Hi All, Not sure where the 4 - 5 strings or more drifted into this conversation but the setup is basically in two strings of 16 GC batteries (48v) vs. 8 L-16 batteries in one string that I am recommending. With 7 year warranty for the Surrettes vs 1 year for the US Batt.; half the number of cells to water and check - and this is important as the maintenance on these 4 systems is being done by a third party who is not always reliably taking care of business; half the number of connections; half the footprint ...
The only reason I can see someone recommending GC batteries in this scenario has to do with the company who set the systems up - Xantrex and their rationale seems to be the easy availability of the GC batteries e.g. in automotive stores etc. vs the more specialized distribution of the L-16's. Xantrex want to sell "arrive and drop" systems that will be sold through mass retailers from what I can see. The Rolls d.o.d. at 80% shows 800 cycles for the 4000 series batteries vs. 675 on the U.S. Battery chart but the U.S. battery chart doesn't differentiate between GC batteries and L-16's or any other type so I find it a bit suspect. Ron Young earthRight Products - Solareagle.com Alternative Energy Solutions ~ Renewable Energy Products On 2011-09-16, at 1:06 PM, RM You wrote: > forwarded from earth2 > > > Begin forwarded message: > >> From: Ray Walters <[email protected]> >> Date: September 16, 2011 1:03:43 PM PDT >> To: RE-wrenches <[email protected]> >> Subject: Re: [RE-wrenches] battery cycle life, US Battery >> Reply-To: RE-wrenches <[email protected]> >> >> Larry, >> >> 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. >> Here's some quicky math, with costs pulled off the internet: >> 3 strings of S530s (@24v) would get you 1200 AH for $4200. cycle life at 80% >> DOD about 450 to 500 cycles. >> HUPs group 25 have 1270 AH and cost $7392, but last 2100 cycles to 80%DOD. >> 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. >> 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. >> Its very fair to say that the HUPs are more cost effective by about a 3 to1 >> ratio. >> >> Ray >> >> >> >> Having 6-8 parallel strings of golf cart batteries is a terrible idea no >> matter how much better the GC2 may be. >> >> Larry >> >> >> On Sep 16, 2011, at 10:01 AM, Ray Walters wrote: >> 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 >> >> >> _______________________________________________ >> List sponsored by Home Power magazine >> >> List Address: [email protected] >> >> Options & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> List-Archive: >> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org >> >> List rules & etiquette: >> www.re-wrenches.org/etiquette.htm >> >> Check out participant bios: >> www.members.re-wrenches.org >>
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