Cannot understand this Chinese solar charge controller

[OffGridForGood]

And like a float valve, if the SCC settings are wrong, you can 'over-flow' the battery/bucket and have a mess on your hands!

 

[Bop]

And like a float valve, if the SCC settings are wrong, you can 'over-flow' the battery/bucket and have a mess on your hands!

Actually it makes for a good analogy for something said at the beginning of the thread

You have the hose coming in filling the tub (the solar panels putting charge into the battery)- the charge controller is the float valve and stops the tub overflowing by shutting off the water flow as needed (stops the battery overcharging if it is 'full') and turning on if the water level drops...

The tub is the battery bank itself (need to store more water- get a bigger tub (more Ah batteries) or add another tub next to it (batteries in parallel)- and you have another hose draining the tub (the load/inverter)...

You don't need to unplug the second hose and plug it into the first hose to use it (ie the 'not fond of tapping into the battery while it is being charged' thing) it just 'happens automagically'- if your second hose is pulling out less water than the first hose is putting in- your tub still fills until the float valve partially shuts off the flow to stop it overflowing... and then just keeps it 'slowly filling' at the exact same rate water is coming out the second hose... ie the tub is neither dropping nor overflowing...

Stop draining the tub with the second hose, and the float valve shuts off the first hose altogether (ie the battery is full and the charge controller stops the panels overcharging the battery)

And why you can end up with a 'flat battery' even if you are charging it if you have a big enough load on it.... you have a 'firehose' sucking water out (big load, big current)- and are filling it with a garden hose (smaller current) your float valve can be 'completely on' and flowing as much water as it can- yet the tub soon empties...

 

[corporal_Canada]

Got tired of waiting for the battery to reach full charge, so I disconnected it and now the battery barely reaches 5v... What did I do wrong ?

 

[Bop]

Ouch- if it is only at 5v after being on charge- you have severely overdischarged it or otherwise abused it, and your battery is now a 'Norwegian Blue' ie an ex-parrot...

Six months if abused could indeed see a battery almost at the end of its service life (I have seen many fail after only a month or two when severely abused by people who were massively overdischarging them (and yours is a SLA- they have charging current limits that can see them failing quickly if not followed as well)- most gel/SLA batteries have an initial maximum charging current (usually less than 30A for a 100Ah rated one) which limits the wattage of panels you can handle unless you have a quality charge controller that limits inrush current on SLA settings... and often have a relatively low output current (which limits the inverter size they can handle)

This bit from before seems pertinent... and a bit predictive...
Sorry to say it, but that battery is probably toast...
(you can try to recover it wih a low powered mains charger (just in case your charge controller is also toasted) but even if it accepts a charge now, its capacity will have been dramatically reduced...)

 

[OffGridForGood]

so I disconnected it and now the battery barely reaches 5v.

Sorry but a 12v battery at 5v is done.
could be a good door stop.
Back at post #1 you were describing the cheap SCC - the type "with only three buttons" and a "little picture of a light bulb" - ie for the load side.
I had one of those back in the day - I used it to charge up car batteries on a shelf while I did autobody work on the cars. I left it too long, and even though I had set all the parameters that POS charger killed a perfectly good car battery one day. I don't trust those little "wallet sized" SCC''s
and I should have known better since it was like $20 or less.
Cost me a $100 battery to learn that life lesson.