# Laptop Batteries?



## Tesseract (Sep 27, 2008)

arftist said:


> ...Has anyone tried to purchase enough laptop batteries to power a car?...


You can do this, theoretically, but I seriously doubt it would be economical. You want at least 10-15kW-hr of energy storage for an EV while most laptop batteries have around 50-100W-hr of capacity. You could need as much as 300 laptop batteries to do this, in other words.

E.g. - A Dell 85W-hr laptop battery on Amazon costs $80. 10kW-hr of capacity would cost you $9400. To get the same capacity in lead-acid would cost about $1500.

So, yes, it is possible, it just isn't very practical.


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## arftist (Mar 20, 2008)

Thankyou for the response. Not to waste anyones time here, but can a comparison between lead acid batteries and lithium ion really be valid? Would not the lead acid result in less range due to extra weight alone? What abount the energy density? Also wouldn't the lithium ion batteries require less frequent replacement?


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## jwdsail (Dec 7, 2008)

I believe what Tesseract was trying to say (he can correct me if I'm wrong) is that with Lead-Acid, you're paying for the battery in more or less the configuration you're going to use it in. 

With laptop batteries, unless you find someone able to properly wire up a battery bay with proper contacts/way to lock them in place for the laptop batteries, you're paying for the Lithium cells, as well as the external packaging, charge status lights, contacts, internal circuitry, etc. that wouldn't necessarily be used.

There's some possibly more affordable ways to get the lithium cells ... some on this forum are looking into Lithium battery suppliers and group buys..


jwd

edit - of course if you find extraordinary deal on a few pallets of laptop batteries on a gov surplus web site and feel like experimenting...


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## order99 (Sep 8, 2008)

From what i've heard, Lithium batteries are superior in nearly every way. But they haven't been around long enough for a full shakedown of long-term ability, and until the Lithium Iron Phosphate chemistry came around they had a tendency to burn/explode when overcharged. Lead Acid has the virtue of being incredibly cheap-about 11-14% of Lithium chemistries, but if you have the money Lithium-based will outlast and outpower Lead nearly all the time.


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## TX_Dj (Jul 25, 2008)

Keep in mind... few "laptop batteries" use the safe LiFePO4 chemistry. Most are Lithium Cobalt or Lithium Manganese (or was it magnesium, I forget).

Those types are more sensitive to improper charging and discharging, and more prone to thermal runaway which usually results in fire.

Another problem imposed by using such modules would be that each module is not designed for high rates of discharge, so to power an EV you would need to build dozens or scores of parallel packs to "share the load", or you would need to build a custom controller that can take several hundred volts in order to bring the amps down low enough to not cause an explosion the first time you pressed the accelerator, due to "uncontrolled" high-rate discharge.


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## arftist (Mar 20, 2008)

Thanks for the replys folks. Good food for thought there. I spent months researching batteries before I even found this forum, and was faily well convinced that lithium in one form or another was the way to go. Being that lithium is the lightest of all metals and lead is for the most part, the heaviest, I still think it bears investigating. Any thoughts of forming a purchasing syndicate of forum members to pursue wholesale Lithium Batt. procurement? And has anyone identified the most logical choice yet?


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## TX_Dj (Jul 25, 2008)

There's a thread open in regards to a LiFePO4 group buy.


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## martymcfly (Sep 10, 2008)

On my laptop, I broke the pin off where the cord plugs into the motherboard. I could not charge the battery making my laptop useless. I was looking for a way that I could charge the battery while not in the laptop. I had no luck, just got a new laptop. So I think that finding a way to charge them would be difficult.


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## Doctorbass (Dec 12, 2008)

Hello,

I know i'm new here, but i would be gald to give you some of my experience with powertools battery

If that could help, i would recommand using powertoold battery instead of laptop.

1: they are cheaper
2: they can take much higher current
3: they are SAFE ad not the Lothium cobalt from laptop
4: they are easier to charge.. the Lithium manganese dont need and balancing! and are 3.7V instead of 3.3V like LiFePO4
5: they can be found easuly on ebay for mass quantity for low price
6:They dont suffer of peukert effect like SLA so the Ah delivered are real

I build my own battery pack of 2.3kWh for my electric bike (100V 23Ah) with used deffective Makita pack and i can do 210km without any pedaling. 

EV is great... EV with recycled stuff are wonderfull! EV with recycled battery are GREENLY wonderfull

Doc


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## Guest (Dec 22, 2008)

In the short term they seem to be superior but in the long term not really as far as laptop batteries go. They are expensive and so far the best I have seen life wise is maybe 3 years. At about 3 years the my batteries usually hold only about 1/2 or less the original ah and go dead before I have time to do any thing. My last batteries were for my mac and before 3 years were up they only held about 10 minutes worth of power. Nothing helped. They just up and died. I don't really want to keep spending that kind of money to replace my EV batteries every 2 to 3 years. Cycle life shows that they are gone before they magic 2000 cycles are up and usually I let the batteries go to the point of the computer saying it needs to be plugged in for a charge. My camera uses NiMh AA batteries and I have 3 sets and use them and charge them daily. So far my original set of 4 has lasted a good 4 years with no sign of letting up. My other 2 sets are only about 1 year old but still show no sign of letting up and hold a charge and do real good. I use the camera for movies and photos galore. I may go with trying to make a pack of these for a bicycle conversion using an old VW Generator motor as a drive motor. I am not sold on Lithium because for one the price is just not worth 3 years worth of recharging and the other is too much hype on a new technology. NiCad's had to prove them selves and NiMh had to do the same. I like the NiMh. I'd like to see a return of these. Small or large format. Small can be build into large format. Not the best as finding one dead cell in a batch of hundreds or thousands is not an ideal thing. 

Pete : )




order99 said:


> From what i've heard, Lithium batteries are superior in nearly every way. But they haven't been around long enough for a full shakedown of long-term ability, and until the Lithium Iron Phosphate chemistry came around they had a tendency to burn/explode when overcharged. Lead Acid has the virtue of being incredibly cheap-about 11-14% of Lithium chemistries, but if you have the money Lithium-based will outlast and outpower Lead nearly all the time.


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## arftist (Mar 20, 2008)

Yeah, about those nickel metal hidride batteries, they were actualy one of my first choices, when does Exxon or Chevron or whatevers patent expire on those?


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