Too low power for that. :smile: Assuming you're running class AB amps (not class D), it would only be good for "only" ~450w rms max.

I use it to charge my batteries! Although it wouldn't be bad for a 10" sub on a class D mono with a good capacitor. I have two DTX ICE chargers to run at the same time, plus I use it to test ESCs. They really should put a switch on it for $200 though...

I never liked the sound of class D. There's just something about them that sounds different, but I can't put my finger on it. So, I run only class AB and deal with the efficiency losses. I run an OLD PPI PC2600 on my sub and another OLD PPI PC2400 on a set of Diamond Audio 6.5" Hex drivers - also old. Sweet.

I would think running ESCs on a PS would be bad because of the reverse spikes from the motor. Maybe some transorbs would be better for that.

I don't test brushless systems for long, just to make sure everything's hooked up ok before I install it. Also makes it easier to program the ESC I think. I don't need to fiddle with batteries, just plug it in.

One of the downsides of listening to metal: subwoofers sound really crappy unless they're perfectly tuned. I had a pair of Logic Soundlab ZDX 12's with one of their LSX-2802 amps. The sound was crystal clear, and loud, except the music was like continuous thunder! Too much double-bass drumming I guess... Also if you go to their site, my ZDX subs had the same back structure as the EXL subs, and they could handle 2000W max! IDK why the changed them...

Yes what ever the stupid thing was it was crap. I never really tried to work out what sort of transformer it was. Live and learn I suppose. I now use a charger with the built in transformer and it's better but not that much. Still better then carting around a charger and big transformer though.

Do you think you can open up the charger and solder in some larger caps? That might help a bit with the output filtering.

Yeah, my RS PSU was/is heavy! I think the X-former weighed about 10 pounds by itself. The whole unit is only like 12 pounds. Switching supplies are definitely the way to go.

You can certainly do that. If I was going to go that far, I'd solder several 2200-4700uF caps in parallel and then add a 0.01uF cap at the power input leads in the charger itself (helps to have the high F filters closer to the circuits) to help with any high frequency filtering.

Howdy all,

I'm trying to find a good power supply for this mod. I just ordered a Hyperion 1210i with 2 LBA10 balancers. The manual says I need a power supply between 8A and 25A.

Do you think this psu in the pic below would be a good candidate? Should I be looking at the 16A under 12v1 or the 18A under 12v2?

For now I will be charging two 3s 5K packs or two 2s 6K packs at the same time while linked with the two balancers. I would like headroom though for when I get higher capacity and voltage packs in the future.

Thanks!

Brian

http://i192.photobucket.com/albums/z...w/psuspecs.jpg

Well, by the specs, it can supply 18A on one of the 12v rails. According to this, to utilize the full potential of the 1210i, you'd need at least around 25A. If you don't charge the max cell count at the max current, you might be ok.

Note how that PS has dual 12v rails. Most of the time, you'd be better off finding a PS with only one 12v rail since the current will be greater. Also, the cheaper PS units tend to drop their voltage when drawing the rated current to the point where the charger might not like it. It's not uncommon for the 12v output to drop below 11v under high currents.

This one would suit you better IMO. I know it's getting a little pricey, but high currents aren't cheap. Note how it is good for up to 34A. That means it will most likely maintain a more solid voltage at "only" 25A.

Depending on the unit, there may be an internal potentiometer to tweak the 12v line to something a little higher, say 12.5-13v. Higher voltage will make the charger pull a little less current.

Thanks for your reply!

How about this one?

Do you think it would work?

Thanks again!

