[RE-wrenches] battery cycle life, US Battery

Fri Sep 16 19:37:20 PDT 2011

Here's the Rolls chart for cycle life:
http://www.surrette.com/content/agm-faqs?q=node/81&php
The cycle life is considered to be the point before the capacity begins 
being reduced.
I'm not seeing anything close to 800 cycles at 80%DOD. It looks like a 
typical L16, not over 500 cycles.
Are you using a different chart than what Rolls is posting on their website?

Ray

7 PM, Ron Young wrote:
> 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 <http://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 <ray at solarray.com <mailto:ray at solarray.com>>
>>> *Date: *September 16, 2011 1:03:43 PM PDT
>>> *To: *RE-wrenches <re-wrenches at lists.re-wrenches.org 
>>> <mailto:re-wrenches at lists.re-wrenches.org>>
>>> *Subject: **Re: [RE-wrenches] battery cycle life, US Battery
>>> **Reply-To: *RE-wrenches <re-wrenches at lists.re-wrenches.org 
>>> <mailto:re-wrenches at lists.re-wrenches.org>>
>>>
>>> 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
>>>
>>>
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