On Sat, 18 Nov 2017 20:02:47 +0000, newshound
wrote:

snip

'Ordinary of what age / spec. I think most recent wet LA batteries
(especially those marked as sealed but are still 'wet') I would think
they would (have to) be.

I agree, modern "sealed" batteries are likely to be.

If they were truly sealed (as in not operable for refilling) they
would have to be.

IIRC this one was
on a car about 15 years old (but it would have been replaced at least once).

Is that like Triggers broom? ;-)

Hmm, the technology has been about for some time now but you might be
able to tell if they are by looking at them. eg, If they are obviously
a plain plastic cap then they aren't. ;-)

https://www.sunaxy.com/products/roll...on-battery-cap

snip

No, quite and that would be expected. The 'issue' is that you should
check the electrolyte levels more regularly so that they are above the
plates at all times, not just as you are about to recharge them? ;-(

"If low on electrolyte, immediately fill the battery with distilled or
de-ionized water. Tap water may be acceptable in some regions. Do not
fill to the correct level before charging as this could cause an
overflow during charging. Always top up to the desired level after
charging."

http://batteryuniversity.com/learn/a...d_acid_battery

Hadn't come across that point before, although I have seen small
motorcycle batteries with a sort of overflow pipe. On a Japanese bike
you are trying to get maximum capacity in minimum volume, so the plates
are going to go near the top. But on this battery which came from a
diesel car but curiously is identical to the battery on my old tractor
there's a good half an inch of space between the level marker and the
bottom of the cap threads. I agree that you might expect some change of
volume between discharged and fully charged but its not an effect I have
ever noticed on car batteries.

Shouldn't the same theory apply to any flooded lead acid battery
whatever it was to be used on. ;-)

snip

As an example, on the night of the big local firework display I got two
hours of light out of about 50 watts of CFL, and I'd estimate that I
have also had a similar amount of light out of the rest of the last charge.

Is that 50W 'equivalent of incandescent' (and so say 10W of electrical
load) or 50W of actual load?

Actual load. IIRC, four 11s and a 9, or something like that.

Ok.

Cheers, T i m