How often do you top up open cell batteries?

geem

geem

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We have four 8D commercial truck batteries as our domestic bank. They are 65kg each. Dont know amp hrs as they are not deep discharge batteries. They are configured as 24v to suit our boat electrics. Over night with fridge freezer running, anchor light and the usual chargers plugged in etc they never drop below 25.4v. They are open cell types. We have 380w of solar and they get a boost from the sterling ultra pro 30 amp@24v battery charger every two or three days whilst we run the generator to make water etc. Normally only 1/2 hour or so.
We installed these batteries in October last year and I check the levels monthly. We have not needed to put any water in yet. All cells are nicely covered. Is this normal? How often would you expect to fill this type of battery with distilled water?
 
In Greece I top up about twice per season, sometimes adding a surprising volume of water, up to 2 litres to three 120Ah batteries. It sometimes becomes apparent that the batteries are not quite performing at their best, for example not reaching the expected voltage on charge, which prompts me to check electrolyte levels.
 
vyv_cox said:
In Greece I top up about twice per season, sometimes adding a surprising volume of water, up to 2 litres to three 120Ah batteries. It sometimes becomes apparent that the batteries are not quite performing at their best, for example not reaching the expected voltage on charge, which prompts me to check electrolyte levels.
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Vyv, when you see less voltage on charge, does this mean the plates are starting to uncover?
 
The answer to "how often do you need to top up open cell batteries" is basically "how long is a piece of string". Or in another words, it all depends ...

It depends on the battery type and it depends on the usage / charging cycle

If the batteries are regularly recharged gently from a moderate state of discharge, very little water will be lost from the electrolyte and it could be years before they need topping up. If, however, they're deep cycled and recharged by a suitably high output charger the water levels can drop dramatically quickly

From scratch, I advice my customers to check the electrolyte levels once a month initially and if they go through a season without topping up then if they wish they can reduce the frequency of checks (although checking once a month is hardly onerous) unless they change the normal usage pattern (say a one off deep discharge) in which case I suggest checking the batteries once recharged to be on the safe side
 
geem said:
Vyv, when you see less voltage on charge, does this mean the plates are starting to uncover?
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Yes, that's been my observation. Depends on circumstances of course but being on board constantly for six months it becomes easier to recognise subtle changes.

Bru - The advice with my Sterling alternator regulator is that topping up frequency is likely to increase after fitting one. I am talking about living aboard in Greece, fridge running constantly, anchoring for several nights at a time with solar panel charging, then running the engine when departing the anchorage. In a six month season it is not unusual to top up 3-4 litres of de-ionised water.
 
My fridge is on 24/7, some lights (now LED) pumped water, some phone/tablet charging and an Eberspacher. Last Summer the 120w solar almost kept up, apart from the laptop which i used on the marina shore power. Every 2 or 3 days a top up with the Sterling mains charger, same as you, but from shore power.

Through the Winter i had the Eber on 24/7 for a lot of the time and with the lack of Sun i just left the mains charger on all of the time.

I have now replaced the 60w aft panel with a pair of 100w back contact panels and no longer need to use the mains charger. The laptop and a 24" LED TV are still on mains, but i am in the process of fitting DC-DC convertors to run them from 12v too. I think the solar panels will cope. My 3 x 110ah domestic batteries are usually fully charged by mid morning, at the latest and don't drop below 12.2v overnight.

Have checked batteries at random times and in the past year i have not needed to add any water at all.
 
vyv_cox said:
Bru - The advice with my Sterling alternator regulator is that topping up frequency is likely to increase after fitting one. .
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Yup. The Sterling maintains a higher charging rate for longer (compared to the older standard alternator regulators) so there's an inevitable increase in gassing

The amount of water given the usage pattern doesn't greatly surprise me, I used to go through about the same in a year on Erbas with a smaller battery bank and somewhat lighter (UK part time liveaboard) use. Pagan has flash gel batteries (fitted by the previous owner, my piggy bank doesn't run to things like that!) so it's currently a non-issue
 
We have a similar usage pattern to Vyv. We have been onboard for six months at anchor. We have used no water but we are only dropping batteries over night to 25.4v on 24v system so equivelent to 12.7v on a 12v system.
 
PaulRainbow said:
Seems a lot of water Vyv. Why do you suppose you use so much ? Greek temps, the Sterling charger or what ?
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Combination of everything I guess. On the Sadler 34 the batteries are surrounded on five sides by insulation and bed cushion on the sixth, so they do tend to get warm. I added a small fan to help but that may not do a lot with ambient temperatures in the saloon of 35 - 40 C. Even in northern Europe we topped up occasionally but nowhere near as much as we do now.

