Pulling power from cig outlet

[mjthomas59]

I've been looking for a temporary way to install a mobile radio into my vehicle. The unit transmits 50 watts max. I was curious if a cig outlet could handle the power or if it would damage my radio?

Figured i'd better ask before I gave it a shot. I understand this isn't the ideal way of powering a mobile radio but i'm wondering if it would get me by for a while.

Thanks

 

[nexus]

It most likely will not handle the full 50 watts. You should be ok if you set the radio to mid (15) or low (5) watts. Also its unfiltered and if for some reason too much voltage gets to the acc outlet you could very well damage your FINAL amplifier in the radio. Therefore turning it into a receiver only.

Bit if advice if you do go the cig outlet way, you should have it unplugged after each use, plug it in only after the engine has started, and do not jump the battery off while it is plugged into the cig adapter. gud luck

 

[N_Jay]

It most likely will not handle the full 50 watts. You should be ok if you set the radio to mid (15) or low (5) watts. Also its unfiltered and if for some reason too much voltage gets to the acc outlet you could very well damage your FINAL amplifier in the radio. Therefore turning it into a receiver only.

Bit if advice if you do go the cig outlet way, you should have it unplugged after each use, plug it in only after the engine has started, and do not jump the battery off while it is plugged into the cig adapter. gud luck

Wouldn't you think that if his 50 Watt radio was designed for mobile use it would handle the transients from the automobile just fine?

How many Amps does you radio draw?
Most Cig outlets are rated at 10 to 15A but may share that load with other equipment.
Additionally, the cars wiring is notoriously underrated as the types of things plugged in usually don't care about a little voltage drop.

It should work temporarily with a modern radio, but you are likely to not get full power due to the voltage drop.

 

[mjthomas59]

The radio is a midland olympian. It only has high (50 watt) or low (5 watt) settings. I'm not sure how many amps the radio pulls and i've checked the owners manual with no luck.

I didn't pay all that much for the radio but i'd still hate to ruin it. Getting the full 50 watts isn't a huge concern as it will be running through a 5/8 wave antenna anyway. Our portable radios have decent coverage in the county I work for which further convinces me that 50 watts isn't necessary.

I'm just concerned for the well-being of the radio. I'd only be transmitting with the engine running which would ensure adequate voltage to the radio.

I guess i'll have to check the fuse that is running to the cig outlet/power outlet and see how big it is.

 

[N_Jay]

AT 5 watts I would not worry at all.
At 50 Watts I would not worry much.
The voltage drop is there even with the engine running if the wires are not heavy enough.
The fuse is probably 10 or 15 A, and rule of thumb is you fuse at 125% to 200% of load (Load being 50% to 80% of fuse.)

 

[kb2vxa]

Drawing on a LOT of collective experience the cig lighter is the worst possible place to tap power from for a host of reasons. One that immediately comes to mind is electrical noise, alternator whine is one of the worst. If you don't have a DC outlet and probably don't since that's the logical first choice your best bet is straight to the battery terminals. ALWAYS fuse the positive line AT THE BATTERY for safety, should a short develop somewhere in the line without it you have toast for a vehicle. If the radio isn't permanently mounted it's a simple matter to obtain a second DC power cord, one for mobile and one for the home. If it's one of those not having Molex connectors at the rig end, install them.

Don't take the lazy way out, do it right and you won't be sorry. Oh one last thought on that fuse, the type of holder you use is paramount. I've had nothing but trouble with in line cartridge fuses, even the ones that come supplied with ham rigs are subject to contact resistance heating causing the element to fail up inside the end caps where you can't tell it's blown just by looking at it. Max fuses are those you find in late model vehicles, the blades make a much tighter low resistance contact. In line Max holders are commonly available and completely seal up making them impervious to moisture, oil and contaminants found under the hood, I sincerely recommend them.

 

[slicerwizard]

I've been looking for a temporary way to install a mobile radio into my vehicle. The unit transmits 50 watts max. I was curious if a cig outlet could handle the power or if it would damage my radio?

Radio damage is unlikely, but how much power does the radio draw to get 50 watts out? 100 watts? 150 watts?

Figured i'd better ask before I gave it a shot. I understand this isn't the ideal way of powering a mobile radio but i'm wondering if it would get me by for a while.

