I have just added some things to the car. CompuStar alarm, DVD double din unit with 7 inch screen, 1000W Amp with two tens(unsure of amps), a radar detector, and a 400W Invertor. I put the invertor on there for the PS2 or carputer. When is it too much for one battery to do the job? The battery I am using is the Interstate MT-35.

Here's the info on that battery.
http://www.ibsa.com/estore/search.as...CRank%7C1&js=1

What do you guru's recommend?

Am I good with my current battery or will I need a secondary battery. I want that PS2 and Carputer...

 

it's not the battery that's going to matter in the end, it will be the alternator capacity... basically your alternator must be able to put out more than your combined load, otherwise your battery will be drained all the time and never charge...

adding another battery wont solve the problem... it will just prolong the time before you're totally drained...

few things...

do you plan on running everything at the same time? Your biggest problem is the 400w inverter...

the 1000w amp probably runs 250 watts on average or less...

the alarm, radar and hu should not be a problem.. if you have amps for your speakers, disable the internal amp for the HU....

I would not run everything with the engine off though...

and btw, buy a good jumper cable...

just my 2 cents..

 

Anyone know how big our alternators are in watts or amps?

90 amps is a pretty common size which would deliver +1200 watts. Starting your car draws the most amperage - that starter motor turning over the motor draws big time amps.

The headlights/highbeams/running lights is another pretty big load and if you've swapped out the 55 w high beams for brighter ones like many have you've also increased the load.

That 400 w inverter will draw a load equal to what's plugged into it plus some. If you're running a PS2 you''ll draw the 65 watts (whatever) the game machine needs plus some more depending on the quality of the inverter. I have a 2500 watt one that is 90% efficent which is about as good as they come.

 

it's a 110 amp alternator...

but it's never that efficient all the time, and you don't want your alternator running at max capacity for extended periods...

small inverters are very inefficient and can easily draw more current than it puts out (that's where all that big fins come in handy... heat dissipation)...


you're probably ok, but I'd test your battery's paramters in the morning after a run with everything on and then re-check again in a week to see if the stored energy is dropping...

 

According to the calculations you gave me I am still pretty safe right now. I would still be safe even after adding the two things I mentioned above. BTW I am using a Vector Invertor.

 

350Z alternators are 110amp and don't seem to be too stressed with 1800watts in my experience.

 

you should be fine... but I'd still test your battery load levels after using it for a week

 

Do you use a multimeter for testing?

 

yup... and see what your voltage and amp readings are....

make sure you use a voltmeter that can handle the amperage... not sure how much that actually is..

or you can see what happens, if you can still start your car on a cold morning after a few weeks, you'll be ok