Asked — Edited

Power Issues

Hi all I am trying to run a Motherboard processsor hard drive with my battery.

I have 2 4200Mah 4S battery packs wired in parrallel.

I built my own power supply using 2 LM4712 Votlage regulators w/ heat sinks. I am poweringthe EZB from the 12volt power supply as well as the motherboard.

I am using a PICO PSU 160 (200watt) The motherboard is rated for 200watts as well.

My problem is the board powers up and then as soon as windows starts to boot from the drive it shuts off. I tried putting a fan on the regs because I thought that might be the issue but it didnt work. Shuts off at the same place.

Using a volt meter I can see the 12 volts fluctuates as it is booting and goes from 11.89V to about 11.6 when it shuts off. Would that matter?

I then thought maybe the Pico psu is being over taxed as the mobo takes 200watts. So I re wired the hard drive sata connector to directly to the EZB for 5v and my powerbar for 12v to the hard drive directly. But same problem happened again.

I am pretty new to working with hardware on this scale. But the power bar I made appears to be working. I am at a loss of what to try next...

Please help!

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Yep simple answer , well two at least , your battery isn't able to maintain voltage under current draw , the Pico auto shuts down to prevent overdrain , also your underpowering your board , I have the 160 and I had to use a 25 watt AMD CPU and onboard graphics only with one HDD so the 160 watt PSU could support it. You can't just add up total wattage , the 5v pos , 5v neg 12v pos 12v neg all have different ratings. There are two ways to test this , connect to a car battery 12v and see if it boots fine , if it does you need better batteries , if it doesn't your PSU is too small ;)


the batteries say 14.8 volts but the voltage meter says 16.8 would wiring the batteries in series instead of parallel fix the issue? if it is the battery that is the prob?


Oh no , series doubles the voltage , only parrallel, but as soon as a load is.put on those batteries the voltage will drop down, anyways , try using your car battery and see if your computer boots , if it doesn't boot you know for sure you need a better computer power supply to run that board , so either get a more powerful one or get a motherboard that uses a atom series CPU like atom 330 , they draw like 16 watts...

My setup... User-inserted image

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Its never a good idea to run 2 batteries in parrallel unless they are isolated from each other. They need to be same, type, age, charge. What type are they?

Try just one battery see if that works for now.

Read this


Get yourself hi amp diodes from radioshack if your worried about unbalanced cells feeding to a lower voltage battery pack. But all kinds of systems parrallel batteries , especially larger rc planes where we would parrallel 20 packs together , like I said if you want to be super safe put a diode on the positive off your pack and that insures power only moves in one direction.


Ive seen conflicting info on the parrallel lipo setup. this site

and the hobby shop that sold me the lipo packs say that it is safe to parallel them together.

These packs are both identical $130.00 4200mah packs bought with a week of each other. So I don't think the parallel is the problem. I have also found parallel adapters to balance charge both of them at the same time using my x1 charger although right now i am just individually charging them.

I will hook the robot up to my car battery and see if the system will boot. If so then I hope wiring in series will allow more voltage which will allow more draw?

Otherwise I just wasted $260 on batteries :(


once agian wiring in series DOUBLES your voltage and your going to damage electronic equipment that way , only parallel ( that's all pos grouped together as on connection and all negatives from the batteries grouped together) That's a lot for batteries , personally I would return then because I could find you tons of deals at 1/3 the price , even for Lipo , last time I bought packs with your packs specs they were turnigy brand 45 bucks rack from , I have 20 in mine , lead acid 12v 17000 mah (thats 17ah). , when you hook this to a car battery be ready with a meter to watch current draw (thats amps not volts on the meter) that way if it boots and starts running fine you can take note of amperage it was drawing, that gives you a figure for min amp draw at startup , take note its a good idea to do Somthing intensive like run disk defragmenter in Windows utilities and look at current draw then as well , a computer will run about 80 percent load while defragging a hard drive. Unfortunately my best guess is the Pico Power supply is just too small but this test will tell you for sure.


Ok so it turns out the problem is my voltage regulator that I built, The car battery worked just fine if I bypassed my regulator board that I made but as soon as I connect it the same issue happened with the lipos so thats definately it.

So my question is is it a bad solder or is my wiring wrong. I have attached a basic schematic to show how I wired the power board (Sorry for my ignorance on making a real one)


Why are you using a voltage regulator? You should be able to run direct to battery , voltage drops to around 13 - 13.5 when load applied and goes down from there. I have a 250 watt m4atx for sale if you want it and a 160 watt automotive PSU , either I hook you up with , I could do the 160watt for 25 bucks.


the batteries output close to 16.5 volts and it will not post unless regulated

once i get the regulator working i should be ok