Prices are coming down on the lithium. I just ordered an Antigravity ATX20 Battery for $369 with free shipping. 780 cca, 25 amp hours, under 5 pounds. It's getting mounted on the inside of the framerail, very close to the starter to save the weight and voltage drop of long cables. They said a standard alternator will charge it fine, as long as it doesen't discharge to under 10.5 volts. If it goes under 10.5V, it shuts off and a special charger is needed to wake it up. So I am putting a sensitive digital voltmeter in the car.
I have a 7 year old dyna-batt that is 14 pounds and will start a car, but I don't trust it 100%. So I will build the battery box to fit the anti gravity and the dynabatt, and bring the dyna for a spare.
I'll let you know how it works out.
OK, here is my update:
I installed the antigravity battery in my hot rod coupe, along with a 105 amp GM alternator. Then I did some street driving, a couple drag strip tests, then completed Drag Week 2018.
I love my little 4.5# AntiGravity battery! It performed flawlessly. With the powermaster starter, it cranked my 13:1, 468" hemi over like the plugs were out of it. Except one time it wouldn't start the car when I forgot the radiator fan on for about 40 minutes. It did not get low enuff to put the battery to sleep. If it does go to sleep, you need a special charger to wake it up. I brought the special charger along on Drag Week, plus a jumper pack that has a built in 110 volt inverter/outlet. So I could plug the charger into it and wake up the battery if it ever got ran that far down.
Not only did I save the weight of the battery, I saved about 20# of cable by mounting the battery a foot away from the starter on the inside of the frame rail, instead of in the trunk. The NHRA mandated battery cut off switch is right there too, with the lever of it on the floor inside the car where I can reach it if I forget to turn it on. A 3/8" x .030" wall stainless steel tube runs from the lever, back through the trunk and out the back of the car as a remote control for the switch. That is much lighter than a Morse cable.
Bottom line, I liked my battery so much, I started down the path of becoming a dealer for them. But their terms regarding liability and indemnification for dealers were unacceptable to me, so I passed on that opportunity, but I still love their battery's.
