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Inverter/Charger/battery, alternator problem?


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Details are that I have a Beta 43 HP engine with associated alternators for charging starter and deep cycle leisure batteries (4x110 batteries and one starter battery.)

 

The past seven years have always been fraught with battery issues and I now have a situation where the batteries are once again shot and will dry out at the drop of a hat. I have been replacing wet cell batteries every couple of years always with the same problem of dry cells leading to knackered batteries. On one occasion I did see a flicker of "overcharge" on the battery monitoring system but it has not repeated this indication.

 

The invertor is a Victron 2.5 inverter/charger which seems to do the business and at the end of a five hour cruise having settled will indicate around 12.5 volts which overnight will drop to around 12 volts.

 

Where do I start looking for the source of my problems? Inverter, charging system of the inverter, batteries, alternator. The starter battery is still the original from way back and is always unaffected.

 

Bit poor on detail I'm afraid as not being into all these wiggly amp things I am uncertain of what detail is required.

 

Any thoughts?

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A start would be to invest in a battery monitor so you KNOW what's going into and out of the batteries. Also, it will greatly assist to do a power audit.


ETA: 12.5 Volts after cruising, doesn't sound right - how is this being measured?

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1/ how are your domestic batteries charged? Just from the engine alternator, or also from the Victron from shore power or a Travelpower?

 

2/ you mention batteries drying out. Presuming they are unsealed types perhaps you should add some water before they dry out!

 

3/ can you give us an idea of usage eg live aboard or holiday boat?

 

4/ if live aboard, TBH 2 years from bog standard (cheap) leisure batteries is about right. In fact we are not live aboard although do use the boat a lot, but managed to wear out cheapo leisure batteries in 2 years.

 

In order to really know what is going on you need some sort of monitoring. A hand-held Clampmeter at the very least, preferably a proper battery monitor. Electricity is invisible!

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Details are that I have a Beta 43 HP engine with associated alternators for charging starter and deep cycle leisure batteries (4x110 batteries and one starter battery.)

 

The past seven years have always been fraught with battery issues and I now have a situation where the batteries are once again shot and will dry out at the drop of a hat. I have been replacing wet cell batteries every couple of years always with the same problem of dry cells leading to knackered batteries. On one occasion I did see a flicker of "overcharge" on the battery monitoring system but it has not repeated this indication.

 

The invertor is a Victron 2.5 inverter/charger which seems to do the business and at the end of a five hour cruise having settled will indicate around 12.5 volts which overnight will drop to around 12 volts.

 

Where do I start looking for the source of my problems? Inverter, charging system of the inverter, batteries, alternator. The starter battery is still the original from way back and is always unaffected.

 

Bit poor on detail I'm afraid as not being into all these wiggly amp things I am uncertain of what detail is required.

 

Any thoughts?

So many variables here. A few more questions to add to the others...

 

  • what voltage is going from the alternator to the batteries when cruising? around 14v is normal. 14.2ish would be idealish.
  • what alternator do you have?
  • what appliances are drawing the power (you mention dropping from 12.5v to 12v overnight, what's running overnight?)
  • Are you simply measuring the voltage on your 'dashboard' dial or are you putting a voltmeter directly onto the batteries?
  • how well do you maintain your batteries? (water top ups)
  • how low do you let the charge go before recharging?

Remember, battery voltage isn't the only factor. Voltage drop will occur depending on the length and thickness of your wires. Also, slightly knackered batteries will often show good charge on a dial but drop rapidly as soon as a load is put on them.

 

As Nick mentioned earlier, typically, chandlery batteries won't last a lot longer than 2 years anyway if you're regularly charging/discharging.

 

Re-reading your post, it seems to indicate that your cells are drying out very quickly when cruising. This isn't normal. Others here are far more expert but dissapearing water from cells is often linked to charging at too high a voltage (15v or more) - see bullet point one.

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A repeat of the How / where / when question about your battery voltage readings.

