Originally Posted by peterwilliam
Thanks Bill, This is what concerns me. The question is why are these voltages low, on solar charging I assume it is just available sunlight but under generator/battery charging??? Do you think the chargers might be faulty?
and yes they are 12V for 1260 Ah,
The solar controller equalizes automatically once a month (subject to available sunlight) and the monitor usually synchronizes itself at this stage.
And another question. Are they close enough to full (when down 100 odd Ah) not to damage an AGM battery.
Again, don't trust the battery monitor. There are all kinds of reasons not to, which MaineSail has recently elucidated nicely.
Well, a 100AH draw on a 1260AH capacity battery bank is NOTHING -- that's only about 7% of the total capacity. And, if that's all you usually draw, then you have a battery bank which is WAY too large for your vessel.
Why don't you try putting a good load on the batteries, and draw them down by 300-400AH? Or even more. How to do this? An easy way if you have an inverter
is to put a heavy AC load on the inverter
....using, e.g., a space heater or a water
heater or other appliance which draws a lot of current.
When you get down by 25-30%, then see what kind of current the chargers are putting out.
One thing I'd do: cut the solar panels out of the picture. They may be providing a sufficiently high voltage to "trick" the battery chargers into believing the battery voltage is higher than it really is.
Do the tests with the charger(s) only. And, again, there's no substitute for good meters: a good multimeter and a good clamp-on DC ammeter. Fluke is a good brand..almost any models. There are a few Chinese meters which are very good also, e.g., the Mastech MS-2108 (not the 2108A) clamp meter now selling for under $60 online. IMHO, every boat should be so equipped.