Did Victron BlueSolar Kill My Batteries?

[CatNewBee]

I agree with that 100%. However, if one cell in a battery bank has an internal shortcut due to corrosion of the plates / age it will discharge quickly the bank.

Vessels in the marina or on the dry stay unattended for longer periods of time. A single cell can deep-discharge the bank and the cells can be covered in sulphate crystalls because of the deep discharge and loose permanently their capacity.

Batteries wired in series for 24V or using 6V packs in series without monitoring / balancing can be destructed by a failure of a single cell that has a shortcut because the other cells will be overcharged and may dry out / get overheated.

Lead-Acid/AGM/GEL battery banks are not so carefully monitored as Lithium batteries and this issues will not be noticed in an early stage before the whole bank gets unrecoverable damages.

[john61ct]

Yes but I see no takeaway from this other than "keep an eye on your bank so this doesn't happen".

There are ways, like split monitoring, or routinely checking cell voltages to identify a weak cell long before it shorts.

Unless you're advocating for 12V paralleled batts over serial strings?

[john61ct]

Originally Posted by zstine

you say "shallow cycles mean longer life", then "it is best to follow a deeper discharge with a 100% SOC re-charge"

Both are true together. Perhaps phrase the second as "if you do go deeper, then it is even more urgent to get back to 100% asap"

Originally Posted by zstine

So what is better, 400 cycles to 88% SOC or 200 cycles to 75% SOC?

The latter. If the SoC diff was much greater, say 88% vs 60%, then the answer would be less certain.

Originally Posted by zstine

The batteries are made by East Penn, qty 3 of Duracell Ultra 12V golf Cart batteries rated at 155Ahr each. So when I leave the boat with no load for a week or 2, is it best to turn the solar controller off or leave it on, which puts a 14.4V charge on for a short time, then holds 13.8V all day?

Leave it on, but if it were a more sensitive batt and truly no load, I would minimize Absorb time, or even set Absorb to equal float when it's over a week.

When you next replace your batts, the Duracell 6V flooded GCs are much more robust for deep cycling than the 12V, especially if the latter are sealed.

[admiralslater]

I have the traditional 2,6 volt batteries wired in series with the diagonal take off . They are fed by a 275 watt Lg ion 2 panel through a 100/30 victron controller with dongle.
The company I purchased from sell a lot of stand alone pv sets for remote traffic equipment and all sorts of othe applications ,he even has an all electric Mazda Miata. Their main business is supplying and maintain traction batteries for industrial fork lifts .
I tell you all this just to give the back ground of the people who gave me this next piece of advice . Our refrigeration is a little power hungry and is always on ,we are on a mooring . and I was concerned about PSOC etc.
The guy at the battery store said that even though it is considered not the best way to get the batteries up the traction batteries that he maintains often get equalized several times a week and some of these batteries are 6-7 years old

He suggested I consider using the programable feature to equalize the batteries every day . His thinking was that since you generally don't get many hours of perfect PV sun ( new phrase ?) you won't do any damage to the batteries and it will help finish the charge . Using the history from the charger I could tell how often it popped into equalize by looking at the highest voltage in the day and how long it was on for . I did this for 8 weeks with no discernible difference in water use ,but very full batteries. In the off season I have changed back to once a month . The victron made that very easy to do.
What does the group think
FYI did not always meet the parameters to start equalizing every day

[john61ct]

For flooded no problem long as you watch water.

For expensive Lifeline, depends how high how long

Generally speaking equalizing should be manually only.

[admiralslater]

I agree ,but as luck would have it the sun is pretty good at the on off thing . When I have equalized with battery charger it is hydrometer first and foremost .
Glad you think it is reasonable John

[john61ct]

Hydrometer needs resting period to be accurate, just like voltage.

Use an ammeter to measure tail amps, only accurate way to go.

[Maine Sail]

Originally Posted by john61ct

When you next replace your batts, the Duracell 6V flooded GCs are much more robust for deep cycling than the 12V, especially if the latter are sealed.

He is using a golf cart battery already, the GC12 format. These not a run of the mill G-24, 27, 29/30/31 format but a 12V golf car battery.. GC12's generally have comparable durability to a GC2 6V...

[admiralslater]

Originally Posted by john61ct

Hydrometer needs resting period to be accurate, just like voltage.

Use an ammeter to measure tail amps, only accurate way to go.

Once again I must ask Obiwan( John61ct) a question . What are tail amps and do I use a hand held ammeter? Where would I measure from .
Thanks
David

[john61ct]

As the Absorb cycle finishes, SoC approaches 100% Full, amps are falling.

Say the tail amps spec from the batt mfg is .005C and the bank is 430AH.

When your ammeter shows tail amps falling to 2.15A **still at Absorb voltage** then that point is 100% Full and you stop charging.

Measured at the battery, but there shouldn't be any significant V drop between there and your charge source anyway,

By any type of ammeter, long as it is accurate.

Rather than using SG which (like voltage) requires a long rest period to be accurate.

And this End Amps point should also be used to benchmark all charge sources to make sure they aren't going to Float way early, as they tend to do left at default settings.

[john61ct]

Originally Posted by Maine Sail

He is using a golf cart battery already, the GC12 format. These not a run of the mill G-24, 27, 29/30/31 format but a 12V golf car battery.. GC12's generally have comparable durability to a GC2 6V...

I thought I compared the Deka DoD vs cycles charts in the past, but can't find them now, so will defer to you by default, long as we're talking FLA.

However if they are **sealed** Deka, those may be labelled for GC use, but barely are even deep-cycling at all, it's definitely better to stick to flooded.