At what stage do you replace house batteries?

[fireball]

Now we're in a marina (only over winter!) I can charge the batteries properly and then let them stand ...
Did that this week - charger on till the weekend - took the boat out on Sat but not at all on Sunday. Charger left off Mon-Wed ... but still a solar panel (30w) attached ...
Looked at the 'voltage' with the inbuilt meter on Wed evening whilst checking lines - 12.2v ... Engine battery was at 12.6v

Went down again last night to ensure we were all ok before the wind picked up again - this time I turned on all the lights - which showed that the stern light had failed again and one cabin light bulb has gone - checking the voltage whilst these were on showed 11.7v (I expected it to be lower - total wattage was iro 150w Nav & deck lights, 100w cabin lights)

The batteries are from 2004 and are on the 'replacement due' list ... but it might just wait another 6-12 months ....

 

[dt4134]

Now we're in a marina (only over winter!) I can charge the batteries properly and then let them stand ...
Did that this week - charger on till the weekend - took the boat out on Sat but not at all on Sunday. Charger left off Mon-Wed ... but still a solar panel (30w) attached ...
Looked at the 'voltage' with the inbuilt meter on Wed evening whilst checking lines - 12.2v ... Engine battery was at 12.6v

Went down again last night to ensure we were all ok before the wind picked up again - this time I turned on all the lights - which showed that the stern light had failed again and one cabin light bulb has gone - checking the voltage whilst these were on showed 11.7v (I expected it to be lower - total wattage was iro 150w Nav & deck lights, 100w cabin lights)

The batteries are from 2004 and are on the 'replacement due' list ... but it might just wait another 6-12 months ....

One thing you could do is try to imagine scenarios where the batteries let you down. i.e. if you had an engine fault and had to sail home through the night would your nav lights go out. If you can't trust the batteries change them but if you think you'll get away withit and have more important things to fix maybe risk putting it off.

I changed mine after I got water in the fuel and had to sail somewhere sheltered to anchor and bleed the fuel system. Once I'd sorted that I found the batteries linked together wouldn't start the engine. After that I changed both engine & domestic batteries and sorted out the battery charging arrangements (the batteries weren't the only issue - in fact the whole set up was a mess when I bought the boat but up until that point I thought I had more important things to fix).

 

[fireball]

The engine battery appears to be fine - it starts the engine without an issue - it's also a year newer ...
The battery compartment is easy enough to get too - and a jump lead will sort out one bank not working (having disconnected the bank first!).
I'm not phased by the batteries going down - after all, it is a sailing boat - Nav lights would be the worst bit - if we happen to be out at night, but that can be rectified with a torch/lantern ...

 

[vyv_cox]

A couple of things that might help:
1. Check acid levels, assuming it's possible. Low levels will give low voltages, usually recovered by adding distilled water
2. I have had some success with a small, cheap de-sulphater gizmos that put a small A/C into the batteries. Mine came from here cost was about £40 IIRC.

My domestic batteries are 2004, still going well so far.

 

[fireball]

Ta, the batteries were topped up with distilled water (at least - that's what the bottle says it is!) a couple of weeks ago - a couple of the cells were low, exposing the tops of the plates.
Am I right in recalling that giving the batteries a good 'blasting' as in rapid discharge through a high power bit of kit would help from time to time - as far as I can make out these are standard 140ah batteries (x2) ...
If so - I could happily connect them up to the engine and crank it a few times ...

 

[tim_ber]

A couple of things that might help:
1. Check acid levels, assuming it's possible. Low levels will give low voltages, usually recovered by adding distilled water
2. I have had some success with a small, cheap de-sulphater gizmos that put a small A/C into the batteries. Mine came from here cost was about £40 IIRC.

My domestic batteries are 2004, still going well so far.

Does it not have to be de-ionised water as opposed to just distilled? Is there a difference? And what is it? I just bought de-ionised water from the local garage is all and wondered what the difference is?

Hygrometer is a useful bit of kit - or is it hydrometer - anyway the one that checks specific gravity of the acid is what you want - Halfords I guess. (Buy two - they break easilly - you know how I know - and that was with it placed in a tupperware box!)

 

[tim_ber]

Ta, the batteries were topped up with distilled water (at least - that's what the bottle says it is!) a couple of weeks ago - a couple of the cells were low, exposing the tops of the plates.
Am I right in recalling that giving the batteries a good 'blasting' as in rapid discharge through a high power bit of kit would help from time to time - as far as I can make out these are standard 140ah batteries (x2) ...
If so - I could happily connect them up to the engine and crank it a few times ...

I always thought a big amp, and rapid CHARGE was what was needed rather than opposed to a big DISCHARGE to knock a bit of the sulphuration off... I think those clever charges do that - pulse charges and all of that stuff.

 

[vyv_cox]

Does it not have to be de-ionised water as opposed to just distilled? Is there a difference? And what is it? I just bought de-ionised water from the local garage is all and wondered what the difference is?

Hygrometer is a useful bit of kit - or is it hydrometer - anyway the one that checks specific gravity of the acid is what you want - Halfords I guess. (Buy two - they break easilly - you know how I know - and that was with it placed in a tupperware box!)

I'm very old, so I wrote distilled because that's how I think of it. Probably quite difficult to buy distilled these days. You're quite right, de-ionised is the correct term.

Hydrometer. Yes, very useful. Mine stowed aboard is more than 20 years old - is this a record? It's in a length of plastic pipe lined with foam.

 

[tim_ber]

Anyone know what ions are in ordinary water?

Are they talking about trace elements of Fluorine and whatever?

