View Single Post
  #35   Report Post  
posted to rec.boats.cruising
navti navti is offline
external usenet poster
 
First recorded activity by BoatBanter: May 2007
Posts: 25
Default AGM Leisure battery 110AH arrived flat

On May 30, 1:22 pm, Jeff wrote:
* navti wrote, On 5/30/2007 2:29 AM: UPDATE UPDATE UPDATE

Both Batteries were charged on full last night for 3 hours .
I put some lights on them for 2-3mins before checking voltage to
remove the surface charge (as advised by Ken Heaton).
They showed 12.69V and are sitting steady. Will leave them to settle
until till tomorrow evening then start using them and try and figure
out their performance over the next few days.


This means they are not totally dead. Only a load test (which could
simply be running a bright light for a while) will tell if the
capacity is seriously diminished. Unfortunately, the capacity could
be well below 50% and they would still behave like yours. With
traditional wet cells, the electrolyte can be sampled, making this a
bit easier. With AGM's you really have to measure how much they can
deliver before the voltage gets too low.


Jeff

I am curious as to how the battery capacity can be 50 % diminished and
still deliver 12.6 volts (or thereabouts.

Are the individual cells in the battery wired in series or parallel ?

If I had four 12 volt cells wired in parrallel each with a capacity of
10 amp hours then I would have 40 amp hours at 12 volts,

If one cell went dead then I would have 30 amp hours at 12 volts,

If I had four 3 volt cells wired in series each with a capacity of 10
amp hours then I would have 10 amp hours at 12 volts,

If one cell went dead then I would have 10 amp hours at 9 volts,

How does it go with my battery ? Is it a combination of series and
parallel ?