Need straight info on extra battery installation.

[Bushmaster]

Hello...

I'm going to post this question in several catagories so that I can get the best number of responses possible.

Here's my specific situation:

I have a '96 Nissan Sentra with a stock 75 amp alternator. I'm presently getting ready to install a Cobra XL-450 amplifier to run behind my Lincoln radio. The amp pulls 40 amps.

In the past, I have fried several alternators after a couple of years of regular use of smaller amps (also in Nissan Sentras), albeit older models. I'd like a bulletproof setup, even if it is slightly overkill, because I don't want any additional headaches in the future. If the smaller amps eventually toasted the alternator, this one probably will too. What I'd like is some more capacity.

I need to know if adding a second battery in the trunk is the best way to go, short of adding a bigger alternator. If so, how EXACTLY do I wire this system? Do I merely run a heavy cable from the positive battery post on the battery in the engine compartment to the positive battery post on the battery in the rear? And then run a short heavy cable from the negative post (on the trunk battery) to the nearest ground in the trunk?

If so, I assume that I then simply run an adequately sized set of power leads from the trunk battery to the amplifier. Correct?

Also, would it behoove me to piggy-back the power lead coming from my positive output on my alternator to the positve terminal on the original (engine compartment) battery? It does have a built in voltage regulator in the alternator. Then would I just piggy-back the negative terminal from the alternator to the nearest ground?

Any special considerations here?

Which would be the cheaper way to go? Extra battery (and related accessories), or bigger alternator?
Which way is the best?

Thanks for any help you can offer. Please give the most thoughtful advice you can, because I'll be using it!

 

[Switch Kit]

Your asking a lot of good questions here Bush , I run the same amp and I don't think it pulls 40 amps total ? I could be wrong , but I have had no troubles what so ever and I only have a 65 amp alt in a GEO Metro , 8 gage multi stranded from battery to amp , (the battery is nothing special) but I do run my amp wisely meaning my motor is always running when ever IM flapping my jaws,at night I barely dim my lights at all , I mean you would really have to look closely to even notice it. I think in my case it's just knowing my limitations. With 4 settings on the amp , the low side is real nice if I just want to talk for a while with out burning that 3.50 cent a gallon petro. Good luck to you and I look forward to reading others answers to your questions. I think you will be very pleased with your Cobra XL 450. .......My stuff

 

[DTB Radio]

I wouldn't expect to have any problems with the alternator with that setup, unless its with a regulator that fails. Alternators with internal regulators tend to be a pain sometimes, because if the regulator fails, you have to replace the whole thing. In your situation, I would opt for the bigger alternator.

 

[Bushmaster]

Hello.. and thanks for the replies.

Preferably, I'd like to have a situation where I can run any power level (stage) that I want without dimming headlights, and otherwise taxing the sytem. I don't want to end up stranded with a fried alternator ever again if possible. (of course, that could happen to anyone, even without an amp in their car too!)

DTB Radio said:

"In your situation, I would opt for the bigger alternator."


I'm kind of leaning in that direction. I really don't like the expense involved, so where would be the best type of place to find the best deal on something like that? It's for a '96 Nissan Sentra. Reconditioned is fine.

Your help is truly appreciated.

 

[Switch Kit]

it's all good Bushy , shoot man ,I can turn on my a.c and put a slight flicker in my running lights , like I said before ,you really have to look closely to even notice them dim on the high side of my amp. Maybe I've just been lucky over the years ? I run a 29.99 Walmart special battery that truly ain't nothing special, (no 150.00 deep cell) I guess IM just not that hard up , hell ! whom am I kidding here !! IM just grateful that the situation works for me. IN your case ,I'd lean toward a new alt if that should be the case ? I still say you should be fine with what you have for that amp with what you have now , but then again ,like i said before ,man has got to know his limitations. Good Luck to you.