Just try it. It might work OK or the radio might complain or the accessory fuse may blow. Either way, you'll have your answer. Having said all that, it sure isn't ideal. Can't you just run lower power?

 

[NWI_Scanner_Guy]

Drawing on a LOT of collective experience the cig lighter is the worst possible place to tap power from for a host of reasons. One that immediately comes to mind is electrical noise, alternator whine is one of the worst. If you don't have a DC outlet and probably don't since that's the logical first choice your best bet is straight to the battery terminals. ALWAYS fuse the positive line AT THE BATTERY for safety, should a short develop somewhere in the line without it you have toast for a vehicle. If the radio isn't permanently mounted it's a simple matter to obtain a second DC power cord, one for mobile and one for the home. If it's one of those not having Molex connectors at the rig end, install them.

Don't take the lazy way out, do it right and you won't be sorry. Oh one last thought on that fuse, the type of holder you use is paramount. I've had nothing but trouble with in line cartridge fuses, even the ones that come supplied with ham rigs are subject to contact resistance heating causing the element to fail up inside the end caps where you can't tell it's blown just by looking at it. Max fuses are those you find in late model vehicles, the blades make a much tighter low resistance contact. In line Max holders are commonly available and completely seal up making them impervious to moisture, oil and contaminants found under the hood, I sincerely recommend them.

I don't use my Yaesu 2800M in my car too often, but when I do I've been powering it thru the cig lighter. However, after reading kb2vxa's comments, I'm seriously considering getting a second power cord and hard wiring it to the battery. The radio didn't cost me a lot but still I don't want to accidentally fry something in it.

SSSG

 

[N_Jay]

I don't use my Yaesu 2800M in my car too often, but when I do I've been powering it thru the cig lighter. However, after reading kb2vxa's comments, I'm seriously considering getting a second power cord and hard wiring it to the battery. The radio didn't cost me a lot but still I don't want to accidentally fry something in it.

SSSG

You need to reread his post.

You are NOT at risk of frying anything inside your radio. Even Warren's over-alarming post does not imply you are.

 

[NWI_Scanner_Guy]

You need to reread his post.

You are NOT at risk of frying anything inside your radio. Even Warren's over-alarming post does not imply you are.

Originally Posted by kb2vxa
Drawing on a LOT of collective experience the cig lighter is the worst possible place to tap power from for a host of reasons.

My bad.

I guess since he said the cigarette lighter was the worst possible place to tap power from I just assumed my radio could be in danger.

I stand corrected.

 

[kb2vxa]

"The radio didn't cost me a lot but still I don't want to accidentally fry something in it."

It's not a matter of frying your radio, that's highly unlikely. The thrust of my post was directed at poor performance experienced by quite a few who went the cheap and dirty route.

"Even Warren's over-alarming post does not imply you are."

Over alarming? Only to those who may have misunderstood my verbiage so thanks for straightening that out guys. Anything worth doing is worth doing right the first time so you won't be sorry later simply means you won't have to tear it all out and do it all over again. On the other hand I've released the magic smoke on a few occasions, such as it is when you wire something wrong and discover transistors can also be firecrackers.

So South Side, The Asbury Scanners are SOL since the PD went encrypted; you'll just have to rename the band. Well, the ham repeaters still work as always so all is not lost. (;->)

 

[N_Jay]

Cig lighter is cheap and dirty, but also just fine about 90% of the time for temporary installations.
Try it and see.

 

[HIPCHIP]

I've asked a similar question and the way I was told is that for a quick, emergency type of set-up you can use the cigarette lighter, but for any permanent type of set-up you definitely want to have direct wiring as the cigarette lighter can't handle the amps pulled by the radio. It really shouldn't take too long to run a couple of wires from the battery to under the dash someplace, even if it's just a temporary set-up until you can make it all pretty.
Dan'o :}

 

[N_Jay]

I've asked a similar question and the way I was told is that for a quick, emergency type of set-up you can use the cigarette lighter, but for any permanent type of set-up you definitely want to have direct wiring as the cigarette lighter can't handle the amps pulled by the radio. It really shouldn't take too long to run a couple of wires from the battery to under the dash someplace, even if it's just a temporary set-up until you can make it all pretty.
Dan'o :}

Running a couple of wires "quick and dirty" can be very dangerous (as Warren pointed out).
You must fuse the wires close to the battery (under the hood with weather proof fuse holders).
You must make sure the wires do not rub or get caught by moving parts, or burnt by hot parts, or affected by gas and oil.

