Battery flat :( anyone know y? M4-ATX PSU

**jellymonster** · 06-09-2009, 08:10 AM

Hi,
Yesterday, I finally got round to fitting the carputer

. Basically, what I did was put through all the wires and everything without the fuse in. Turned it on, and was playing around with it for about half an hour maybe with the engine off. When I finished, I took the fuse back out.
Today, I went to use it, put the fuse in, PC and amp turned on, lasted about 5 minutes and turned off, would not turn back on.
I had a feeling that it might have turned off due to battery getting too flat to start the car, so I tried starting my engine. It failed to start, (not being good on knowledge of cars) it sounds like ticking but did not tick over. I guessed this was my battery being flat.

I have a UK X reg Fiat Brava, m4-atx (used as normal power supply), battery and alternator are stock, 1000W amp, subwoofer, 6X9's and door speakers (5.25").

I don't know if I did something when I was installing it or if this is normal, but I'm sure that the M4-ATX turned off before the battery got too flat.
My old OEM head unit has 4X50W speaker outputs, and I've replaced this with a 250W M4-ATX so I don't know why it would drain power so quickly :S.

Thanks
JM

**Sonicxtacy02** · 06-09-2009, 09:06 AM

sounds like ur battery was ready to go. But in any event you cant assume just because the max wattage on your head unit is 200w that it means ur battery is ready to assume a 250w power supply. Head units barely ever hit there peak output. What are your timer settings on the m4?

**jellymonster** · 06-09-2009, 09:10 AM

By timer settings, do you mean when it turns on and off?

if so, at the moment, the fuse is always out when off, to turn on I just put the fuse in. This then turns on my touch screen, PC and amp.
To turn off, I shutdown, this turns off amp (I think, haven't checked but should do), screen and PC. I then take the fuse out.

I will get this hooked up to my ignition soon, I just want to know why this is happening.

Thanks for your reply

**jpinkerton** · 06-09-2009, 09:25 AM

Why are you taking the fuse in/out? There are dip switches on the side of the M4-ATX, those control the timer settings Sonic is talking about. M4-ATX Manual

**jellymonster** · 06-09-2009, 09:32 AM

Well, my dad the mechanic just jump started my car and it's sat running atm. He reckons that the battery was drained from all the messing around i did with the PC and stuff yesterday.
He also reckons that after about half an hour with my PC/AMP turned on and engine off, it will drain the battery. Is this correct?
If so, are there any batterys that can hold more juice?

Thanks

**jellymonster** · 06-09-2009, 09:34 AM

Originally Posted by jpinkerton

Why are you taking the fuse in/out? There are dip switches on the side of the M4-ATX, those control the timer settings Sonic is talking about. M4-ATX Manual

I havn't got it hooked up to the ignition yet so the dip switches will do nothing. I'm hoping to get this sorted soon though

. But until then, this is my only option.

**jpinkerton** · 06-09-2009, 09:39 AM

You can get a bigger battery, how long it lasts will depend on the draw you're pulling from the battery and the battery itself.

I can't find it now, but yesterday there was a good post with the math of figuring out how long you can run on a battery. I wouldn't suggest runnin' your battery down very often, as your dad can attest, you'll kill your battery and prevent it from keeping a charge entirely.

EDIT: Found the post from this thread.

**Sonicxtacy02** · 06-09-2009, 09:39 AM

Originally Posted by jellymonster

Well, my dad the mechanic just jump started my car and it's sat running atm. He reckons that the battery was drained from all the messing around i did with the PC and stuff yesterday.
He also reckons that after about half an hour with my PC/AMP turned on and engine off, it will drain the battery. Is this correct?
If so, are there any batterys that can hold more juice?

Thanks

if your battery was on its way out yea it'll die after 30 mins. But a healthy battery should allow 90 mins minimum. Ive done that with full atx desktop PCs in the car.

**jpinkerton** · 06-09-2009, 09:42 AM

Originally Posted by jellymonster

I havn't got it hooked up to the ignition yet so the dip switches will do nothing. I'm hoping to get this sorted soon though

. But until then, this is my only option.

In the manual link I posted make sure you read and understand Page 3.

NEVER use “hard-off = NEVER” settings unless you understand the risks of battery depletion. Even with safety limits in place, your battery might be not be able to start your engine. “Hard-off=NEVER keeps your 5VSB rail on at all times”

**jellymonster** · 06-09-2009, 09:55 AM

I now read page 3. So the M4 will only turn the PC off if the Hard-Off is turned on?
Also, when I wire in the ignition, I will use P1(recommended). Which means dip switch 1 is on. Why does the manual show only 3 dip switches and in reality there are 4?