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Larry, <br>
<br>
I totally agree, that's a ridiculous # of batteries and strings. If
that's really the case, it seems L16s will still need 4 to 5
strings, which is also crazy. I see only one solution to this
battery bank, and that is the HUP or other large 2 v cell battery.
Comparing golf cart batteries to L16s isn't even on the plate for
good design in this case. For me, HUPs become a no brainer, as soon
as the required amp hours gets into the 1000 AH or higher range.
BTW, don't ever use the 100 hr rate for the Rolls, as they are way
too optimistic. The 20 hr rates are much closer to reality. The
Rolls S-530 becomes a 400 AH battery at the 20 hr rate, also they
list cycles @50% DOD, when everyone else is looking at 80%DOD, be
aware.<br>
Here's some quicky math, with costs pulled off the internet:<br>
3 strings of S530s (@24v) would get you 1200 AH for $4200. cycle
life at 80% DOD about 450 to 500 cycles.<br>
HUPs group 25 have 1270 AH and cost $7392, but last 2100 cycles to
80%DOD. <br>
That's about 11.5 cents/ kwh for the life of the battery compared to
about 29.2 cents/ kwh for the Rolls S-530s. <br>
This quicky calculation doesn't even include the extra maintenance
required for watering the L16 type battery, nor the fact that you
will have 4 battery replacements for the same time the HUPs just
have one replacement. <br>
Its very fair to say that the HUPs are more cost effective by about
a 3 to1 ratio.<br>
<br>
Ray<br>
<br>
<br>
<br>
Having 6-8 parallel strings of golf cart batteries is a terrible
idea no matter how much better the GC2 may be.
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<div>Larry
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<div>On Sep 16, 2011, at 10:01 AM, Ray Walters wrote:</div>
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<div bgcolor="#FFFFFF" text="#000000"> The real point is
that the Xantrex guy is correct from a scientific stance.
Experimental battery cycle life data shows that some golf
cart batteries (T105) do have more rated cycles to 80%DOD
than the Trojan L16. (750 vs about 600) A really crappy
golf cart battery (some have cycle life below 400 cycles)
isn't as good as an L16, yes. You have to base your
decision, and your mouth, on test data for the batteries
considered. Also, you must always compare at 80% DOD, for
an apples to apples comparison. Its usually a clue if a
manu doesn't publish their cycle life data. Of course you
must temper the golf cart vs L16 decision with good
paralleling technique.<br>
We use golf cart batteries (never more than 4 strings),
jump straight to the HUPs for larger banks, and skip the
L16s all together. They just don't make sense when you
look at the cost/ amp hr vs their lifespan.<br>
The only time I could see using L16s, was if the battery
bank requirements were beyond 4 strings of golf cart
batteries, and the customer just could not afford the
HUPs, or were going to sell the property soon, and
wouldn't appreciate their long term value.<br>
I've spent a lot of time looking at cycle life data,
comparing costs, adding in maintenance and replacement
labor, etc..<br>
L16s are serious losers on a $/ kwh operating cost
comparison, so this is a chance to up sell the customer to
HUPs (or equivalent) and make both of you happier in the
long run.<br>
<br>
Ray Walters<br>
<br>
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