Yeah, that should work. 30A is a litle more than you need, which is good. That means the 12v line shouldn't dip too much. The voltage might be more stable if you load the 5v with a couple resistors, but there's no way of knowing until you get it and run it.

alright i know this is old but i need to ask will. will my 300w ATX power supply be enough?? it puts out 10 amps at 12 volts and at 5 volts 24 amps. i want to get this hyperion charger ; http://www.maxamps.com/EOS0610i.htm would it be good or would i be pushing it?? the most biggest packs i will use are 8000mah and maybe 10000mah if i parrallel up my 5s1p batts taht i ordered.

simple sum. 5s = 5x 4.2v x 10A charge = 210W of power going INTO the battery... the charger isnt 100 percent efficient and would need 20%+ to be safe = around 250W

now, your supply can supply at 100% *assuming the stats are correct...* atound 10A at 12v = 120W... you need something more than 2 times this to run these high voltages!!

ok, so how many A could you charge at? well, 120W divided by (4.2x1.2(to get 120%, safety margin))5 = 120W/25v = 4.8A, and that is using the supply to its greatest, and wht voltage would only be like 10.5 or less, so you would most likely only be able to charge @ 3.5A

hmm wow this supply i guess isnt powerful enough for it then. i found this one in my room so that means im looking for 600w power supply? i think i might have another one with more wattage. even if i have to go out and buy one its cheaper than buying and rc car one.

also i know this might sound stupid but what if i combine the 12 volt and 3 volt wires to make 15 volt??? or that isnt possible? thanks again

No, that's not possible. What you would get is a dead 12v line and/or a blown fuse. The 12v would try to "charge" the 3.3v line and the resulting current flow would be huge until the PS shut down. You are thinking of wiring in series, but you can't do that either as both rails share a common ground.

hmm i figured that would be the answer just couldnt help myself but ask. so iether i use this to slowly charge my cells or use it on low capacity batts?? then i guess im going to get me a bigger supply then. thanks alot. and when i make the connections do i hook up +12 and then -12 or +12 and GND ??? that is what is confusing.

should i plug my charger into the -12v for black and +12v for red?

BL_Maxx:

No. If you hook your charger across the +12v and -12v leads, you'll have 24v and at low current (the -12v rail is rated for low current). Use the yellows (+12v) and equal number of black wires (ground). All the rest of the wires aren't being used. The only exception is the green "power-on" wire, and maybe a red & black and/or orange & black pairs in case one or both need to be loaded with resistors.

is there any way i can raise the voltage because i need 5 more amps(15A@12v)

Depends on your PS.

Sometimes, adding a 1A-2A load on the 3.3v line (orange wire), or the 5v line (red wire) can make the feedback regulator work better and bring up the 12v line more.

Sometimes, the PS has a small trim potentiometer than you can tweak the output a bit.

Sometimes, you can "trick" the rail with the feedback line into thinking it is lower than it really is, and the result is that it will boost it accordingly. This requires that a seperate feedback wire be present and is usually the same color as the rail it's monitoring, and connected at the connector (probably to negate v drop due to wire losses). But, determining how to use this wire is too complex for this thread IMO. Here is a hint though: use the feedback wire and a voltage divider of the right values. That's all I'm gonna say on that.

where can i locate the feedback wire? is it the black one? and where cani get a voltage diver? Radioshack?

well i got the power supply to work for about 4 days and now it just shuts down, the fan doesn't work and its plugged in, every connection is good. the LED i put in works for only about 5 seconds.what could be wrong

an internal short perhaps? carefully check all the wires u unsoldered/cut and taped/heatshrinked up to make sure they are not touching each other. u also need to put the green and brown wires from the mobo plug onto +5 and ground (PLEASE NOTE: I DONT KNOW WHICH ONE GOES TO WHICH OTHER CABLE SO MAKE SURE U CHECK FIRST AND ONLY USE ONE OR THE OTHER, NOT BOTH!)

so once you figure that out, (its on the net) then try again. if it doesnt work add a reasonably heavy (>1A) load on the 5v rail and it should work better.

black is usually ground.

Sometimes the psu needs a load to run properly, I got a 10ohm 10W power cap on the 5v rail on mine for this purpose, does the job :P

i found the problem, one of the pins on the male connector that connects to the fan slid out and tore the circuit board slightly, but i can try to resolder it bck and hope for the best

well i fixed the fan, but not the power supply. it still shuts down, any ideas to fix it?

