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'[EE]:: Lead Acid batteries - Yuasa especially'
|I was looking for some Sealed Lead Acid battery dimensions and found
the yuasabatteries.com site.
A more useless site for practical applications would be hard to find.
Their UK site is utterly superb:
A vast array of intelligently presented information on the wide range
of Yuasa's excellent lead acid battery products.
All their SLAs plus NiCd, NimH
NP series SLAs
Sample chart from a data page
Discharge curve for an NP series battery at 25C (77F) for selected
discharge rates from 0.05C through 3C.
It's interesting (but not unexpected) to note that while the ratio of
discharge rates between 0.05C and 3C is 60:1 the ratio of times to 11V
(on a 12V battery) is about 350:1. ie the battery has only about 20%
as much capacity when "crash discharged" at 3 times its nominal
amp-hour rating than when discharged over 20 hours. You even get an
extra 25% capacity when going from the 10 hour to the 20 hour rate.
Homespun free advice - observe or ignore as you see fit :-):
When specifying lead acid batteries you will seldom go wrong if you
buy Panasonic or Yuasa (and I have no financial or other interest in
either company). Other batteries may be cheaper or even much much
cheaper, and sometimes you may get even better value for money than
when buying from P or Y - but there's also a large number of very very
bad LA batteries made, so if buying on price you need to be extremely
vigilant. In the local market I can buy equivalently rated batteries
for about 40% of the cost of eg Panasonic's products - and I certainly
am happy to do so in some cases. But be aware of the differences. When
buying (especially in NZ) do shop around a little. Prices for the same
product vary vastly and you can easily but no-name brand junk for
substantially more than the very best if you insist on doing so. eg
DSE sell batteries I have never heard of, and which MAY be OK for
about 50% more than you can pay for Panasonic batteries elsewhere.
Jaycar are cheaper than DSE and sell both Panasonic and "other brand"
lead acid batteries.
On Tue, 17 Apr 2007 01:16:43 +1200, Russell McMahon wrote:
> When specifying lead acid batteries you will seldom go wrong if you
> buy Panasonic or Yuasa (and I have no financial or other interest in
> either company).
I can agree with that (Yuasa that is - I've never even seen Panasonic SLA batteries). I bought a set of 4 x 100Ah 6V
Yuasa NP batteries second hand (they'd been used by a radio amateur for field trips) and I charged them when I got
them home, then ignored them for about three years. When I went back and checked, they were still reading around
1.9V per cell, and on recharging have stayed over 2.2V for months afterwards. I bought a different (but still
well-known) make of similar batteries, and after charging them and leaving for a few of months they were utterly
dead, and will not revive, so are going for recycling. And they weren't cheap! :-(
So I now always buy Yuasa and Hawker "PowerSafe" which seem to be similarly reliable.
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