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stuntjunkie199
04-30-2013, 10:16 AM
I recently replaced what I believe to be the original alternator (200k+), a pretty good lifespan, and I went with an OEM replacement. However, now I am looking to install a pretty small sub system. The amp I would use would be an old Alpine 80watt I'm guessing from the 90's running into 2 10's. I'm not looking for ground shaking bass just something to add to the stock system. My question is would the stock alternator handle this load easily? I definitely do not want replace the alternator again.

POS carb
04-30-2013, 10:22 AM
I ran 900 watts rms to my subs and 300 watts rms to my speakers for a long time on a stock alternator without any charging problems, but I had a 1000 amp Group 49 battery and 3 farad cap in the trunk. I played my music loud but I doubt the amps were ever at 100% load
I had it re-wound to a higher amperage but it wouldn't charge at idle so I went back to a stock one.
The stock alternator is capable of producing around 900 watts maximum.
Later on I modified the mounting bracket and put in a 90 amp from a 97 Accord, that one supports around 1200 watts

Hash_man_Se_i
05-10-2013, 10:33 PM
You will have no problem at all with what you are planning to run. My current amp draws 150 amps of current at max draw, I am running an upgraded odyssey battery, stock alternator on by B20b and only have slight issues now.
I ran my old amp with a max current draw of 120 amps on my stock motor for over a year with no caps, just upgraded grounds.

dieselgus
05-11-2013, 11:06 AM
I ran my old amp with a max current draw of 120 amps on my stock motor for over a year with no caps, just upgraded grounds.


^^^^^^^^^^^This^^^^^^^^^^

I used to see it all the time. Kid gets a big system, puts it in, runs 2 or 0 ga from the battery for it all, headlights still dim etc, adds a cap because that is what the salesperson told him/her that it needs (and back in 1992 when pretty much every 12V car amp was a class AB current pig, they did, in fact, help slightly. Most any amp built and designed within the past 10 years has better power supply design and is much more efficient. You don't see many 300w 3 channel amps with 100A worth of fusing on them like say for instance an old Xtant 3300ic. Then again, that old Xtant is a pretty awesome sounding amp. Anyways, I digress).

But you have to think of electrical as a balance. If you are feeding a 100A potential load with a 4 ga conductor, then the current needs an equally sized return path to the electrical system of the car. Add a 4 ga run to the back of the car, you best be adding a 4ga ground from your battery to the frame of the car. No need to overthink it, just think of it all as a balancing act. The OEM electrical is designed for the expected load that a car running with everything on at once will have, plus say 15-20% margin. If you add a load on the positive side, you also need to add an appropriately sized ground. The 8 ga or 4 ga body ground that the factory stuck in there is good enough for the car, not the car plus whatever you add.

A cap is a waste of money bandaid for actually adressing the issue with a couple feet of wire and a couple terminals.

MessyHonda
05-18-2013, 10:05 AM
i ran a 300 watt amp 150rms with a 10 inch kicker subwoofer 150rms and i never had any problems. Just be sure you battery is good. I have a yellow top optima battery. my last system i had a 500rms sub amp and a 200rms 4ch amp

CzEcHy
05-18-2013, 11:12 AM
I have a 1600 watt amp with two 12's.. Its an audiobahn a8002t amp and I'm unsure on the RMS but I have no problems on the stock alternator and battery.. I have a volt gauge installed and barely see the needle move while driving with lights on and w.e.. headlights never dim even while sitting..

My A/C uses more power than my system :/

Hauntd ca3
05-24-2013, 02:10 AM
you'll be fine. 80 watts flat out will suck less than 6 amps, add a head unit running flat out, maybe 15 amps combined.
i run bout 300watts rms for 2 subs and fronts. i had an ammeter inline and ran the system till it was to loud for me, it drew bout 12 amps, or in watts talk, bout 170watts which is bout 20% of our alts output