Power Inverter

[pardinkle]

Hey Guys,

I have a '97 Cavalier Z24. I have a 300 watt power inverter in my car for my ps2 and a 7 inch HD TV and such, cell phone charger etc... I have a system too and stuff, power cap, subs, two amps, 800 watt and a 300 watt.... so anyway, the problem is i just bought a coffeemaker and had it fabricated into my dash, but when i plug it into my inverter, it kicks it off and it's obviously because the inverter doesn't supply enough power. I've unplugged everything else and it still draws too much power to solely run the coffeemaker. I wanna buy a bigger inverter, but im wondering if i get a bigger one, accompanied with the sterio system, it's gonna draw on my battery too much. so should i invest in another battery and what all is involved in hooking up a second battery with the alternator, and mounting it etc.... im just looking for some opinions and a point in the right direction. any input is much appreciated....

Mike

[curtis73]

Its not tough at all. I run an 800w inverter in my car. I supply it with its own 6ga wire. I also have two 300w amps for the stereo. I'm running a 140 amp alternator supplying two batteries. Hooking up two batteries is simple. Just hook up both positives and both negatives. You will double your storage and amperage potential while keeping 12v. It has its price, though.

12v systems are designed with certain things in mind. They are designed to operate the vehicle and we consumers stretch its operation to include big stereos, laptops, TVs, and other additions, but you are talking about some serious power. Equate it this way; Its as if you have a Honda Civic with a 4 cylinder. Most people operate it as a 1-4 passenger vehicle which is within its parameters. What you are asking it to do is the equivalent of towing 2000 lbs as well. It can be made to handle it with many mods, but it will never handle it as well as a truck with a V8. The analogy is; you are asking your 12v system to handle what normally is accomplished by a 110v system and although you can modify the heck out of it, expect pitfalls. Short battery life, short alternator life, and corrosion and fuse problems. You're trying to fill the grand canyon with a garden hose. It can be done, just be patient

[pardinkle]

curtis,

thank you for your help. i didn't put in another battery, instead i ran a 4 gauge hot wire to a distribution box i mounted underneath the stearing wheel, then an 8 to the inverter near the ps2 where the glove box was, and the other 8 back to the system. it seems to be working well. but i have yet another question that i think you might be able to help me with, maybe not though... anyway:

this might seem crazy to most, but i want to put a coffeemaker in this beast somewhere. i have the coffeemaker already, it's a mr. coffee, 4 cup maker.... is this thing gonna work off of that inverter or not? is this probably gonna be the cause to put in the second battery, or a bigger inverter? you'd think it would run with no problem, but the more i thought about it, im sure it takes ass loads of power to heat up water that quick in those things, but i dont really know... if you're not sure either that's cool, but maybe some insight?

mike

[curtis73]

Not crazy at all! I love custom stuff. I knew a guy who put 12v cooler in the trunk that held a 1/4 keg and he put a tap behind the license plate. I think a coffee maker is far more unique.

My 4 cup coffee maker is rated at 985 watts. The inverter should therefore be a 1000w inverter, which will draw about 84 amps. Ouch. Your starter probably takes just over 100 amps during cranking, so a coffee maker will be like cranking your starter for 10 minutes. That would drain any battery, and its doubtful that your alternator would be able to keep up. The other problem is that your electrical system (alternator, etc) is designed for 20-30 amps continuous and breif periods of peak output like when your stereo takes a bass hit. Your lights dim because the system isn't up to supplying that much power for a second, let alone long enough to brew coffee. The charging system is not operational during starting, so the only thing happening there is the starter draws power directly from the battery through that huge wire. Then the alternator replaces that juice over a period of about 20 minutes. 5 seconds of cranking takes 20 minutes to replace. Your stereo amps (even ones rated at 3000w) only run those peak numbers for 3 or 4% of its life, hence why it can get by on 4 ga wire. Contiuous loads require much more than standard 8 or 4 gauge wire.

Here's my best idea. Shoot for 1/0 ga wire and three parallel 30 amp fuses. Upgrade your alternator to a 140 amp, run two 4 ga wires from it; one directly to the battery positive and the other to the starter (replacing the factory charge wire). Supply the inverter with 1/0 wire and do a test run with the coffee maker. Grab each of the joints of the wires, like at the alternator, battery, inverter, etc. If they're hot, its not good. If they get warm that's fine, but if they get hot it won't be long until they fail. Make sure each one is clean (preferably a non-tarnishing metal like gold plated) and has a lock washer. They bite in and make better transfer of electricity. Lastly, lay your hand on the alternator. If its hot, its not good. I fried a 140-amp alternator trying to jumpstart another car. In its defense, the other car had two batteries that were DEAD; like 4 years dead. It was hooked up 2 ga jumpers for about 15 minutes and it just started smoking and whining. It was fried. I love breaking stuff.

I guess you'll never know until you try! Keep me posted, I'm really interested.

Are there maybe other options, like a 12v coffee maker?