What the differences in batteries? Isn't a battery a battery? Why
should I spend $160 for an Optima Yellow Top when my local auto parts
store has a battery with more power for half the price?
Lots of questions there and the answers are more complex than they
first seem. Let's try to break it down a little.
Battery Types:
Just as you don't buy a Prius to tow a trailer and you don't buy a
pickup because of its great gas mileage, you don't buy a starting
battery for your electric motorcycle. Let's start by dividing types
into two categories, Application and Construction.
Application can be further broken down into three sub-categories:
starting (or automotive), marine, and deep-cycle. Construction can
be broken down into three sub-categories too: flooded, gelled, and
absorbed glass matt (AGM).
Application:
Let's look closer at the Application sub-categories starting with
automotive. These are most often called starting batteries because
that's what they do. These simply turn your car on and can deliver a
lot of power for very short periods of time and they can not stand to
be discharged very much (between 2 and 5 percent). Think about it
like this, as soon as you turn your key, huge amounts of power go the
starter in your car. Once the car is started it charges the battery.
Lots of power but can't be run down very much.
Marine batteries are the bastard children of starting and deep cycle
batteries. They don't put out as much power as a starting battery but
they can be discharged quite a bit more (up to about 50%).
Deep Cycle batteries are what we want in our electric motorcycles.
These are designed to be discharged to almost empty (about 80%) but
they put out about 20% less power than a starting battery. Do not let
that last part fool you. These still put out enough power to kill you
if you don't treat them with respect.
Construction:
No let's take a look at how some batteries are constructed. We'll
first look at flooded. These are probably what most people think of
when they think big batteries because most starting batteries are
flooded. Not all flooded batteries are starting batteries however.
Floodies (in lingo) can be marine and deep cycle too. They have lead
plates hanging in liquid acid. Flooded batteries can slosh around and
spill their acid and they generally have to be kept upright to avoid
such unpleasant events. Some, but not all, flooded batteries require
maintenance to keep the acid PH at the right level.
Gelled batteries contain acid that's had Silica Gel mixed in. This
turns the acid into Jell-o like substance that you'll never see Cosby
trying to sell on TV. A big advantage gelled has over flooded is that
gel stuff doesn't leak out. On the downside, you can't charge them
very quickly. If you have a gelled deep cycle battery in your
electric motorcycle and try to charge it too fast the gel can break
down, 'cook off' and toast itself.
Absorbed Glass Mat or AGM are what most of use because they can be
positioned in pretty much any conceivable position and can be charged
in a hurry. The acid in an AGM is held in a Boron-Slicate glass mat.
This is nice because you can't spill them like you can a flooded but
its still a liquid so you don't have to worry about damaging the gel.
Sound pretty good? The problem is price. AGMs run as much as 3 times
what floodeds do.
So no, not all batteries are the same. Each has a tole to play and
forcing one into a role for which it wasn't designed can be as
painful as watching George Lazenby play James Bond in 'On Her
Majesty's Secret Service'.
Below are some links with much more detail that I've provided:
The Ultimate FAQ for Deep Cycle Battery Basics and Information -
http://www.windsun.com/Batteries/Battery_FAQ.htm
Car and Deep Cycle Battery Faq - http://www.batteryfaq.org/
Electric Vehicle Battery Information - http://www.madkatz.com/ev/battery.html
--
The Electric Motorcycle Portal
http://www.electricmotorcycles.net/
Electric Motorcycle Listserv
http://www.electricmotorcycles.net/listserv
