rckowal

Can an automobile battery charger be used as a power supply to provide the 12 volt input power for my Triton Jr. RC battery charger?

I have a brand new Vector car battery charger and would like to use it on my work bench at home to recharge my NIHD batteries.

Replies will be much appreciated.

Figure.N9ne

car battery chargers aren't a regulated 12v power supply so it wont work. the only way I've heard of it working is to connect a 12v battery in line to regulate the power.

Bub Steve

rckowal::I use a lawn-Mower 12V batt as a regulator on mine ( small and easy to move around) bub, steve

CHELLIE

If you have a old Computer laying around, they make the best power supplys,
and its FREEEEEE

http://www.marcee.org/Articles/PCPowerSupply.htm

Buck Rogers

It might work but it depends on the charger you are using. As already pointed out the supply is not regulated and is very rough.

Some chargers can handle a range of input voltages so they might work depending on what input voltage your charger needs. The only snag is you might blow up your charger if there is a spike in the supply as the car battery charger will not filter it out.

rckowal

Thanks for all of the helpful replies.... OK, I'll scratch the idea of using the car battery charger but the one about the old computer power supply is a good one. I may just have one that I can use.

CHELLIE

Hi rckowal here are a few threads on the computer conversion, have fun, Chellie

http://www.wattflyer.com/forums/show...r+power+supply

http://www.wattflyer.com/forums/show...r+power+supply

http://www.wattflyer.com/forums/show...r+power+supply

Bill G

The problem with the car battery chargers is that they are not filtered. The votage regulation is not always as critical, as some lipo chargers will accept +/- several volts input. The ripple is what will burn out the lipo charger. Folks make the same mistake trying to use them to test car stereos and destroy the stereo, or at least the input filter caps, by overworking them. If you have the charger connected to a car battery at the same time then you may be ok, as the battery acts as a cap filter, but stand alone it will not work. I would not use it irregardless.

cliffh

Computer power supplies make great power supplies....BUT....try to find the OLDEST computer you can find. The old ones have very powerful 12 volt sections. Many new computers are much more dependent on the 5 volt sections and have only 3 amps or so available at 12 Volts. Some old supplies can operate at 18 to 25 amps continuous at the 12 volt section!

Try to find the oldest, heaviest, most unwanted boat anchor you can find.

By the way, many computer repair shops have little use for those big old supplies and will give you one.

CHELLIE

Great Advice yes the higher the amp rating the better

amarquez

Hi, DEFINITELY the PC power supply is the way to go!
Mine is a 300 watt unit that requires the green wire to be shorted to ground to turn it "ON"... AND THEN you have to put a load on the 5 volt output. I definitely recommend you that you DO NOT use large 10 Watt power resistors. They overheat too much...
You will be much better using an automotive tailight bulb with two filaments that can be connected (either of them or both at the same time), gives three possible load values, so that your PC power supply is forced to deliver a little more than 12 full volt to the charger. Use an automotive socket to house the bulb and avoid shorts or intermittent contacts, when test is succesful, wire it permanently.
Without the bulb load, the 12 V output only rise to 11.3 or so, but as soon as there is a load of several watts on the 5V circuit, the 12 V regulates beautifully to 12.4 or so, and maintains it up to 70 or 80 watts (6 amps to the charger or so).

It is true that older, beefier supplies were better, but beware that really old ones could be approaching the life limit or the capacitors inside, so please test it fully before connenting your charger to confirm it is still working properly. I used a 12V headlight bulb to place a 65 watt load on the 12V output, and my supply gave 12.01 volts, which are more than enough for my TRITON II to work perfectly, even charging a 12V car battery at its maximum setting of almost 7 amperes for hours without a hitch!

Finally, most good quality PC power supplies are well protected against brief shorts, mine has been "tested" a couple of times, it muted for several seconds and restarted by itself without damage...
Good Luck.
amclaussen, Mexico City.

Crasher

I bought a bench top DC power supply that I use for my Triton2 as well as for other 12vdc input chargers that I have. It is a $150.00 unit, with analog meters for current and voltage. The voltage is adjustable from 0 to 15vdc with a current rating of about 30 amps! I use it for my ham radio transmitters and all kids of other ham station equipment. It will charge most batteries too. I am not home right now, so I don,t know the model number. But the manufacture is MFJ out of Mississipi. I want to guess and say that the model number is 4036 or something like that. It is a transformer supply, not a switching solid state supply that can give you all sorts of trouble. I would not use a power supply from a old computer; radio hams don't even do that if they know what they are doing! This power supply may sound expensive, but belive me, in the long run, you will find additional uses for it and it will be well worth it. I loved mine so much, that I currently own three of the same unit! They weigh about 16lbs, so I don't bother to carry them around with me! Thats the tip from me, Crasher, flying over Silverwood, MI farms weather permitting and on the air too from this rare location!

