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gboulton
07-25-2005, 05:04 PM
I own the Apache Smart-Charger Li-Pol 2500 charger, which I use to charge my Thunder Power 3 Cell 2100maH battery. The charger works great.

Currently, the only source of power I have for it is my truck battery. I'm wondering how difficult it would be to purchase some sort of AC-DC 12V converter from Radio Shack (or wherever) so that I could plug it in at the house when I returned from the field, so as to have a fresh charge on the battery when I head to the field the next day.

I know not to leave it charging overnight or anything...I'm just looking for a way to power my charger without having to pop the hood on the truck. :)

Would it be cheaper/easier to simply by a 12V battery and leave it in the shop?

TIA,

gb

Jason T
07-25-2005, 06:24 PM
gb,

Welcome to Wattflyer!

I use a Radioshack AC/DC power supply to run my DC chargers when at home. I can't remember the model but it is the expensive one that puts out 13 or 15 amps. You may not need one this big. I know they have one that is in the $40 range that puts out 3 amps. So I use this one when at home and then I drag a 12v deep cycle marine battery for the field.

Jason

Red Scholefield
07-25-2005, 07:00 PM
Radio Shack are a bit over priced. You might be able to do better.

Here are three on line sources at good prices.

http://www.efunctional.com/new-pyramid-power-supplies.html

http://www.millionbuy.com/caudio-kit-sup.html

http://www.buyreliant.com/psupplies/pyramid_power_supplies.htm

If you are at all handy with a soldering iron you can convert a PC power supply quite easily. A link to instructions may be seen at
the Battery Clinic.

RickAvery
07-25-2005, 07:18 PM
What I did was to purchase a battery caddy jumper unit. It plugs into your 110vac to keep charged and you can then just clip your LiPo and other non-110 chargers to it. Then when you go to the field, just carry it out to your spot and charge right there. No more hood popping!
Rick

gboulton
07-25-2005, 08:21 PM
Thanks for the input guys!

Jason T
07-26-2005, 02:02 AM
Wow, I paid too much for my power supply.:o Oh, well I know next time. :)

ragbag
07-26-2005, 02:35 AM
I've been told that an automobile battery that reads 12.0 is a dead battery. 12.6 is half full/half empty, optimist/pessimist.

I do know that when it reads less than 12.0 volts it has a bad cell and will not start anything. That I know from experience. It happened to me recently and I just happened to have a meter in my van.
George
Gainesville FL

Hey George, It can read slightly less than 12 volts (11.8 actually) and still be good. It may just need a charge. Leaving it at this low level however will end up in sulfation fairly quickly and you can't charge it - but you knew that. :-)

Red

admin
07-26-2005, 05:21 AM
I use this one from Hobbico:

http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXL356&P=RT

$89.00 and handles up to 11.5 AMP load

http://www2.gpmd.com/image/h/hcap0250.jpg

Fly-n-3D
07-27-2005, 02:40 PM
I use one from hanger nine with my lipo charger. 120v AC input/12v DC output.

gboulton
07-28-2005, 06:35 PM
Sorry I hadn't jumped back in here in a while. :)

As it turns out, found a small, easily portable in my field box, motorcycle battery that fits the bill nicely. Charges the LiPol in roughly the same time as the truck's battery did, and doesn't require me to carry the plane up the hill to the truck, or pop the hood. Also picked up an inexpensive charger for it. Works like a charm. :)

Red Scholefield
07-29-2005, 03:18 PM
What I did was to purchase a battery caddy jumper unit. It plugs into your 110vac to keep charged and you can then just clip your LiPo and other non-110 chargers to it. Then when you go to the field, just carry it out to your spot and charge right there. No more hood popping!
Rick

I just picked up a Husky Jump Start unit at Home Depot with a 17 Ah Gel Cell battery for $39.95 (price just a 17 Ah lead Acid battery). I has a charger included, cigarette ligher plug and state of charge indicators. The switch on it didn't work (and neither did it work on 4 other off the stack when I went back to Home Depot to get a good one). But I bought it for the the purpose stated above, to operate chargers at the field and to have a few Ah of 12 volts available for the next hurricane. Took out the switch, took off the cord storage unit (all just screwed on), took out the heavy jumper cables, added two bananna jacks where the switch came out by epoxing a 1/16 in thick plastic plate back of the hole and drilling two holes for the bananna plugs. Makes a real neat power unit.

