Voltage Stabilizer questions.

[Vern_in_IL]

I need a voltage stabilizer for my mobile radio. It draws 20 amps(max) can I parallel two 10 amp voltage stabilizers and get 20 amp capacity?



My concerns is they might not run in sync and start supplying each other.

 

[PolarisX]

Are you referring to a capacitor?

If so they are a band aid to a problem that is deeper. During transients they will drain quickly to alternator output. Do your big three wiring and then check your alternator output.

 

[Vern_in_IL]

Quote:
Are you referring to a capacitor?

No, I'm referring to a regulated voltage stabilizer. It is a switching power supply that regulates the output and boosts the voltage to your equipment.

Radio shuts off during engine starting, equipment is turning off during car starting and other voltage sags.

The radio is wired directly to battery.

 

[PolarisX]

You need to investigate the condition of your battery. Also it should have a remote turn on lead to be commanded on, not wired directly to source blindly. The radio probably shuts off under 10.5V or so and is falling under that while cranking.

I would use an ATC add a fuse, and wire them (remote turn on) to unused slots for sunroofs or heated seats. This way they are only on with the car, and turn off when cranking like a normal accessory would and come right back on. They don't mind being fed 12V DC. This implies that the existing remote turn on was not usable or it was a remote amp install and we didn't want to disturb the OEM harness if keeping that head unit.

If you are wiring directly to battery you need to fuse that link as well.

 

[Virtus_Probi]

Load sharing with two voltage output regulators is a tricky problem and you probably won't get what you want if you just hook them up in parallel...one will generally want to regulate a bit higher than the other and will support most of the load. I'd go with a dedicated 20A supply if you really need that much DC current and maybe a just bigger output cap if you're trying to ride out a transient.

 

[PolarisX]

Originally Posted By: Vern_in_IL
Quote:
Are you referring to a capacitor?

No, I'm referring to a regulated voltage stabilizer. It is a switching power supply that regulates the output and boosts the voltage to your equipment.


I missed this line, disregard.

 

[i_hate_autofraud]

DC switchmode power supplies aren't designed to load share unless they are spec'd that way.

During engine cranking when the 12V sags likely can't be compensated by the supplies anyway, during input voltage sags while under load the input current would climb dramatically and could blow the supplies. Switching supplies work hardest under 'low line' conditions.

If it's a real bother, consider a small garden tractor battery feed by a 30 amp diode from the alternator or car battery, the idea is that the cranking voltage sag will be blocked by the diode and the small battery will keep the radio on with 12V.

A cheaper solution could be a 30 diode connected to 25V 1,000,000 microfarad capacitor that is connected to the radio 12V input.

The diode is 'forward biased' when the engine/ alternator is running supplying 13-14.5V charging voltage, during a dip the diode blocks the low voltage from dragging down the radio. Be sure to connect the diode the right way around.

 

[kc8adu]

mfj makes one for hf radios.
good for 20a.
keeps the rig at a solid 13.8 over a wide range of input voltage.
helps a lot with hf rigs to get max power out and better imd.
paralleling 2 lesser units is a[censored]gamble

 

[DriveHard]

why not just add a second isolated battery?

 

[Win]

Originally Posted By: kc8adu
mfj makes one for hf radios.
good for 20a.
keeps the rig at a solid 13.8 over a wide range of input voltage.
helps a lot with hf rigs to get max power out and better imd.
paralleling 2 lesser units is a[censored]gamble


Yep - I've always heard them referred to as battery boosters:

http://www.mfjenterprises.com/Product.php?productid=MFJ-4416C

 

[Vern_in_IL]

Thanks guys, giving that MFJ a try!