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Felshampo

Toilet water pump problem

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Hi. Another odd toilet question.

Very occasionally the water switch to our macerator toilet doesn't work. You press it and no water goes into the bowl. Maybe three or four times in the past year. But if you press the button a few times it will work. Then this morning again pressing the rocker switch... Nothing. Pressing the other way to flush into the macerator worked fine. I had a look at the switch inside but that was OK. Tried a few times with no effect. Gave up. Tried again this afternoon but nothing. Then put on the generator to charge up the batteries, which are only a month old, and the water pump worked again. The toilet is 12v. Before I had the new batteries the old ones went down below 11v most days and the toilet still worked. Any ideas as to why would be helpful, thanks. 

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2 minutes ago, Felshampo said:

Hi. Another odd toilet question.

Very occasionally the water switch to our macerator toilet doesn't work. You press it and no water goes into the bowl. Maybe three or four times in the past year. But if you press the button a few times it will work. Then this morning again pressing the rocker switch... Nothing. Pressing the other way to flush into the macerator worked fine. I had a look at the switch inside but that was OK. Tried a few times with no effect. Gave up. Tried again this afternoon but nothing. Then put on the generator to charge up the batteries, which are only a month old, and the water pump worked again. The toilet is 12v. Before I had the new batteries the old ones went down below 11v most days and the toilet still worked. Any ideas as to why would be helpful, thanks. 

You can very easily kill new batteries in under a month.

 

If the pump didn't work, but when you charged the battery it did work, it sort of indicates that you have a flat battery.

 

What voltage are you showing at the battery terminals ?

What voltage are you showing at the pump terminals (to allow for volt-drop)

 

Taking a battery down to 11 volts is giving it a death sentence.

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The batteries were showing 94% according to the MasterVolt battery monitor with a voltage of 12.5v.

We never let them down much lower than this and charge them every day either through the engine or generator. I know I need a volt meter to test them properly across the terminals. Since the last lot died I am a bit paranoid about them. 

The water pump works fine as does the boiler, which was the first thing to stop working when the old batteries got flat. All the toilet switch does is open the tap into the toilet, I presume, because when it is on the water pump can be heard working. 

I tried the switch only a minute after putting the generator on so the batteries would still be low? 

Edited by Felshampo
Missed a bit

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Switches do die. Especially ones used on DC. A 12V DC switch can have a lot lower life than a mains one, especially if it was designed for mains, rather than DC, or being used to switch a large current. Multiple presses to get it to work is a clue this may be what's happening. Worth seeing how much a replacement switch is. Is it part of the toilet, or a more general purpose one mounted separately?

 

Jen

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Looked at the switch as that was my first thought and it's OK. But it doesn't turn on the water in the toilet. I wonder how that works. Is it a relay operated valve? Still wonder why switching on the generator cured the problem. 

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10 minutes ago, Felshampo said:

Looked at the switch as that was my first thought and it's OK

You took it apart and inspected the contacts?

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3 hours ago, Alan de Enfield said:

You can very easily kill new batteries in under a month.

 

If the pump didn't work, but when you charged the battery it did work, it sort of indicates that you have a flat battery.

 

What voltage are you showing at the battery terminals ?

What voltage are you showing at the pump terminals (to allow for volt-drop)

 

Taking a battery down to 11 volts is giving it a death sentence.

I think they died and that's why they went down to 11volts. The new ones, which are used more than the old ones, are on 12.5 or more in the morning and that's with the temp higher so making the fridge work harder overnight (it's on the lowest setting before you ask). 

But I am still paranoid about batteries. I don't know if they were knackered when I got them or if they were OK and I killed them. Or if I treated them well but there is something wrong with my charger, generator, alternator or solar panel and one of them killed them. 

They were 7 years old but the boatyard that put in the new ones said they should have lasted 10 years or more. 

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1 minute ago, Felshampo said:

They were 7 years old but the boatyard that put in the new ones said they should have lasted 10 years or more. 