SargentM
08-01-2005, 10:54 AM
I scored an ATX style power supply from a PC store for nothing, It can handle up to 8 Amps at 12V and is fine for anything my Apache charger can handle, right up to my 4S 2450 tanic packs.

Usually all that is required to make a PC supply work is a large (5W) resistor on the 5V line so that that supply will give the full 12V, I also put a nifty illuminated red rocker switch in to tell me when I have power.

Red Scholefield
08-01-2005, 05:42 PM
Don't for get to bring that 5 volts out on a couple of banana jacks also. It makes a great source for bench testing servos and set ups without needing a battery.

unloco2
08-10-2005, 05:20 PM
Just mofified 2 power supplies. An ATX pc unit that died in my our pc. repaired it and increased the voltage to 13.4 volts on the 12 volt line. Don't reccomend this for anybody except those with electronic background. The unit uses the TI tl494 which appears to be the most popular switchmode controller, and is the most flexible to fool around with.
The other supply is an old automobile battery charger I had around and haven't used in years. I made some fun mods by adding an adjustable voltage regulator and a power transistor. Set it at 13.5 volts and it regulates like a rock.
These mods are cheap if you have these supplies laying around, but check out the two items posted by Red S. with respect to the sources for low cost supplies and the Home Depot charger/field supply.

allena99
08-19-2005, 11:10 PM
I also have the Husky Jump Start unit from Home Depot that Red mentioned above. The switch seems to control only the jumper cable output, the cigar lighter receptical is hot all the time. I bought an adapter at Radio Shack for the receptical that comes out as banana jacks for $7.95. The unit has some serious capacity at the jumper cable terminals like 250Amp for several minutes or 400Amps for a short burst. I just left the cables on and use the banana plugs. I think that can handle about 5 Amps. I use mine all the time on the bench as a second power supply. The charging system is automatic and can be left on without damage according to the manual. The unit is very compact with a nice handle on the top and handy to take to the field to power my field charger. Can't beat the $39.95 price...

ragbag
08-20-2005, 12:55 AM
I made one of the power supplies from a pc power supply, followed the instructions from the RC Battery Clinic. I did pull out a 5 volt tap also. Use it to break in brush motors and other lower voltage things.

www.rcbatteryclinic.com

I just put on an extra positive pole, the 5 volt one.

728

The picture is worth a thousand words, well thats what somebody said anyway.

By George;)

Red Scholefield
08-20-2005, 12:04 PM
I also have the Husky Jump Start unit from Home Depot that Red mentioned above. The switch seems to control only the jumper cable output, the cigar lighter receptical is hot all the time. I bought an adapter at Radio Shack for the receptical that comes out as banana jacks for $7.95. The unit has some serious capacity at the jumper cable terminals like 250Amp for several minutes or 400Amps for a short burst. I just left the cables on and use the banana plugs. I think that can handle about 5 Amps. I use mine all the time on the bench as a second power supply. The charging system is automatic and can be left on without damage according to the manual. The unit is very compact with a nice handle on the top and handy to take to the field to power my field charger. Can't beat the $39.95 price...

I found that removing the jumper cables cleans up the unit a lot. You can unscrew the back and get to everything real easy. I removed the bracket in bacj as well as the switch and replaced it with two banana jacks mounted on a plastic plate and screwed in place where the swithc was. This gives me two outlets from which to run things if needed.

Slent thndr
08-20-2005, 08:01 PM
A few months ago when I was building my new PC I bought a fancy 400W power supply and just discarded the inferior one that came with the case I bought. As it turns out, the old one will work just fine for the Triton charger I am buying. It’s only worth $25 if you were to buy one new but it is capable of supplying 20A at 12V. That’s more amps than the $100 power supplies you guys are buying for your chargers.

Take this PSU for instance: http://www2.towerhobbies.com/cgi-bin/WTI0001P?&I=LXL356&P=V (http://www2.towerhobbies.com/cgi-bin/WTI0001P?&I=LXL356&P=V). It costs $90 and can only supply 11A. The thing that puzzles me is that a $25 PC Power Supply would work better. Is there some feature that my PC power supply won’t have that these other ones have?

