Power for radio/amp with engine off.

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Super60
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Power for radio/amp with engine off.

#409571

Post by Super60 »

Hello Folks. Hope you all are enjoying the DX ,I know I am. It's getting towards winter here in the state of MA and I have a question about my setup. I will pull into a good spot to try some DX and my modest setup does well. Smiled on Mckinley and a KL 203 to a Sirio Performer 5000 Mag mount on top of my Tundra truck. I am happy with this setup and since all the lighter sockets were designed for laptops etc there is no noise and the system works great. However once I turn the engine off and put the key on acc to run the radio and transmit people say I am breaking up or sound strange or robot like. The only way to talk is to turn on the engine and I guess run up the voltage to 13.8 instead of 12.6. When running the engine everyone says I sound very good. My question is this . I want to be able this winter to park and shut the engine down ,run my equipment at 13.8 or so. All fuses are factory rated at 15 amp and have never blown a fuse. The radio and amp are on separate fused circuits. Nothing is shared. Are there setups with extra batteries that can be charged while driving and when needed provide the voltage I am looking for? I would also like to upgrade to a KL 503 in my truck. Or maybe I am on the completely wrong track. Thoughts would be appreciated.







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#409572

Post by Windwalker 1 »

Battery voltage is 12.6 on paper. (( six cells in a car battery @ 2.1 volts per cell equaling 12.6 volts )) In reality your alternator is causing the battery to be at a higher voltage around 13.8 or so. Unfortunately the battery voltage will drop to 12 something pretty quickly when being used without the use of an alternator. ( especially for a linear ). Even a deep cycle battery will drop the voltage. Deep cycle batteries are NOT meant to be charged constantly like a regular car battery. As far as xtra batteries even if you separate them from the alternator you will have to charge them at some point. If you are charging more than 1 battery from an alternator at a time it will run the alternator hot and shorten the life of the alternator. ( sometimes pretty quickly ). Further !! running a linear of any size off of a lighter plug is not a good idea. So I think you should run the linear straight off the battery with heavy wire and make the wire as short in distance as possible. Always use an inline fuse on the positive side as close to the rating of what you need for power. Dont put a huge fuse in !!!!! The inline fuse on the positive side should be close to the battery and NOT inside the vehicle. If the radio is doing 4 watts or so it is OK to run it off of the lighter plug. That radio if peaked and tuned may draw more power than you would like from a lighter plug especially if you are using SSB. If you still have problems then run the radio also straight from the battery. Just a note !! That linear is easy to overdrive so a peaked radio would be too much for it to live a long happy life.

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#409573

Post by Scipio Kid »

Your Toyota has a relatively small battery (compared to larger trucks) since that's all it needs to run the starter for a few seconds. Your Tundra may have a 400 CA battery while my Powerstroke has (2) 1000 CA batteries. That's what it needs to crank that diesel, but it also provides 5 times the available power to run accessories when the engine is off. I once left it at a jobsite for 3 weeks and didn't realize I'd left the CB on the entire time, but it started right up when we picked it up! On the other hand, I once left a CB radio on in a Honda Civic and had a dead battery in the morning.

Batteries, at their best, provide 12.5 volts. The alternator runs at 13 to 14 volts in order to charge the battery. Once you shut down the alternator you instantly drop to 12.5 volts and, as you keep a load on that battery, the voltage slowly drops. The larger the load, the faster it drops. Adding a battery will help, and the bigger the extra battery, the more it'll help. Your challenge will be finding a spot for the battery and wiring it in parallel to the stock one. There isn't a lot of room under your hood. You can probably run your radio equipment on #10, #8 or #6 wire (depends on the draw of your linear), but if you want to have the battery help out when starting or jump starting someone else, you'll need to run much larger cables. I always use #2 or larger when running dual batteries.

You mentioned you're running through the ignition switch by having to "put the key on acc". Running a direct circuit from the battery to your radio equipment will help immensely, even on one battery. Using larger wires (possibly #8 or #6) will reduce voltage losses in your vehicle wiring harness and will also protect that harness from the high amperage draw your linear may be pulling. Your supply will also be "cleaner" as no other accessories will have power (with potential interference) coming off your accessory circuit. I suggested wires, meaning run a (fused) hot (preferably red) from the positive terminal, as well as a ground (preferably black) from the negative terminal instead of using the frame and body of your truck for a ground circuit. This also helps you with a cleaner supply when the engine is running.

