Captain Midnight wrote:

"okbran" wrote in message
ps.com...
Hi,
I don't know much about batteries and I am simply curious about the
regular 12V car battery.
Everytime I go to the store, I see all these batteries labeled with
number of Cold Crankcing Ampere or Cranking Ampere, etc. I understand
the definition of CCA and CA but,
My question is:
1. What about the average output current? What's the common output
current(A) for a 12V car battery? How come they don't label the
current output on these car batteries?
2. If I have a jumper cable made of 16AWG copper wire with current
rating of 10A. What happen if I connect the jumper cable to a battery
gives 13A output current?
3. Similar to question 2, if the cranking ampere is 540, will anything
bad happen to jumper cable made of 16AWG copper wire?

I would really appreciate your feedback.
Thank you,


Motorcycle batteries are rated in Amp/HRS. A fully discharged 14A/H battery
will take 14 hours to charge at one amp.


No, a 14 Amp hour rated battery will deliver 1 amp for 14 hours, to
the rated discharge voltage. It will take more than 14 hours to
recharge, because some of the current becomes head, instead of stored
energy. Actually, the lower the discharge rate, the less of the stored
energy is lost as heat.


Starter motor current is ~50amp.


For a motorcycle? Some cars don't use that much current to turn the
engine over.


Obviously they can put out much greater current than their A/H rating.


Yes, that is the CA/CCA rating, and it is for very short bursts
during starting. Extended cranking, or a short circuit causes the
battery to generate a lot of heat. That can either cause it to explode,
or to melt the internal lead connections between the individual cells.


They're rated this way mostly to keep them from being over charged. A car
battery is used for starting only so cranking current is all that's really
needed. Theirs no good reason to short either type battery. A 10A rated
cable means it's rated to carry 10A, not that 10A will flow when shorting
across a battery.

If you want to now what happens, hold the ends of paper clip on to a fresh
D-cell battery with your fingers.;0)


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida