Starting vehicle with radio on

[WX5812]

I try to make a good effort to not start my truck with the radio on but it does happen. It reduces the power just enough to restart my radio when it happens. Is there any type of capacitor that can go inline with the power cord that won’t drop voltage when engine gets started?

 

[vagrant]

I believe the MFJ-4416 will do what you need.

 

[voyger522]

I believe the MFJ-4416 will do what you need.

wire direct to battery

 

[belvdr]

wire direct to battery

That can be hit or miss. Worked fine for me in one vehicle but not another. I recommend doing that regardless.

 

[W5lz]

Capacitors aren't the answer, "more" battery is...

 

[Lauri-CoyoteFrostbite]

WX5, what you are seeing is an Ohmic drop along your wire(s) that power your radio.

You didn't say where you are drawing your power from- hopefully its a direct connection to your battery using the cable supplied by the radio's manufacturer.

You will open a Pandora's Box of comments as to where the ground should connect-- directly to the battery or to the vehicles chassis. Irregardless, make sure that the wire is as heavy as can be, the connectors are good and solid; use solder --
No Mickey Mouse stuff ! - and of course fuse it.

As far as capacitors are concerned, your battery is the Mother of All capacitors; anything strung along the radio's power line will not be necessary if that line is adequate.

Think your Ohm's Law and a voltage drop across a resistor- for that's what that powerline is

Also a good, stiff voltage thru a low resistance wire is essential for powerline noise reduction, not to mention suppressing high voltage spikes caused momentarily by things like starters, blower motors etc.

Revisit that power cable and all your connections........ and avoid the temptation for gimmicks


Lauri

 

[WX5812]

Yes it is connected direct to the battery and with the original power cord thanks for the reply!

 

[mmckenna]

Yes it is connected direct to the battery and with the original power cord thanks for the reply!

Check, double check and triple check all your connections. Especially anything that is crimped. Pay close attention to fuse holders, especially the ones that hold the glass tubular style fuses.
Check for corrosion on all the connectors. If it's corroded, stop and fix.

Check your battery. Could be your battery is getting weak. If the voltage takes a nosedive when you crank the engine, it may be time to replace the battery.

Length of the power feed is important, too. There is loss in all cable, and if you are using a long run with small cable, you may be experiencing enough voltage drop to create an issue when the engine is cranking.

As for where to ground, yeah, it can be contentious, but some newer cars are very specific about this. Check your owners manual. Some newer cars have sensors on the negative battery lead that watches how much current is flowing to/from the battery. The manual may tell you to not bypass this by connecting any accessories directly to the negative post. They'll want you to ground to the chassis. Which is a good thing to do anyway, especially close to the radio. Do not rely on the long negative power lead as the radio ground, nor the grounding from the antenna mount. Run a short strap from the radio chassis/ground point to the vehicle chassis.

If all those things check out, I'm willing to place a small wager that it's time to get a new battery….

 

[RFI-EMI-GUY]

I believe the MFJ-4416 will do what you need.

That is certainly a pricey solution. A cheaper solution might be a DC-DC convertor that takes a wide range of input voltage and outputs 13.8V at whatever current is needed.

 

[mmckenna]

That is certainly a pricey solution. A cheaper solution might be a DC-DC convertor that takes a wide range of input voltage and outputs 13.8V at whatever current is needed.

Yeah, I agree. Seems like a product aimed at amateurs that are too lazy to do a proper installation. Using properly sized conductors, properly installed connectors, all connected directly to the battery, this should not be needed. If, if the battery is good.

The DC-DC converters will certainly hide the issue, and might solve issues where you are using small wire, weak battery, etc.
If you are using a transceiver, doing a proper install will negate the need for most of these items.

 

[RFI-EMI-GUY]

Most scanners are not happy with vehicle cranking electrical transients and a DC-DC convertor is only fix. Transceivers of good quality by reputable manufacturers will put up with the transients. In all cases proper wiring is a must. I have seen some shoddy attempts at wiring.

