Overfilling batteries - is it a problem?

jeremyshaw

jeremyshaw

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When I put my boat into store in the Caribbean I always get someone to check the batteries from time to time. But quality of service is unpredictable. Once I returned to find the water below the level of the cells, yet the chap insisted he'd checked them just the previous week...

So I'm wondering about overfilling my Trojan T105s on the basis that when I come back the level will be normal.

What is the actual consequence of overfilling batteries though? Does is damage them at all or just maybe reduce capacity in some way?

Any expert advice would be greatly appreciated.

Thank you
 
If they're being left on a charger, they could bubble and make a mess of their own terminals and other things in the immediate vicinity. Sounds like the guy might not have done a good job and/or you are over charging them. They should just be given a wee burst once in a while. I leave a timer on the car battery when on long cruises, giving an hour of 'off-peak' once a week.
 
It's kinda worrying that the level changes so much while you are away.

If that much distilled water evaporates, I have a suspicion that the batts are knackered or there's a hole in your bucket, sorry, battery.

Is there anything connected to the batteries that is active ? Either charging or discharging. Or a non-obvious leak / crack in the casing?

In any case, overfilling should not be needed.
 
Overfilling them as such will cause no harm. The reason for not doing so is that if they overflowed it would make a mess and acid lost would lead to a reduced capacity

Perhaps you should look at "Battery Maintenance" in the Technical support pages of the Trojan battery website. In particular the page on "watering"
 
[qoute]So I'm wondering about overfilling my Trojan T105s on the basis that when I come back the level will be normal.[/qoute] NO, absolutety no problem
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Artificial Intelligence is no match for Natural Stupidity
 
Not a problem, provided you don't overdo it. If they are gassing enough to spit electrolyte out of the breather, it will make a mess and of course you will have lost acid from the battery. The air space above the max line is there for a reason, but if you're keeping them level, it should be ok to overfill a bit. But when you engine charge them, perhaps at an angle, due to sailing, it would be better if the level had gone down by then, as the higher charge rate will often cause some gassing.
Perhaps a better charger would help. The time witch is quite a sound idea too!
 
[ QUOTE ]
The time witch

[/ QUOTE ] Any connection with a time Lord?

<span style="color:white"> ............................................. </span> /forums/images/graemlins/laugh.gif
 
Many thanks for all the advice.

My bank is 1050 amps, consisting of ten Trojan 6v batteries. It is charged while I'm away by 3 42 watt solar panels which put in 8amps at peak. So there is not really a problem with overcharging - the panels are regulated. I only put the Trojans in at Christmas, and judging from friends experience, and so far, they seem to need a little more water than some batteries, at least in this climate.

Based on the advice given I'll overfill them a little and see how that goes.
 
[ QUOTE ]
My bank is 1050 amps, consisting of ten Trojan 6v batteries.

[/ QUOTE ]

I assume you mean amp hours (Ah) rather than amps, and that this is based on 10 batteries each being rated at 105Ah? You do not say what voltage your boat runs on, but 6V would be very unusual. 12V and 24V are much more common, and would involve connecting 6V batteries in series chains of 2 or 4 respectively which would then be paralleled. Each series chain would be 105Ah and the total 12V bank would have a capacity of 525Ah. (To construct a 24V bank would require the number of 6V batteries to be divisable by 4.)
 
[ QUOTE ]
I assume you mean amp hours (Ah) rather than amps

[/ QUOTE ] I decided , uncharacteristically, to over look the error with the units.

I also looked at the Trojan batteries on offer and as I could not see 105 Ah 6 volt ones concluded that Jeremy probably had a bank of ten 210Ah T605 batteries connected to give 12volts and 1050 Ah

Where have you found these 105Ah Trojan batteries. Not confusing them with T105 s are you which have a capacity of 225Ah . Odd labelling I must admit
 
Apologies, I was being sloppy. Too tired from ten hours boat fixing a day in 30C is my excuse!

Yes, I have 5 pairs of T105s rigged to give 12 volts. So 1150amh at 225 per battery/pair, not 1050 as I said.

I got them in Curacao. As you probably know they are popular in the US and thus readily found in the Caribbean. They seem to last well, and as they are taller than most batteries I was able to get this capacity in a space where I previously got only 640amh – with just a 1cm larger footprint in both directions. And the price was less than I paid in Greece for my last bank 4 years before.
 
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