Red Scholefield
08-20-2005, 08:21 PM
A few months ago when I was building my new PC I bought a fancy 400W power supply and just discarded the inferior one that came with the case I bought. As it turns out, the old one will work just fine for the Triton charger I am buying. It’s only worth $25 if you were to buy one new but it is capable of supplying 20A at 12V. That’s more amps than the $100 power supplies you guys are buying for your chargers.

Take this PSU for instance: http://www2.towerhobbies.com/cgi-bin/WTI0001P?&I=LXL356&P=V (http://www2.towerhobbies.com/cgi-bin/WTI0001P?&I=LXL356&P=V). It costs $90 and can only supply 11A. The thing that puzzles me is that a $25 PC Power Supply would work better. Is there some feature that my PC power supply won’t have that these other ones have?

The only feature they have is making big bucks for Tower Hobbies. You can buy much better at much lower prices on line if you are not comfortable with converting a PC power supply.
Here are three on line sources at good prices.

http://www.efunctional.com/new-pyramid-power-supplies.html

http://www.millionbuy.com/caudio-kit-sup.html

http://www.buyreliant.com/psupplies/pyramid_power_supplies.htm

Slent thndr
08-20-2005, 08:25 PM
I'm fine with converting it i was just making sure that i wasn't missing some feature that it had to have.

Red Scholefield
08-20-2005, 09:19 PM
I'm fine with converting it i was just making sure that i wasn't missing some feature that it had to have.

While you are converting it, don't forget to bring out a couple of jacks to access the 5 volts. Great for powering your plane on the bench or breaking in electric motors (imersed in water).

unloco2
08-21-2005, 03:27 AM
SlentThndr

The main problem with PC power supplies is that they sense the 12 volt line short of the output. What that means is that between the regulation point and the output voltage is a choke and capacitor. The choke is a wirewound device used to improve the noise and ripple charecteristics, but it does have some resistance. At the current levels specified, that small resistance develops a substantial voltage drop across it. Regardless, the design is such that with max voltage drop, the power supply will put out 12 volts +or- 5%.

There is a way around this by placing a resistor in parrellel with one of the reference resistors, and creating a slightly larger voltage out put. If you want details please email me and I'll be glad to give you an example and how I did this. My supply puts out 12.5 volts minimum at full load. 13.5 volts no load, with no increase in noise or ripple. The other thing is that I never need more than 4 or 5 amps to chage my packs, (park flier)..

Slent thndr
08-21-2005, 04:09 AM
Hey guys thanks.
Now I accually found one of the Newer AT style PSUs. But it is from a CD tower and not a computer, which should mean that when switched on it gives constant 12V power regardless of seeing a 5V load from the MB.

Do I still need to the mods with this one? Well i will probably have to do the risistor thing like you said but if I dont care about the more frivilous things like adding lights and posts and switches and 5V power for servos and such...

The other thing is that it can only supply 11A, while the Triton reccomends 13A. I will only be charging small 3Cell 1500 Mih Lipo Batts, and some 6 and 8 cell Nicds and NiMH batts.

rcers
08-21-2005, 10:29 PM
The other thing is that it can only supply 11A, while the Triton reccomends 13A. I will only be charging small 3Cell 1500 Mih Lipo Batts, and some 6 and 8 cell Nicds and NiMH batts.
You will be fine with that. 11Amps are plety for the triton on all but very large packs at 5 amp charge rates.

Slent thndr
08-22-2005, 02:26 AM
ok so it will work... but will it need less conversion than the others? :( I guess I diddn't realize this was so much work. If I still have to do all the stuff that the batt clinic site says, then i might as well just buy the $40 Pyramid 10 amp PSU from one of those sites red showed me. :o

Does the CD one (mentioned earlyer) help anything?

Slent thndr
08-22-2005, 08:37 PM
Hey guys I tested the CD tower 11A PSU I had with my multimeter, and to my relief found that when I turn it on it supplies 11.82V. No need to add a fake load. It slowly flips between 11.81 and 11.83, but I assuime that this is normal. I know that it is supposed to be 12V but is 11.82 ok?

