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.
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.
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.
I've spent a lot of time looking at cycle life data,
comparing costs, adding in maintenance and replacement
labor, etc..
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.
Ray Walters
On 9/16/2011 10:15 AM, Larry Crutcher, Starlight Solar
wrote:
Hi Ron,
Have a look back a few months ago to the
discussion about multiple battery strings. My
synopsis: large, parallel banks are not good;
fewer strings are always better. How large a bank
are we talking about here?
Scientist?? That sounds kind of like “Yea, I
been a ‘lectrician for XX years...”, something I
have heard hundreds of times. It’s just pride
saying “Look, I can pee that far too!” when in
reality they are clueless about DC power systems.
I’m ranting but my point is you should convince
your customer that a hands-on, real world
experienced professional has a much broader
understanding of RE system intricacies than a
“scientist”.
Larry
Sent: Thursday, September 15, 2011
5:11 PM
Subject: Re: [RE-wrenches] battery
cycle life, US Battery
Hi Larry,
Client has asked me to compare the cycle life
because he is upgrading a large battery bank and
has been convinced by a Xantrex "scientist" that
golf cart batteries are superior to L-16's even
though it involves twice as many batteries,
connections, cells, footprint etc. So to
convince his purchasing committee he wants to
know the difference in cycle life between a
U.S.B 208 and a Surrette S-460.
Ron
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