Lithium Ferrous Batteries.

[Lynn]

Does anyone have experience with lithium ferrous batteries? They are fairly expensive, but are much lighter than anything else. They can be rapid recharged with a standard battery charger. I understand that the F1000 cars are using them.

[hardingfv32-1]

They are VERY expensive, $800-$1000 for a car battery size. Generally the same volume (size) per amp/hr but half the weight. They require a very special charger, maybe $100-$200.

Brian

[dric53]

http://www.kwsmotorsports.com/batteries.htm

[hardingfv32-1]

I missed the lithium ferrous description and jumped to lithium-ion (lithium cobalt oxide?).

Now for some research on lithium ferrous (lithium iron phosphate?).

Brian

[hardingfv32-1]

Looks like lithium iron phosphate batteries are more user friendly than lithium ion. The cost relative to energy density is more favorable the lithium-ion (lithium cobalt oxide). Amazingly small and generally 1/5 the weight.

I only found three companies/brands so far: Ballastic, Braille, and Antigravity. Any others?

Good informative thread for those with weight issues.

Brian

[Matt King]

If you're looking for a very lightweight, compact battery, here's another choice:

http://www.ebracing.com/shop/product65.html

We used these on Buell race bikes for sprint and endurance racing. They will easily crank over a high compression 1340cc air-cooled Vtwin engine, so I'm sure they would work on a Vee.

[tiagosantos]

I was reading about speedcell's last night but can't remember which type of lithium they are.

For those of you that run full data loggers and everything, what's the lowest AH rating you are willing to go with? I have no weight problems (I need to add weight somehow..
) but have limited room to put a big battery. I'm looking for the most energy in the smallest packaging!

[SR Racing]

Tiago. The data acquisition systems draw VERY little currrent unless you have a wide band 02 (they draw a bit, but even that is only a couple amps for a few minutes,) Figure your ignition system takes 4a. (2ah in a 30min race) Guages and rain lamps are effectively nothing to consider. Other than cranking you could easily run off 6 flashlite batteries if you wanted to. A safe AH rating is about 17, but you could get by with less if you charge after each session. But cranking current is a bit different. It's less than 50-100a for a couple seonds typically, so in AH it's not much. But batteries are rated in AH at their designed load. (Usually about 75% of its AH rating.) So a big draw could far exceed it's real capabilty. I would go with 17 or more. Here are some typical ones: http://sracing.com/Store/Electrical/Electrical.htm

Do get a AGM or Gel Cell battery. They can be mounted in any position and are easier to maintain as long as you charge at the correct rate.

Hope that helps.

[smsazzy]

If you use a jumper battery to start, you can get away with just about anything.

I use a PC310 Odyssey Battery. Bought it at batterymart.com.

[tiagosantos]

Not being able to use a jumper battery is my biggest problem.. I use it when I'm warming up the car in the morning and whatever checks I need to do, but being a one man show I usually have to start the car on the main battery in my paddock spot and at pre-grid. That's at least 6 times a day, 12 for a weekend. I'll be using an inverter to charge the battery between sessions next season, and I'll rig up the jumper battery (with a stake and a bit of string) so it'll unplug from the car as I drive off, so I think I'll be alright with a 17Ah battery. Haven't really checked the power consumption of my data thingy, but you're right, it shouldn't be that much!

[hardingfv32-1]

I figured out what cells are used to make these ultra light batteries. I can now make a battery any shape I want. It turns out that a Dewalt 36V battery is the perfect source for these cells. You can make your own battery for half the cost, about $150.

Brian

[tiagosantos]

Oh wow.. So you'd just dissect a dewalt battery, rig up 3 cells in series (3.6x3 = 12v) and then groups of 3 in parallel to get the capacity up.. They're just A123 cells, so I guess that's what every other company is doing, eh? Would you need any fancy electronics for load balancing or whatever? Looking at speedcells, it really just looks like a pack of cells shrink wrapped together. Hmm...

edit: the above is just out of curiosity.. I NEED more weight, can't be throwing easy weight out like that

[hardingfv32-1]

It takes 4 cells to get 13.2 volts. I believe there is 10 cells in the Dewalt battery. The RC guys have a tutorial on the subject. These are A123 System cells, maybe a little newer technology. Looks like you do not have to worry about individual cell voltage. The cells can accept some over charge while all the cells balance.

Some of us have space issues. Something like this could fit in the frame rails.

Brian