Lieutenant Loughead

Just buy a $40 Cosel power supply on eBay, and forget about everything else. Mine has worked great for 6 years.

amarquez

I agree that a LARGE and HEAVY 30 AMPS capable adjustable Power Supply IS the best one!, (except for its price...) It should be capable of even charging a 12V CAR battery at 15 volts, probably reaching currents of more than 15 AMPS in that scenario.

But those fellow flyiers without the $150 or so, can charge their batteries with the Triton ans similar units fed by the PC Power Suppies at almost no cost.

Mine has been working beautifully even when subjected to some degree of abuse, like recharging my car battery after it was discharged flat when my wife left the auxiliary lights on all night! For this I had to push my Triton2 to its limits (6.5 Amps) since it is limited to 90 watts...

I have accidentally shorted the PC Power Supply briefly two times, but it self protected and shutdown, to resume working soon. Even the outlet airstream from the PC P.S. can be directed to help cool the Triton2 !

Overall, the PC Power Supply is an option for frugal fliers, mine received some additions like a DIGITAL Ammeter, a DIGITAL Voltmeter, (both work with the 5 volts outlet) and a variable output regulator based on the LM- 338 three leg adjustable regulator. (I use that for my PROXXON miniature jigsaw, that is tremendously helpful when I cut rounded fuselage formers from 1/8" plywood!).
Have a nice Christmas all of you.

flydiver

I am using the resistor and agree, they get hot. Mine are mounted to an internal heat sink with thermal compound.

I don't understand your advice to use a bulb to test then wire it permanently without the bulb.
Don't you need something to provide the resistance?

amarquez

I am using the resistor and agree, they get hot. Mine are mounted to an internal heat sink with thermal compound.

I don't understand your advice to use a bulb to test then wire it permanently without the bulb.
Don't you need something to provide the resistance?


Sorry flydiver, I was trying to make the suggestion that an automotive bulb (those with two filaments, one for brake and the other for turn signals) are MUCH better than the power resistors, since they produce less heating inside the Power supply case, they don't need a heat sink, and also serve as a pilot light! (and the bulb with the socket plus two switches were cheaper than the large power resistors where I live).

The glass, gas filled bulb itself insulates the very hot filament from the case, therefore the heating is less than the heating effect of the power resistor. My P.C. power supply case stays completely cool to the touch even when delivering 8 amperes to the charger.

I was talking about the socket for the bulb, I meant to test it and then wire the socket permanently, then reinstall the bulb. I used two small single pole switches to be able to put one filament as the load for the 5 volt circuit, or the other filament, or both at the same time! Sorry for the confusion, english is not my native language...
Good Luck.

amarquez

For those of you interested in adding a panel display to their modified PC Power Supply, I used these two DIGITAL displays, the Voltmeter is 0-20 volts DC, the Ampmeter is 0 to 5 Amps. Both use the 5 volt available from the PC power supply, are very accurate and the modified power supply looks impressive with them. I decided to buy the displays instead of having to continuously use my digital multimeter because if I forget to change the test leads, I frecuently used to leave the multimeter connected as an ammeter, which put a direc short circuit when trying to read voltages, so in the end I opted to install permanent panel displays, which give me a very good and fast way to check the status of a given pack or the recharge progress at a glance, with the great precision and resolution of the digital displays (0.01 Amp and 10milivolts)!

Here are the PDF datasheets of the units I bought, at less than 11 dollars each...in one local store here in Mexico City.


http://www.agspecinfo.com/pdfs/H/HB513520.PDF

http://www.agspecinfo.com/pdfs/U/UP-5A.PDF

The Ammeter is limited to 5 amperes, but I only use it for the 12 VDC variable voltage output that I built for my Proxxon mini jigsaw and when charging delicate small batteries for electric indoor fliers where small charging currents are a must.

Merry Christmas to all.

birdDog

Hee hee, Got an Astron bench 0-15V 50amp off Craigslist for $40! Check that site out. Sure, I had to drive 20 miles, but that beats shipping 30 pounds.