 

[voyger522]

Check, double check and triple check all your connections. Especially anything that is crimped. Pay close attention to fuse holders, especially the ones that hold the glass tubular style fuses.
Check for corrosion on all the connectors. If it's corroded, stop and fix.

Check your battery. Could be your battery is getting weak. If the voltage takes a nosedive when you crank the engine, it may be time to replace the battery.

Length of the power feed is important, too. There is loss in all cable, and if you are using a long run with small cable, you may be experiencing enough voltage drop to create an issue when the engine is cranking.

As for where to ground, yeah, it can be contentious, but some newer cars are very specific about this. Check your owners manual. Some newer cars have sensors on the negative battery lead that watches how much current is flowing to/from the battery. The manual may tell you to not bypass this by connecting any accessories directly to the negative post. They'll want you to ground to the chassis. Which is a good thing to do anyway, especially close to the radio. Do not rely on the long negative power lead as the radio ground, nor the grounding from the antenna mount. Run a short strap from the radio chassis/ground point to the vehicle chassis.

If all those things check out, I'm willing to place a small wager that it's time to get a new battery….

yes I had problems like that.weak battery

 

[jim202]

Not trying to duplicate what others have said, but a battery that is like 4 or 5 years old needs to be replaced. It has reached it's end of life. As they get older, the internal resistance goes up and the cold crank capacity goes down. This also will effect the stability of the vehicle voltage.

The other issue is why do you want to have your radio turned on when the vehicle is not running? When an engine starts up there is a voltage surge as the alternator kicks in and has not settled down to the correct voltage. It is not a very long time for this to happen. Unless you have a storage scope to look at the voltage spike, you will never see it on a digital or analog volt meter. It could be dangerous to your radio.

You never said what kind of a radio it was or the model number of it.

Jim

 

[W5lz]

The original question is fairly simple to answer, there are two solutions.
The first one is to simply turn off the radio when starting the vehicle, then turn it back on. Easy to implement. Hard part is to remember to do it.
Second solution is to have a device that will do that turning on/off for you. That device has to be taught what to look for, sort of. That means it is going to be a little more expensive, you know it's all that 'teaching'.
Either are certainly possible... which you wanna do?

 

[popnokick]

There’s another thread somewhere here on RR saying these will work to protect from the starting surge or voltage drop -
DROK 180050 DC-DC 80W Auto Boost Buck Voltage Regulator Stabilizer 5A 3.3V-30V to 0.5V-33V LED Display Volt Stabilizer Transformer Adjustable Output https://www.amazon.com/dp/B01DXEU4KA/ref=cm_sw_r_cp_api_i_zJc1CbYW675J3

 

[vagrant]

I try to make a good effort to not start my truck with the radio on but it does happen. It reduces the power just enough to restart my radio when it happens. Is there any type of capacitor that can go inline with the power cord that won’t drop voltage when engine gets started?

Let us know what solution worked for you, as others may stumble onto this thread via a search.

 

[eaf1956]

Most scanners are not happy with vehicle cranking electrical transients and a DC-DC convertor is only fix. Transceivers of good quality by reputable manufacturers will put up with the transients. In all cases proper wiring is a must. I have seen some shoddy attempts at wiring.

Thank God the SDS 200 isn't one of them like the 536 was.

Sent from my SM-N960U using Tapatalk

 

[WX5812]

I ordered a dc 12v to dc 13.8v 18amp converter I will update when it gets delivered and installed


Sent from my iPhone using Tapatalk

 

[eaf1956]

I ordered a dc 12v to dc 13.8v 18amp converter I will update when it gets delivered and installed


Sent from my iPhone using Tapatalk

Note that if left powered on all the time a DC to DC converter will drain your battery fairly quickly. I found that out the hard way with my direct to battery connection. Had to put in a switch to turn power off for like overnight or extended off times.

Sent from my SM-N960U using Tapatalk

 

[WX5812]

Thank you for telling me that. I didn’t know it would draw when the radio was off. I could always use it with my 12v server power supply to bump up to 13.8