[tcb] Re: Batteries (again)
- From: "Gerald V. Livingston II" <gerald.tcb@xxxxxxxxxxxxx>
- To: tcb@xxxxxxxxxxxxx
- Date: Thu, 16 Oct 2008 22:27:28 -0500
What Denis said.
These are for running auxiliaries for long periods of time. The 4 orange
batteries in the Rivi will run my radio at "reasonable" volume for
somewhere between 2 and 4 days. If I crank it up they're good for
somewhere between 12 and 24 hours.
Real life example (and the main reason I'm looking for more).
I have a 3000Va UPS hooked up to a bunch of my servers in the office. It
uses a 48V inverter so, 4 batteries. The original batteries that came
from the manufacturer were 17Ah batteries. The literature for the unit
said we would get approximately 30 minutes of standby power at *half*
load or 10 minutes at FULL load --- those "4-packs" of 17Ah batteries
cost about $200 each and the boss bought 4 of them to extend the run
time to about 90 minutes (it's not a linear thing and takes an engineer
to explain 4x batteries = 3x run time).
Those little batteries are good for about 3 years. When they died he
bought complete new UPS units that use *10* batteries each but only use
5Ah batteries. I have exactly 10 of the orange batteries still and I
want to put those on one of the newer UPS units then go with 4 of the
bigger batteries in the old UPS and 3 in the Bus.
Anyway, I took the old 48V UPS and installed 4 of the 92Ah orange
batteries -- remember, original spec called for 30 minutes at *half*
load. We grabbed a 1500 watt electric space heater and plugged it in
plus a few other random devices. Completely maxed out the load meter.
After listening to the UPS beep at us for 2.5 hours running that heater
we finally plugged it back into the wall to make it shut up (I later
disconnected the beeper and replaced it with a flashing light). The
battery meter showed that the batteries were only about half depleted so
I'm figuring between 4 and 5 hours at FULL load and 10 or 12 hours at
HALF load.
I have a small, cheap, Energizer brand 650Va (about 350 watts) UPS
installed in my office with a single orange battery attached. It will
run 2 computers and a monitor at least 3 hours. the original package
said 15 minutes at half load 5 minutes at full load.
These are deep cycle batteries made to run at near full voltage right up
to the point where they die. And they are designed to be run completely
dead over-and-over. If you drain your car battery more than a few times
it will start to lose capacity quickly and will be garbage in a year.
Car batteries, if you can find an actual Ah rating in the specs (because
that's not what they're designed for, you'll usually find CCA and
"reserver capacity") are usually rated between 40 and 50 Ah. The orange
batteries I sold are 92Ah and these new ones are 120Ah.
I use one of the orange batteries and a 750Watt inverter to make coffee
at campouts. At the classic I forgot my single-battery charger and it
did fine making 2 pots a day for the whole weekend. My coffee pot has a
750 watt element so it's drawing whatever the max amperage is for hat
inverter.
OK, got me rambling. I quit now.
Gerald
Brian Denning wrote:
are you serious??? did i read that right $275 for a car battery???
guess i'm a cheapo. my duralast powers my radio for 2 days constant with
quick start up after that...why would you need to spend that kind of
money on a car battery???
ridiculous in my book...i have better things to buy with that kind of
money...sorry, just my .02
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