Hello. I do not yet know very much about solar installations, but I want to ask if it is possible for my Victron 100/30 MPPT controller to automatically stop sending current to the 12v battery after it fully charges at 100%?
Right now, I have to carefully monitor the charge rate so it won’t continue charging despite the battery reaching 100% charge. Further, I would like to ask what’s the recommended Amps for charging a flooded 12v 85AH battery? Thank you very much. 
Is the battery you are asking about charging the flooded lead acid you mention later. Have you got the right battery type set on your MPPT. When the battery is full the voltage should fall to around 13.5V but you will always have a small voltage going into the battery, this is called float and is normal. Normally on lead acid you leave it on float once full, you do not need to stop the MPPT as long as the voltage has dropped to 13.5V or so.
How are you measuring 100% SOC, are you sure that this is accurate. It may be that your SOC is not accurate and it needs more charge. Do not take your knowledge of charging things lime phones with lithium batteries to lead acid.
For an 85Ah battery a typical charging current would be 10A with the very most being 15A.
Have a read of Victron’s energy unlimited document as this covers battery charging.
https://www.victronenergy.com/upload/documents/Book-Energy-Unlimited-EN.pdf
Hey! Thank you very much so for replying. The reason why I asked the question is, I heard “bubbling” sound coming from the battery, but it was very minimal and quite hard to hear. (But that was probably my mistake due to it charging at 15amps)
I appreciate that you sent me the link to the battery manual, I will save it. However, since I never owned a wet battery before, I never heard this sound, so I am worried a bit of damaging the battery.
I had connected my battery charger with clamps to the battery to see its charged stated, and it was at 100%. I will test it again using ~10 amps as charging current, I think that should do it.
Forgive me if I have misunderstood you, but I thought that the MPPT controller automatically changes to “float” setting while charging?
Thank you for your precious time and will of helping me to figure this out, I deeply appreciate it!
Flooded lead acid batteries can bubble when.they are nearly full and this is normal. The water in the acid is being broken down to hydrogen and oxygen during charging and is called gassing. This type of battery needs the liquid level checking regularly and topping up with distilled or de-ionised water to replenish the water lost as gas.
Whatever you are using to check for charge may not be accurate, let the MPPT charge, it should run at more than 14V for an hour or two then reduce to 13.5V. See if it completes the cycle properly. I think you may be turning it off before it gets to float. If you have a SmartSolar model you can use the VictronConnect app on your phone and set the maximum absorption time to say 2 hours to make sure it goes to float after that time.
Thank you for the reply, will apply your suggestions right now. Also, could you recommend me the right absorption and float voltage for long-term safe charging?
Note: My MPPT controller is the “SmartSolar” type.
My current absorption voltage is: 14.25V (I think that’s safe, as I looked it up on internet)
My float voltage is: 13.50V
Equalization voltage is: 14,70V.
Thank you for helping me out here!
-Edit: I have found the setting, and have set it to two hours as you said.
-Update: battery is now at 14.19V. Still in “bulk” charging mode. Still waiting to change to float.
-Update2: battery is now at 14.20V. in “absorption” charging mode, currently pouring in 8.7 Amps.
-Update3: battery finally reached “float” mode. 8.7amps gradually decreased and now reached the float mode. And as you said, it is back at 13,5ish volts right now. The amps are currently fluctuating between 2,8 and 2,7.
14.25V is the lowest I would charge at, 14.4V will be a bit faster but may use a bit more water. 13.5V is good for float.
Here is another useful link.
https://batteryuniversity.com/article/bu-403-charging-lead-acid
Thank you very much! I will check out the link. Also, I’ve read in the Victron battery manual that you previously sent me that it is not recommended to keep the battery on float for long (several weeks). Would love to hear what you have to say about that. Thank you very much for guiding me through all of this, I’ve learned so much! 
If the batteries are frequently cycled then float is OK. If they are left unused then I normally leave my AGM batteries on a 13.2V storage setting.
Thank you for sharing this. Will do the same. Thank you for being kind enough to address my questions. If I will have anymore, I will make sure to ask you
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