At 7 years you didn't do a bad job of looking after them.

 

If the boatyard told me that I would be very reluctant to have them do anything for me - they obviously don't realise that the battery life will depend on both the usage and the re-charging regime.

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3 hours ago, Felshampo said:

The batteries were showing 94% according to the MasterVolt battery monitor with a voltage of 12.5v.

We never let them down much lower than this and charge them every day either through the engine or generator. I know I need a volt meter to test them properly across the terminals. Since the last lot died I am a bit paranoid about them. 

The water pump works fine as does the boiler, which was the first thing to stop working when the old batteries got flat. All the toilet switch does is open the tap into the toilet, I presume, because when it is on the water pump can be heard working. 

I tried the switch only a minute after putting the generator on so the batteries would still be low? 

 

If that monitor is an Amp hour counter (I think it probably is) then it is telling lies. 12.5 rested volts is approximately 50% charged.

 

As we say so often PLEASE ignore the percentage charged numbers and Amp hours left display. Use rested volts to ell you how well charged the battery is and amps when to stop charging.

 

Only use the percentage charged etc. displays if KNOW you have properly set it up with the correct battery capacity and you resynchronise it regularly.

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8 minutes ago, Alan de Enfield said:

At 7 years you didn't do a bad job of looking after them.

 

If the boatyard told me that I would be very reluctant to have them do anything for me - they obviously don't realise that the battery life will depend on both the usage and the re-charging regime.

I thought that at first. But the electrician at North Kilworth marina said as they were AGM's they should have lasted longer.

I have no idea how they had been treated. The one thing I do know is the mastervolt inverter was only a year old because the previous one had gone wrong. Apparently its almost cheaper to replace than repair them, something to do with the nearest service centre being in Holland? So the previous owner said. Anyway he gave me the receipt and the guarantee. 

So this could have damaged the batteries but like so much I know about the boat it's based on educated guesses. 

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3 minutes ago, Felshampo said:

I thought that at first. But the electrician at North Kilworth marina said as they were AGM's they should have lasted longer.

I have no idea how they had been treated. The one thing I do know is the mastervolt inverter was only a year old because the previous one had gone wrong. Apparently its almost cheaper to replace than repair them, something to do with the nearest service centre being in Holland? So the previous owner said. Anyway he gave me the receipt and the guarantee. 

So this could have damaged the batteries but like so much I know about the boat it's based on educated guesses. 

The electrician rather than saying "should have lasted longer" really means "could have lasted longer if they had been meticulously maintained".

 

  • Greenie 1

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13 minutes ago, Tony Brooks said:

 

If that monitor is an Amp hour counter (I think it probably is) then it is telling lies. 12.5 rested volts is approximately 50% charged.

 

As we say so often PLEASE ignore the percentage charged numbers and Amp hours left display. Use rested volts to ell you how well charged the battery is and amps when to stop charging.

 

Only use the percentage charged etc. displays if KNOW you have properly set it up with the correct battery capacity and you resynchronise it regularly.

Yes I have read that before. 

I have got a chart of volts to % charged. 

OK. This is what I can explain. 

Batteries were charged by the engine for about 7 hours cruising yesterday. 

Monitor showed 100% (I know) 

Voltage was 13.9v

We watched some TV and charged a couple of phones and had a 230v fridge on all the time. 

In the morning the monitor said 94%. 12.5v and 85ah used. 

We have 6 x 160ah AGM batteries. 

 

I have not got a multi meter with me, we are cruising, so can't measure resting volts. (or can I? I presume that is the reading with everything switched off) 

4 minutes ago, Chewbacka said:

The electrician rather than saying "should have lasted longer" really means "could have lasted longer if they had been meticulously maintained".

 

Fair enough

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8 minutes ago, Felshampo said:

I have not got a multi meter with me, we are cruising, so can't measure resting volts. (or can I? I presume that is the reading with everything switched off) 

Fair enough

 

You can use whatever meter that is showing the voltage reading you have obtained to measure resting voltage.