Just plug the darn thing in and have fun!

As you said "I've been looking for a temporary way to install a mobile radio into my vehicle."

 

[Navycop]

Cig lighter is cheap and dirty, but also just fine about 90% of the time for temporary installations.
Try it and see.

I run my PRO-95 from the cig lighter while I am running errands. Is this good for a portable?

 

[RKG]

AT 5 watts I would not worry at all.
At 50 Watts I would not worry much.
The voltage drop is there even with the engine running if the wires are not heavy enough.
The fuse is probably 10 or 15 A, and rule of thumb is you fuse at 125% to 200% of load (Load being 50% to 80% of fuse.)

One doesn't size circuit protection devices (fuses or breakers) based on the current draw of a device. One sizes CPDs based on the size of the wire feeding the device. A CPD has no function or capacity to protect a device, only the conductor that is feeding it power.

One way to start is to go to the manual for the car in question, identify which fuse in the car's fuse block covers the cigarette lighter, and put a flashlight on that fuse and read its rating. One presumes that the manufacturer sized that fuse for whatever wire is feeding the lighter.

A general rule of thumb for solid state radios is that transmitter draw in amps at 12VDC (nominal) is equal to three times rated RF power, divided by 10. I'd expect a 50W transmitter to draw about 150 watts of power, or about 15A at 12VDC (nominal).

However, this is only half the issue; you also have to know what the wire run length is for the power feed and what the voltage drop tolerance is for the device. In practice, I'd expect a 50W radio fed by something capable of only 15A to drop voltage to the point where the radio likely shuts down and reboots. 20 or 25A is more like it.

 

[N_Jay]

One doesn't size circuit protection devices (fuses or breakers) based on the current draw of a device. One sizes CPDs based on the size of the wire feeding the device. A CPD has no function or capacity to protect a device, only the conductor that is feeding it power.

OK, maybe I should have been a bit clearer.

Circuits are usually designed (and therefore fused) at 125% to 200% of anticipated load.

 

[hill]

Should alright to use for temporary install. I have used a Yaesu FT-1500 at 50 watts powered via the lighter in a temporary mobile install. The data for this radio lists current at 8 amps at full power of 50 watts. Directly wired would be better for a permanent at install in a vehicle, but for a quick set up in a different one this can work. I would look the data on your radio and should show the max current draw at high power.

Larry

 

[kb2vxa]

Temporary or not I still shy away from the cig lighter plug, I've seen plenty of them fried because of high contact resistance. For receive only and QRP operation they're fine if you don't get killed by electrical noise but they just can't handle the amps.

A bit beside the point but one worth making about electrical noise is alternator whine. Quite often the receive is just fine but it shows up on transmit, I remember a YL's 2M rig that sounded like she had a siren in it. You probably have heard it coming from vehicles heard on your scanners too, it's a fairly common problem with mobile installations. If you hear a repetitive "twee twee twee twee" sound it's the strobes, just about anything that has an AC component to it can inject ripple into the DC line.

Common everyday filters are a waste of time and rewiring the vehicle can be a hair puller trying to get rid of it but I stumbled on the only thing that worked for me and I found it at a supplier of those high powered amps and "kickers" that drive people nuts with that BOOM BOOM BOOM going down the street. It was a 30A active filter, active meaning that rather than the usual passive choke and capacitor circuit it uses high power IC voltage regulators similar to how ripple is filtered and voltage regulated in "base station" power supplies. I just connected it up in the DC line from the radio to the battery and POOF, the siren went bye bye.

 

[swstow]

lets go this way depending on your vehical you could very well have a hot outlet some where under the dash made for that use, look n your owners manual, if you do go buy a qulilty outlet plug and not a cheep add on cig lghter plug and use that ( or just buy the outlet and wire it yourself to the battery and yes use a fuse that matched to the equpment reguirements but the wire needs to be 125% of fuse rating, also when i build a car i also include a curcit breaker near the power supply starting point)