24v step downs (1 Viewer)

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I have been reading everything I can on here about step downs. I have a BJ73 24v that I am looking at building a 12v fuse panel for to power my Ham radio, 12v outlet, and maybe some misc accessories down the road. I believe I only need about 20-25amps (Yaesu Ham is 15amps at 80 watts, and 12v cigarette lighter charger is 1-1.5amps). I have an ARB mt45 that runs on 24v and a 24v stereo so those are common stepped down accessories I don't need to worry about.

I cannot find a Pyle PSWNV720 in stock in the US (looks like its discontinued). Victron Energy Orion IP20 25amp at $70 looks like the next best option. Those who have installed a 24v step down recently, what are you using?
 
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I can't talk about anything recent, but the Samlex converter I bought 15 years ago is still working perfectly... It happily runs a stereo, Icom VHF, and whatever other 12 volt lights, iPhones, etc... I think it's 20 A...
 
I can't talk about anything recent, but the Samlex converter I bought 15 years ago is still working perfectly... It happily runs a stereo, Icom VHF, and whatever other 12 volt lights, iPhones, etc... I think it's 20 A...
me too, Samlex SDC-23 model via amazon. works like a champ.
 
Victron Orion Tr 24-12 20A
 
I also used a Samlex SDC-23 for a GMRS radio and have been happy with it aside from the fact that I felt like it needed an upstream relay to keep the vampire drain down.
 
My Samlex also is switched to prevent phantom power drain.
 
Here's my setup
Cole Hersee 24 v continuous duty solenoid Amazon product ASIN B001FQMZO2with the orion 70 amp converter installed in the glovebox. the downside is none of my 12v accessories are available unless the key is on.
The orion has a built in fan, so the drain would be too much to not have it switched.
IMG_20220203_083104.jpg
IMG_20220203_082954.jpg
n the glovebox
 
Is there a way to set up a converter so that the radio doesn’t reset every time you turn the key off?

I have had great success with doing the main 12v power requirements as mentioned above. I am using an ICT 24 to 12
30 amp converter that is switched on the key with a 24v relay so it will not present any parasitic draw to the batteries.
In the past for the memory power requirements I have gotten away with pulling 12volts off of the low side battery. This however is not a good long term solution as the draw albeit small will start to mess with you battery equalization which the alternator needs to see to do it’s job correctly.
You eventually will end up with unbalanced batteries which is hard on both batteries and alternator.

I found a solution that for me has fixed the problem. I installed a small “Buck” converter that I got off Amazon. It is a very small 24v to 12v 3amp in line converter that I wired to an un switched 24v supply and then to the radio memory power. I do not know what kind of draw it presents but after having it installed for a year or my batteries are staying equalized and no issues with radio presets or dead batteries anymore.

This is what I got......

Cheers, Rob
 
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I have had great success with doing the main 12v power requirements as mentioned above. I am using an ICT 24 to 12
30 amp converter that is switched on the key with a 24v relay so it will not present any parasitic draw to the batteries.
In the past for the memory power requirements I have gotten away with pulling 12volts off of the low side battery. This however is not a good long term solution as the draw albeit small will start to mess with you battery equalization which the alternator needs to see to do it’s job correctly.
You eventually will end up with unbalanced batteries which is hard on both batteries and alternator.

I found a solution that for me has fixed the problem. I installed a small “Buck” converter that I got off Amazon. It is a very small 24v to 12v 3amp in line converter that I wired to an un switched 24v supply and then to the radio memory power. I do not know what kind of draw it presents but after having it installed for a year or my batteries are staying equalized and no issues with radio presets or dead batteries anymore.

This is what I got......

Cheers, Rob
Ok cool. Thanks a lot for the insight!
 
The main issue with the memory wire, is that the way most head units are wired, the memory wire also pulls full power when the unit is turned on, which can overload a small converter. I've given up trying to keep my memory powered up, after trying many differerent ideas. One day I'll get a Jensen 24 volt head unit with solid state memory chip and fix all my problems at once....
 
Yes, the memory/power conundrum is why I used diodes.
Problem solved.
 
Scored a Pyle 720 off ebay for $20! So this weekend I am digging into the 24v to 12v step-down. I've been reading through a ton of threads on this, and most of them involve a 12v stereo. Since I don't need that, here is what I am thinking, basically following @mongoose2231 's diagram below.

24v off the high side battery and using the lighter into a relay so the step-down functions when the ignition is on. Running that to a 6-fuse Blue Sea fuse panel for a 12v cig lighter and ham radio. Thoughts? Should I ground the step-down separately or run it back to the battery?

1644604469943.png
 
I grounded the converter to the body not back to the battery.

Is the cig lighter not powered when no key is inserted or present?
I thought it was on 24/7. I can't remember now.
 
I am going to test the lighter with a multimeter this afternoon and confirm. Ive read its key power, but I cannot guarantee someone along the way changed that on mine. Someone tinkered with a decent amount of wiring in the past.
 
I changed my cig lighter to 12v since there are many devices with that style power connector.
I think I took the original 24v lighter power and used it with a mini converter to power radio memory.
 

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