 

After charging, take the load off the batteries and take the reading after at least an hour has passed, or (more conveniently) put a largish (say 20 amps) load on for a minute to dissipate the surface charge, the take the load off and take the resting voltage.

Edited by cuthound
Clarification

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1 minute ago, cuthound said:

 

You can use whatever meter that is showing the voltage reading you have obtained to measure resting voltage.

 

After charging, take the load off the batteries and take the readi g after at least an hour has passed, or (more conveniently) put a largish load on for a minute to dissipate the surface charge, the take the load off and take the resting voltage.

OK. What about in the morning. If I switch everything off. Light fridge invertor etc. Will the mastervolt battery monitor give me a truer reading? 

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17 minutes ago, Felshampo said:

OK. What about in the morning. If I switch everything off. Light fridge invertor etc. Will the mastervolt battery monitor give me a truer reading? 

It will give you an accurate voltage but not the State of charge (%)

 

These monitors are only as good as the information you programme them with.

 

Yes - when you have brand new batteries 'tell' it you have X Ah capacity.

 

Simply using a battery (discharging, waiting a few days before charging, repeat...……..) reduces its capacity so after (say) 6 months the capacity could be 90% of X

After a couple of years it could be 70% of X.

 

Unless you 'tell' the monitor what the 'new' true capacity is it will 'tell you lies'

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8 minutes ago, Alan de Enfield said:

It will give you an accurate voltage but not the State of charge (%)

 

These monitors are only as good as the information you programme them with.

 

Yes - when you have brand new batteries 'tell' it you have X Ah capacity.

 

Simply using a battery (discharging, waiting a few days before charging, repeat...……..) reduces its capacity so after (say) 6 months the capacity could be 90% of X

After a couple of years it could be 70% of X.

 

Unless you 'tell' the monitor what the 'new' true capacity is it will 'tell you lies'

 

And it will need periodically "re-synching", (resetting the % charge monitor to 100% when the battery really is fully charged which also resets the "amp hours used" reading).

 

Providing the battery capacity is accurately programmed (unlikely unless you have an accurate way of measuring it such as Smartgauge or actually discharging the battery at a known rate by a known amount) this keeps the percentage SoC reading accurate, but will need doing say every 3 months.

 

This is why almoat nobody bothers. They just use rested battery voltage instead as it is much less of a faff.

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36 minutes ago, Alan de Enfield said:

It will give you an accurate voltage but not the State of charge (%)

 

These monitors are only as good as the information you programme them with.

 

Yes - when you have brand new batteries 'tell' it you have X Ah capacity.

 

Simply using a battery (discharging, waiting a few days before charging, repeat...……..) reduces its capacity so after (say) 6 months the capacity could be 90% of X

After a couple of years it could be 70% of X.

 

Unless you 'tell' the monitor what the 'new' true capacity is it will 'tell you lies'

So am I right in assuming that at the moment the voltage reading this morning of 12.5 v was under the resting reading because I still had the inverter on, fridge and maybe a couple of lights. 

If so how long do you wait after switching everything off to get a realistic reading? 

 

I have had the generator on for the past four hours and the charger was down to 10amps so I switched it off. I have waited an hour, switched every thing off and waited a few minutes and the reading is 12.8v.

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Much depends upon the inverter's resting current draw. First thing in the morning the fridge is likely to be shut down on the thermostat and the inverter asleep (no mains type loads). If it was just an LED light and a quality inverter (Mastervolt is) then I would suggest the voltage is all but accurate.

 

If you have 2 x 110Ah batteries they will not be as fully charged as possible until the   charging amps drop to between 2.2 and 4.4 amps.

 

Edited to add - getting confused with another topic. Keep charging until the charging current has fallen to between 1% and 2% of the battery capacity. Older batteries will probably not drop to 1%.

Edited by Tony Brooks

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16 minutes ago, Felshampo said:

I have had the generator on for the past four hours and the charger was down to 10amps so I switched it off. I have waited an hour, switched every thing off and waited a few minutes and the reading is 12.8v.

