Hello again,
As far as I can tell, it all depends on care and feeding, in a big way.
I believe that the guy who was asking about rejuvenating his HydroCaps
said his GC bank was going on 11 years...
That would be me. This weekend, I was cleaning them up, and checked
the date stickers. Turns out they are "only" 10 years old (D-4) not 11.
They are all still in great shape. Not a single cell has gone bad. I just
cleaned them up this weekend, and checked voltages of each battery. They
all were within a couple tenths of a volt. I didn't bother to check
specific gravity this time, because I'm too lazy to check 48 cells, and
I had just watered them, but not equalized to mix it up the electrolyte.
I'm not sure if it helped or hurt, but here's what I did:
I have 16 sams club batteries, wired series-parallel for 24 volts (4 x 4).
1: Before hooking them up, I charged them all, let them sit, then
arranged them so that each string was almost exactly the same voltage.
(Cheap batteries can vary by one or two tenths.) This way, there will
be less chance of one string charging the others.
2: They have had hydrocaps on them for most of their life. I just went
back to the original caps this weekend, and plan to look closer at
someone's suggestion of "washing" them. BTW, I opened up one of them,
and the catalyst is a 1 inch high, by 3 inch round thing, about the size of
a stack of 5 or 6 quarters.
3: At the suggestion of a Bob-O (from Home Power Magazine), I kept the
voltage high. 30.0 volts bulk phase charge voltage, but let them settle down
to 26.8 volts during float. I also left the bulk->float switchover
current low (8 amps) so that they stay at bulk for a long time each day.
On a good sunny day, they boil for almost an hour before going into float.
I wanted to give them a mini-equalize every day, reducing sulphates and
mixing up the electrolyte.
4: I built 8 battery pulsers, based on a home brew article in Home
Power magazine. Each pulser is 12 volts, so I have one pulser for every
two batteries. They run 24/7.
5: I have individual ammeters on each string, so that I can see at a glance
if anything is wrong. These are cheap inductive ones that I got for a
couple of bucks each at a surplus/junk store. They slip over the battery
cables. If the coffee maker and microwave are running at the same time,
I like to take a quick look to make sure that each string is providing
roughly the same amount of current. Similarly, I check every now and
then when the sun is in full force to make sure that each string is
taking its share of the energy.
Now that I removed the hydrocaps, I dropped the voltage down by a half
of a volt, and increased switch-over current, so that I won't have to
water them quite as often. Hopefully, the catalyst washing idea will
work, and I can put the hydrocaps back on. However, I can't justify
buying another set for these old batteries. I have no idea how
long they will last, but based on what I've read, they are pretty old.
I'm not sure what I'll do for replacements when the batteries finally
die. From a pure numbers standpoint, cheap golf cart batteries seem
like the way to go. Even if they only last half as long as good ones,
they seem cost effective based on Dollars/(AmpHour*lifespan).
However, I'm also considering the nice 800 aH Rolls/Surrettes. The
thought of only maintaining 1/4 the number of batteries is appealing.
The extra life span would also be nice. I dread the thought of swapping
out the entire set.
Anyway, IMHO, there is nothing wrong with golf cart batteries, if you
don't mind dealing with more cells, and knowing that the life span
will be shorter. Also, they give you a bit of insurance by not costing
as much to replace if you make a mistake.
Bob S.
