Re: A.hr definition; discussion [ampere - hour battery ratings]

[Guest guest]

Hi All:

I've noticed some lingering missunderstanding regarding this - as

below.

Ampere hour rating; definition:

If your 12 Volt car battery has an ampere hour rating of 650 ampere

hours - you can draw out 10 amperes for 65 hours total - [or any

combination that, when multiplied together, comes to 650] before the

battery voltage goes below the acceptable level; plus a bit more.

If you then attempt an engine start - you MIGHT get lucky and hear

the starter solenoid 'click' - as your dash lights go out. You WILL

NOT hear the starter run - you spent too much charge at the 10 A

rate. This does not include deterioration from aging / shelf life

where it may have started out at 650 [or have cruddy cable

connections] but is now an unknown amount less.

SO - down to our applications - at 6 Volts. Mostly, you will need

to look up in a catalog to get the ampere hour rating. 6V batteries

can be a single lantern battery [actually several smaller, grouped

together internally], a pair of lithium camera batteries [3V each,

typically at about 0.8 A.hr {when in series - no A.hr change}], 4

AAA, 4 AA, 4 'C' / 'D', a lead acid sealed type of varying sizes,

each having a separate A x hr rating that is roughly proportional to

the package size, plus a couple others including [sort of

rechargeable 'gel cell' - that once fully discharged, will need a

recharge voltage of near 50V to begin the recharge], NOT sealed lead

acids that will leak all over if tipped, will rot your pants & hurt

your leg, ... .

Any of those listed can perform interchangeably - for a while.

You now get to make a decision: HOW PORTABLE does it need to be?

Fit in a shirt pocket, with restricted life? Need longer life and

can put up with a set of 4 D / lantern / 1 at 1.3 A.hr rechargeable -

in your fanny pack? Need yet more life [maybe on a trip] so you

spring for a 6V motorcycle battery that could fit in a LARGE fanny

pack [but will spill acid all over when tilted]? Get a 6V car /

truck battery for antiques [by special order, before 1955] with a

1200 A.hr rating that can last about forever but gets you a hernia

if you try to move it?

Your choice.

If you spring for a pair of lithium camera batteries [800 mAhr;

about $9] to get a better life [and can find the odd sized holder

needed] - you should expect to lose voltage with a 1 mA drain at

about the 600th hour but still be useable to around the 730th hr.

[That's about 24 consecutive days continuous use; nobody does that].

Joe.

> >

> > I'd like to hear.

> >

> > bG

> >

>

[Guest guest]

Thanks Joe

That clarifies A.h issue. Its confusing for the uninitiated.

In the meantime fount that wrapping the electrodes in cotton wool that

comes on a roll/sheet ex pharmacy, securing with cotton twine and

soaking thoroughly delivers quite a punch. Wont be trying 9v or 12v,

that would be reckless!

Suz

-- In , " Joe " <aubug2@...>

wrote:

>

> Hi All:

>

> I've noticed some lingering missunderstanding regarding this - as

> below.

>

> Ampere hour rating; definition:

>

> If your 12 Volt car battery has an ampere hour rating of 650 ampere

> hours - you can draw out 10 amperes for 65 hours total - [or any

> combination that, when multiplied together, comes to 650] before the

> battery voltage goes below the acceptable level; plus a bit more.

> If you then attempt an engine start - you MIGHT get lucky and hear

> the starter solenoid 'click' - as your dash lights go out. You WILL

> NOT hear the starter run - you spent too much charge at the 10 A

> rate. This does not include deterioration from aging / shelf life

> where it may have started out at 650 [or have cruddy cable

> connections] but is now an unknown amount less.

>

> SO - down to our applications - at 6 Volts. Mostly, you will need

> to look up in a catalog to get the ampere hour rating. 6V batteries

> can be a single lantern battery [actually several smaller, grouped

> together internally], a pair of lithium camera batteries [3V each,

> typically at about 0.8 A.hr {when in series - no A.hr change}], 4

> AAA, 4 AA, 4 'C' / 'D', a lead acid sealed type of varying sizes,

> each having a separate A x hr rating that is roughly proportional to

> the package size, plus a couple others including [sort of

> rechargeable 'gel cell' - that once fully discharged, will need a

> recharge voltage of near 50V to begin the recharge], NOT sealed lead

> acids that will leak all over if tipped, will rot your pants & hurt

> your leg, ... .

> Any of those listed can perform interchangeably - for a while.

>

>

> You now get to make a decision: HOW PORTABLE does it need to be?

>

> Fit in a shirt pocket, with restricted life? Need longer life and

> can put up with a set of 4 D / lantern / 1 at 1.3 A.hr rechargeable -

> in your fanny pack? Need yet more life [maybe on a trip] so you

> spring for a 6V motorcycle battery that could fit in a LARGE fanny

> pack [but will spill acid all over when tilted]? Get a 6V car /

> truck battery for antiques [by special order, before 1955] with a

> 1200 A.hr rating that can last about forever but gets you a hernia

> if you try to move it?

>

> Your choice.

>

> If you spring for a pair of lithium camera batteries [800 mAhr;

> about $9] to get a better life [and can find the odd sized holder

> needed] - you should expect to lose voltage with a 1 mA drain at

> about the 600th hour but still be useable to around the 730th hr.

> [That's about 24 consecutive days continuous use; nobody does that].

>

> Joe.

>

>

>

> > >

> > > I'd like to hear.

> > >

> > > bG

> > >

> >

>