Hi Capt. Mike,
Odd that you should mention that. From what I was given to understand, Corbin relied on some testing outfit's data that seemed to certify the Optima for vehicular use.
A closer read of their experiments revealed that all testing was done in a temperature controlled chamber that kept the air streaming into the chamber at 50 degF.
Anecdotal evidence suggested the premature failures (less than 1 year) of the Optima battery bank were only sustained from folks driving in warmer climates (90 degF). Those Sparrow owners in cooler climates had battery packs that lasted longer.
I don't believe any of the packs lasted longer than 3 years though. Most of the premature failures were accelerated by the Zivan charger that attempted to charge the series connected 13 batteries (156v).
Don
--- In electricboats@yahoogroups.com, Mike <biankablog@...> wrote:
>
> Desulfater:
> Â
> Interesting. I read a report a few years ago that was life cycle testing battery banks using the round Optima batteries. They had to stop testing at some point because one of the batteries developed a hot spot. As I recall researcher thought the battery may have suffered some damage in shipping. Where the pressure of the shipping hit shorted some of the spiral plates inside the battery.
> Though it might also have been the heat buildup that you mentioned that caused the failure too.
> The round cell design of this battery always looked like more of a marketing gimmick to me.
> Â
> Capt. Mike
> http://biankablog.blogspot.com
> Â
> --- On Thu, 7/15/10, desulfator <desulfator@...> wrote:
>
>
> From: desulfator <desulfator@...>
> Subject: [Electric Boats] Re: Optima vs Lifeline
> To: electricboats@yahoogroups.com
> Date: Thursday, July 15, 2010, 12:02 PM
>
>
> Â
>
>
>
>
> It has been my experience that Optima and other lead acid batteries with "Spiral Wound Cells" are the worst AGM battery on the market.
>
> It was the biggest coffin nail in the Corbin Motors Sparrow downfall when Corbin was stuck with trailer loads of failed Optima batteries. Optima provided no relief and the company shortly went into bankruptcy.
>
> Corbin shares part of the blame for squeezing batteries into battery boxes with little to no cooling provided. But, that is a common battery powered vehicle engineering mistake that prevails even to the present day in all electric vehicles.
>
> http://en.wikipedia.org/wiki/Corbin_Sparrow
>
> The spiral wound cell achilles heel is due to heat buildup in the center of the cell. It results in early cell failure due to dehydration from heat buildup, pressure relief valve popping and eventual cell death. Leaking pressure relief valves are common in the AGM battery.
>
> In the case of Sparrow, it was excaberated by the use of Zivan (and others) chargers attempting to charge the series connected battery bank of over 100 volts. This is when we first learned of bank cascade failures due to an unbalanced high voltage bank.
>
> It is one of the reasons why,
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> 1. I would never recommend AGM batteries
>
> 2. I always recommend seperate 12 volt chargers for any bank over 12 volts
>
> -
>
> So some of the leasons we learned from the Corbin Motors experience are,
>
> 1. Never use AGM batteries
>
> 2. Have seperate chargers for each battery
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> 3. Desulfate batteries before permanent damage sets in
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> 4. Insure battery boxes are well ventilated or the batteries are water cooled
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> 5. Multiple battery banks should never have the batteries sides touching one another. It forms a large thermal mass that is virtually impossible to cool.
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> 6. Pulse chargers are best
>
> --- In electricboats@yahoogroups.com, "davidhughes_casaba" <davidhughes_casaba@> wrote:
> >
> > Just currious. I noticed on a random Torqeedo piece of liturature that I came across that Torqeedo recommends Optima Batteries over others. I was currious in what others have found or think when comparing the 2. I do know that Optima does not offer anything larger then Group 31 and that the amp hours for their group 31s are rated lower then Lifeline's. Makes me wounder why Torqeedo aligned themselves with Optima.
> >
>
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