If so than all i will have to do make a connection for the charger. Red, I saw you installed posts to clip the aligators on to. I was thinking of putting female bananna plugs in a block of wood with the 12V attached to them, and then making a Y in the charger's cord between the charger and the aligator clips, and installing male bananna plugs. That way I can use the alagator clips for field charging, but not have to mess with them at home. Would this work? My only concern is with putting a Y in the Triton's power cord.

rcers
08-22-2005, 09:04 PM
I know that it is supposed to be 12V but is 11.82 ok?
Most chargers are OK in the 11.5v-15v range. Mine pumped out 11.9v and was fine on my Triton.

My only concern is with putting a Y in the Triton's power cord.

I just used some of my favorte connectors and cut the clips off. Then added the connector to all three ends. One wire with connectors from my charger PS and the same connector to the clips. Works very well and easy to do. Just as simple as adding them to your battery!

Mike

Red Scholefield
08-22-2005, 09:11 PM
Hey guys I tested the CD tower 11A PSU I had with my multimeter, and to my relief found that when I turn it on it supplies 11.82V. No need to add a fake load. It slowly flips between 11.81 and 11.83, but I assuime that this is normal. I know that it is supposed to be 12V but is 11.82 ok?

If so than all i will have to do make a connection for the charger. Red, I saw you installed posts to clip the aligators on to. I was thinking of putting female bananna plugs in a block of wood with the 12V attached to them, and then making a Y in the charger's cord between the charger and the aligator clips, and installing male bananna plugs. That way I can use the alagator clips for field charging, but not have to mess with them at home. Would this work? My only concern is with putting a Y in the Triton's power cord.

I never use Aligator clips. All my charging stuff has banana plugs. For field charging I have a cigarette lighter plug adapter made to accept banana plugs. If you want to use Aligator clips, just solder on about an inch of 5/32 IDbrass tubing (take some banana plugs with you to make sure it fits) that will accept banana plugs and your can quickly convert to aligator clips.

Slent thndr
08-22-2005, 10:03 PM
Well I want to just use the alligators to connect directly to the car battery. So I guess I could just cut them off halfway and then solder deans on to them and to the charger end and the PSU as well, like rcers said. I guess it would be a bad idea to use deans though, because thatís what all of my batts use. It wouldn't be pretty if someone accidentally plugged a lipo directly into a car battery. :eek: What is a good connector other than deans? Banana plugs maybe?

Red Scholefield
08-22-2005, 10:28 PM
Well I want to just use the alligators to connect directly to the car battery. So I guess I could just cut them off halfway and then solder deans on to them and to the charger end and the PSU as well, like rcers said. I guess it would be a bad idea to use deans though, because thatís what all of my batts use. It wouldn't be pretty if someone accidentally plugged a lipo directly into a car battery. :eek: What is a good connector other than deans? Banana plugs maybe?

Yes, banana plugs - they are pretty much the standard for connecting to a power supply. Don't cut off the power cord, just put banana plugs at the end and fixe the aligator clips with banana plug recepticals (1" piece of brass tubing the ID to tightly fit the banana plug).

Slent thndr
08-22-2005, 10:39 PM
Yeah that’s what I meant... I think. Basically put banana plugs in between the alligator clips and the charger, and then fix the Power Supply like the alligator clips so that ether one can connect to the charger. Right?

this part I don’t get:

(1" piece of brass tubing the ID to tightly fit the banana plug).

Don’t they sell male and female banana plugs that I can use? Or are you talking about some kind of special insulator or something that I can make out of brass tubing?

rcers
08-22-2005, 10:47 PM
Don’t they sell male and female banana plugs that I can use?Yes they do.

But Red is just saying you can use brass tubing as well.

Mike

Slent thndr
08-22-2005, 11:00 PM
Oh i see, thanks

simibill
08-25-2005, 11:12 PM
I also have the Husky Jump Start unit from Home Depot that Red mentioned above. The switch seems to control only the jumper cable output, the cigar lighter receptical is hot all the time. I bought an adapter at Radio Shack for the receptical that comes out as banana jacks for $7.95. The unit has some serious capacity at the jumper cable terminals like 250Amp for several minutes or 400Amps for a short burst. I just left the cables on and use the banana plugs. I think that can handle about 5 Amps. I use mine all the time on the bench as a second power supply. The charging system is automatic and can be left on without damage according to the manual. The unit is very compact with a nice handle on the top and handy to take to the field to power my field charger. Can't beat the $39.95 price...
Can you give me the P/N for the Radio Shack adapter you mention? My Radio Shack doesn't seem to know what i'm asking for.
Thanks,

