extra battery
 

I know ill need to run a extra battery soon so I don't completely burn up my alt (eventually will be upgraded) but I read somewhere said not to mix match lead and AGM battery, is this true? nothing surprises me anymore so IDK. also which battery should I get (99 grand prix with typical walmart battery)

It is true that mixing isn't the best idea. The ESR for AGM's is a fair bit lower than it is in a standard lead acid. The difference in the resistance makes for a difference in potential and causes current to flow from one battery to the other and back which over time will run them down. However it takes a bit of time for that to happen so in a vehicle that you drive everyday or nearly everyday it would never be an issue.

However don't think that a second battery will help the situation on your alternator if you feel its on it's last leg. A second battery will be another load on the alt to charge and will just quicken it's demise.

If the current alt is working good a second battery should be okay to put on it. It's not typically the best practice to mix the battery types nor is it typically the best practice to put a standard lead acid battery inside the vehicle due to the gas vented. That being said there are an innumerable amount of people who have done both without having issues. If you're driving it everyday or almost everyday mixing the types should not be an issue.

I feel my alt is fine. only diming I get is at clipping (which I know is bad which why I don't clip)

whats a reasonably priced AGM batter that's not your typical audio batteries (without breaking the bank lol) and what's a good brand battery isolator.

If you are clipping at any point, your gains in your amp are not set properly.
Fix that problem first, then you wont have to worry about dimming lights, since it only does it when clipping :icon_dance-disco:

Unless you plan on this car sitting a lot you won't need the isolator. It wouldn't hurt anything to have it but it's not absolutely necessary. Considering what a decent one costs and the trouble they are to install I wouldn't screw with one UNLESS it was absolutely necessary. I have had two batteries connected in the van now for several years without an isolator and the van has sat for almost two weeks without being started and driven, it's gone a week on more than one occasion during the bad weather we've been having recently and it's had no ill effect. Not running an isolator in the Jimmy either for that matter.

If you have a Sears near you the Diehard Gold AGM's can be picked up for about $150 +tax. That's about the cheapest you'll find a decent AGM battery priced. They're simply not as cheap as a standard battery. You could get lucky at O'Reilly's as well as they sometimes have an in house brand that can be picked up fairly cheap. If you mount a standard battery in a box and vent that box to the outside of your vehicle there's no problem with using a standard battery. When you consider that you can pick up a brand new 650CCA, 850CA EXIDE manufactured battery from Ruralking for $50 and a little extra work it's hard to justify spending another $100 on an AGM.

considering it would be in a trunk, a agm would be nicer, and the only time I do play it with the car off is if I have messed with the system and just checking to make shure everything is getting power.

are any of these a good deal?


Orion CO552C 5.25" 100W Cobalt Series Component Speaker System at Onlinecarstereo.com


Pioneer TS-A1304C 5-1/4" 300W Component Car Speaker System at Onlinecarstereo.com


Orion XTR62 6-1/2" 80W 2-way XTR Series Component Speaker System at Onlinecarstereo.com


Soundstream H-300BAR TV Sound Bar with Wired Sub-Woofer at Onlinecarstereo.com

Gimme your budget for speakers and I can get you a better recommendation. Personally I wouldn't go for any of them but that's me.

If you can swing $100 the Incriminator Audio components are well liked by a lot of people, the Pioneer TS-D1720C components are quite good for the money. The Alpine Type-S components aren't bad either along with the JBL GTO608C's.

At that price range no single one is going to far excel over another. To make that price point they're all giving up major compromises but IMHO from what I've heard from the one's above they do about the best for the money.

Well the GP is 5.25 not 6.5. And I dontbplan on cutting up the door panel.