In article 2cfAg.306263$iF6.139599@pd7tw2no,
Gary wrote:

The panel I have is a 46 watt panel and I will be running it into two
100 amp batteries. It produces a maximum voltage of 14.6 and maximum
of 3.6 amps. I was wondering just how self regulating it would be.
Do you leave yours on all the time?

Ours is on full time. All indications are that it isn't overcharging
the 120 AH battery.

I no longer parallel even "identical" batteries for any length of time.
If one of them is slightly weaker, it will likely go south.

My preference would be to install an 8D or a couple of big 6v in series.
Doubt that panel would hurt either of those.

Of course, I'm talking without knowing anything about the
self-regulation. If it actively limits the current at high voltage,
you're safe. If it simply has a diode to keep from draining the battery
at night (like ours), you are less protected, though a max of about 50
watts is easily dissipated.

BTW, expect your panel to perform better than the numbers, as they rate
for what they expect after a few years' service.

As I think, with a max 15 volts, you probably have active regulation,
since modern cells are designed to charge even when slightly shaded.

Keep track of things for a bit. If you have to add water quickly, your
panel is too big for the battery, so get a bigger battery. It's tough to
have too many AH.

--
Jere Lull
Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD)
Xan's Pages: http://members.dca.net/jerelull/X-Main.html
Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/