I have this old Antec 250w PS, but the voltage is 11.12v with no load and it goes below 11v when theres more than 15w load on the 12v wires. It's rated for 8A on the 12v rail. I don't want to spend any money on this piece of junk (especially since its only 96w), so is there any appropriate resistors I could take out of another circuit board from something else?

Kyosho: There could be any number of possibilities. If there was a broken PCB at one point, powering it up could have caused something else to go bad. It's really hard to tell. At any rate, fixing these becomes pricey as they are fairly complex and there are so many variations that there is no one schematic to follow.

TopSpeedTimmy: Wow, 8A? It hardly seems worth it. Usually, adding resistors boosts the voltage a little, but it does more to stabilize the voltage under load. Even if you could get 12v @ 8A, it would only be good for an approx 50w charger.

That said, a broken TV may have a few power resistors in it (CRT type), but it's a toss-up if they will be the value you need. If you do decide to go poking inside a TV (which I do NOT recommend), BE VERY CAREFUL AS THERE ARE VERY HAZARDOUS VOLTAGES IN THERE. Depending on the size of the screen, VERY high voltages can still be present even after sitting unplugged for a while.

I had an old broken Antec TruePower 330w PS laying around in my parts bin. The motherboard connector had melted at the 5v pins, so it was either throw it away, repair it, or do something else. I chose "something else". It is rated 17A @ 12v, so should make a decent 12v supply.

This supply is a bit different than most supplies I've seen. This one has seperate feedback lines for each of the main supply rails. So, on each of the main 3.3v, 5v, and 12v wires, there is a smaller gauge wire of the same color that is connected to the main wire at the connector. Presumably, this feedback wire reads the voltage at the connector. During heavy current draw, there could be voltage drop along the wires, so the PS can compensate for this by boosting it a little.

Loading the 3.3v and 5v lines did nothing to change the 12v line. This PS uses seperate feedback circuits for each line. Nice. This is the way all supplies should be built IMO.

Also, there was no fine-tuning potentiometer to boost the voltage.

So, I got to thinking about those feedback lines; what if I use a voltage divider to trick the 12v circuit into thinking it's only putting out ~10v? The circuit would then boost the output so the feedback wire is at 12v. A quick test confirmed this. After some playing around with different resistor values, I found that anytime I tried to go over 13.5v, some other protection circuit would engage when powered up. I was hoping for ~14.5v, but that's ok. Also, it seems I needed to draw at least 1A for the feedback circuit to act according to my calculations. 1A at 13.5v is too much wasted power IMO. The resistors would heat up for nothing, and I'd have that much less 12v current available.

So, I decided to use a couple series connected diodes with a resistor to draw ~250mA. The combined diode voltage drop of ~1.5v at the sense wire will boost the 12v to 13.5v. I used two 100ohm 10w resistors in parallel to get the 50 ohms I needed. Then, to make sure the diodes wouldn't overheat, I used 3A barrel diodes because they have larger packages to dissipate any heat. Below is a picture of the circuit.

http://scriptasylum.com/forumpics/ps3.jpg

No on to testing. The output of the supply was actually at a default 11.89v with the sense wire attached to the power wire (no v gain). So, after the circuit was added, the actual output voltage rose to 13.35v. What surprised me is that even at over 16A, there was only ~0.1v of voltage drop! Wow, talk about good regulation! I don't think I've ever seen a supply (linear or switching) that doesn't sag more than that when run at so close to the max value. This supply just became my new field PS! :smile:

Other mods I did: It comes with two fans. I removed the rear fan and kept the one that blows directly on the heatsinks/circuits. Where the rear fan was, I attached a piece of plastic, and on that is where the banana jacks go. The resistor/diode package was mounted to a piece of channel aluminum (for protection and heat dissipation) on the rear of the PS. All extra wires were completely removed for neatness and I used Deans 12GA wire from the PCB to the banana jacks.

