Can car batteries work upside-down?

The "traditional" car battery size is "Group 24" (modern car batteries seem to be much smaller...) - West Marine lists deep-cycle batteries that size as about 75 AH, with Group 27 at 90 AH. You have to get up to "8D" size (weighing 130 pounds or more) to get over 200 AH.

--
Peter Bennett, VE7CEI  
peterbb4 (at) interchange.ubc.ca  
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca

"Dave Vanden Bout"

** I hope your application discharges the battery SLOWLY - or you will not get anything like the quoted Ahr figure, which it obtained over an 20 hour discharge.

BTW 240 Ahr is one huge "car battery ".

..... Phil

I think you're maybe thinking of "Cold Cranking Amps", which has to do with the way the plates are designed. I've never seen an amp-hr rating on an ordinary car battery in the ordinary car battery places, and I've looked! - I guess you're supposed to just know (or follow the car mfg's recommendation). I think I read somewhere once that a typical car battery is about 55 AH. I think in boat places they DO publish the AH rating, but you'd damage a marine battery if you tried to get 200A out of it. =:-O

I know a little about batteries - a few years ago, I worked for an industrial battery charger manufacturer. :-)

Cheers! Rich

I'd go look at the Concorde Aircraft battery site. Aircraft batteries are generally intended for use in any configuration without leaking. The old flooded plate batteries had a little marble in the vent cap that sealed off the vent cap when the aircraft was inverted. The new AGM batteries are pretty well completely sealed.

Jim

-- "It is the mark of an educated mind to be able to entertain a thought without accepting it." --Aristotle

Tested that idea today - it is false. Gel cell batteries (at least the ones I tested) do charge inverted. My guess is that the Wiki statement ought to say they _should_ not be charged inverted as opposed to they _cannot_ be charged inverted.

Ed

There are Lithium Phosphate in an automotive package. They quote capacity (at C/2 yet!) as 100Ah compared to 45.6Ah for lead acid.

They claim "Can be recharged using most standard lead-acid chargers (set for AGM/GEL cells)". I would expect a cost premium though.

240Ah is high for a standard lead acid automotive battery. A US-8VGC is only 160Ah and it's larger than an automotive battery, only 8V and optimized for deep discharge to boot.

Robert

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All that and I didn't include a reference

Robert

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