A battery can be considered to be fully charged when the charging voltage is 1% of the battery capacity - however you'd be running your generator for another X hours (12 hours ?) for very little gain.

 

If you can get below 2% then I'd suggest you can consider it charged.

 

You have 220Ah (but we don't know what it actually is now) so lets say if you get the charger down to below 4 amps you are fully charged. 

When the charger is still at 10 amps you possibly have another 6+ hours to go.

 

Hopefully you can now see how easy it is for people to get into 'trouble' with undercharged batteries.

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1 hour ago, Alan de Enfield said:

A battery can be considered to be fully charged when the charging voltage is 1% of the battery capacity - however you'd be running your generator for another X hours (12 hours ?) for very little gain.

 

If you can get below 2% then I'd suggest you can consider it charged.

 

You have 220Ah (but we don't know what it actually is now) so lets say if you get the charger down to below 4 amps you are fully charged. 

When the charger is still at 10 amps you possibly have another 6+ hours to go.

 

Hopefully you can now see how easy it is for people to get into 'trouble' with undercharged batteries.

As I said above I have 6 x 160 ah batteries. That is 960ah. So I assumed (wrongly?) that once the amps were down to 10ish Amps the batteries were fully charged. 

So is it 2% of one battery eg 3.2amps or 2% of all six which is 18.2amps.

I have left the charger on all day a couple of weeks ago to see what would happen and it went into float mode but still showed 4 amps. 

1 hour ago, Tony Brooks said:

Much depends upon the inverter's resting current draw. First thing in the morning the fridge is likely to be shut down on the thermostat and the inverter asleep (no mains type loads). If it was just an LED light and a quality inverter (Mastervolt is) then I would suggest the voltage is all but accurate.

 

If you have 2 x 110Ah batteries they will not be as fully charged as possible until the   charging amps drop to between 2.2 and 4.4 amps.

 

Edited to add - getting confused with another topic. Keep charging until the charging current has fallen to between 1% and 2% of the battery capacity. Older batteries will probably not drop to 1%.

One thing I have noted is that the voltage showing on the battery monitor during absorption charging is 13.9v. Shouldn't it be 14.4v. 

I've also read that AGM batteries have different voltages when fully charged. Eg. 12.8 = 100%   12.6 = 75%  12.3 = 50%

Edited by Felshampo

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2 minutes ago, Felshampo said:

As I said above I have 6 x 160 ah batteries. That is 960ah. So I assumed (wrongly?) that once the amps were down to 10ish Amps the batteries were fully charged. 

They were just getting you crossed with a different boat & battery set up that we were discussing earlier.

 

3 minutes ago, Felshampo said:

So is it 2% of one battery eg 3.2amps or 2% of all six which is 18.2amps.

Of the whole bank, so anywhere between 1% (9.6A) or 2% (19.2A) would be fine. If your batteries are allowing you to charge down to ~10A that's excellent- keep it up.

 

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4 minutes ago, Felshampo said:

... it went into float mode but still showed 4 amps

Sadly irrelevant. It’s the charging current at Absorption voltage that counts (14.4V+). 

 

Take a a look at this:

 

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1 minute ago, WotEver said:

Sadly irrelevant. It’s the charging current at Absorption voltage that counts (14.4V+). 

 

Take a a look at this:

 

Thanks WotEver. I have read this post, several times. And I actually understand some of it now! 

As I said above my mastervolt inverter charger shows 13.9v when in absorption mode since I had the new batteries. With the old batteries it was 14.4v. Any ideas why this is? 

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7 minutes ago, Felshampo said:

my mastervolt inverter charger shows 13.9v when in absorption mode since I had the new batteries. With the old batteries it was 14.4v. Any ideas why this is? 

At a guess, you could have the wrong battery type selected, although 13.9V is too low for absorption with any battery type. Try doing a factory reset and see what happens. Let us know

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