Plane_freak
08-26-2005, 12:07 AM
For my power supply I went to Goodwill. thats right a thrift store. First buy a cheap old computer. make sure it will handle the draw current though. then using a voltage meter find the 12 volt plug and cut them apart. Seperate negative from postitive then solder the wires to two at least 2 inch long bolts. Make sure to test the power source and be sure to remove the power source from the computer. And for safety mount the power source on a piece of wood and make sure the terminals do not touch. This should cost about $5.
hey it is better than paying 100 bucks for the same excact thing just a little fancier.

vtwinguy
08-26-2005, 12:11 AM
I use a converted computer power supply, it works real well and cost $13.00.
Check on ebay, there usually are quite a few available ;)

Red Scholefield
08-26-2005, 01:53 AM
Can you give me the P/N for the Radio Shack adapter you mention? My Radio Shack doesn't seem to know what i'm asking for.
Thanks,

Radio Shack
Cigarette Lighter Plug with Banana Jack
$7.99 Brand: RadioShack
Catalog #: 270-1521

simibill
08-26-2005, 03:20 AM
Thanks

ragbag
08-26-2005, 04:14 AM
The one thing some people forget is that a computor power supply is very "clean" power. They are filtered and put out a very clean, as in no pulsing, power.

Some power supplies have an 60 cycle AC noise running through it. That is why a car battery charger doesn't make a good power source, it wasn't designed to power electronic equipment, just charge a battery.
By George

Slent thndr
08-26-2005, 02:50 PM
hey cool (the adapter thingy). But can that provide the same amps and everything as directily connecting to the batt? I guess it might depend on the car.

jrb
08-26-2005, 03:40 PM
Neat, but only 1amp: http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F009%5F001%5F005%5F000&product%5Fid=22%2D505


6amps: http://www.vectormfg.com/catalog/vec004-acdc-converter-p-320.html

Can be found @ Best Buy; filtered?

mikenlapaz
08-27-2005, 02:27 AM
Thanks to the infomation on Red's site, I recently converted an older PSU. (250W output. 12v 8A)
I added sand type resistors to the exterior of the slotted air intake. A piece of U channel aluminum with back cutout made the mount. I reversed the cooling fan position to allow the air to exhaust over the resistors.

(I fiddled with 10 ohm 10 watt resistor(s) but they got too HOT. Ended up using (4) 1 ohm 10 watt resistors wired in series between a 5V wire and Grd. 12V outlet now reads 12.8.V. Resistors are only warm to touch 120-130F.
I reversed the fan to allow the cooling air to pass over the resistors as it exits the case.
Total out of pocket: less than $10 US Powers a friend's Triton without problem.

Slent thndr
08-29-2005, 12:45 AM
Very proud of my new homemade converter :)
I used a PC PSU from an old CD tower so it is allready designed to work withought the MB (mother board). It puts out 11.8V at 11A whenever you flip the switch:). And I made a cool connector system. Basically mounted some thick machine screws in a block of wood, ran the power to them, put a plastic safety devider between them, and velcroed it to the top of the psu. When i want to charge i just clamp the alagator clips from the charger onto it. It works like a charm. :) Will post pics soon hopefully.

Robert53
11-09-2005, 04:25 PM
Hello
I am very new to electric flight but not RC. wattflyer forums has helped greatly, getting me started, Thanks.
I have seen the PC power supply conversion (why didn't I think of that!) but haven't seen anything about a source for a new PS, so hopefully this post will meet the sites standards.

Try this site for a PS if you need one. I have been buying PC parts from them for years. They are one of the best places, if not the best to buy from.

site - http://www.newegg.com
power supply search results, generic, cheap.
http://www.newegg.com/Product/ProductList.asp?Manufactory=&PropertyCodeValue=0&PropertyCodeValue=0&PropertyCodeValue=0&PropertyCodeValue=0&PropertyCodeValue=0&PropertyCodeValue=0&description=&MinPrice=&MaxPrice=&SubCategory=58&Submit=Property