Re: battery hydrometer


"Miike G" <postmaster@xxxxxxxxxxxxxxxxxxx> wrote in message
news:6uplhuFgb0dtU1@xxxxxxxxxxxxxxxxxxxxx

"Duncan Wood" <nntpnews@xxxxxxxxxxxx> wrote in message
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On Mon, 02 Feb 2009 17:31:44 -0000, Miike G
<postmaster@xxxxxxxxxxxxxxxxxxx> wrote:


"Stephen" <invalid@xxxxxxxxxxx> wrote in message
news:195eo415spi37ec3agteq6421nminp8huk@xxxxxxxxxx
On Mon, 02 Feb 2009 12:18:35 GMT, "Mrcheerful" <nbkm57@xxxxxxxxxxx>
wrote:

A accurate DVM is actually more use in general terms, and a loading
type
tester is even better.

Please don't get me started on that again ;)

I posted about battery testers a couple of weeks ago and I was told
that testing under load with a DVM was the way to go. Apparently the
people round here didn't like the load testers because the load of the
tester doesn't necessarily equal the load of your starter motor. I had
read quite a few old posts recommending load testers and was about to
buy one until everyone here talked me out of it!

I don't think a load tester 'has' to equal the load of a particular
starter
motor, to give give a good idea of a batterys cranking capability.
They do put a heavy load on a battery, and as long as the volts don't
drop
during the test, the chances are that even a higher load wont make a
significant difference.
Mike.

Yep, it does, battery resistance is very non linear. If the volts don;t
drop during the test then your tester's knackered :-)

Of course there is an initial drop when the tester is switched on after it
reads the no-load volts, but the voltage shouldn't drop during the 10 secs
or so when the test load is actually applied.

If it does drop with a fully charged battery, IME the battery is no longer
reliable.
It might still start the car in the summer, but come winter and cold
mornings and the chances are that it will not.

I've had my load tester for well over 10 years. I know how to read it and
I also know it's not knackered.
Mike..

If the battery volts do not decrease to some extent when the starter
operates or the load is applied then you have the tester connected to the
wrong battery. It is a fundamental principle that the battery volts will go
down when load is applied, the extent of the drop can give some indication
of the battery condition/state of charge, with knowledge of the ambient
temperature and the size of the load you can judge battery condition.


.

Relevant Pages

  • Re: battery hydrometer
    ... that testing under load with a DVM was the way to go. ... tester doesn't necessarily equal the load of your starter motor. ... They do put a heavy load on a battery, and as long as the volts ... When first connected it simply reads the no-load battery voltage. ...
    (uk.rec.cars.maintenance)
  • Re: battery hydrometer
    ... that testing under load with a DVM was the way to go. ... tester doesn't necessarily equal the load of your starter motor. ... They do put a heavy load on a battery, and as long as the volts ... When first connected it simply reads the no-load battery voltage. ...
    (uk.rec.cars.maintenance)
  • Re: battery hydrometer
    ... that testing under load with a DVM was the way to go. ... tester doesn't necessarily equal the load of your starter motor. ... They do put a heavy load on a battery, and as long as the volts don't ... When first connected it simply reads the no-load battery voltage. ...
    (uk.rec.cars.maintenance)
  • Re: battery hydrometer
    ... that testing under load with a DVM was the way to go. ... tester doesn't necessarily equal the load of your starter motor. ... They do put a heavy load on a battery, and as long as the volts don't ... When first connected it simply reads the no-load battery voltage. ...
    (uk.rec.cars.maintenance)
  • Re: battery hydrometer
    ... that testing under load with a DVM was the way to go. ... tester doesn't necessarily equal the load of your starter motor. ... They do put a heavy load on a battery, and as long as the volts don't ... When first connected it simply reads the no-load battery voltage. ...
    (uk.rec.cars.maintenance)
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