battery watering systems [RE-wrenches]
Robert Warren
robertwarren at mail.com
Thu Oct 23 21:39:30 PDT 2003
Brad,
You are absolutely right to say you can't be too careful around
batteries. I have been thinking more about how Charlie put together his
automatic battery watering system, and I now I remember a bit more:(this
was about 12 or 14 years ago). He left the vent caps untouched, so they
could still vent off H and O. The tubes were inserted into holes he
drilled through the top of the battery case. I know this sounds
impossible for a blind guy, but he build his own log house practically
single-handedly, with only the help of a 16 year old boy. He wrote a NY
Times best seller about how he learned to find his way around after
becoming blind, called "Snakewalk. Anyway, the bubbles for the most part
come off the top of the solution, though it is concievable that a few
could come up the tube. For this reason, there can not be any dips or
extra humps in the tubing. But you will have to have one spot, a hump,
where the tubing bends down because the water reservoir is pretty much
even with the level inside the battery. Even if you have some 1/2 long
bubbles, you still have a syphon set up, and the water will still make
its way down into the batterey. Like any sysphon set-up, the tricky part
is getting it started. In this case, you do this by having to wait until
the batteries actually need some water to get it started. It is a tricky
business.
Also, you don't get back-feeding into the reservoir if it is done right.
You must allow air to get to the top of the battery liquid level through
the holes in the vent caps, so you do not have positve pressure inside
the battery, as this would force acid up into the reservoir. This guy
Charlie was pretty smart, and knew what he was doing, but I would not
recommend drilling holes in battery cases for the inexprienced.
The one other installation I saw where someone drilled holes through
battery tops was in Amhurst, WI, at the Real Goods store, but for a
different reason. They had the batteries confined in a basement, and
they manifolded all the plastic tubes into a PVC pipe which led to an
upstairs outside vent. In this case, the caps were sealed off, a
different situation entirely.
If ever you have PV controller or battery charger that fails in such a
way that the batteries are consistantly overcharged, the outgassing can
increase dramatically, which means they can lose water fast. This is why
it is always a good idea to check the batteries regaularly, even if you
have a customer who is squeamish about being around batteries. Give him
an instruction manual, or at least write him a one page set of
instructions he can post on the wall above his batteries!
I would say the best thing is to use a cap which is made by the
particular manufacturer of the batteries you use. There are some good
ones out there that have little built in floats, and will minimize water
loss greatly.
Now, about those "almost new" Hydrocaps: they are always made for a
particular battery and charging system, as they vary in size and
capacity. They too can be mis-used, but still they are a good product.
Daryl, I would say that it is more likely your battery fire was caused
by either a serious overcharge or more likely, an internal short, which
can happen when the batteries get old and the slag piles up at the
bottom like stagmites, and short out the plates. I have seen this happen
once in a battery room I had to clean up and re-build for the Navy,
about 8 years ago. Once the short happened, the others in the string
started feeding current into the short, boiling off the sulpheric acid.
Fortuneatly this triggered an alarm and the Haz-mat team came in and
dumped the couple 50 pound sacks of baking soda over the mess before it
got hot enough to start a fire.
On the subject of battery fires and explosions, I had a Best UPS
customer at Boeing with a 7 or 8 year old gel battery that exploded. The
security guy heard it, and called me in to deal with it. While it made a
noise like a small gun going off, it was contained somewhat by the fact
that it was surrounded by other batteries on two sides and inside a
metal cabinet. but there was only a small smear of paste on the inside
of the cabinet and a pretty good split on one side. the inside of the
gel cell was pretty damn dry and it doesn't look like it could have
started a fire or damaged much of anything. so ever since that, I have
always considered sealed starved electrolyte batteries quite a bit safer
than wet cells. The real downside is that you don't get as many cycles
or years out of them.
I hope this is helpful.
Robert Warren
HI all
We need a battery expert here, I am not one. Is it
not possible to have electrical conduction through the
liquid to the different cells to discharge the
potenical difference between cells? I think of a
battery fire I experianced that was acid flowing over
the top of the batteries and contacting the next
battery,causing Flash over.
Daryl
Brad Bassett wrote:
>
> An ingenious solution. It's likely an improvement over other automatic
> watering methods, which I've heard occasionally cause the batteries to
> overflow, causing a nasty mess.
>
> However, if I understand this correctly, it seems to me that there would
>
> be a possibility of the acid backing up into the water reservoir. This
> could conceivably happen if the battery became hot because of
> environmental temp change or heavy charging, causing expansion of the
> electrolyte. There is also the possibility that O and/or H from the
> charging could gather in the hose and break the suction. Since the
> system worked fine for many years maybe these are not great concerns,
> but the consequences are potentially a mess. Different setups or
> batteries could change the possibility for something wrong happening.
> Perhaps it would be adequate to cover the water reservoir and make sure
> it's acid proof and well protected from spills, or that spills are
> collected safely.
>
> Just thoughts since you can't be too careful around batteries.
>
> Brad
>
>
> Robert Warren wrote:
> >
> > Marco,
> > One of the first off-grid systems I built maybe 14 or 15 years ago was
> > for a blind gentleman in Oregon, Charlie Weaver. I installed 12 or more
> > Trojan L-16s in a big insulated cabinet in his garage. Since he was
> > blind, he couldn't see the water levels or stick a finger into the acid
> > to check the levels, so he used his head. He rigged up a simple gravity
> > feed watering system with 1/4 inch plastic tubes coming from a
> > Tupperware container placed so that the top of the water in the
> > container was precisely at the top water level mark of the batteries.
> > The tubes went to holes he drilled in the caps, and extended down into
> > the battery so it touched the plates, and thus would never break suction
> >
> >
> > as long as the top-off tank was always filled. A run-off tube near the
> > top drained off excess water if he overfilled the water container. I
> > went out to the site about 6 or 8 months after the intital installation,
> >
> >
> > and everything was in tip-top condition, and I thought this was the
> > slickest thing I ever saw. He was also careful not to block off the
> > vapor ventiation through the cap.
> > Robert Warren
> >
>
>
> Brad Bassett
> Alternative Energy Engineering
> Olympia, WA
What will we do if there is another fuel shortage?
Did you know that there is a pollution free, completely
renewable fuel which you can use right now in your own car?
Don't replace the engine, replace the fuel.
Check out my website on making your own fuel:
http://running_on_alcohol.tripod.com
robertwarren at mail.com
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