There are also dual and multiple battery setups available at RV and trailer supply outlets (and on-line) that allow you to use an accessory battery or batteries while leaving the stock battery out of the circuit. This allows you to run your radio and other accessories, computers, TV etc. without the possibility of draining the main battery and not being able to start your truck later. Once you start your engine, these systems will engage your alternator and charge your accessory batteries while you drive.

Good luck with your project!


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Added 7 minutes 50 seconds after previous.
I just read Windwalker 1's reply. Apparently, he was walkin' all over me when I was replying. His advice about alternator size is very important, especially if you have a relatively small alternator and use a much larger battery as a backup. During normal use, you'll be fine, but if the bigger battery is low or dead, the alternator will try to charge it quickly and may not be able to without damage. So you need to also check the amp rating of your alternator. If it's 70 or higher and your second battery is 800 CA, you'll be fine.

Also, what he said about sizing your fuse to the load is CRUCIAL. Some folks think a bigger fuse means more power. That isn't right. Sizing your wire to the load is the important issue. If your radio equipment draws 15 amps, put in a 20 amp fuse, not a 40 or 50. If you oversize the fuse and something goes wrong, the fuse won't blow and the wires can heat up and start a fire. I've seen it happen and burn a truck to the ground.
Last edited by Scipio Kid on November 6th, 2022, 5:40 am, edited 1 time in total.






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#409574

Post by Windwalker 1 »

Scipio Kid I dont fully agree with you. When an alternator goes bad it is usually the voltage regulator or the rectifier.
The alternator components that actually make the amperage like the rotor or the stator often times are still good.
An 800 CA battery is pretty big compared to todays standards so the alternator regulator and rectifier will get hot and burn out leaving the rest of the alternator OK even though it wont work. Plus todays alternators are only designed to run the vehicle and charge 1 battery. If you do go buy a set up to only charge the extra batteries while the engine is running then you will surely burn out the alternator. Especially if you are on the highway for a trip. The standard Toyota set up just will not do it for very long and even more so if the batteries are weak or low on charge.
Lastly I must admit you are not way off base !! And I wasnt walking on you !

WW1


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Super60
Here is what I would do !!!!!!!!
I would go buy a big battery (( say maybe 800 or 900 cranking amps )) and use that in a single battery setup. (((DO NOT USE A DEEP CYCLE BATTERY ))) I would then hook the linear and possibly the radio straight to the battery as described earlier in this thread. That would be just fine for your Toyota alternator and give you lots of talk time with still being able to start the truck.


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Inline fuse placement {{
You must place the proper inline fuse on the positive side close to the battery.
DO NOT put the fuse inside the vehicle.
If the positive wire gets cut or makes contact with the vehicles metal somewhere (( say like where it goes through the firewall )) then the fuse being close to the battery makes the length of live wire very short after the fuse blows
and not as likely to make any other further contact with a metal part of the vehicle.
If the fuse was ten feet away from the battery and it blows then you still have 10 feet of live positive wire that can make a really bad contact somewhere else and wont be protected by a fuse.







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#409575

Post by Scipio Kid »

Windwalker was walkin' all over me. He's got a bigger Linear. I'm thinking of hooking one up to my computer. Then we'll see who walks all over whom. So, do you put those linears in the power cord or the one to the printer? Not sure but I've got wire cutters and lots of black tape, and a few used wire nuts, so I'm good.

He's right about the voltage regulator and brushes etc., especially when you're charging from a severely depleted battery. If you're transmitting at high amps for long periods, you'll drain both batteries, so checking your voltage regularly would be in order. Just turn the key on and look at the volt meter, if it's down to 11 or less, start the truck and charge 'em up for a few minutes. Alternators weren't designed to be charging batteries from dead to full, although we all have that need from time to time. They're designed to top off your battery after the quick and heavy amp load of the starter, and then simply keeping it charged while powering all the accessories when you're driving. If you're going to do a lot of serious high amp transmitting, and you put that bigger battery in there, you also ought to look into getting a heavy duty alternator. They're available for most trucks. I have a service truck that uses a lot of power for hydraulics, lights and special accessories when the engine might be off. So it came with dual batteries (1100 CCa each) and a 135 amp alternator (the same as many semi tractors) even though it's only a one-ton truck. If you're not constantly draining the batteries, you should be good with your stock alternator. You'll see lots of guys pulling big RV trailers with big batteries, even deep cycle, with no mods to the alternator in their pickups. Even though they charge those big batteries (off the stock alternator) daily while vacationing, when they're home or at a campground, most are plugged into a power source and charging the batteries off inverters. If they were traveling and using those batteries 24/7, they'd quickly run into the problems Windwalker cautioned you about and they'd need to upgrade. You'll have to decide if your use is high enough to warrant extra or bigger battery(ies), heavier cables or a beefier alternator.


