Power Cap Problems!

Post by **redline** » 12 Nov 2004 08:47 am

I love it when you talk dirty James

Post by **petefarrell360** » 12 Nov 2004 10:35 am

James,

Thanks for your help. The main reason I've got the power cap is not due to the battery going flat, but as the MP3 Mststaion runs a hard disk drive, it is very sensitive to power surges or dips, so on starting the battery is having a large amount taken by the starter, so the power to other items dips, such as when your radio may cut out on starting. Also the sub on a high setting will cause the power to dip and it unsettles the power to the Mstation causing it to freeze. For some odd reason it doesn't happen as much on the switched ignition live. Although they both have the same source, it may be regulated in some way!? When I asked in the shop about connecting it to permanent live they weren't too sure, as at the time no box was available! I had decided, like James says, it shouldn't draw anything from the battery once it is fully charged and still connected. Also then it will not cause the car to run on as it does when connected through the switched ignition. Cheers everyone.

Pete

Post by **Chris_C** » 12 Nov 2004 05:14 pm

Whilest your right James, most power caps have an extra bit of circuitry in them that prevents any cocked wiring etc to damage the cap itself. It was this causing the current drain I was thinking about, not the cap itself, which your definition of is spot on.

The other thing about the cap when used normally is you want to keep the wires from it as short as possible from the amp, so that you dnon't end up with any extra distortion (definately going into James' field now, so will back out again!)

Might be worth measuring current draw (because don't forget while lead acid batteries can deliver stupid current for short times, they don't like a small amount (in a car battery around an amp or two, which the cap shouldn't be near, and if it is chuck it

) and if deemed, put a beefy relay switched from the ignition on the cap run.

Later's guys, of to wales for the weekend

Post by **petefarrell360** » 20 Nov 2004 04:17 am

Thanks for your help guys, I still haven't had time to put it in, but hopefully later on today, (Sat!) I will find some time, and actually put things in correctly, for example mount the Mstation in a box, rather than have it floating around the boot! I'm hoping it should sort the problems, as the Mstation really is sensitive to power changes, such as starting, or when the revs dip very low, and especially when all of the electrical items are running, fan, lights, window demister, head unit, sub..........! Anyway, thanks again, I will let you all know how it goes, here's hoping it will cure the Mstation freezing problems! Pete

Post by **Kyuss** » 25 Nov 2004 10:05 pm

an idea that the other guys may be able to confirm or deny the validity of, is to run a high current relay (40A headlamp relay may suffice) switched by your ignition with powers the "cap" this would potentially remove any issues around the car running on due to the stored power in the cap, because it would be disconnected from the battery when you switch the ignition off...

Post by **foggyjames** » 26 Nov 2004 12:33 am

If you wire it up properly, you should never need a relay. Strictly speaking, if you wire it up properly, you shouldn't need a capacitor - my head unit doesn't cut out when I crank the engine - it all depends on where you take the power from (and how healthy your battery is). A headlight relay would work in principle, but you'd want to carefully watch the rating, as the current draw could go mental as it charges.

cheers

James