Power Cap Problems!

Post by **petefarrell360** » 10 Nov 2004 07:25 pm

Hi, I need a little help with fitting a power cap, to keep my battery supply for the electrical gadgets at a constant 12V to stop items cutting out due to a power dip, either on starting, or when the sub drains plenty of power for a lot of bass! I bought a new one yesterday, looked simple enough to fit, except the shop couldn't find the box for it, but said simply, positive in one side, a negative ground the other, easy, connect from it and your away. Well, connected it to the switched live, definitely a grounded cable from the negative, then a cable continues from positive to gadgets. However, switch the ignition on and the battery light is dim, start and you can switch off and take the key out and the car will run on until the power cap discharges its supply! What stupid mistake have I made!?! Chris_C, as you're a bit of a DIY In Car Entertainment man, any ideas? Normally I manage to bodge my round problems like this! Thanks,
Pete

Post by **SteveP** » 10 Nov 2004 09:56 pm

Hi Pete,

Sorry I can't help you with your power cap problems, but wondered what the name of your hard disk car player kit, quite impressed and interested in looking it up myself.. but can't remember what its called!

Steve

Post by **Chris_C** » 10 Nov 2004 09:59 pm

If it was a straight amp install, then you'd just run the cap in parralel (as close as possible) to the amp's power terminals (which would be coming straight from the battery). Not ever having put one in, I'd say that for your's you'll want to run a direct wire (make sure it hefty enough) from the positive battery terminal to the cap + and from the nexative (or body) to cap -. Whether or not this would drain your battery if you left it for too long I wouldn't be sure without doing some maths. (Oh, and remember to fuse it!!)

The reason the car is satying running is because the cap stores energy (i.e. Power, 12V at x amps) and when you turn the ignition switch, charges to just under 12V until needed. One time it's 'needed' is when the key is turned off, the switched live is going dead, but the cap still has (nearly) 12V in it, keeping the ingnition realy closed.

I'll see what I can work out about the current drain on the idle battery for you (and see if anyone else has any other ideas)

Post by **petefarrell360** » 11 Nov 2004 01:38 am

Cheers mate, I'm couldn't see that I had it installed wrong, as any other viable ways didn't produce power! I will ask in the shop tomorrow, as I can't have it like that! I have left the option open to put it on the permanent live, switch it, and remember to switch it off to prevent power drain of the battery! Can't personally see me remembering! So any other help is greatly appreciated.

Steve, how are things going? I'd keep out of them car parks mate! The MP3 device is a TraxAudio MStation, however, TraxAudio went bust! I believe a company called Neo took over producing the Mstation for a while, you're best bet is Ebay, make sure it's new and boxed, many are, and a Version 2, as the early one's had a few errors etc.! If you can attach it via RCA's to the head unit, it's a lot easier, no messing about with the FM Modulator. I was thinking about upgrading the hard drive, as they normally come with 10 Gb, and you can apparently add any standard 3.5" IDE hard drive up to 180 Gb! I've loaded about 11 hours worth of music on, which takes up 10 % of the drive so far, I think! Not bad, won't be upgrading for a while!

Pete

Post by **redline** » 11 Nov 2004 09:30 am

I think your system Is sounding great Pete but if 10% gives you 11 hours then your looking at 110 hours of music total.So I have two questions .
1) Is there actually 110 hours of music you like ? and 2) when are you going to drive for 110 hours to test it out (that s like 4 days and 14 hours of solid driving mate, LOL )
day one

day 2

day3

day 4

last 14 hours .. following week

Post by **petefarrell360** » 11 Nov 2004 11:04 am

Well Mick, it is a lot! But I've still a lot of CD's to transfer onto it. I don't think I'll fill it up just yet though. It means I've an entire library of music to choose from. You can be guaranteed not to listen to the same song twice in one journey, unless it lasts four days and 14 hours , I hope not! Pete

Post by **5lab** » 11 Nov 2004 01:31 pm

i've 14000 mp3s on my hdd at home- thats like half a YEARs worth

Post by **Duvel78** » 11 Nov 2004 01:40 pm

5lab wrote:i've 14000 mp3s on my hdd at home- thats like half a YEARs worth

14000? May I forward your message to the RIAA?