My Sterling is not a mains charger but an alternator controller.

My motorhome, with engine charging and 100 watts of solar, two domestic batteries well ventilated in the lower part of the van use a couple of litres in a year.
 
All this talk of water uses has got me thinking , we have sealed lead battery's 4x110AH , there getting on to four years old now nothing special just normal HD batterys , I not into spending hundreds of pound on a battery.
Charging mainly by solar panels or Generator ,
like vyv and Geem we spend most of out time on anchor at less nine months a year ,
Just now wondering what the water situation may be inside my bank .
 
sailaboutvic said:
All this talk of water uses has got me thinking , we have sealed lead battery's 4x110AH , there getting on to four years old now nothing special just normal HD batterys , I not into spending hundreds of pound on a battery.
Charging mainly by solar panels or Generator ,
like vyv and Geem we spend most of out time on anchor at less nine months a year ,
Just now wondering what the water situation may be inside my bank .
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Some "sealed" batteries have tops under the labels.
 
vyv_cox said:
Combination of everything I guess. On the Sadler 34 the batteries are surrounded on five sides by insulation and bed cushion on the sixth, so they do tend to get warm. I added a small fan to help but that may not do a lot with ambient temperatures in the saloon of 35 - 40 C. Even in northern Europe we topped up occasionally but nowhere near as much as we do now.

My Sterling is not a mains charger but an alternator controller.

My motorhome, with engine charging and 100 watts of solar, two domestic batteries well ventilated in the lower part of the van use a couple of litres in a year.
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Interesting, the difference between the amounts of water some of us are using. At the moment, my batteries are at about 20 C and charging is via solar, i only have a standard alternator, so that all adds up, as you say.
 
PaulRainbow said:
Some "sealed" batteries have tops under the labels.
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Indeed, mine are the same, although "sealed" I do take the tops off once a year and inevitably I put in about half a litre per battery. They are 110 amp hr leisure Numax cheapos, nearly eight years old. Fed by a std Valeo alternator with a Sterling booster and 150 watts of solar. Plus a Sterling smart mains charger for when on shore power.
Stu
 
So from what people are saying, does bank size have anything to do with water loss? Our battery bank is probably equivelent to about 900 amp/hr at 12v. We are hardly dropping them over night. Last night I left the inverter on to charge some equipment up. Its been on for 24 hours. Battery bank this morning is at 25.3v with the inverter on. Its 0630 in the morning. Battery temperature is 30degC. So larger battery bank less water loss for the same amps removed daily? Just a guess!
 
geem said:
How much water do you use and how large is the bank?
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I have a two battery bank. A group 27 starting battery and a group 31 house battery. I have consumed less than 10 ounces of distilled water over the six month sailing season. I have no refridgeration and a manual windlass so my requirements are minimal. These battery watering systems are frequently used by travel trailers (caravans).
 
We have 4 x Trojan T105S, charged by standard alternator (up to 14.4V) and 340W of solar with programmable MPPT controller delivering up to 14.8V. Based in the Med, spend most of our time at anchor. Systems are not power-hungry: all-LED lighting, efficient keel-cooled fridge, batteries back to full charge by mid-day if sunny.

The batteries are checked every two weeks or so and usually take about the same as Vyv's. This is perhaps not surprising as with low consumption they spend much of their time in the 'boost' phase. I'd be more worried if they didn't need topping-up.
 
macd said:
We have 4 x Trojan T105S, charged by standard alternator (up to 14.4V) and 340W of solar with programmable MPPT controller delivering up to 14.8V. Based in the Med, spend most of our time at anchor. Systems are not power-hungry: all-LED lighting, efficient keel-cooled fridge, batteries back to full charge by mid-day if sunny.

The batteries are checked every two weeks or so and usually take about the same as Vyv's. This is perhaps not surprising as with low consumption they spend much of their time in the 'boost' phase. I'd be more worried if they didn't need topping-up.
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We have about twice your battery capacity, more solar capacity plus wind charging. We have only LED lights and an efficient well insulated fridge so I expect our amp hr consumption per day to be similar. The only difference is you will be pulling your batteries down by about twicw the percentage discharge compared to my battery bank as you are about half thr battery bank size. So, does this impact on water consumption? I have found some information on an American webiste that also suggests my batteries are designed for low water comsumption. I dont how they can do that but that is what it says.
 
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