Lead acid battery water consumption.

[Vara]

Standard non sealed lead acid, 85ah..so called leisure batterys.

They seem to consume water at a rate of 300mls every three months is this about right?

Boat is in fairly constant use, and batterys are on constant charge when along side.

 

[sailorman]

Standard non sealed lead acid, 85ah..so called leisure batterys.

They seem to consume water at a rate of 300mls every three months is this about right?

Boat is in fairly constant use, and batterys are on constant charge when along side.

mine use nothing
how fast are you charging them

 

[RAI]

Batteries lose water by gassing, which is caused by overcharging of one sort or another. You could lower your shore power charger's voltage and save a bit of water, but why bother, water's cheap.

 

[blackbeard]

How well is the battery box ventilated?

(I understand there was a fairly recent case in which hydrogen and oxygen from over-charged and gassing batteries ignited, and the resulting explosion did rather a lot of damage.)

How many volts are you getting from the charger?

 

[Birdseye]

I seem to remember from the blurb that came with my sterling alternator regulator that 14.4v was the max you could go without gassing and 14.8 volts, the max their system would allow would cause significant gassing. But once your batter charger oif alternator reaches 14.4 at the battery it should drop the voltage down to something like 13.4 anyway. Thats sufficient to counter act the njatural internal discharge of a lead acid battery.

In short get out the digi volt meter and check your batteries. If the voltas are OK and the batteries still gassing then you have a duff cell.

 

[vyv_cox]

Standard non sealed lead acid, 85ah..so called leisure batterys.

They seem to consume water at a rate of 300mls every three months is this about right?

Boat is in fairly constant use, and batterys are on constant charge when along side.

Mine use about the same, with solar panels and engine charging, very rare mains charging. The Sterling alternator regulator literature warns that this is likely to happen.

 

[Trundlebug]

The strange thing is that although the Sterling charger manual warns that with fast charging this can happen, I've noticed a dramatic improvement (i.e. reduction) in water consumption since installing smart chargers for both engine and shore power.

I leave the CETEK shore power charger on permanently and the batteries hardly ever need topping up - maybe once a year if that.

I've concluded that water consumption says a lot about the charging system, as the old charger used to boil them quite a bit.

 

[KellysEye]

>They seem to consume water at a rate of 300mls every three months is this about right?

That sounds about right we were charging our batteries every day and not overcharging them, we had a voltmeter on them and a smart charger. As the batteries have sealed caps on each cell to stop leaks when heeling I have no idea where the water goes or how an explosion can occur unless the caps leak.

 

[VicS]

>They seem to consume water at a rate of 300mls every three months is this about right?

That sounds about right we were charging our batteries every day and not overcharging them, we had a voltmeter on them and a smart charger. As the batteries have sealed caps on each cell to stop leaks when heeling I have no idea where the water goes or how an explosion can occur unless the caps leak.

If they are losing water they will be losing it as hydrogen and oxygen. If the gasses can accumulate in the battery compartment then there is potentiall for an explosion if anything ignites the mixture

 

[Bodach na mara]

This thread comes at a time when I have found that one of by domestic batteries is down to 10.5 volts and I have started looking for a replacement. I have found that water consumption of the existing ones is about the same as that reported in this thread and am looking for non-sealed batteries for that reason, but all I can find are sealed ones. I am not keen on sealed batteries as you cannot top them up. Has anyone found unsealed ones recently?

 

[Vara]

This thread comes at a time when I have found that one of by domestic batteries is down to 10.5 volts and I have started looking for a replacement. I have found that water consumption of the existing ones is about the same as that reported in this thread and am looking for non-sealed batteries for that reason, but all I can find are sealed ones. I am not keen on sealed batteries as you cannot top them up. Has anyone found unsealed ones recently?

I got mine from Tayna, good price and apart from needing topping up do the job.

Phone them and haggle.

To all the other repliers,many thanks, the charger is a Ctek, so can't be adjusted, checked all the individual cells with hydrometer and all seems well, so I will have to live with consumption, no big deal 20 mins and about 50ps worth of water every 3 months or so.

The battery compartment is well ventilated, so hopefully explosion risk is minimal.

 

[sailinglegend420]

mine use nothing...

Then you are undercharging them. Batteries need to reach their gassing voltage to stir up the electrolyte to avoid stratification and remove sulfation.

Batteries lose water by gassing, which is caused by overcharging of one sort or another. ...

Batteries are only "overcharged" if they spend too long at the gassing voltage when they have already reached full charge. Batteries will limit the current they take when fully charged, but sitting for a long time with a high voltage - above the gassing voltage - will cause excessive gassing.

....once your battery charger or alternator reaches 14.4 at the battery it should drop the voltage down to something like 13.4 anyway.....

Not True - once the battery voltage reaches the absorption voltage - about 14.4v - it will stay there for a pre-determined time, about 1-4 hours - depending on the complexity of your Multi-Stage charger. Only then will it drop down to a Float voltage of 13.2 to 13.8v, even if the batteries aren't 100% fully charged. This is well below the gassing voltage so will stop any more water loss and continue charging the batteries, but at a much slower rate.

 

[pampas]

open your Sterling up and set to Gel battery, in 5 years of heavy usage only had to top up once. And before I shot get down, the battery1s get their full charge with slight increase in time to do so. advised to do this by no other, than Mr sterling himself.

 

[sailorman]

Then you are undercharging them. Batteries need to reach their gassing voltage to stir up the electrolyte to avoid stratification and remove sulfation.


Batteries are only "overcharged" if they spend too long at the gassing voltage when they have already reached full charge. Batteries will limit the current they take when fully charged, but sitting for a long time with a high voltage - above the gassing voltage - will cause excessive gassing.


