What Are The Effects On Batteries Of Low Electrolyte Level And Can This Be Reversed

[Deleted member 36384]

This winter I left a Sterling Pro Charge Ultra 24V 20A/600W model permanently hooked up to the batteries and on. During my pre season checks I found that the fluid level was below the top of the cells on the domestic batteries only. Close inspection of the batteries and cells (using a torch with a clear view inside) indicated that the cells looked damp and normal with no obvious damage. I used about 2 litres of distilled water on 4 x 6V batteries, 12 cells in total). I have no idea how long they had been like that but the fluid levels were fine 5 months before. I topped all the batteries up and launched the boat. My power needs are modest and so far I have not noticed any difference in battery performance.

The Sterling has been on the boat now for two seasons, the batteries are at least 5 years old.

What damage do you think would have occurred and is it reversible by me topping up and the smartness of the Pro Charge Ultra? I am off for a long cruise later in the summer and as such the batteries will be tested quite a bit more than the current weekend jaunts; would you expect them to have lost a lot of their capacity? I cant really give you any low down on the charging regime as I am poor at recording such facts. I am planning on changing the batteries out next season anyway.

Your opinions and guidance are appreciated,

Thanks,

BlowingOldBoots

 

[Plevier]

Any manufacturer will tell you that letting the level get below the top of the plates will rapidly cause irreversible sulphation and of course will void any warranty.
In reality you may get away with it for a while and at worst you'll only lose the part that's been exposed.
Just see how they go, it's not predictable.
At 5 years old they are likely to be well down on capacity anyway, it'll be hard to distinguish between any damage from this incident and general ageing.
If your charger has a desulphation cycle you could try it. (I don't personally have much faith in desulphation cycles or gadgets.)
Nothing else you can do.
If the charger is operating correctly the batteries should not have lost significant water in a few months of maintenance charge. Maybe you have a charger fault or maybe it's just the age of the batteries.
There's really no need to keep batteries on permanent charge when not used over winter. Just a periodic refresh is enough. New batteries in store at manufacturers are generally only charged 6 monthly (and the distribution manager is asked why the hell they are still there!)

 

[Deleted member 36384]

.... There's really no need to keep batteries on permanent charge when not used over winter. Just a periodic refresh is enough. .....

Yes, thanks for that. It's the conclusion I have now arrived at along with the fact that "smart" does not mean ignore! I am guilty of leaving the charger on when I am away from the boat, believeing that the "smart" feature means that there should be no issues with overcharging and that the machine will monitor and respond as appropriate. I am not so sure now that this was a wise move by me and "smart" just allows the machine to charge the batteries efficiently, no more.

 

[Plevier]

believeing that the "smart" feature means that there should be no issues with overcharging and that the machine will monitor and respond as appropriate.

That's what one would hope!
It claims to have "New, low activity, standby mode to increase battery life." What happened to that? No explanation of what it means.
It's supposed to go automatically to 13.4V - presumably 26.8V for you - float. At that voltage batteries should not lose any significant water.
I think something is not right with either your charger or batteries.

 

[charles_reed]

One possible cause could be inherent in the Sterling control system.
I've noticed that if there is any loss of AC power, for however short a period, my Sterling charger restarts in the absorption phase (high voltage, low current), whether or not the batteries are fully charged, rather than reverting to float charge.
It's very difficult, in Charles Sterling's marketing-speak, to sort out technical fact from hyperbole.
What doesn't help is that he brings out a new model every 3 years or so.

 

[Deleted member 36384]

Charles that is very interesting. Certainly over the winter there were numerous breaker trips when I was working with tools and heaters. I am going to change the way I use the thing. I wont now leave it constantly on when I am off the boat and I'll make battery fluid level a check every visit. The batteries are at the bottom of the boat, behind a bulkhead, in the cockpit locker which needs to be emptied for access; must be more disciplined.

 

[Plevier]

I've noticed that if there is any loss of AC power, for however short a period, my Sterling charger restarts in the absorption phase (high voltage, low current),

But for how long?
My carpy Crystec charger goes onto a timed 6 hour boost if this happens, but the Sterling is meant to be smarter. Does it switch to float after just a few minutes? That would do no harm.
The Crystec has a switch to disable the boost if you are leaving it connected.

 

[charles_reed]

But for how long?
My carpy Crystec charger goes onto a timed 6 hour boost if this happens, but the Sterling is meant to be smarter. Does it switch to float after just a few minutes? That would do no harm.
The Crystec has a switch to disable the boost if you are leaving it connected.