 

If after a days (5 hours) cruise, the batteries are only showing 12.5v then they are only 80% charged, by morning when they are showing 12v they are down to 42% charge.

 

If 80% is the maximum you ever charge the batteries to I am surprised they have lasted 2 years.

 

Every charge / discharge cycle will 'damage' your batteries - have a look at the manufacturers specification and it will say something like 200 cycles - 'the normally accepted depth of discharge' to maximise usage versus battery life is to never go below 50% state of charge.

 

Batteries are 'disposable' items, and you can kill expensive ones just as easily as cheap ones unless you monitor (and act on) your usage and charge levels.

Edited by Alan de Enfield
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The 12.5V concern isn't so much that this indicates 80% charged for a rested battery drawing no load (it doesn't - unless the batteries ARE rested AND there's been NO loads, which I doubt...and also its dependent on the time they're left), but if this is the reading JUST AFTER cruising, I'd expect some surface charge, to show they had been charging very recently.

 

Voltages are a basic/easy first indication of troubles but the more you look at them, the more meaningless they become (if that makes sense). BUT the trends are a useful indication of what's occurring.

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Thank you so much people's for your very quick and knowledgable responses.

As best I can I will reply to your questions.

 

First I guess I should say that we use the boat throughout the summer as constant cruisers. The remainder of the year is on an as and when basis but quite regularly for three or four days at a time. The remainder of the time the boat is in a marina connected to shore power which is running through the inventor and is supposed to be trickle charging the batteries. Nothing on the boat is left on when we are not on board on a regular basis.

 

In answer to the following:

 

Paul C

I do have a Smartguage monitor which gives both battery voltage and percentage charge.

 

nicknorman

1.During running the batteries as you would expect are being charged from the alternator which in my case I believe to be 45 amp for the domestic and 110 for the leisure batteries. This is the factory set as delivered but I am at home right now and can't check the exact details but I believe this to be correct.

 

2. A good point, well made but as a result of previous problems the batteries have been over checked for several seasons and are when on board topped up every two or three days and certainly no greater than 7 days when on the boat(problem there).

The batteries are not way out expensive but are not low level range batteries based on my previous experiences. You get what you pay for.

 

Dave P

Charge when running shows around 14.2 on the Smartguage.

 

Only thing running overnight is the mains TV (240 volt) and only for a couple of hours at most and a very small fridge also 240v.

Batteries I feel are well attended and I am very aware of topping up.

I never let the batteries voltage fall below 12 volts even if that means running the engine after a short days cruise and on the Smartguage not below 50%

 

Alan de Enfield

 

On shutdown the batteries will show 14.2volts but once settled will show 12.5volts

 

So that is where I am at right now.

 

Thanks for your help chaps

 

Paul

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1) Check the accuracy of the smartgauge voltage reading - settling to 12.5V after being charged at 14.2V and no loads applied, just sounds wrong, to me.

 

2) Do a power audit

 

3) At the end of a day's cruising, check the current going into the battery bank. This needs an ammeter.

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Open wet cell batteries shouldn't need topping up more than once every few months. If they are consuming a lot of water it is because they are either being over-charged dramatically, or they are getting very very hot from being next to something very hot.

 

The voltages you describe seem reasonable but something is wrong! I wonder if it is the charging voltage when on shore power? The Victron should go to float, maybe around 13.25v, once the batteries are fully charged. If it holds the voltage up at 14.2v permanently that will use a lot of water over time and shorten the battery life substantially.

 

My suggestion is to get a digital voltmeter to manually check the voltages with the engine running and when on shore power. A clamp meter such as the Unit-t UT-203 is handy as it also does DC current up to 400A. About £30.

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As Nick says^^

 

IMO the charge regime cruising is probably OK but the permacharge regime is probably not good, Can you fit some type of timer so that the charger comes on say friday at noon for 12 hours than goes OFF. dry batteries means that something has gassed the water off usually charging for too long at too high a current. Have you checked the charger settingsfor the type of battery?

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