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Old 06-26-2009, 08:17 PM   #9 (permalink)
The Atomic Ass
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Originally Posted by Electric Frenzy View Post
In the other posts I feel like I'm being talked AT. The above post makes sense but leads me to more questions...

Why should I wire my batteries in series or parallel? What is the physical difference in wiring them up this way? I only know of one way to tie the batteries together.

If I'm using a 9" DC motor which type of battery connection should I be using and would I need to focus more on kW ratings then??
Wiring in series increases the voltage, which is almost universally necessary, as you won't run across many batteries over 12V, and you need higher voltages to achieve higher speeds. I think 48V is good for 35-40 mph, but I could be wrong. I think the rule of thumb for highway speeds is a minimum of 96V.

On the other hand is wiring in parallel, which increases amperage, an example being if you have a pair of 100ah batteries, in parallel, they become a single 200ah battery. It's generally not useful unless you simply can't find high-enough capacity batteries.

You can run combination's of the two, but generally if you can find batteries with a high enough capacity, getting them and wiring in series is the better bet.

The physical difference is more easily explained by the pictures on this page.

As for what configuration of battery to use, that will be dictated by what voltages your controller is capable of handling, and how much weight your car can handle, or you've allotted towards the batteries.

KW simply give an idea of how much power potential is in the pack, and it's found from pack voltage multiplied by AH rating, and your poll choices give the following:

Odyssey: 1.872 KWh
Marathon: 4.608 KWh
8V: 0.921 KWh

The closest to a usable pack comes from the Marathon's.

For a comparative reference, the Zap! electric car and truck have 6, 12V, 100ah batteries, giving them a 20-mile range on a good day with a careful driver, and the pack comes out to 7.2KWh. This in a car that weighs maybe 1,800lbs curb...

Last edited by The Atomic Ass; 06-26-2009 at 08:46 PM..
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