Exactly what I was trying to warn you about, guess I’ve failed again. What you suggest might be possible, but not very practical. Under load it might work, as long as the switching noise doesn’t cause stability issues…switch mode supplies are inherently unstable, why they always need some load, built in or added. But under no load the output voltages probably won’t match up exactly, causing a lot of current between the two, something has to give… and let out the magic smoke. Unless the built in load I mentioned is enough to save the day, but it is risky.

At best you would end up with a $50 10 amp supply with no warranty, when for essentially the same cost you could have had a 20 amp supply and kept the warranty. This is why some of us say you get what you pay for, but we’re always told we’re full of it. OK, rant over.

And I can’t believe I’m defending dear ol’ Uncle Ernie (Trinity), actually I’m not, but at least the I-balance charger does have a built in supply so it’s not quite a fair comparison. Still pretty pricey, plenty of fine options cheaper than that I agree.

Uncle Ernie's been ripping people off for years!!!!! His motor prices have been on par over the years but anything else and my A$$ hurts...:lol:

i cant remember exactly what a 80mm 12v fan pulls, but .08A comes to mind. the fan uses some amperage of course, but not much. not enough to worry about is the point.

I dremeled and hack sawed the cover to split them hehehe.

I then replaced output wires into female bullet connectors and covered with a battery pole cover. A pair of battery pole could also be an option but it would require sawing off the screw end to shorthen it otherwise it might have contact with the internals of the charger.

I also tapped the power for two small fans (12v 0.09A) into the output of the charger. IT DOES NOT affect the power output. In fact, I also parallel tap two bigger (12v 0.14A) fans while charging my batteries.

I aso use the two bigger fans to cool my batteries during the charging process - very helpfull for my nicd and nimh.

To attached the fans in the cover (which I dremeled out to create an opening for the fans) I simply CA it in place. I suggest cutting out a tight fit hole for the fans so that will have a good fit.

To put it back, I "temporarily" zip tied the covers together...hopefully (someday) I will glue them together hehehe.

To Dave H- sorry I didnt notice the built in AC power input. But the features of the I-balance
charger are exactly the same sa the 3Racing's. Even the words are the same, like "copy and paste".
Can you further explain the "switching noise" issue? Wont a noise capacitor cure this problem?

To Wile E Coyote- Man! Thats inspiring! Im gonna gather some courage this
coming weekend so I can open up my PS. Are your fans putting cool air
from the outside or sucking hot air from the inside? One fan isnt enough?
I also see you're not using any fuse anymore, is this safe? I think Im going
to put an "ON OFF" switch.

I did it "temporarily"... I will still put a switch someday hehehe. I think one fan was not enough...kaya 2 fans ang ininstall ko.

Pull out air was much better because the PSU is "almost" sealed. I tried blow in air... it did not work efficiently because the hot air gets trapped inside the case.

You will be hacking some 2-3mm thick plastic... so take it easy

Switch mode supplies work by rapidly switching an inductive circuit fully on and off many times a second. Not sure offhand, but I think it’s generally in the 50,000~200,000 times a second range. Inductive circuits force current, not voltage. Thus the external load, as well as the built in following circuitry, becomes an important part of the voltage generated. Depends on the sophistication of the design, but in general switch modes are sensitive to reactive loads, inductance and capacitance.

Some of that switching works its way through to the output. Possibly the worst feature of switch mode supplies. If you connect 2 outputs directly, any small voltage mismatch, either average or switch noise, will drive a lot of current. The better the average voltage regulation, the better the quality of the supply if you will, the harder they will fight each other. Switch modes are typically well regulated baring any reactive issues, normally one of their best features. Switch noise might be less of an issue in a higher quality design however.

In regards to adding output capacitors, it depends a lot on the supply design. Again simpler switch mode designs are very sensitive to loaded capacitance and inductance. To be fair if your supply is like some of the laptop bricks I’ve seen, well they seem fairly heavy and large for a 5 amp supply, so maybe it’s a more sophisticated design, perhaps not so sensitive. I don’t know.

Bottom line, I’m not saying it absolutely won’t work, just reasons for caution. If you do try it please let me know how it worked out. Cheers!