I'm afraid, not, with the Sterling Pro-Charge which I have. It then goes on to run the absorption phase for the # of hours set on the dip-switches. The Pro-Charge has now been replaced by a new range (it has a bulkier carcass) but I'm not sure how much the internals have changed.
As I have already said, it's all obscured by the marketing-talk.
The Pro-Charge is a simple 3-outlet charger with one controller. I haven't yet worked out whether it senses the most-charged or lowest-charged battery.
For what they are, the Sterling chargers are reasonable quality switch-mode chargers, but marketing hype does infer they're smarter than they are.
The maximum length of time you can set the absorption charge phase, on my Sterling, is 4 hours, with 1, 2 and 3 hour alternatives. As far as I can ascertain the charger maintains 14.4 volts @ 1.8 amps for the set time. Maximum volts are also set by dip-switches - these can be set at 14.2/14.4 for sealed, AGM or gel batteries and a recommended 14.8 for open. Mine is set @ 14.4, as is the MPPT controller. I personally think that a 14.8 input voltage, into an open lead/acid cell is going to result in loss of electrolyte.
At this time of year, with my PV panel array, in Greece, I need no other input to keep my batteries charged.

 

[Plevier]

That's disappointing.
If the OP's charger does the same it could well be the explanation. There should be the facility to disable boost.
Yes 14.8V will cause gassing.

 

[charles_reed]

That's disappointing.
If the OP's charger does the same it could well be the explanation. There should be the facility to disable boost.
Yes 14.8V will cause gassing.

Yes a pretty crude device, but serviceable if you know what you're doing.
Some chargers, like the Dolphin and C-Tek have a de-sulphation programme which, as far as I can make out involves squirting pulses of current at about 15v - thereby promoting gassing and, theoretically de-sulphating - however I'm unpersuaded by the theory behind that and suspect the improvements claimed have more to do with de-stratifying the electrolyte than anything else.

Expressed battery theory has, I suspect, more in common with theology than science.

 

[BruceDanforth]

I just leave a 10w solar panel connected over winter. It keeps the battery topped up nicely for free and with no loss of electrolyte. I'm pretty sure it is cheaper than a Sterling Pro Charge Ultra 24V 20A/600W whatever exactly that is too.

 

[AntarcticPilot]

Expressed battery theory has, I suspect, more in common with theology than science.

You mean it depends on rigorous logic? Logic was invented by theologians, scientists (of whom I am one) are Johnny-come-latelys!

 

[Deleted member 36384]

I just leave a 10w solar panel connected over winter. It keeps the battery topped up nicely for free and with no loss of electrolyte. I'm pretty sure it is cheaper than a Sterling Pro Charge Ultra 24V 20A/600W whatever exactly that is too.

You see Ed, I have been sucked in by the consumer machine and believed what the internet told me: -

11 pre programmed battery curves including Lifep04.
1 custom set, can be set from charger, no need for computer.
2 x digital meters for current and voltage measurement.
1 x power meter to show what reserve power left on the unit.
PFC, active, up to 0.99 pf, ensuring efficient power conversion, up to almost 90% as opposed toabout 50% for older non PFC technology. Combined with (below)
6)New synchronised rectification output as opposed to diode output, giving up to a extra10% efficiency
High voltage de-sulphation cycle.
New, low activity, standby mode to increase battery life.
Battery health program.
Multiple speed fan control to reduce unnecessary fan noise experienced by the customer, even though the new extreme efficiency reduces the need for fans, at high ambient temperatures (40-50 deg c) fans would still be required to ensure operation.
Primary (processor digitally controlled) and an emergency backup secondary (analogue controlled) high voltage trip.
32 L.E.D. information panel
Internal scan and systems check
Remote control
Small footprint and light weight
Include battery temperature sensor
As with all our marine chargers all metals used are non ferrous

I mean, fek me, the only thing missing is a fusion reactor, it must be great. You are correct with the solar panel thingy, it probably would have been better. Anyway, I live and learn, which is something I suppose, although I am notorious for repeating the same mistakes over and over.

 

[charles_reed]

You mean it depends on rigorous logic? Logic was invented by theologians, scientists (of whom I am one) are Johnny-come-latelys!

Theology is based upon beliefs - not reproducible facts. Logic is the means to an end.

 

[AngusMcDoon]

Sounds like some serious feature creep has gone on there. I expect the engineers wanted to make a product with an on/off switch, a guage and a LED. Then marketing got involved.

 

[William_H]

The operation with low electrolyte may not have damaged the batteries much. Some batteries were supplied new with no electrolyte to increase their shelf life. However with half of the plates covered and half not their may be some damage. However I reckon the 5 years old bit might be more reason to believe they are not operating at full capacity. So worth a check.
Re winter service of batteries. I would prefer to see an old style dumb charger set up for some small charge current and or set on a timer to just give batteries a boost like 1% of capacity every 4 days. I don't really believe that smart chargers are really that smart.
good luck olewill

 

[Plevier]

The operation with low electrolyte may not have damaged the batteries much. Some batteries were supplied new with no electrolyte to increase their shelf life.

Batteries supplied new dry charged are different.
The plates are washed and dried after tank formation before assembly to remove most of the acid, and the batteries are sealed to exclude air. It's not a case of taking a charged battery and pouring the acid out.
The main reason for doing it is for ease of non-hazardous shipment.
Commissioning a dry charged battery properly (and most distributors don't!) is more than just pouring acid in.