Q for deep cycle battery experts

I have one of the high-tech battery chargers in my garage.
It is showing V and % of charge.
When I switch it to 25 amp charging on single battery, it will go to 16.5V, but when it go to maintain mode, it will keep 13.2 -13.4V
Than my designated battery maintainers keep 13.5V

drmopar wrote:
Deep Cycle batteries are not all the same. Having owned a Large Marina and RV park over 25 years, and selling and installing solar and Batteries, I only used high quality AGM batteries, like "Lifeline" and others. The typical RV convertor is normally locked at 13.1 volts DC. Some newer ones are converters and chargers. A Deep Cycle Battery will only be fully charged at 14.4 volts. No more or less. This is the voltage that creates the chemical change on the plates. If you do not reach this voltage, you will not fully charge the Battery. I always use a meter to double check this important issue. Sometimes the voltage will rise a lot higher when charging. This means the battery is done and it has a dead cell. Avoid 6 volt series wired battery banks. Use 12 volt banks for the best performance. We find most 6 volt batteries have different resistance with the same brand batteries. Poor charging and short battery life. For example, our AGM batteries will last 10-15 years if properly charged and used. Never drain a battery completely. If you do, plan on replacing it soon. Any electrical-battery-solar questions, please ask!

A number of questionable statements in this post.

Typical converters these days are three stage and do well at maintaining batteries.

Current is what charges batteries. Voltage is the motivator. Batteries can fully charge at less than 14.4 volts. It just takes longer.

Higher voltage does not necessarily mean a bad cell. In fact one takes the voltage much higher in order to equilize the battery.

Batteries in parallel also have issues. Battery, connection, and wiring inequalities will result in load sharing and charging inequalities.

I use a progressive Dynamics Intella-power 9180 with charge wizard (The RV's converter"..

now, that said, The Intella Power wizard controlled jobs are top of the heap, I have been searching for years and have yet to find a better one.. Some are as good, but none better. Not all RV's have such good hardware.. Some older models come with magnetek 6300 line.. And that.. is the bottom of the pile,, in fact it's so far down they had to dig a hole for it.

Deep Cycle batteries are not all the same. Having owned a Large Marina and RV park over 25 years, and selling and installing solar and Batteries, I only used high quality AGM batteries, like "Lifeline" and others. The typical RV convertor is normally locked at 13.1 volts DC. Some newer ones are converters and chargers. A Deep Cycle Battery will only be fully charged at 14.4 volts. No more or less. This is the voltage that creates the chemical change on the plates. If you do not reach this voltage, you will not fully charge the Battery. I always use a meter to double check this important issue. Sometimes the voltage will rise a lot higher when charging. This means the battery is done and it has a dead cell. Avoid 6 volt series wired battery banks. Use 12 volt banks for the best performance. We find most 6 volt batteries have different resistance with the same brand batteries. Poor charging and short battery life. For example, our AGM batteries will last 10-15 years if properly charged and used. Never drain a battery completely. If you do, plan on replacing it soon. Any electrical-battery-solar questions, please ask!

Does acid NOT stratify @ 13.5v?

12.7V could not boil the batteries. It had to be 14 or above.
Solar panels can deliver battery killing 16v, so if you run them without sophisticated. controller, that is what they will do.
Even with good controller, I wonder if solar charging few hr a day would win v/s plug in maintainer with 24/7 maintenance voltage.
Again maintaining voltage is generally 13.5V, but would not hurt to call battery manufacturer and ask for precise advise.

bbaker2001 wrote:
Battery tender for us. plug it in and leave it.
do not leave batteries plugged into TT unless you have a GOOD 3 stage unit, my brother left his plugged it, and I checked his voltage at 12.7 all the time. boiled the battery

Are you saying that a charging voltage 12.7v boiled his batteries? If not what was the charging voltage that boiled his batteries?

12thgenusa wrote:
Temp compensated solar 24/7 maintains the batteries better far better than I could by any other means.

X2

Temp compensated solar 24/7 maintains the batteries better far better than I could by any other means.

Battery tender for us. plug it in and leave it.
do not leave batteries plugged into TT unless you have a GOOD 3 stage unit, my brother left his plugged it, and I checked his voltage at 12.7 all the time. boiled the battery