On Tue, Oct 11, 2011 at 05:44:55AM -0700, Michael Mccomb wrote:
>
>
> i've heard that batteries can be discharged to about 50% without doing any long
> term damage... considering that why is it that automatic recharging is set to
> come on at 80% rather than say 60%
Looking at it as "damage" isn't particularly useful; it's an inverse
relationship between the depth of discharge and the number of times that
batteries can be cycled. The graph is non-linear, meaning that a low DOD
(like 20%) will give you quite a long lifetime and a high one (like 80%)
will kill your batteries *very* quickly. 50% is an average design goal
that lets you keep the number of batteries reasonably small while
keeping their lifetime to something less than horrible.
Of course, if you can afford the space and the weight, more capacity
(and a lower DOD) is a better approach. Captain Mike's system combined
with his usage model lets him run at 20% DOD, so he's jumped that hurdle
without even ticking the top bar. :)
--
Ben Okopnik
-=-=-=-=-=-
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