Not True - once the battery voltage reaches the absorption voltage - about 14.4v - it will stay there for a pre-determined time, about 1-4 hours - depending on the complexity of your Multi-Stage charger. Only then will it drop down to a Float voltage of 13.2 to 13.8v, even if the batteries aren't 100% fully charged. This is well below the gassing voltage so will stop any more water loss and continue charging the batteries, but at a much slower rate.

Mine are sealed :encouragement:

 

[sailinglegend420]

mine use nothing...

If yours are sealed why post such a stupid comment, or are you trying to get your posts up to 100,000?

 

[sailorman]

If yours are sealed why post such a stupid comment, or are you trying to get your posts up to 100,000?

The point is the OP is charging at a too high a rate. i had one of the early charge boosters made by Kestrel if my old memory serves me correctly. since that experience, i would never ever have another.
I have a std alternator + wind gen & a 20 amp mains charger. The past 3 sets of batteries on my boat have done 9 yrs, 9 yrs & 5 yrs. the latest are now @ 3 yrs.

 

[Bodach na mara]

So, let me get this right. Batteries need to reach gassing voltage to fully charge. Gassing means that the water in the electrolyte dissotiates to hydrogen and oxygen. These gases bubble off. Even sealed batteries must have a vent to release any gases that are generated. So sealed batteries will lose water over time and, being sealed, you can't top them up.

So why are so many suppliers only selling sealed batteries?

Thanks Vara, I have already bought a battery from Tayna and would recommend them to anyone. I asked them about this last year and they recommended a battery hen, however on looking through their list this year I found that one is discontinued and all the rest are described as sealed. Which, if what I suggested above is true, means they are going to run dry due to water loss.

 

[charles_reed]

So, let me get this right. Batteries need to reach gassing voltage to fully charge. Gassing means that the water in the electrolyte dissotiates to hydrogen and oxygen. These gases bubble off. Even sealed batteries must have a vent to release any gases that are generated. So sealed batteries will lose water over time and, being sealed, you can't top them up.
.

Perhaps a trifle disingenious - the trick, to maximise charge and minimise entropy, is to charge them at just below gassing voltage. If you're having to top up it's because you're charging @ too high a voltage.
It's perhaps significant that Sterling, on my charger, recommend the highest charge voltage for open lead acid, presumably on the assumption that you can top them up.
I've bypassed the Adverc, modern alternators appear to charge at a much higher rate than the ones originally fitted by the manufacturers, and the one now fitted starts @ 15.1v and comes down to 13.8. The MPPT tracker is set to 14.4v to float and the 20 amp charger to 14.4 to float and 13.6v for float and 4 hours at 14.4 for equalising.
I use about 100ml/12months, on the open 120ah battery (lasts about 10 years). The sealed 90ah batteries which double up as starter batteries only do 5-7 years and have half the use of the open-cell battery.

IMHO most are driven, by current theory, to charge their batteries at too high a current (volts and amps), when I increased the switch-mode charger from 8 to 25 amps, battery life appeared to be reduced.

 

[sailinglegend420]

So, let me get this right. Batteries need to reach gassing voltage to fully charge. Gassing means that the water in the electrolyte dissotiates to hydrogen and oxygen. These gases bubble off...So why are so many suppliers only selling sealed batteries?.....

They are called Maintenance Free (partly sealed and re-fillable) or Low Maintenance (totally sealed) so are supposedly safer on a boat and easier to use. They may emit much less gas than open FLAs because of the different metals added to the lead plates. They may also recombine most of the gas - hydrogen, H2, and Oxygen, O back into water, H2O. They also contain more electrolyte to combat the loss that will occur. So overcharging a sealed battery is bad news. This will only happen when the voltage is too high for too long, or the temperature rises and the gassing voltage falls, so batteries should never be in an engine compartment.

....IMHO most are driven, by current theory, to charge their batteries at too high a current (volts and amps), when I increased the switch-mode charger from 8 to 25 amps, battery life appeared to be reduced.

It's very hard to charge batteries at too high a current for too long - THEY decide how much current they will take. Charging batteries is all about the right voltage - and it must get to the gassing voltage to do the job properly. A higher voltage will increase the current, and the temperature, which is what crazy Mr Sterling does to achieve his "Fast Charging". I bet he doesn't know what entropy means! To minimise entropy ALL chargers should also have temperature sensors on the battery to reduce the charging voltage as the temperature rises.

If you're a fan of Mr Sterling you will know he says sealed batteries should not be on a boat - because they can't be "Fast Charged".

I agree they shouldn't be on a boat but for a different reason - if they can't be equalised regularly their performance will suffer as they sulfate.

 

[Bodach na mara]

Thanks for the advice.

I did think that sealed batteries were not what I wanted, it is nice to have that confirmed.

I thought that I had read somewhere that some batteries incorporated a catalyst to recombine the hydrogen and oxygen but thought it was only gel or AGM batteries, not those described as "sealed.

I will try the trick of resetting the Sterling regulator to "gel". At present, when the engine is started, the charge rate is 30 amps for a while. Unless the batteries are well down, the charge rate falls to a few amps after a short while, well within the 1 hour that I have the boost time set for.

I cannot remember how old the domestic batteries are (there are two, my Watermota engine uses a 24 volt system.) But I do not think they are over 7 years old as they are the second lot I have fitted in 17 years. When I got the boat, the 12 volts for domestic supply was tapped off one battery, the other merely acting as a voltage reducer, which knackered it. Last year, one of the batteries was down to negative 2 volts at one time, but it was recharged and seems to hold charge well. It is the other one that is reading 10.5 volts now.

I will be getting on to Tayna soon, but I also saw a good deal on batterymegastore.co.uk A bit of haggling may be called for.