Check, and thanks for the advice.
The second battery was going to be isolated for accesory items, (Light and Tailight, Fan, Windows, YES the DP Actually has Power Windows, lexan but power....and POSSIBLY the Fuel pump since all the other items are pretty isolated.)
The "Accesory" items were going to run off the second battery but the input/and draw from the alternator will be isolated as I will run an inline switch to handle it aside from the elctronics package. So Im not charging the accesory battery when I dont want to.
I asked the old man to go grab me an underdrive pulley for the alternator, I thought he brought back a damm balancer...lol....but I can get a smaller pulley, the alternator is one of the 50amp mini denso's so......
And the ballast was a consideration as well depending on what the car scales out at.....My other buddy who is a circle jerk is back in town he stopped by the shop this morning, and theyve got 3 cars going south for some roundy round but hes gonna bring his scales over this week later so Ill have a better idea.
The battery is a marine deep well unit I have , high amp (950 @ 32f I think, if my memory is right) and not so heavy (odd for a marine battery but true) so ....
Quote:
Originally Posted by magnumv8
drooze.....you don't need a second battery just the right one for your application.....most stockers add it for the ballast not the extra capacity....if you take into consideration that a modern street car has a MUCH higher electrical demand than your race car, after all they have to be able to power everything in the car at once including A/C, interior blower fan, power windows,rear defoggers, high powered stereos and they are doing it with one battery.....yes the alternator in newer vehicles have a higher output, but they also rely on the battery reserve to start the vehicle after setting for one, two or longer number of days.....you will probably be throwing a charger on it between rounds and leaving it on a maintenance charger when not at the track....for your app, I would use a Braille battery 12v....they have one with 850 CCA @ 0 degrees (over 1100 CCA at 32 degrees)...it weighs 41 lbs. giving you a good compromise between power, weight and size....
Alternators take on average 1hp per every 25 amps of output that they are required to provide so as long as the battery (batteries) are at full charge the alternator will not go to full output, what hurts is when you have dual batteries and the alternator has to provide enough output to keep 2 batteries up instead of just one also if one starts to create a heavy current draw you have to figure out which one it is, you can end up with a performance issue that becomes difficult to diagnose and could be as simple as a battery that "pulls" more current to charge than the other even though they are the same....
To create a "rule of thumb" calculate your total current draw and size your alternator to provide just enough output to cover it, this way with fully charged battery (batteries) to provide the starting power once the car is running you will actually be running on the alternator so available power is a non issue with you race cars electrical needs....
The fuel pump voltage boosters are really only for cars with no alternator to keep the voltage constant at the pump while the voltage is being drained by the rest of the electrical items in the car.....alternators usually output between 13.5 to 14.5 volts constant during operation so the pumps output is usually fine....
D L RAMBO....
PS.....twrs2006.....for a "legal" stocker items #1 and #2 are good
#3 has to be PARALLEL or you end up with (again) 24volts which will cook most of your 12 volt accessories, also in parallel the alternator only has to be connected to ONE battery positive since both are connected together at the positive posts....
#4 and #5 aren't LEGAL in stock.....
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