Henry Sistrunk

I use two that I made from old PC power supplys
Henry

Henry Sistrunk

Here are the instructions I used to convert mine.
http://www.hangtimes.com/id45.html

kyleservicetech

I've used my 20 Amp lead acid battery charger WITH a 120 ampere hour deep cycle battery many times as a good 12 VDC supply. It works, my home built switching power supply type A123 chargers pull 25 Amperes out of the 12 volt battery.

But, check out www.digikey.com for their part number 102-1947-ND

Or direct to the Digikey part number.
http://search.digikey.com/scripts/Dk...7-ND&x=26&y=17

This is a commercial 120 VAC input and 12 VDC output at 8.5 Amps power supply. This unit costs just under $40, not including shipping. And Digikey will sell to anyone with a credit card.

Simple to use, just connect 120 Volts to its AC input, and connect your 12 volt load to its output. This unit has a simple screw type terminal connections.

I've used these type power supplies at work before retiring, and five that I bought are still in service after 6 years of continuous operation, 24 hours a day 365 days a year.

The nice part of these type power supplies is they have regulated DC outputs. This one is regulated to within 0.5% ripple or noise. They are designed for continuous use and usually have built in overload protection. These are brand new units and also have a three year warranty.

You don't need to worry about blowing up an expensive charger with one.

amarquez

Now that Dennis mentioned the Digikey 102-1947-ND, let me tell you that I have seen them working perfectly since they are built for "Commercial" applications. That means the components and design is well though to work at a heavier duty than plain designs. At $40 they are certainly a sure bet.

If you open it and take a look inside, you will find it is practically the same design and (almost) the same construction as the ubiquitous PC "ATX" power supplies, but the 5 and 3.3 volts sections are absent. The "Commercial" use designation could signify an above average construcction.

ON THE OTHER SIDE, beware of the "Pyramid" brand transformer based regulated power supply... I bought two for a friend and me at EPO (Electronic Parts Outlet in Houston TX). That piece od crap, model PS8KX 6 Amp 12-Volt is a complete fraud.

It is sold and advertised as a "6 Amp Constant / 8 Amp Surge" current capacity, but the sad truth is that both of them are really only capable of less that 3 Amps... at 2.5v Amps the 2N3055 power transistor and the smallish heatsink are way too hot to touch, requiring an old 120 mm computer fan to be blowing hard on it to avoid shutdown. Anything over 3 Amps and the transformer starts to smell like burning. I was fool enough to buy a couple of them without realizing that the 100 watt electrical power consumption is completely insufficient to make it deliver the claimed 8 or even 6 Amp. (Typical power supply Efficiency is much lower for transfomer type supplies, Switched types like the PC and the Digikey above are always more efficient, reaching 90% is some cases.)

This is the offending piece of crap:

DON'T WASTE YOUR HARD EARNED DOLLARS IN THIS PIECE OF CRAP !!!

Enough rant. My two cents: get a used PC ATX type power supply. They run beautifully when the 5 V circuit has a load (I used a car turn signal bulb), are well protected against short circuits and can be found at low prices new or almost for free used.

Now, if you happen to have $40 and live in the USA, the Digikey option mentioned by Dennis is an excellent one. (thanks for sharing, Dennis).
amclaussen, Mexico City.

kyleservicetech

Sounds good, I've also used those ATX supplies for projects. But as you've indicated, some of them depend on loads connected to the other power supply outputs, not a problem with the proper instructions. And, you can't beat the price on these units.

And, if you've looked at the other power supplies Digikey offers, their prices skyrocket, if you go to 10 or 15 ampere outputs. Some of them go past 200 Amps, but you need a BIG credit card to buy one!

Nice thing about those supplies sold by Digikey, Mouser, and others, you just connect 120 / 240 VAC to its input, and connect your load to its output. And, Digikey sells a number of other power supplies with multiple output voltages, output currents, and so on. Their 2000 page catalog has some 20 pages of power supplies.

And you're right about those "Linear" type power supplies. I've designed and built more than a few of them over the past 40 years, and they will run danged hot. Now days, it's cheaper to simply buy a switching power supply that will do what you need, right out of the box.

If you want a severe case of sticker shock, take a look at the 12 Volt DC 200 AMPERE power supply below:

http://search.digikey.com/scripts/Dk...me=102-1498-ND

amarquez

OOOPS !!!

You are certainly right!

kyleservicetech

And, Digikey has power supplies with TWICE the power rating of this Thing!