2nd Battery-Help Please!

 

Silver Member
Username: Mgbcs

Lincoln, Nebraska

Post Number: 236
Registered: Dec-06
OK...theoretical question-sort of. I am getting a Jeep Grand Cherokee this summer and I plan on running a KX1200.1 and some sort of 4-channel for the components. Question is, would I be fine with just a H.O. alternator, and Kintek HC1800 up front, or would I need to get a battery in back too?

Also, there is a possibility that I would run two KX1200.1 or a ZX2500.1, therefore making it a certainty that I would need a second battery. If this is the case, how do I wire it up? I know I would have a HC1800 up front and a HC2400 in back, but what is the wiring process, what else do I need to buy? Thanks!
 

Gold Member
Username: Carguy

Post Number: 5850
Registered: Nov-04
You're basically asking the same question as this thread:
https://www.ecoustics.com/electronics/forum/car-audio/314265.html

You don't have much room in a Cherokee to start with, so unless you're into SPL, one amp should be enough. You shouldn't need to add 2nd battery unless you plan on listening with engine off. As I stated in the other thread, if safety is an issue, then add 2nd yellowtop battery in whatever location you have with an isolator. That way, you will always be able to start your car.
 

Silver Member
Username: Mgbcs

Lincoln, Nebraska

Post Number: 240
Registered: Dec-06
OK thanks. I am always in the city or near the city, so I wouldn't be too worried even if my battery was drained (plus I won't listen to it with my car off).
 

Silver Member
Username: Mgbcs

Lincoln, Nebraska

Post Number: 241
Registered: Dec-06
However, if I ran 2 15" Qs with a KX2500.1, I would need another battery wouldn't I? I thought there was some rule of adding a battery every 1000 RMS after the first 1000, or something like that? Or is that only neccesary when listening without the car on? Thanks.
 

Gold Member
Username: Carguy

Post Number: 5851
Registered: Nov-04
There is no rule of thumb. If your alternator can handle it, then you're fine. If not, the amp will draw power from the battery. That's the situation you want to avoid (meaning you're pushing the alternator too much).
 

Silver Member
Username: Mgbcs

Lincoln, Nebraska

Post Number: 245
Registered: Dec-06
OK...well I am going to try to do a 240 amp alternator, so I am guessing I'll be fine. And the way to know if you need another battery is if the lights are dimming after the HO alternator is put in?
 

Gold Member
Username: Carguy

Post Number: 5853
Registered: Nov-04
Even with HO alternator the lights will still dim, but not as much. Lights are sensitive to voltage fluctuation. At normal driving condition, the voltage reading will be around 14.2 - 14.8v. At high current draw by the amp, it might drop to 13.5v. This will cause the headlights to dim. As long as the voltage stays above 12.5v, then you're fine. If it drops below that, it means the battery will be supplying the power. For a short period of time, it's okay, but not for long prolonged use.
Don't forget to do the "big 3" upgrade. If not, you won't be maximizing the HO alternator.
If you don't know what that is, do a search on this forum.
 

Silver Member
Username: Mgbcs

Lincoln, Nebraska

Post Number: 253
Registered: Dec-06
Yep...I've heard all about it. That's the first thing I will do, but I need to actually get the car first so I know how much 1/0 gauge to get. I saw a kit to do one for $50 with all the 1/0 wire and ring terminals...good deal or just pick out my own stuff from knukonceptz?

Anyway, one more question. What tool do I need to pick up to read the the voltage and where would I probe to check it out? Thanks!
 

Gold Member
Username: Carguy

Post Number: 5854
Registered: Nov-04
$50 isn't that bad. If you had to buy it individually, it'll be a bit less. It's up to you.
You can buy a DMM from just about any electronics store, including mass chains such as Walmart/Circuit City/Home Depot and eBay of course. If you plan on working with electronics for a long time, then invest on a good unit. Don't go cheap. A DMM with RMS will cost $50 - $80. It's well worth it.
You can measure voltage just about anywhere it has power, battery posts, amp's input terminals, alternator etc. You also use DMM to check for short or cuts. Very handy tool to own.
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