12V Bench Charger as a Power Supply

[dayradebaugh]

My 40 year old Craftsman 12V bench charger just quit, and I'd like to replace it.

My hobby is restoring trucks. When I wasn't charging a battery, I could use this charger as a sort of "power supply" to test 12V components, such as heater motors, bulbs and the like. To accomplish this, I would switch the charger into "Activate" mode, which I assume provided ~13V to a load up to the rated current capacity of the charger.

I have a very large wheeled charger for big jobs:



I have a few of questions:

1. There seem to be a lot of chargers out there for modest prices but which appear to me to be of very dubious quality. Would you have any recommendations about a good quality unit that would replace this old Craftsman that would have this "power supply/Activate" functionality? The high-quality brand was Schumacher back in the old days, but I don't know if they still deserve this reputation.

2. Alternatively, when I want to test a 12V component, could I simply put my big wheeled charger on 12V Start mode and hook up the leads to whatever it is that I'm testing?

3. Finally, one feature that I like on my chargers is a dial that shows how much current is being supplied to the charging process. Do any units still offer these, or has it all gone "automatic", such that you can't really tell what's happening in the charging cycle, or if anything is happening at all.

Thanks for your advice.

 

[ipgenie]

I have a 12v Victron charger that can also function as a power supply. It's got settings for all different types of batteries and the app shows lots of data like power used and charge cycle data. Kind of spendy but excellent quality.

Victron Energy Blue Smart IP67 12-Volt 25 amp 120VAC Battery Charger NEMA 5-15 (Bluetooth) https://www.amazon.com/dp/B07TMRJQTH/?tag=atomicindus08-20

 

[dayradebaugh]

Thanks. I see this provides data via smartphone. Is this the new trend?

 

[JWC86]

Following this closely. I’ve been keeping a motorcycle battery on my bench for years to use as a power supple for the same purpose.

Something as described that says the current used would be handy for sure.

 

[AffableCurmudgeon]

For testing components that don’t draw a ton of amps, a PC power supply works great. PC power supply has three separate buses. I have one on my workbench with terminals for 3.3, 5 and 12 volts. I even added a USB port to it. You can get used ones for less than $10.

 

[Pontiac787]

Not sure how much testing you’re doing but my recommendation would be to either use an actual 12v power supply or a battery. Please don’t test anything with your charger on start mode.

 

[ipgenie]

Thanks. I see this provides data via smartphone. Is this the new trend?

There are probably others who use a phone but I'm not aware of which ones. I've used a few Iota chargers that are also power supplies and they are good quality but no gauges unless you use your multi meter. I didn't expect to like the Victron as much as I do but the data in the app is nice and it's water tight and no fan to fail or make noise. Only downside is the cost.

 

[theoldwizard1]

Get a used PC power supply. 12v @ (?)A

 

[AdAstra]

The Victron Smart IP65 and IP67 series are the best on the market for being able to charge most any chemistry and set all parameters to your liking, and see data on charging status, current, voltage and energy (and even history of these for past charges), as long as you are OK w using the (excellent) phone app to configure/monitor it.

Being able to set the absorption/float voltages to exactly what the battery manufacturer recommends is invaluable vs relying on fits-none presets from other chargers. (Different AGM battery makers use different alloys etc w different potentials, even before getting into lithium and others.)

And yes they also have a power supply mode.

The IP65 is probably a better form factor for a bench/shop charger.

Notting else even close in this segment, these have same features of much more expensive/fancier Victron and other marine battery bank chargers (with the one exception of temperature monitoring probe for battery, but that’s more for the high charge rates of big battery banks.)


I got mine on eBay, there are a few sellers who are dealers that sell open box ones.

 

[fourjeepin]

For low amp testing, I use an old 12v wall wart. I considered a pc power supply but wasnt motivated enough after looking at the required years ago

 

[AffableCurmudgeon]

Here my PC power supply with 3D printed components.

 

[Walkers]

Another option is simply a 120vac to 12vdc transformer. These were available in lots of furnaces for many decades, are cheap and available.

 

[dayradebaugh]

Not sure how much testing you’re doing but my recommendation would be to either use an actual 12v power supply or a battery. Please don’t test anything with your charger on start mode.

Would I be correct in assuming that the reason for not doing this is that the charger will supply a lot of current, and if the device being tested has a short, you will simply fry it?

Thanks

 

[dayradebaugh]

For testing components that don’t draw a ton of amps, a PC power supply works great. PC power supply has three separate buses. I have one on my workbench with terminals for 3.3, 5 and 12 volts. I even added a USB port to it. You can get used ones for less than $10.

Thanks. The used one I found out there are about ~$90.

 

[dayradebaugh]

Here my PC power supply with 3D printed components.

That's a nice unit. Can you remember where you got it?

Thanks

 

[nadogail]

I like a battery, with a Charger or Power Supply to recharge the battery. The battery will provide Rippel Free DC and act as a filter to smooth the the output of a connected charger.

 

[AffableCurmudgeon]

That's a nice unit. Can you remember where you got it?

Thanks

I bought the power supply on OfferUp for $5. I designed and 3D printed the faceplate, and the lug covers. The USB port is from the dollar store, lugs are just stainless-steel nuts and bolts.

 

[dayradebaugh]

I bought the power supply on OfferUp for $5. I designed and 3D printed the faceplate, and the lug covers. The USB port is from the dollar store, lugs are just stainless-steel nuts and bolts.

Pretty nice!

