Batteries and New Battery Technologies

I assume that their bankbalance had a firm knock and that they did not have a charger with 72 control points on the bike. I fully agree that Lithium has a very good weight/power ratio. Will you do me a favor, and just shortcircuit your lithium battery? Are you willing to tell me what happened?

As a second thought, don't do it, the battery will most likely explode.

Lithium is still far from fully developed, but I feel NiMH is enough. The super capacitor is a disaster, I need a powerfull affordable power bank. Just help me upon to improve the battery on battery contact. "Kontakt 390" is promissing.

Bert

 

Hope this helps

Porta

 

Hope this helps

Porta

 

Battery selection

Hi all,

Last week I was at the Microchip Microcomputer presentation. Attached some excellent slide show (1,7 Mb pdf) information on the various batteries. Again , "A small decrease in Voltage accuracy results in a large decrease in Capacity" - Lithium batteries. This is probably the final reason why I stick to NiMH or alternative to NiCD.

Bert

 

why do you want to use a cork for that?
PVC is a strong enough material to screw a cap on and i do think that there are PVC caps out there meeting your requirements....
this you could than easily seal off with a O-ring...

Li-Ion batteries are widely used for years already in the toys department...
model -airplanes, -helicopters, -cars etc - whatever you can think of and since also kids are playing with them i must say, that this technology by now IS safe!
it all depends on their charge/discharge controlers and some security wiring... everthing is there, everything tested on the streets for years...
when was the last time you heard of an Li-Ion battery blowing up?

but they do have a drawback: their absolutely nuts and through-the-moon pricetag!

 

Hi Capt Vimes, yes indeed, thank you for the input. Let me first make the complete casing for the powerbank. Only then you can see why certain off the shelve parts are usable and which one not. But yes, a 40mm endpiece with "O" ring could do the job.

Bert

 

It is a different ballgame to have 1 or 2 cells or a 1000 parallel/serial. There are reports and I have done a test (go back quite some posts) wherafter I am not too keen to have such a powerfull chemistry, which if heated up, i.e. with a short circuit (sea water spill example) or a faulty charger, can explode. Refer also the Microchip presentation attached to 531

Absolute true.
Bert

 

Hi Masalai,
You are still for the time being, better of with your 16 deep charging Lead Acid batteries.
I passed the Battery place and inquired about the price.
Here they cost R820,- all inclusive each. They are 60 Amperhour each and weigh 14,5 kg and has a volume of approx 7,5 liter.
The total price is thus R 13120,- for 11.5 Kwh ( USA$ 1795)
Total weight thus 232 Kg
Total volume is thus 120 liter

This in comparison with what I am building
Type "D" batteries
Volume = 111 liter,
Weight is 167 kg + casing 76 kg = 243kg
Cost at USA$ 3.60 x 1000 + shipping + casing = R 35330,- for 10,8 Kwh
Time making the casing +/- one week (USA$ 4833)

If made from 4000 type "AA" batteries R 28600,- for 13,4 Kwh (USA$ 3912)
Weight is 120 kg + casing 79 kg = 199 kg

The only thing I would do is NOT to connect the batteries parallel, but to make 8 x diode boards.
To have 50 x 6 Ampere diodes placed parallel between 2 printed circuit boards. Total cost +/- R320.00 + some offcuts for R 40,00 from the printed circuit board manufacturers and some solder. Total R 370.00 ( USA$ 50)

You use thus 4 of those (anode) to the plus line and 4 of them (kathode) to the Genset plus line and your other solar, wind etc chargers.

What is the opinion from everybody in connecting 16 batteries 4 x 4 parallel ??? without diodes as per simplified drawing.

B <> B <> B <> B
B .... B .... B .... B
B .... B .... B .... B
B .... B .... B .... B


Bert

 

A spreadsheet for you. Medion NiMh AA is the cheapest but LiFePo4 is likely more economical.

Please do not consider ordinary Li-Ion or Li-Po safe. Please read the safety data available for the relevant cells. Some (as most commonly used in laptops, cellphones, RC toys) are flammable or explosive and can ignite themselves if mistreated or defective.

 

Hi Sigurd,

Thank you for the spreadsheet. Very usefull.
I see, you also have a second thought about the risk, which Lithium brings over and above the absurd high price.

Bert

 

Whale

Sadly the battery from this quite young whale gave in and died on the beach here 800 meters from my home. very sad.
Bert

 

Bertku, please understand that just like redheads, not all li chemistries are flammable/explosive. SOME ARE! SOME ARE NOT!!!! :O

Yes they are more expensive than NiMh but if you can bear the investment you can get more storage for the money due to the longer lifetime of SOME!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"¤#¤%&&/("#¤%!!"#%/ lithium chemistries.

I have skimmed the thread and added altairnano to the spreadsheet and some motors. The altair is about a dozen times cheaper per kwh over its life than the medion AA, according to data within this thread.

You can please add stuff and republish the sheet if you wish.
(edit - 21.10.2009 ver.)

 

I have started a thread specifically for lithium based rechargeable batteries:
http://www.boatdesign.net/forums/projects-proposals/battery-electric-lithium-choices-29450.html

I am interested in suppliers, price and actual performance if you care to contribute.

Rick W