What's that Lassie? You say that SteveB fell down the old rec.crafts.metalworking mine and will die if we don't mount a rescue by Sun, 5 Oct 2008 14:00:04 -0800:
Look here:
The 500W to 1000W size is at the upper end of how much current you can send reliably through a .250 Tab Quick Connect fitting.
My Tripp-Lite Smart-UPS 2200W unit has four 12V 17AH high-rate batteries - two 24V battery banks in series-parallel, bolted posts with ring terminals, each battery bank fused at 100A and feeding into the unit through 100A Anderson Powerpole slide connectors.
And I'm about ready to replace them AGAIN, but this time with four low maintenance type deep-cycle batteries (90AH or 105AH) that will cost about the same as the special batteries but give roughly 4X to 6X the run time.
The batteries being able to source more current than the load needs is not a problem at all, it's smart design and/or overkill. In the case of the Power Toy that the OP wants to repower, those batteries should last longer with the same treatment.
But the opposite can be a HUGE problem, when the load needs more current than the batteries can provide /something/ isn't going to work as designed. And THAT is the reason I brought up the warning in the first place.
If you buy batteries for a UPS or other high-draw application based on price alone (and buy the wrong batteries) you are setting yourself up for a very painful and expensive fall. Saving $10 on batteries in a critical application is dangerously false thinking.
A small UPS needs to reliably source a full 40A to 60A battery bank draw continuously for ten minutes or so before the voltage starts to fall off indicating a dead battery. The UPS is expecting high-rate batteries with a predictable discharge voltage curve.
If you put in cheaper regular gel-cell batteries built for a 10A max discharge rate, the voltage will start to drop almost immediately because of the higher internal resistance, and when the battery reaches total discharge instead of a slow and steady voltage drop the output voltage will crash like a rock.
The UPS is expecting 30 seconds of remaining run time to issue shutdown commands to the attached computer before the batteries run critically dry. If the power fails only 5 or 10 seconds after the low-voltage point (before the shutdown process can complete) you can hose the computer, and corrupt all the program data from whatever software and database applications that were running.
If the lost or scrambled records are the main bookkeeping database with all the Accounts Receivable, or customer service queue for your company, expect months of reconstructing them - if you are still in business in three months...
And that's the real message here.
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Why? I can go get a Group 51R battery (from a newer Hyundai, IIRC) that drops right in an early Corvair and works fine - and a LOT less than $279, more like $50.
The Group 57 batteries are almost unobtanium now.
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These little fellers are a bit lighter - the CorvAir engine will be in an airplane.
I actually got the batteries with the idea of a bike pusher trailer, and they will likely go in the replica "Red Bug".
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