my UMPC project.

armasmike · Post by **armasmike** » Wed Jul 30, 2008 8:48 pm

Is there a way to find out ?

And What is mAh ?

Again i don't know ANYTHING about battery

Can you add more then one ?

Valium · Post by **Valium** » Wed Jul 30, 2008 9:00 pm

armasmike wrote:Is there a way to find out ?

And What is mAh ?

Again i don't know ANYTHING about battery

Find the total draw of your rig using a multimeter, and divide it into the mAh rating of your battery. If the total draw was 2500 mAh like previously stated, you'd get 2 hours of battery life.

mAh stands for Milli-Amp hours. It is the total power of the battery. A 5000 mAh battery (or 5 Ah) is capable of outputting 5000mA for one hour, or 10000mA for a half hour, or 1000mA for 5 hours, depending on how much power whatever you're hooking it up to needs.

If you do find the total draw using a multimeter, remember that it'd only be an estimate. On start-up, it'd use more power than when it's idle, less battery life if you're playing intense games, stuff like that.

armasmike · Post by **armasmike** » Thu Jul 31, 2008 7:31 am

can i use more then one like

2 6v 5000mah

for a total of 12v 10000 mah for long life ?

Also if both the LCD and mouthboard need 12v how to i added them to one plug ?

Valium · Post by **Valium** » Thu Jul 31, 2008 7:34 am

To get 12v and 10000mAh, you'd need 4 batteries. 2 pairs in series, and then those pairs in parallel.

armasmike · Post by **armasmike** » Thu Jul 31, 2008 8:14 am

Thank you for you help in this.

But i don't understand 4 batteries 2 pairs in a series.

so do i need 4 of

http://www.batteryspace.com/index.asp?P ... rodID=1494

or 2 of them ?

Post by **bicostp** » Thu Jul 31, 2008 10:07 am

Connecting batteries in series (connect the positive of one to the negative of the other), adds the voltage, but not the capacity.

Connecting batteries in parallel (tie the positives together and the negatives together), adds the capacity, but not the voltage.

Making two series battery packs, then connecting them in parallel, adds both capacity and voltage.

armasmike · Post by **armasmike** » Thu Jul 31, 2008 10:31 am

O i get it now so i want to do is a parallel

get 2 12v 5000mAh connect them as parallel and i will get a 12v with 10000mAh.

I also found out the LCD use 12v and 900mAh

The mouthboard power is a PicoPSU 120W and this is the chart saids.

Input Required 12V DC regulated
Maximum Output 140W*
Output Voltage (V) 5VSB +3.3 +5 +12 -12
Output Current (A) 1.5 6.0 6.0 7.0 0.05
Output Power (W) 7.5 19.8 30 84 0.6
Peak Current (A) 2.0 8.0 8.0 10.0 0.1

I now what some of this saids but i guess i need is the

Output Current (A) 1.5 6.0 6.0 7.0 0.05

This i don't understand how much does this little thing use as in mAh ?

Rekarp · Post by **Rekarp** » Thu Jul 31, 2008 10:40 am

If it can supply 130Watts and runs off 12Volts then it can AT MOST draw 10ish amps. I highly doubt that system will draw that much. Best bet is to wire the whole thing up and just stick an amp meter on it.

armasmike · Post by **armasmike** » Thu Jul 31, 2008 10:46 am

Ok i will do that later today.

I was thinking if the LCD has it's own power block 12v 900A and the PicoPSU 120W i got has ones also how do i put both together in to one plug ?

There both 12v but i am guessing they don't have the same mAh.

What would happen if the PicoPSU 120W need less the 900mAh and i use the 12v 900mAh on it will it not work or blow up ?

Post by **bicostp** » Thu Jul 31, 2008 11:52 am

No, it will simply draw the power it needs.

As long as you give it the voltage it requires, it will be fine.

Rekarp · Post by **Rekarp** » Thu Jul 31, 2008 2:06 pm

bicostp wrote:No, it will simply draw the power it needs.

As long as you give it the voltage it requires, it will be fine.

and not go over the rated amps

Post by **CronoTriggerfan** » Thu Jul 31, 2008 4:31 pm

bicostp wrote:
CronoTriggerfan wrote:Coming from a guy in a community like this, Bic, this surprises me.
He said he wanted to build an "Ultra Mobile PC", and I assumed he wanted to use it as an everyday word processor / web browser. (After all, a 1 gig VIA processor with integrated graphics doesn't get you much in the way of gaming, unless you happen to be a Puzzle Pirates or Diner Dash aficionado. ) And no offense but I wouldn't exactly call a Mini-ITX based homemade laptop "ultra mobile", especially if it's going to have batteries that last longer than 20 minutes.

There's a big difference between consoles and PCs when it comes to portablizing. (Consoles generally run cooler and draw much less power, and of course most don't require a keyboard and mouse...)

I'm not saying he shouldn't build one, I'm saying he shouldn't build one and expect it to be a practical machine he'd want to live with every day.

Besides, hasn't the general consensus around here regarding PCps always been "just get a real laptop"?

Ah, gotcha, I misunderstood your first post. In the sense that it probably will have piss-poor battery life, I'd have to agree.

armasmike · Post by **armasmike** » Thu Jul 31, 2008 6:27 pm

why would it have bad battery life ? if i get one with 10000 or more mAh it will last.

Rekarp · Post by **Rekarp** » Thu Jul 31, 2008 6:40 pm

I would get double that. 10Ah will probably get you 1 to 1.5 hours. But I want to know the total draw of the components before hand.

Bibin · Post by **Bibin** » Thu Jul 31, 2008 6:50 pm

USB Wifi is total crap; even 802.11b over PCMCIA or PCI is faster as the data sent back and forth isn't compressed at a low level then decompressed by the USB controller. 480mbit my arse, it's quite awful.