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Can car batteries work upside-down?

Started by Dave Vanden Bout June 5, 2008


Dave Vanden Bout wrote:

>I have a customer who needs a battery-powered system that will operate >in any orientation. A car battery is the only thing that has the A-hrs >he needs (I think). I assume a sealed car battery solves the obvious >problem of leaking acid, but are there any other considerations that >prevent a car battery from being used when it is upside-down? > >Are there other types of rechargeable batteries I should consider that >give the same A-hrs (approx 240 A-hrs) as a car battery?
Is a nomibnal voltage of 12VDC a requirement? It will be a lot easier to meet your spec if 24V is acceptable. From MIL-PRF-8565K (Supersedes MIL-B-8565J): "The battery shall be capable of operating in any inverted position or altitude without loss of any electrolyte..." [ http://www.advancedpowerproducts.com/otherpdf/Mil-PRF-8565K.pdf ] Keep in mind that doubling the voltage means you only need half as many Ampere-Hours. -- Guy Macon <http://www.guymacon.com/>
On Thu, 05 Jun 2008 15:28:49 -0400, Dave Vanden Bout <devb@xess.com>
wrote:

>GregS wrote:
>> Most car batteries are less than 80 amp hours. >> >> greg > >Really? The two or three websites I looked at all listed capacities >over 200 A-hrs. I'll have to look at some of the battery >recommendations I've received and get actual capacities. Thanks for the >data point.
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"
> > Are there other types of rechargeable batteries I should consider that > give the same A-hrs (approx 240 A-hrs) as a car battery?
** 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
On Thu, 05 Jun 2008 15:28:49 -0400, Dave Vanden Bout wrote:
> GregS wrote: >>>... >> Most car batteries are less than 80 amp hours. >> >> greg > > Really? The two or three websites I looked at all listed capacities over > 200 A-hrs. I'll have to look at some of the battery recommendations I've > received and get actual capacities. Thanks for the data point.
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


"Dave Vanden Bout" <devb@xess.com> wrote in message 
news:4847f703$0$20174$4c368faf@roadrunner.com...
>I have a customer who needs a battery-powered system that will operate in >any orientation. A car battery is the only thing that has the A-hrs he >needs (I think). I assume a sealed car battery solves the obvious problem >of leaking acid, but are there any other considerations that prevent a car >battery from being used when it is upside-down? > > Are there other types of rechargeable batteries I should consider that > give the same A-hrs (approx 240 A-hrs) as a car battery? > > ----------------------------------------------------------------- > Dave Van den Bout / XESS Corp. > (919) 363-4695 > devb@xess.com
Paul Hovnanian P.E. wrote:

<snip>

> According to the Ultimate Authority on Everything, gel cell batteries > cannot be charged inverted. > > http://en.wikipedia.org/wiki/Gel_battery > > It might be worthwhile actually contacting am actual manufacturer to > verify this. But don't get your hopes up if you need to charge while > inverted. >
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
In article <4847f703$0$20174$4c368faf@roadrunner.com>, Dave Vanden Bout 
says...
> I have a customer who needs a battery-powered system that will operate > in any orientation. A car battery is the only thing that has the A-hrs > he needs (I think). I assume a sealed car battery solves the obvious > problem of leaking acid, but are there any other considerations that > prevent a car battery from being used when it is upside-down? > > Are there other types of rechargeable batteries I should consider that > give the same A-hrs (approx 240 A-hrs) as a car battery?
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 ** Posted from http://www.teranews.com **
In article <MPG.22bd1a32ae59eff79898ff@free.teranews.com>, Robert Adsett 
says...
> In article <4847f703$0$20174$4c368faf@roadrunner.com>, Dave Vanden Bout > says... > > I have a customer who needs a battery-powered system that will operate > > in any orientation. A car battery is the only thing that has the A-hrs > > he needs (I think). I assume a sealed car battery solves the obvious > > problem of leaking acid, but are there any other considerations that > > prevent a car battery from being used when it is upside-down? > > > > Are there other types of rechargeable batteries I should consider that > > give the same A-hrs (approx 240 A-hrs) as a car battery? > > 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.
All that and I didn't include a reference http://www.valence.com/products/ucharge_overview.html Robert ** Posted from http://www.teranews.com **