Quote:
Originally Posted by sailinglegend
A "Reserve Capacity" test could be a much quicker way to get a result.
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As
batteries age a RC test and C/20 test can vary by quite a bit, over 20% in many cases.. I am very surprised yours only varied by 5%, as that is far from the norm I see when
batteries start poking below 80% of rated Ah capacity.
Quote:
Originally Posted by sailinglegend
By the way Lifeline recommend the batteries should be replaced when they reach 50% of their rated capacity.
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The industry standard (BCI) is that below 80% is considered dead, but for light loads and
coastal cruising, with quality AGM's such as Lifeline's, I will still stand behind a recommendation of 65%-70% with a
strong caution. Anything below 70%, for actual off shore
work, I absolutely will not recommend to my customers.
I have seen far too many banks fail catastrophically once below about 75% than I do above 75% of original Ah capacity.
Hand
steering, with a two-man crew, from NY to
Bermuda in a storm is no fun.... While the Lifeline Group 31 reserve
battery saved the day, comms wise, it was insufficient to provide
refrigeration, he
lost $300.00 worth of
food, & the ability to drive the AP. The real downer was that when they got to
Bermuda the same batteries were 2.4X the
money they were here in
Maine, so his total cost was a huge punch in the wallet.. I had urged the customer not to proceed with this bank, which was testing at 70.5%....
I would only advise taking any
battery, including Lifeline, to 50% of as new rating if you have a strong & healthy reserve/start battery, that can do double duty, and you're close to your battery dealer. 50% for an Rv'er is one thing, on a
boat it is another story...