Post by **5lab** » 11 Nov 2004 01:46 pm

if ya want.. they're all backups of cds i own

Post by **SteveP** » 11 Nov 2004 03:32 pm

petefarrell360 wrote:Steve, how are things going? I'd keep out of them car parks mate!

Less of the snide remarks haha

Thanks for the info though, I hadn't seen anything like your MStation in a car before and its definitely something I will consider. I think its very good value for the capacity - no messing about with CDs, and you've gotta love a gadget!

Steve

Post by **5lab** » 11 Nov 2004 03:33 pm

a cd/mp3 player would be a better bet imo.. you only have to change cd once every 10 hours anyway!

Post by **SteveP** » 11 Nov 2004 04:06 pm

True.. but I really like the headunit in my car now (especially as it now works properly cleaning the contacts) - and it would cost about £150-200 to get a mp3/cd player equivalent. Therefore the MStation is actually *(slightly) cheaper, with greater capacity!

Steve

Post by **petefarrell360** » 11 Nov 2004 07:32 pm

I've never even looked at MP3/CD units, so can you organise the tracks by artist, genre, add playlists etc, as you can on the Mstation. You can play random from any track at all, the directory it is playing in, such as album etc. Much better than a CD changer, though that is still installed just incase I borrow CD's etc before getting the time to laod onto the Mstation. Also the single disc in the head unit is still available.

Well, things are progressing with the Power Cap too! Called in the shop and they'd found the nice case/box, with instructions, so I'll have another look tomorrow.

I also want to mess about with the FM Modulator, picking up a little bit too much background noise for my liking, especially compared to the other FM mod I have. Shame I haven't got any RCA inputs on the head unit, only rear RCA out's.

Pete

Post by **redline** » 11 Nov 2004 10:17 pm

my jvc radio cassette is fine for now but my 8 track cartridges wont fit in it any suggestions? LOL

Post by **foggyjames** » 12 Nov 2004 03:38 am

Chris pretty much had it right...but I'll answer his point about the battery going flat...in a minute.

First (irrelevant, ranty) question...Do you REALLY need a power cap? Your battery can continuously deliver 600+ amps to the starter motor for about 2 minutes before going flat. That's amazing. That's also well over 10x the current consumed by a 300wrms ('real' power...not 'kenwood watts'

) power amp. The capacitor only really helps you if you have a seriously huge install, an undersized battery, and you have trouble with your lights dimming. I used to run a pretty big install (well...bigger than any of the V3M installs that I know of!), and I didn't even remotely NEED one. Food for thought....

Having said that, they're cool toys, especially the ones with voltage read-outs. Ironically, it takes a voltage readout to show that you need a capacitor...or a new battery

Anyway....ranty bit over....onto the business...will it flatten your battery? Errrrr....nope!

(In simple terms...) A capacitor only charges when it is less than fully charged, and connected to a voltage source higher than its current 'charged' voltage. Obviously charge and voltage are different things, but I think you see what I mean.

The capacitor will charge very quickly as soon as it is connected to the voltage source. In this case (where it is permanently connected) it only charges when it needs to (ie: when it has been drained by the amp), so it is no different in terms of current consumption to connecting the amp directly. There may be a certain amount of leakage which will result in a greater drain....but I would consider it to be negligable.

You pretty much always connect a cap across the power supply - that is between 12v and ground - as Chris says, effectively in parallel with the amp. I would suggest a fresh grounding point for the cap, but I'm not sure what the expert advice on this is!

Hope that makes things a little clearer still...

cheers

James

ps: If things work out, I might be making a SPL-contest-winning 240 estate in the next year or three. It'll most likely have 4 or 8 18" drivers and circa 20kW of power. Hmm!