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Old 06-10-2009, 12:16 PM   #1163 (permalink)
electricman
electricman
 
Join Date: Apr 2008
Location: Toronto, Ontario
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Quote:
Originally Posted by bennelson View Post
By "Premium" battery pack, are you referring to Lithium, etc.?

This whole vehicle project is one big low-budget experiment. ......

I think I am sticking with lead for the foreseeable future.

On a side note. I put my motorcycle's Optima Yellow Top AGMs in the Citicar for this weekend and WON BOTH DRAG RACES! Some variations of lead-acid are still pretty nice.
Here's the thing - What are the motor Specs and what are the Battery Specs? Example - Myelectricfly - Motor Rated 20.9 Hp at 90 V x 184 Amps; Batteries - Trojan SCA 150, group 24, 12V Flooded: Issue - Real Power Available from Lead-Acid (PbA) - Surrette.com specs pages show - a group 24 rated at 80 Ah {at the 20 Hr rate} but in the EV World - we need to know the ability to deliver at the 1 Hr rate - and that is just 29 Ah at 29 Amps!

So - now you know 2 things - 1st - it won't go far, and 2nd - it won't go fast, until you get better batteries! Period! So - Sticking with the same size PbA - you would need about 6 of them in parallel x 8 in series (at 50 lbs each that's about 2,400 lbs!) to get the volts and amp needed to properly drive the motor - AND - not seriously Damage your Batteries, but even then - you are still using the 1 hour rating of the battery - meaning - you clould at least get (in my car) about 100 - 120 Kms in that hour - if - a Big if - you could carry all that Lead!

Even if you go to large single monster 12V Batterie s- Rated at 275 Ah (At the normal 20 Hour rating) - the 1 Hour rating is just 99 Ah at 99 Amps, and these beasties weigh in at 172 lbs each! So - to get the best power from them - would still need 2 of them in parallel, or 344 lbs x 8 (for the 96V Nominal drive train) or nearly 2800 lbs!!! (Please note - My pack is just 400 lbs - so - you can imagine how much abuse that little pack is taking if I try to drive it on the highway, when it drops down to 75 Volts at about 185 Amps! Which I have - 7 - 8 times!)

That is about 13.8 - 14 kW, vs the rated 16kW - so I am using about 17-18 Hp to drive 100 kmh / 62 mph!

In any case - My Synopsis - Use Lead Acid Batteries in an EV - ONLY to prove your wiring, then put in real Bateries - that don't weigh tons, don't have such a large voltage drop under load (PbA about 25%), can handle the cold better if you live up north, and the heat better if you live down south, have a verifyable number of tested cycles at high 'C' Current Drains! (My Batteries - even New - were struggling to deliver 2C or 200 Amps!)

And - going to Spiral wound Yellow Tops - Might be better for High current - they are still Lead based and heavy - plus nearly more expensive than some good LiFePO4's wich have a much longer cycle life!

My Dime's worth - read more of my journey here!
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