[ale] OT need 600-1000W power protection for 3 minutes - cheap

[Ron Frazier (ALE)]

Solomon Peachy <pizza at shaftnet.org> wrote:

>On Tue, Jul 09, 2013 at 04:09:01PM -0400, Ron Frazier (ALE) wrote:
>> This local battery / different battery concept does sound
>> interesting.  I may cruise by the local Batteries Plus store.  I'll
>> have to check where the nearest Interstate Batteries is.  By the
>> way, I calculate that if you're pulling 950W and 12V, that would be
>> 79A.  It would be 40 A at 24V.
>
>Don't forget that 950W is the rated output of the inverter; it isn't 
>anywhere near 100% efficient, drawing more juice out of the batteries. 
>
>
>But yeah, the higher-capacity units run at 24V (or higher) to reduce
>the 
>working currents.
>

OOPS, You got me.  At 80% inverter efficiency, you'd have 100 A at 12 V or 50 A at 24 V.  Yeah.

>> Hmm ... I do have a mostly unused deep cycle boat motor battery
>> sitting in the basement.  I can barely lift it.
>
>Unless you have a UPS that needs 24V, eh? :)
>

Yeah.  I've been thinking if there's any viable way to do this myself.

I could by another boat motor battery for about $ 100.  Or I could buy a couple of small 9-12 AH SLA AGM batteries from batteries plus for the same price.  I could buy a cheap 24 V 1 KW inverter for about $ 150.  Then, I'd have to figure out all the switching and monitoring circuitry.  I could do a double conversion format by adding a 24 V 50 A power supply / charger and eliminate the switching altogether since the battery would always be on.  So for about $ 250 I could maybe do as good as the $ 180 APC for basic usage, but perhaps with longer runtime, and without many of their advanced features like Automatic Voltage Control.  For $ 400, I might be able to do a better double conversion system which would have more immunity to glitches, perhaps more runtime, and VERY rapid charging when the pc is lightly loaded or off.

But, * sigh *, I'll probably just buy the APC unit when I can.

What may be possible is to buy the BR1500G and gang an extra battery on to it.  They even offer an add on battery for sale.  But what I really need is TWO BR1500G's.

Not that it means anything, but those little sealed batteries fascinate me.  I was wishing I could figure out something useful to do with them without spending a fortune.  Maybe a mobile rpi project or something.

Ron


> - Solomon
>-- 
>Solomon Peachy        		       pizza at shaftnet dot org	 
>Delray Beach, FL                          ^^ (email/xmpp) ^^
>Quidquid latine dictum sit, altum viditur.
>
>

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Ron Frazier
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