And a couple pics of the finished product:

http://scriptasylum.com/forumpics/ps4.jpg

VERY nice Brian!!
That makes a sweet power supply.

That's very nice , a voltage over 12 while running 16 amps is very good. All the ps I've done have sagged a lot when pulling hard on them.

My latest was a brand new $20 ps which I simply pluggd in the digital tester to and left it that way. It reads the output voltage for me on a screen , but when pulling hard it too sags to 10 volts or so.

I will open it up to see if it has the seperate sense wires on it. I don't know how to read electronis digrams. So the two diodes (drop voltage) go in series in between the two yellows? and the resistors get put in parallel between the yellow sense wire and black?

I did not have to load the ps any , but the digital tester I have used probably has the load built into it. It says not to leave it on for a lojng time , and it can do the full rating of 200 watts (with voltage at 10 sagged very bad)

If you open it up, you might see a small PCB mounted adjustment potentiometer. Many don't so don't be suprised by the lack of one. Also, sometimes loading the 5v and/or 3.3v lines makes the 12v rail much more stable. It depends on what rail the circuit uses the sample the current flow. The only way to know for sure is to try it.

You don't need to open the supply to see if it has a sense wire. If it DOES have a sense wire, the 12v point on the main motherboard connector will have two yellow wires going into it; the main current carrying one, and likely a smaller sense wire. The diagram I made above shows how to hook it up just by cutting the mobo connector off and placing the components as shown. The wires have to be in that order or it won't work right (don't put the sense wire "on top").

That digital tester sounds like a wattmeter or something. Voltage meters typically have VERY high input impedance (so they won't load the circuit being tested). Kinda odd that it says to not keep it hooked up for long.

Cool... my desktop just died and I pulled an Antec Tru430W out of it.. and to think I was just about to go and buy a new power supply :)

The one I have is rated to 28A@3.3V, 36A@5V and 20A@12V.

Do you know if there would there be any harm in connecting those three in series if I didn't pull more than 20A@20.3V? I'd like to have 400W available for my DUO at home.

I'm not sure I'll do your fancy mod, as I don't quote understand it. What are the diodes for? Is that so your only loading up the sense wire? and if so, why are there two?

Cheers

Sam

No you CANNOT put all three rails in series - they all share a common ground.

Hmm, I thought the mod was fairly straight forward. The diodes are just to drop ~1.4v (0.7v each) so the sense wire sees less voltage than there actually is. So, it causes the regulator circuit to boost the output voltage until there is ~12v on the sense wire. This causes the real output to be ~1.4v higher than that, or ~13.4v.

I could have used simple resistors as a voltage divider to do the same thing, but preferred the diodes method.

Think of the sense wire as the feedback pin on a regular linear voltage regulator, or the - pin of an op-amp. Same basic thing.

Of course.. it seems obvious now lol. Both questions I asked. I really should of thought about that series connection thing. I've done plenty of these hack jobs before, usually just loading the 5v though

Cheers for clearing it up.

Thought as an electronics enthusiast with no formal training, I have another couple questions :)

You said you needed to draw about 1A for the feedback circuit to work properly? How come using diodes you only needed 250ma?

And if you have a psu with multiple 12V rails, can you parallel the rails to achieve the psu's total rated 12V power?

When I was using the voltage divider circuit method, 1A was needed reason for the calculations to work right. Only when I used the diode method did things work right mathematically, and actually. Besides, drawing 1A all the time reduces the available current for the real load (charger), so it all worked out in the end.

The PS specs do say 0.8A min is needed, but it seems to work fine with no load. However, I am drawing 0.250A, and the fan draws about the same, so it's close to the spec'd 0.8A.

Can you use this power supply to charge lead acid batteries?

I'm not familiar with lead-acid charge profile, so I cannot say. But I do know that the supply's output voltage has to be higher than the battery voltage for any kind of charging to take place. But what type of current limiting, if any, is needed, I dunno.