Final note and caution: Don't overlook Windwalker's wise advice on fuse placement if you add a direct circuit from the battery. The fuse must be as close to the battery as possible. This is a must, not just some random suggestion. Running an unfused line into the truck is a disaster waiting to happen, Windwalker explained why.
Last edited by Scipio Kid on November 6th, 2022, 6:37 am, edited 1 time in total.






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#409576

Post by MDYoungblood »

Both of these members have good answers and worth a try but the simpler solution is to just run the engine, cheaper to, even with today’s gas prices.
What is happening when not running the engine, voltage does drop, amperage draws down as well, this is de-tuning both the radio and the amplifier, the reason the radio sounds chippy, robotic, etc.
It sounds like you have a good setup, don’t overdrive that amp though, it won’t last long, good antenna with a excellent whip length.

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#409578

Post by Scipio Kid »

Oh Great!! Now Greg's walkin' all over me too. That does it, I'm puttin' a linear on my monitor and this time I'm using the soldering gun! Now If I can only figure out where my wife hid it.






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#409579

Post by Windwalker 1 »

The basic Ohms Law which has been around for many moons is this. Low voltage equals high amperage.
The starter needs the correct voltage ((( not 11 volts ))) It may start the vehicle at 11 volts but your amps will be higher than the starter is designed for. That will cause premature failure of the starter motor. It works the same with the linear. Amperage is what makes the heat in a circuit. If you are running a linear at 11 volts it will get really hot and degrade in performance and burn out... Do not even think about letting your battery go down to 11 volts unless you just like having problems with stuff burning up. Blood has the best idea with just running the engine but I would still hook up the linear straight to the battery. Ohms law is next !! And I dont have a linear at all ... <<<<< I run a stand alone radio >>>>>


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Ohms Law ... (( Thats amps times ohms equals volts )) but that is just a template for circuit design !!
In the real world it is way different, Start up current, low voltage and component temp are just a few of the factors that can and will alter Ohms law. Using a DC car battery when the voltage goes low the battery will provide more amperage to get the job done. Hot circuit components will burn more amperage just because they are hot.
A perfect example of heat as applied to radio communication is this. A radio may drift in frequency when it is cold and stop when it is hot. That would be more noticeable when using SSB. 2nd You are supposed to tune and peak a radio when it is at operating temps. For bench tuning they used to make ovens to heat the radio up before tuning. When at operating temps you can truly peak, tune and align a radio for optimum performance. Further if you have a constant source of say 12 volts the amperage will change some due to the heat of the device while the constant 12 volts remains the same. I could go on forever but it is enough to say that Low Voltage equals High Amperage and that will burn up anything you got !!! :oops:







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#409583

Post by Super60 »

Well first off I want to thank each and every one of you for your input. Some things I knew and many not and I truly appreciate all of your experience and knowledge on this. My little kl 203 has a rated amp draw rating of 10 amps so my outlet has a factory rated 15 amp so I have never blown a fuse. The radio is on another fused factory circuit at a rated 15 amp fuse and no problems there. I did try for kicks installing my kl 503 as it has a supposed 20 amp draw. When keying down [not at full power] I didn't blow a fuse but a circuit breaker must have tripped and then reset later. So I nixed that. My charging system seems fine although my battery may be a little old. I might try what WindWalker suggested in the future about a larger capacity battery and run lines right to the the battery. The fuse will be as close to the battery as possible and then possibly my KL503 will work with it. Until then I will as Mr Youngblood suggests to just run the engine for now. But one last question ,you guys don't think my radio/amp behaves badly with engine off because of lower voltage , it is because of reduced amperage correct? Thanks again!!!







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#409584

Post by Windwalker 1 »

Usually the lighter plug is on the accesories fuse circuit. Add that to whatever else runs when the ignition switch is in the ACC position. Your fuel pump may be running and who knows what else.
If you want to run the 503 then go ahead and hook straight to the battery so you can run it.
So no I dont think it is because of the lower voltage !!!







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#409585

Post by Super60 »

That's great to hear. Thanks alot.







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#409586

Post by Windwalker 1 »

Any Time !!

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#409589

Post by MDYoungblood »

Scipio Kid wrote: November 6th, 2022, 6:58 am Oh Great!! Now Greg's walkin' all over me too. That does it, I'm puttin' a linear on my monitor and this time I'm using the soldering gun! Now If I can only figure out where my wife hid it.
LOL, that would be a good trick for me as I am radio-less at the moment, I’m in between buying houses.

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