On Thu, 25 Jun 2009 01:12:46 +0000, Larry wrote:

Bruce In Bangkok wrote in
:

What? Amps have nothing to do with time.


Amps X Hours X charging efficiency as a decimal = AH

Amps have a lot to do with time....

You are talking about charging time. I was talking about measurement
:-)

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)

On Thu, 25 Jun 2009 01:14:11 GMT, "Lew Hodgett"
wrote:

Bruce In Bangkok" wrote:


What? Amps have nothing to do with time.

Ah but in the case of a battery, they do.

How big is the batttery?

Recharge rate won't exceed 15% average of the battery AH capacity.

For every 100 AH taken out of a battery, you must replace 125AH.

Wet cell batteries are not efficient, just convenient.

As you can see the number of replacement AH put back in a battery is
very much time dependant.

Again, you are talking about charging time. I was talking about
measurement of current, which has nothing to do with time.

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)

"Lew Hodgett" wrote in message
news
Bruce In Bangkok" wrote:


What? Amps have nothing to do with time.

Ah but in the case of a battery, they do.


In the case of a battery, you find, typically, a battery.

--
"j" ganz @@
www.sailnow.com

How much voltage do you need to pump 2,000 amps into a battery?



Bruce In Bangkok" wrote:


Again, you are talking about charging time. I was talking about
measurement of current, which has nothing to do with time.


Flow rate (current) is by definition, time related.

Lew

On Thu, 25 Jun 2009 02:08:30 GMT, "Lew Hodgett"
wrote:

How much voltage do you need to pump 2,000 amps into a battery?



Bruce In Bangkok" wrote:


Again, you are talking about charging time. I was talking about
measurement of current, which has nothing to do with time.


Flow rate (current) is by definition, time related.

Lew

O.K., if you want to be pedantic,
How much voltage do you need to pump approximately 2000 X ( 6.242 ×
1018^18) electrons per second into a battery.
Cheers,

Bruce
(bruceinbangkokatgmaildotcom)

On Thu, 25 Jun 2009 14:40:38 +0700, Bruce In Bangkok
wrote:

O.K., if you want to be pedantic,
How much voltage do you need to pump approximately 2000 X ( 6.242 ×
1018^18) electrons per second into a battery.

If the battery is sized properly, 14.2 volts will get the job done,
maybe 14.4 for the first 70 or 80% if you're in a hurry.

On Thu, 25 Jun 2009 05:08:26 -0400, Wayne.B
wrote:

On Thu, 25 Jun 2009 14:40:38 +0700, Bruce In Bangkok
wrote:

O.K., if you want to be pedantic,
How much voltage do you need to pump approximately 2000 X ( 6.242 ×
1018^18) electrons per second into a battery.

If the battery is sized properly, 14.2 volts will get the job done,
maybe 14.4 for the first 70 or 80% if you're in a hurry.


Larry posted about people who had multiple 250 Amp alternators
installed. I simply asked how many volts it would take to charge a
battery bank at the installed 2,000 amps.

You seem to be saying that with 14.2 - 14.4 VDC the current flow will
be 2,000 amps, which would make the battery resistance about .00715
Ohms.

Somehow I don't think that is correct..

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)

On Thu, 25 Jun 2009 18:50:25 +0700, Bruce In Bangkok
wrote:

Larry posted about people who had multiple 250 Amp alternators
installed. I simply asked how many volts it would take to charge a
battery bank at the installed 2,000 amps.

You seem to be saying that with 14.2 - 14.4 VDC the current flow will
be 2,000 amps, which would make the battery resistance about .00715
Ohms.

Somehow I don't think that is correct..

Actually it is because that is the voltage that *all* 12 volt lead
acid batteries get charged at. The point is, that to charge at 2,000
amps, you need to have about 8,000 amp-hours of battery capacity,
which is not very practical for a 12 volt system because of connection
and wiring losses.

Bruce In Bangkok wrote:
On Thu, 25 Jun 2009 05:08:26 -0400, Wayne.B
wrote:

On Thu, 25 Jun 2009 14:40:38 +0700, Bruce In Bangkok
wrote:

O.K., if you want to be pedantic,
How much voltage do you need to pump approximately 2000 X ( 6.242 ×
1018^18) electrons per second into a battery.
If the battery is sized properly, 14.2 volts will get the job done,
maybe 14.4 for the first 70 or 80% if you're in a hurry.


Larry posted about people who had multiple 250 Amp alternators
installed. I simply asked how many volts it would take to charge a
battery bank at the installed 2,000 amps.

You seem to be saying that with 14.2 - 14.4 VDC the current flow will
be 2,000 amps, which would make the battery resistance about .00715
Ohms.

Somehow I don't think that is correct..

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)

Hey Bruce,

Your math is correct.

The problem is that the internal resistance of a healthy battery is a lot higher
than that (which would limit current).

Bruce In Bangkok wrote:

O.K., if you want to be pedantic,
How much voltage do you need to pump approximately 2000 X ( 6.242 ×
1018^18) electrons per second into a battery.

Remember this from an earlier post?

"Recharge rate won't exceed 15% average of the battery AH capacity."

Thus:

2000/15% = 13,333 AH of battery bank is required for a 2,000 amp
charging rate.

Normal charging voltage is anywhere from 13.2VDC-13.8VDC.

Lew