[CentOS] OT: UPS battery vendor, cont'd
Warren Young
warren at etr-usa.com
Thu Feb 14 17:09:00 UTC 2013
On 2/13/2013 06:12, mark wrote:
> Huh. No, I want to pay on the order of $12/individual battery,
Please don't misuse "order." It's a corruption of the scientific term
"order of magnitude"[1][2] which, used correctly, means that the values
you're comparing use the same factor of 10 in scientific notation. If
we take your claim literally, you'd be satisfied with any complete
battery that cost less than $120 * 8 = $960.
(I will also come after you if you misuse "literally". :) )
> $100 or so for the set of 8;
You've got one low-ball quote, and now you're demanding that everyone
else meet it? Sigh...
The way I see it is, you've also got a whole bunch of people offering
the same thing for $20-30 per VRLA[3] unit. That means either:
a) $20-30/VRLA is a good price and consequently you should be worrying
about how others are managing to low-ball that; or
b) there's widespread price-fixing.
Given how many news stories you can find about misbehaving cheap
batteries, I'd bet on option a). Just because the label has the same
voltage and amp-hour rating as what came out of the APC UPS, doesn't
mean it's exactly the same thing. Batteries are tricky. Boeing and
Tesla Motors are both in the news now because too few people really
understand batteries.
If you're willing to open up the APC sled and replace the individual
VRLAs directly, the cheapest *reputable* vendor I've found is Mouser.
Their part # 632-GP1245 looks close, but don't take my word on that.
I'm just eyeballing photos and springboarding off the McMaster
dimensions; I have no direct experience on that particular swap.
Mouser wants $16.30 each of these in qty 10. Just for reference, one of
Mouser's direct competitors, DigiKey, wants about $25 for the same
thing. That put's the $22-26 McMaster quote you've tried to reject
right in the same range.
I also don't see that you're accounting for return shipping and the cost
of the sled. If you buy the pack from APC, they ship you a complete,
assembled battery pack, along with a reusable box and return shipping
label. You put the old one back in the box you got the new one in, and
send it back for recycling. That's worth something.
When you buy individual VRLAs, you have to account for your time opening
up the sled, swapping VRLAs, and reassembling it all. Then you add in
your time to dispose of the spent VRLAs. I'm sure you can find plenty
of places locally that will take them, but I'll bet your salary and gas
costs will wipe out your DIY savings.
You're probably not counting opportunity costs[4], either.
---------
[1] https://en.wikipedia.org/wiki/On_the_order_of
[2] http://mathworld.wolfram.com/OrderofMagnitude.html
[3] https://en.wikipedia.org/wiki/VRLA
[4] https://en.wikipedia.org/wiki/Opportunity_cost
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