 

[fireball]

oo ... you don't want foam on boats - it turns to mush ... or is that you don't want potatoes on boats - they turn to mash ??

 

[guernseyman]

Anyone know what ions are in ordinary water?

Are they talking about trace elements of Fluorine and whatever?

Think of it as minerals dissolved at the water source.

[aluminium, calcium, magnesium, iron][sulphate, carbonate, chloride] etc.

 

[VicS]

Anyone know what ions are in ordinary water?

I suppose so.
I've analysed water supplies often enough.

Main cations are usually calcium and magnesium low concentration in soft water, higher in hard water.

Sodium and a smaller concentration of potassium.

Any others normally just in "trace" amounts

Anions,
sulphate ( calcium and magnesium sulphates are responsible for "permanent" hardness)
bicarbonate ( calcium/magnesium bicarbonates cause "temporary" hardness)
Chloride and hopefully only small amounts of nitrate in potable water.


Look on the label of your bottled water and you'll find an analysis.

Re distilled or deionised ( or demineralised).
The terms simply reflect the method of production of "pure" water.
Distillation needs so much heat that it is an expensive method.
Deionisation ( or demineralisation) is a chemical method using ion exchange resins .. similar to those in water softeners and the Brita cartridges.

 

[KellysEye]

>At what stage do you replace house batteries?

When the batteries won't hold heir charge. Fully charge them, leave them for 24 hours, check the voltage. Any significant drop needs a battery change.

You didn't mertion what type of batteries you have. Using cranking (start) batteries for domestic use is wrong it should be a deep cycle battery.

 

[bobgoode]

Fully chasrge the batteries and allow to rest for a day with no load. Should record 12.8V
Carry out a drop test by turning on a load equal to 5% of battery capacity and see how long before the voltage falls to flat (10.8 V I think). Should be 20 hours.
If significantly less ... replacce..otherwise charge immediately and keep using.

 

[fireball]

>At what stage do you replace house batteries?

When the batteries won't hold heir charge. Fully charge them, leave them for 24 hours, check the voltage. Any significant drop needs a battery change.

You didn't mertion what type of batteries you have. Using cranking (start) batteries for domestic use is wrong it should be a deep cycle battery.

There are 2 x 140Ah batteries - as far as I can gather they are just large batteries ...
I'll have to do another charge test - but I know these are on their way out - it's just a matter of when ...
What would you consider 'significant' in the drop in charge .. over the summer they've been around 12.8v - but that's in summer with the solar panel doing it's job...

 

[Heckler]

I'm very old, so I wrote distilled because that's how I think of it. Probably quite difficult to buy distilled these days. You're quite right, de-ionised is the correct term.

Hydrometer. Yes, very useful. Mine stowed aboard is more than 20 years old - is this a record? It's in a length of plastic pipe lined with foam.

Vyv
You know me, try it and if it works, carry on. I must say Ive used defrost water around the world and in Poof Elly tap water. (V soft water in Gwynedd) Ive never had a prob with doing this and Im 63 just turned. Ive always called it distilled water, when we get to our age (my) I dont think we have to be that fussed about the correct term really!
Stu

 

[Heckler]

There are 2 x 140Ah batteries - as far as I can gather they are just large batteries ...
I'll have to do another charge test - but I know these are on their way out - it's just a matter of when ...
What would you consider 'significant' in the drop in charge .. over the summer they've been around 12.8v - but that's in summer with the solar panel doing it's job...

Ive got a 54 watt panel, 4 110 amp batteries, when I get to the boat after a week away, the batteries read anything between 13.1 to 14.1 volts! Thats the surface charge from the panel. The batteries are fully charged. Your figures are lo, without knowing your panel watts I would still hazard a guess that the batteries are knacked and not allowing the panel to fully charge them.
Stu

 

[Ariadne]

You could take them to a battery specialist and get him to put a heavy load tester on them, or maybe borrow one? I borrowed one (100.00€ deposit) in the summer and was surprised that all but 2 of my house batteries were stuffed, although they were holding charge but it dropped significantly when under load.

I replaced mine with Hawker 12v92F batteries, they are designed for telecom UPS back-up. But I called the suppliers and told him what I intended to use them for and he seemed to think they would be great. Info here http://www.eurobatterietechnik.de/info/pdf/t_data_eng_62.pdf

We got ours second hand, as they remove them after 45 months regardless of whether they have been used or not. We tested them all and I only paid 60.00€ for them, they still have 8 guarantee with them.

 

[Ross D]

On a different note, unless you are sailing throughout the winter, don't replace them until you are actually going to sail in the spring, the cold and the lack of use in the winter won't do them any good, better to let your old batteries take six months of chilly weather. Although I would fit and test them before you sail, I bought a yacht with dead batteries and had to sail it from Portsmouth to Plymouth. I bought a new battery in the boatyard and fitted it, once launched I discovered that while it had 13V showing, when it took any load (like an engine start) the voltage dropped to 0V due to an internal fault. Luckily Force 4 were very good and got an employee in another office to drive a replacement to us and we were away an hour later.

Also fairly obviously do not replace your batteries at the same time, and if they are the same amp hours capacity then put the brand new one for engine starts and the older one as your house battery.

Ross

 

[huldah]

I bought similar batteries 8 years ago, (8 x 6 volt), making them about 10 years old. They do slowly loose water so topping up may be necessary. (Not easy). They are now reaching the end of their life. I improved one set by charging and then discharging through an inverter at 23 amps until the inverter cut out at a load voltage of 10.5 volts. Eventulaly they kept going for over three hours.

I am about to play with the more powerful PIC desulfator to see if I can get improvements. (From Courtiestown Marine) Don't forget battery voltages are temperature dependant.