battery question - again

[Caladh]

I have had 4 x Enduroline EXV90's house batteries (assumed I had 360ah of battery!) on my yacht but they are now due to be replaced. One EXV90 was also fitted on the start side and I replaced it earlier this year - all ok. However I noticed that when it arrived it was only a 80ah battery compared to what I thought I was buying - "90" was the clue. So, looking at the spec what is the difference in the C20 and C100 indications - shown here -:
https://www.tayna.co.uk/leisure-batteries/enduroline/exv90/

 

[RichardS]

It's the discharge period, so slow or quick discharge. A battery delivers more overall power if discharged more slowly.

Richard

 

[macd]

The "C" figures simply show the capacity of the battery at different rates of discharge. C20 describes discharge to flat over 20 hours, C100 over 100 hours. All lead acid batteries deliver more Ah when discharged slowly rather than quickly**, hence the "discrepancy" between the C20 and C100 figures. C20 is the figure by which batteries are usually rated, so those are 80Ah batteries..

** The phenomenon is known as Peukert's Effect, if it's a slow day and you want to look it up.

 

[peteK]

Tayna have a 20% off sale on ebay at the moment.

 

[Caladh]

Tayna have a 20% off sale on ebay at the moment.

Thanks for all the info.