator/battery power when the engine is running. It's expensive, it's not small, but it's reliable as hell and i've only had one fail from someone accidentally dumping cleaning chemicals directly into it.

Couple this with a Lind low voltage/timer cutout, and you'll be good. I would advice against using a battery charger to float a load on your car battery, they're not designed for that.

If you're serious about doing this, and you want it to "just work" and at the same time have your car start every time...doing it once, doing it right is the only way.

 

[N4GIX]

The priority start protects all your vehicle electronics from draining your battery.

I agree that this device has more features, but personally I'd find it annoying having to re-program the clock every time this device shuts off the power...

 

[DeoVindice]

I have a bit of affinity for RITRON DTX-450 and DTX-150 telemetry modules. A pair of these can be cross connected as a low power (5 watt) crossband repeater. They each draw between 76 and 86 mA, so a pair will nominally draw 162 mA. They do have a battery saver mode that will put them in a sleep mode. The internal regulator can be bypassed so you can use a more efficient external regulator and perhaps save a few mA.

They are very small, so mounting in a vehicle should be simple. You can even plug in a cheap speaker mike like sold for FRS radios. Add a 2m/70CM Diplexer and dual band antenna, or go for a pair of 1/4 wave whips and be done with it.

These modules have a bunch of other clever options so you can operate CTCSS, DCS, Single Tone, or simply wire wideband mode and make a transparent repeater, perhaps passing DStar, P25 or Fusion with some signal/noise degradation. Two channel operation is as easy as a switch, 16 channel operation requires a resistor matrix (A/D translation).

http://www.repeater-builder.com/ritron/pdf/dtx-150-450-manual.pdf

Now those are downright interesting! Thank you for that rabbit hole, these look like a great SVR-200 equivalent.

 

[RFI-EMI-GUY]

Now those are downright interesting! Thank you for that rabbit hole, these look like a great SVR-200 equivalent.

Yup pretty much! Though the SVR-200 has portable priority interrupt which you will need if your mobile is working through a repeater. But you can work around that limitation.

 

[krokus]

I spec this, for always on loads in vehicles.

It might be a bit of an overkill for a hammy radio in a personal vehicle, but this device takes shoreline power and powers loads (this model to 20a @ 12v) completely from shoreline, and reverts to alternator/battery power when the engine is running. It's expensive, it's not small, but it's reliable as hell and i've only had one fail from someone accidentally dumping cleaning chemicals directly into it.

Couple this with a Lind low voltage/timer cutout, and you'll be good. I would advice against using a battery charger to float a load on your car battery, they're not designed for that.

If you're serious about doing this, and you want it to "just work" and at the same time have your car start every time...doing it once, doing it right is the only way.

Kussmaul makes the shore power connections and battery chargers used on a lot of emergency vehicles, and have a very low failure rate. (I have only seen one failure in person.)

If you really want to ensure minimal affect on your car battery, install a separate battery, and operate the radio from that one. Charging that battery can be fairly simple.

 

[RFI-EMI-GUY]

Yup pretty much! Though the SVR-200 has portable priority interrupt which you will need if your mobile is working through a repeater. But you can work around that limitation.

To do this with a pair of Ritron modules, use a 555 timer to interrupt the COR signal from the inbound (receiving fixed repeater) end of the link every second or two for ~ 100 milliseconds so you can use your portable radio to command TX PTT in direction of fixed repeater.

 

[bharvey2]

To answer the OP's question, I think you'll run in to trouble. There are times that I might not drive my truck for a week or so and I have, in the past, left my mobile radio on in the truck, draining the battery. No transmitting involved, just forgetfulness. If you opt to go this route, do consider dual batteries with the ability to isolate your auto battery from your auxiliary battery when your vehicle isn't in use.

 

[rescuecomm]

That's a lot of trouble for a regular net. Another radio, power supply, and a 1/4 wave antenna isn't that much more especially if you only need a 2 meter rig.