Is it good to keep solar charging fully charged batteries?

[geem]

I wouldn't read too much in the comment about wrecked batteries in Greece. We know nothing about the charging regime, the condition of the batteries, the amount of solar, the type of solar regulators or the settings of those regulators. All of these have a profound impact on battery life. As to potential fires, I don't see that happening in lead battery installations unless there are some fundamental flaws in the setup. The worst thing that normally happens the lead batteries short of water is over charging and a battery explosion that sprays acid in the battery box

 

[Graham376]

I have this quandary. We lift out on Monday for 3 months of hot Tropical summer. Boat temperature internally will be circa 45degC during the day. Batteries get hammered. We have Victron smart solar regulators with temperature compensation. In theory bulk and absorption voltages and run times are automatically regulated using the adaptive settings.
Leaving the batteries disconnected will likely see me coming back to partially charged batteries and sulphated.
My plan is to leave them connected and let the Victron kit do its stuff, albeit with only half the solar connected
Edit
Trojan website suggests storing them in a cool environment. Not going to happen.
Also they say that the self discharge increases with temperature so they need some charge

When we're leaving the boat for 2 or 3 months, summer or winter, I reduce absorption to 14.4v from 14.82v. Float remains at 13.5 as specified by Trojan. They use some water but as I fill to half way up the slots in the fillers, never uncover the plates.

 

[vyv_cox]

I wouldn't read too much in the comment about wrecked batteries in Greece. We know nothing about the charging regime, the condition of the batteries, the amount of solar, the type of solar regulators or the settings of those regulators. All of these have a profound impact on battery life. As to potential fires, I don't see that happening in lead battery installations unless there are some fundamental flaws in the setup. The worst thing that normally happens the lead batteries short of water is over charging and a battery explosion that sprays acid in the battery box

I agree we don't know about all of them but we know quite a lot about some including mine. 3 X 110 Ah wet cell, 45 watt panel, PWM regulator that has worked fine for years. Our return to the boat was delayed due to illness. Batteries would not hold charge.
Another from a very knowledgeable member here with top quality kit. One battery cell seems to have gone down, battery overheated severely and he was lucky to catch it.
I know of many others, all from established liveaboards but not technical info.

 

[geem]

I agree we don't know about all of them but we know quite a lot about some including mine. 3 X 110 Ah wet cell, 45 watt panel, PWM regulator that has worked fine for years. Our return to the boat was delayed due to illness. Batteries would not hold charge.
Another from a very knowledgeable member here with top quality kit. One battery cell seems to have gone down, battery overheated severely and he was lucky to catch it.
I know of many others, all from established liveaboards but not technical info.

These faults are not unique to batteries being stored. These faults occur mid season as well.
A faulty cell will cause overcharging of the bank, loss of water and the death of the batteries if left unattended.
My engine batteries are cheap car batteries from Columbia. They have a dedicated Victron MPPT smart solar reg with temperature compensation. They go through a daily charge regime. (See pic.) With a 40w panel. Still going strong after four years despite the heat trying to kill them here. I don't expect them to last much longer with the high temperatures they have to endure here but I don't believe it is anything to do with their charge regime.
Lots of people use VSRs to connect engine batteries to domestic banks that trigger when solar raises the voltage on the domestic battery. Sat at anchor for weeks, these batteries are getting an uncontrolled charge at the dictates of the domestic bank regulator. That can't be as good as leaving them on their own dedicated controller set to the correct bulk and absorption profile for the right period of time