 

[desertdog256]

You might consider a ham radio power supply. They normally provide 13.8 volts at pretty high amperage ratings. As a bonus the power is typically very clean. I own three to power my radio gear and I think one of them does a true 13.8 volts at 40 amps. One has a switch that sets it to always stay at exactly 13.8v. Flip the switch off and turn the knob to vary the voltage. They start under $100 and go up, way up $$$$ from there.

Astron brand may be the gold standard. I have an Alinco that I like a lot.

MTC Radio, Ham Radio Outlet, Gigaparts, DX Engineering are some recommended sources.

 

[RTM]

Thanks. The used one I found out there are about ~$90.

Good grief. I had a drawer full of them at work. Every time we upgrade laptop PCs, we toss the old PS in the drawer, or recycling. They could be reused about 90% of the time.

The Macs were always trashed or recycled, cuz the changed the plug every three years,

I coulda been rich at that rate.

 

[Walkers]

It had slipped my mind, but I bought a 12vdc power supply to run a big hose reel off of a truck in my shop. This is what I bought. Cheap and works well.

 

[Rabid Badger]

With the proliferation of cheap bench power supplies there really isn't a good reason to press something else into the role or go the DIY route.

Amazon.com : bench power supply

Once you have one you'll wonder how you got by without it.

EDIT: I recommend getting one with an output enable/disable button.

 

[Walkers]

With the proliferation of cheap bench power supplies there really isn't a good reason to press something else into the role or go the DIY route.

Amazon.com : bench power supply

Once you have one you'll wonder how you got by without it.

EDIT: I recommend getting one with an output enable/disable button.

Wow, who knew!

 

[cabranch47]

I have this one and have been very pleased with it. There was a lifetime warranty when I purchased it about 2 years ago, might still have it.

https://www.amazon.com/dp/B08DJ1FDXV/?tag=atomicindus08-20

 

[VolvoRyan]

Get a dedicated power supply, or charger (CTEK, etc) with a dedicated PS mode. Battery chargers can be pretty sloppy with the current output.

-Ryan

 

[dayradebaugh]

I have this one and have been very pleased with it. There was a lifetime warranty when I purchased it about 2 years ago, might still have it.

https://www.amazon.com/dp/B08DJ1FDXV/?tag=atomicindus08-20

Thank you for your suggestion. Have you used this extensively? I checked it out on Amazon and it had a number of bad reviews. Ordinarily I would give this a pass because of these bad reviews. Would appreciate hearing more about your experience with this device.

After some research, my current preference is (for a lot more money)

https://www.amazon.com/dp/B07FD1NX97/?tag=atomicindus08-20

which had a good teardown review

But these decisions all involve what you can learn from the Internet, which is problematic.

Thanks

 

[dayradebaugh]

I have a bare-bones solution to this issue, for very little money at all. I have a good variac, to which I could attach a rectifier, such as

Amazon.com: Customer reviews: YueYang MDQ100A Single Phase Bridge Rectifier,Full Wave Bridge Rectifier ac to dc,100amp 1600volt for Golf cart

Find helpful customer reviews and review ratings for YueYang MDQ100A Single Phase Bridge Rectifier,Full Wave Bridge Rectifier ac to dc,100amp 1600volt for Golf cart at Amazon.com. Read honest and unbiased product reviews from our users.

www.amazon.com

This solution leaves me with a ripple factor in the output, but I'm not sure whether this would be a show-stopper for testing automotive accessories. As a pure lab unit, for testing circuit boards, it would not be suitable, but for automotive shop use, perhaps it would be good enough.

Any comments?

Thanks

 

[cabranch47]

Thank you for your suggestion. Have you used this extensively? I checked it out on Amazon and it had a number of bad reviews. Ordinarily I would give this a pass because of these bad reviews. Would appreciate hearing more about your experience with this device.

After some research, my current preference is (for a lot more money)

https://www.amazon.com/dp/B07FD1NX97/?tag=atomicindus08-20

which had a good teardown review

But these decisions all involve what you can learn from the Internet, which is problematic.

Thanks

I would say that I am an occasional user. I modify/customize golf carts. I use this to test add-ons to make sure they work and troubleshoot problem issues. I can also determine the amperage draw to choose the correct wire size/fusing. I have had not had any issues with it

 

[cabranch47]

Thank you for your suggestion. Have you used this extensively? I checked it out on Amazon and it had a number of bad reviews. Ordinarily I would give this a pass because of these bad reviews. Would appreciate hearing more about your experience with this device.

After some research, my current preference is (for a lot more money)

https://www.amazon.com/dp/B07FD1NX97/?tag=atomicindus08-20

which had a good teardown review

But these decisions all involve what you can learn from the Internet, which is problematic.

Thanks

I looked at the amazon listing. It indicates 3300+ reviews with a 4.5 star rating. Seems pretty good to me.

 

[Rabid Badger]

Thank you for your suggestion. Have you used this extensively? I checked it out on Amazon and it had a number of bad reviews. Ordinarily I would give this a pass because of these bad reviews. Would appreciate hearing more about your experience with this device.

After some research, my current preference is (for a lot more money)

https://www.amazon.com/dp/B07FD1NX97/?tag=atomicindus08-20

which had a good teardown review

But these decisions all involve what you can learn from the Internet, which is problematic.

Thanks

If you don't mind about 15 minutes of assembly, this is the best deal going in bench power supplies:

https://www.amazon.com/dp/B096548QH5/?tag=atomicindus08-20

 

[dayradebaugh]

I looked at the amazon listing. It indicates 3300+ reviews with a 4.5 star rating. Seems pretty good to me.

Good point.