I've been running my Braille GU1R lithium ion battery since Sept 2013, with zero issues. That's through a combination of winter/freezing temps, hot humid summers, daily and non-daily driving, etc.

Still going strong, today, and the second biggest weight reduction item on my list.

 

What's the expected lifespan for one of these lithium batteries versus the OEM batteries? I typically have to change out my OEM battery every 2 or so years due to the hot humid summers.

 

The problem is that we are talking about different applications here. Using a car battery as a deep cycle purpose for powering accessories when the engine is off is totally different to using a car battery for its main purpose, simply starting the car.

The reason lithium batteries are potentially harder on the alternator is that they charge much faster than a conventional battery and accept more current, so theoretically they can put more stress on an alternator. BUT, your car battery should not be getting discharged, except in rare circumstances. So the application of a battery for starting a car is totally different than folks using deep cycle lithium batteries for powering stereos, ovens, fridges,etc.

If you need a high capacity deep cycle battery because you are powering high power stereo equipment when your car is off, then this is not for you. But then again, if you are filling up your car with all kinds of heavy amps, subs, and other components, then you probably dont care about weight savings either

Rafi

 

So I take it the extra $100 is for the bracket/box?

 

It should be much better than conventional race batteries. It comes with a manufacturer's warranty for 2 years. As Lets Drive indicated above, he has a similar Lithium battery installed since 2013 without issues.

also includes the terminals.

-Rafi

 

The charging system the article in the link describes could not be much more wrong. There are no permanent magnets in any alternator, that's why it's called and alternator not a generator. Generators have magnets. Automobiles have not had generators since the '60s. Bikes don't use magnets either - my 1980 Honda CB750 had an alternator as did my buddy's 1976 CB550F. Whoever wrote that is living in the Dark Ages.

An alternator uses a coil (called the field coil) inside the armature to create an equivalent to a permanent magnetic field. The brushes that wear out feed power to this coil. If it were a magnet, no brushes would be necessary. The power output of the alternator is managed by changing the current through the field coil - less current, less power output; more current, more power output. So, if LiFePO4 batteries endanger the "alternator" (actually the regulator is what is in danger), it is as Rafi said, the charging rate of these batteries is different than the design factors used when building the regulator circuitry.

The section in the article discussing AC ripple voltage is probably the most important thing to consider, and could be addressed with some simple passive electronic componentry (L-C circuit) to smooth out ripple and keep it under the 1.4VAC they mention in the article. There is no hope of changing the ripple frequency, and that frequency varies with rpm as anyone who has had a ground loop in their sound system knows.

Truth be told, anything you do to improve the quality of the car's power system by "cleaning it up" will benefit everything electronic. The manufacturers have designed all their devices to run well on pretty ugly power. You'd be amazed at what they do with ECUs to minimize the impact of poorly regulated power inputs or worse yet, foolish people who connect batteries backward.

I've been looking at this whole thing ever since Toothdoc posted about the LiFePO4 battery he built for his car.

 

Resurrection. These numbers are just ball park numbers from memory and this thread.

Carbon roof 110.
2 piece rotors 26.
Front Seats 60.
wheels / tires roughly 24.
strip trunk 58.
sound tar 30.
coils 15.
exhaust 6.
battery 37.

This is an expensive list, but would yield a 3370- 3400 lb ISF. You could also pull carpets and rear seats for an additional estimated 50+.

If you keep the back seats, car will still function as normal, it will just be a bit louder inside.

 

Here's an OEM solution that I brought over from my IS350 with the F-Sport BBK. With the F-Sport BBK, the OEM spare no longer works... so Lexus had to develop a back up solution. That solution for the IS350 also works well for removing the spare on the IS-F, it's the same black foam material that cushions the spare tire from rubbing on the bottom of the spare tire well. Very lightweight, only a 1-2 pounds I think. It's part # PTR5500103 and it's about $200 (it's a big shipping box too!).

 

I have my car sitting for a year at a time.

I disconnect my battery and whenever I'm back in town I connect the battery and the car starts up without any issues (so far now 2 years and the battery hasn't drained).

Would a lithium battery be the same or better in terms of not discharging while sitting ideal for a year?

 

Better for sure.

 

My current non-driver weight of my F is 2924. Sub 3000 can be done, but its not easy.

 

Thats awesome!

 

This is genius, I’ve been thinking of a way to fill the void to put my trunk floor back in. This works better than what I had in mind.

 

I weighed my IS F couple of weeks ago, with just under half a tank of gas, no driver, 3800lbs! It’s 20lbs heavier than my RC F. Got home and removed the spare and tools (around 40lbs, give or take) Filled the void with some packing foam I had left from my RC F rear seat delete project. When I get some extra cash, I’ll order one of those spare tire foam replacement that @autovation got. IS F has a 10lb Braille battery, and carbon recaro pole position front seats, full Tom’s chassis brace less rear strut tower bar, F sport rear underbrace, Icode full titanium exhaust, 2-piece FIGS/RB rotors (380mm 2-piece front rotor weigh the same as factory 1-piece IS F rotor)



IS F


RC F

 

Something is odd here. You’re close to 200 pounds in weight reduction… maybe more. How is it still that heavy?