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Lightweight Battery for the GT3

 
Old 02-26-2010, 07:16 PM
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mikymu
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Smile Lightweight Battery for the GT3

Battery, we need them to turn our engine over and power electronics devices in our modern vehicle. They are as heavy as they come, 40, 50 and some times 60+ lbs for conventional lead acid battery. We have one of those lead anchor in our Porsche and sits right on top of the fuel tank and front axle. I want the dead weight off and replace with a smart and efficient lithium battery. My criteria are as follow:

Weight: Less than 10 lbs is a must. Our OEM battery is over 40 lbs. I want this weight off as much as possible

Brain: Yes, you read that right. I want a battery with brain where it can shut off itself when power is low so I don't have to jump start my car or hot wire from the fuse box just to pop the front hood

Protection: Prevent overcharge or discharge related damage

Remote control: A remote push button to turn the battery back on if it shut itself off due to low voltage

There are several options on the market including the new Porsche Li-ion battery. But the problem with these battery is that they weight more than 10 lbs (13 lbs for Porsche brand), has no brain or remote control and cost some pretty pennies.

After much research, I decide to get a Voltphreaks 5.5 lbs VPH 750 battery. It has everything I was looking for and weight merely 5.5 lbs and cost less than the Porsche battery. Here is their website with some technical description: Voltphreaks 5.5 lbs VHP 750 lithium-ion nano battery

Here is a look of the battery switch process and comparison

Voltphreaks fresh out of the box



Let's remove the heavy OEM battery by first removing the plastic cover then loosen the right base anchor bolt





Remove the 3 lbs OEM battery base



Battery remote control wire can gain driver compartment access through a left side black plastic cover (this opening is used for interior air filter if you have a right sided driving vehicle)



Remove the two Philip's screws and gently pull the cover back to revel interior access





Drop the remote control wire through the opening. I wrap some electrical tape on the wire section that makes contact with the body of the car to prevent tearing the wire cover



Remote switch at the driver side compartment next to the foot pedals. I zip tie the switch next to the black plastic bracket. The top of your foot will kick the plastic bracket and will not touch the switch





OEM vs Voltphreaks battery





41 vs 5 lbs lol





OEM battery plus battery base come up to 44 lbs - that's about an extra 7 gallon of fuel you carry around every day

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Old 02-26-2010, 07:17 PM
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The hardest part of the whole switch is making the battery bracket. You don't need to make something fancy like what I did but this give you a general idea on how to secure the smaller Li-ion battery.

I got an aluminum sheet from Ace hardware for the bracket since they are light and do not conduct electricity.



I measure out the length and width of the battery and the distance between two bolts on the body panel (this is where you secure the battery) facing the battery compartment and bend the sheet with the help of a vice. Wood block was used to sharpen the bend (beat the crap out of metal sheet lol)



Test fit looks pretty good



I also made a center brace to prevent the battery from moving up and down. I drilled 4 holes on the center brace then secure it with aluminum rivets. Ignore the extra holes ... they are for cooling lol.

Flat side of the rivet facing the battery. I used couple self adhesive plastic spacer on the center brace to help it fit perfectly





Here is a look of the finished brace

I cut out a none slip plastic mat from Lowe's for the bottom and back side of the battery for extra cushion



You will have to get two longer bolts (about the twice the length of the OEM bolts) from a hardware store to secure the bracket. You may also need to bend the aluminum bracket ever so slightly to make it fit right. Here is what is looks like once installed





Now you have lost 39 lbs total with this mod. This is about 6 to 7 gallon of fuel in weight so the front of the car will be slightly higher. I measured about 1/4" or 6 mm higher each corner on my car. To compensate for this change, I lower each side of the car by turning the suspension height adjustment by two 360 degree turns.



Finish product with everything installed. Connect the remote control wire and push the little button next the the red positive terminal and you are in business!





The car felt great yesterday at Laguna Seca with 39 lbs lighter in the front. The car tun in better. Battery works fantastic too! I intentionally left the interior lights on with both doors open and front hood and rear engine lid up to see how long it take to drain the battery. It took more than 4 hours for the battery to trigger the low voltage shut off. All I had to do is push the remote bottom and we got juice again. Start the engine and the battery was quickly charges. I had no problem at Laguna Seca yesterday and the battery work great with all the electronics without triggering the low voltage shut off. I will give more feedback in 3, 6 and 12 months for long term follow up.
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