zliminator Posted December 14, 2003 Share Posted December 14, 2003 I have an Optima battery in the rear and I'm thinking about mounting it below the deck like Dan did (except in the middle - my mufflers are on the outside). I was thinking about putting another battery in parallel with it since I have a high-torque starter for the 11:1 CR. My question is this: would it be ok to buy a regular battery from Autozone or whatever and put it in parallel with the Optima or is there a difference in the charge rate and capacity and so forth? Since they are going to be sealed I may as well buy another 2 standard batteries because I already have a new one and besides, I don't mind having more weight in the back because with the V8 in the front and I need more weight dist. and traction. Dan BTW - I know its not supposed to be in series, that would be 24v. Quote Link to comment Share on other sites More sharing options...
Guest Nic-Rebel450CA Posted December 15, 2003 Share Posted December 15, 2003 Since my Z is not a daily driver, I thought I would replace my big, heavy lead acid battery with one from a garden tractor or motorcycle. I know a guy who has done it, drives his car same as mine - in warm weather, not everyday, light use. And no relocation needed. I dont think how often you drive it really matters. Things you have to keep in mind with such a setup is that the current draw when starting the engine can kill the cells in the battery. Then, the charge back from the alternator can burn up the battery. Quote Link to comment Share on other sites More sharing options...
olie05 Posted December 27, 2003 Share Posted December 27, 2003 Optima battery as in Red top or Yellow top? Thoes are Gel Cells not Dry Cells and according to the people I've talked to' date=' you still need a sealed box for them. If you wanted to go really dry cell, look at Odyssey batteries. My Talon has one that would fit behind or under the seats in my ZX... [/quote'] So if you have a dry cell battery you don't need the sealed box? If that is true, could you put a dry cell battery just bolted down to the chassis with no covering right behind the seat? Quote Link to comment Share on other sites More sharing options...
Dan Juday Posted December 27, 2003 Share Posted December 27, 2003 could you put a dry cell battery just bolted down to the chassis with no covering right behind the seat? Yup, or get one of the real small ones and put it under the seat. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted December 27, 2003 Share Posted December 27, 2003 Since my Z is not a daily driver' date=' I thought I would replace my big, heavy lead acid battery with one from a garden tractor or motorcycle. I know a guy who has done it, drives his car same as mine - in warm weather, not everyday, light use. And no relocation needed.[/quote'] I dont think how often you drive it really matters. Things you have to keep in mind with such a setup is that the current draw when starting the engine can kill the cells in the battery. Then, the charge back from the alternator can burn up the battery. Actually, as long as the battery has the capacity to start the car under the conditions, the charge rate is irrelevant - it's just a constant voltage charger, alternator capacity has nothing to do with how fast the battery charges. The reason the battery is so large and heavy is for starting under cold conditions, and to last for years of daily starting. Quote Link to comment Share on other sites More sharing options...
fl327 Posted December 28, 2003 Share Posted December 28, 2003 If you are using a dry cell like an optima, you dont need a really expensive (although, very nice) battery box. I used a plastic box for storing marine batteries that autozone or kragen should have, it fits regular size batterys and can be modded to fit anywhere you want it, it has a cover for hiding the leads. I dont like the idea of those leads being exposed in the car, just me. Quote Link to comment Share on other sites More sharing options...
Guest 81na ZX Posted December 28, 2003 Share Posted December 28, 2003 Except that Optimas are not dry cells. In order to be NHRA legal, an optima needs an approved box - sealed and vented. Quote Link to comment Share on other sites More sharing options...
Guest Nic-Rebel450CA Posted December 28, 2003 Share Posted December 28, 2003 Actually, as long as the battery has the capacity to start the car under the conditions, the charge rate is irrelevant - it's just a constant voltage charger, alternator capacity has nothing to do with how fast the battery charges. The reason the battery is so large and heavy is for starting under cold conditions, and to last for years of daily starting. It is my understanding that the amperage the alternator puts out does have an affect on how fast the battery charges. As with any charging system, the more amperage, the faster the charge. And too much amperage will damage any battery. That is why if you put a motorcycle battery on a charger you have to use a low amp setting. This is also why it is bad, if not dangerous, to use a car to jumpstart a motorcycle. Too much amperage. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted December 28, 2003 Share Posted December 28, 2003 Just speculation here; Can it be considered correct in saying that the amp draw in starting the engine will be considerably higher (several fold) than any charge current? I believe the amount of current used in a charge is based solely upon the voltage difference between the charge circuit (alternator output) and the battery voltage at the time of the charge. The discharge of the battery for a quick starting engine is less than on an engine that takes a little cranking to get it started. Hence the lighter discharge (on the quick starting motor) will allow the battery to maintain a higher voltage when the engine starts, and will "draw" a smaller amp charge to recover. In my case, the motor takes a few rounds to get it started (no choke), and thus the requirements of a large battery for these deeper cycles is necessary. Folks with a quick starting motor in mild climates could probably get away with a smaller, space effecient battery. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted December 28, 2003 Share Posted December 28, 2003 Just speculation here; Can it be considered correct in saying that the amp draw in starting the engine will be considerably higher (several fold) than any charge current? I believe the amount of current used in a charge is based solely upon the voltage difference between the charge circuit (alternator output) and the battery voltage at the time of the charge. The discharge of the battery for a quick starting engine is less than on an engine that takes a little cranking to get it started. Hence the lighter discharge (on the quick starting motor) will allow the battery to maintain a higher voltage when the engine starts' date=' and will "draw" a smaller amp charge to recover. In my case, the motor takes a few rounds to get it started (no choke), and thus the requirements of a large battery for these deeper cycles is necessary. Folks with a quick starting motor in mild climates could probably get away with a smaller, space effecient battery.[/quote'] Yes, that is my point exactly. On a constant voltage (regulated alternator), the charge current is based on the voltage difference between the regulator output and the battery voltage. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted December 28, 2003 Share Posted December 28, 2003 This string has opened up new possibilities for me. I've never been totally satisfied with my current rear mounted battery set-up. I had to raise it up to clear the mufflers (from the race set-up), and now it sits too close to the tail light pigtails. After looking at the various batteries discussed, I may go for a dual 6v system and place these smaller batteries in each of the bins behind each of the seats. These batteries are smaller than I expected and may open up some badly needed space in the back of the car. Quote Link to comment Share on other sites More sharing options...
BobsZTwins Posted January 25, 2004 Share Posted January 25, 2004 I had a stainless box built specifically for an Optima battery. It's sized to just fit under my strut brace. It's secured to the deck by a well nut and allen head bolt. There's a pic of the box in place in my gallery. I've got the drawing with dimensions that I gave to the fabricator if you need it. Cheers! Quote Link to comment Share on other sites More sharing options...
Guest zerpie1 Posted March 28, 2004 Share Posted March 28, 2004 I put mine behind the passanger seat. Its out of the way, low COG, and to jump start all you have to do is roll down the window. Quote Link to comment Share on other sites More sharing options...
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