Brand new leisure batteries going flat

[peterboat]

I have 900 watts of flexi solar panels it makes life a lot easier. Winter time my whispergen runs for 3.5 hours a day at up to 72 ah at 12 volts [it is a battery charger and runs the central heating] I also have 1500 ahs of full traction batteries with watering system.

What I am trying to say is plan your electrical generation carefully, buy good batteries once and look after them, and monitor your usage of electric to save destroying those expensive batteries

[Justme]

sorry to be pedantic, but you refer to 175a/h alternator and 0.52kW/h fridge.

 

these units should be independent of time, i.e. 175amp and 0.52kW.

 

it helps to understand the units as a starter, before you try to analyse your power usage and generating capacity.

 

 

The 0.52kWh could be the total daily consumption.

[Drayke]

You can turn your inverter off over night, maybe just as you go to bed then back on in the morning, just make sure you don’t open the fridge whilst the inverter is off. That’s what we did till we forked out for 12v fridge. Just don't stay in bed to long

[Johny London]

Yeh, might start doing that for a bit - having the fridge just makes life that bit more civilised though, especially while it has been so hot. I think the fridge uses about 2 amps an hour so even with the added inverter drain, it's not that bad really. A while back I was using the angle grinder a lot though, so that might have been when the rot set in - was busy putting on good locks before bringing my main stuff aboard.

 

So - what is the outlook for my batteries? Also, if they are down on capacity, will they re charge quicker now? If so might be ok to live with for now, long as they last 24hrs each time. Funny thing is the inverter low battery led has never come on (I think the inverter even shuts down). Got as low as 11.5v today late afternoon but I did a 4 hr engine run - will see if doing that each day can help a bit.

[Guest]

Yeh, might start doing that for a bit - having the fridge just makes life that bit more civilised though, especially while it has been so hot. I think the fridge uses about 2 amps an hour so even with the added inverter drain, it's not that bad really. A while back I was using the angle grinder a lot though, so that might have been when the rot set in - was busy putting on good locks before bringing my main stuff aboard.

 

So - what is the outlook for my batteries? Also, if they are down on capacity, will they re charge quicker now? If so might be ok to live with for now, long as they last 24hrs each time. Funny thing is the inverter low battery led has never come on (I think the inverter even shuts down). Got as low as 11.5v today late afternoon but I did a 4 hr engine run - will see if doing that each day can help a bit.

Yes they will appear to be fully charged much quicker than when they were new, much the same as a bucket will fill quicker with water if someone keeps chucking a couple handfuls of mud in it before you top it up each time. The amount of usable water will diminish day by day.

[boathunter]

You're best to tackle this from both ends. More charging, less using. When it's under control, more using is possible because you'll understand the implications. I can see your usage is 5x mine for instance, I couldn't be bothered with keeping up the charging regime for that kind of usage. It's a balance though, everyone's values are different.

[RLWP]

Using a similar charging regime as yours we managed to kill 5 new 110ah leisure batteries in around 18 months.

 

Amateur - we kill batteries much quicker than that!

 

Richard

Yes they will appear to be fully charged much quicker than when they were new, much the same as a bucket will fill quicker with water if someone keeps chucking a couple handfuls of mud in it before you top it up each time. The amount of usable water will diminish day by day.

 

Good analogy!

 

Richard

[MtB]

Yeh, might start doing that for a bit - having the fridge just makes life that bit more civilised though, especially while it has been so hot. I think the fridge uses about 2 amps an hour

 

 

Sorry to keep on about this but no, your fridge uses 2 Amps while it is running, for however long. Not 2 amps per hour.

 

An amp is a unit of current and therefore independent of time. Please try to grasp this concept or you will remain mired in confusion about battery charging.

[rogeriko]

If the fridge is using 2 amps at 240v thats around 500 watts which is what you mentioned previously, that sort of power from a 12v battery is in the order of 40 amps plus at least another 10 or more amps lost in the inverter. Your poor batteries have only 200 useful amps no wonder they are dying/dead. You need real forklift batteries and 2 alternators if you want to live like that.

[valrene9600]

Hi All,

I picked up my newly built boat in May. It has 4 leisure batteries (100amp hour according to the d of c though they are tricky to get at) and I fitted a Victron 3000 inverter/charger. Only ever used the engine for generating. These days, I'm running the engine for three hours a day and by the next morning the batteries are down to like 11.7 volts or less. The only thing on overnite (aside from the inverter) is the fridge which supposedly takes .52kw/h, and the microwave with its digital clock. I have two or three hours of laptop in the evening for tv etc, and an hour or two of music through a 240v amp which is turned off (not standby) when not in use. Microwave some times for 5-10 mins. The batteries didn't used to go this flat, I can't think what I might be doing differently to cause this? When I first had the boat I was cruising a lot more, though I'm not quite sure when this apparent discharge started.

The fan belt squeaks for a minute when I start the engine but reads well over 14v when charging. A while after and they sit nice and high around 13v.

Surely not knackered the batteries already???

Well over 14v when charging....how much over. Sit nice and high around 13volts......13. What. How long after. Edited August 29, 2016 by valrene9600

[MtB]

Well over 14v when charging....how much over. Sit nice and high around 13volts......13. What. How long after.

 

 

Quite. There is a world of difference between 14.2v and say 14.8v. These apparently tiny differences are highly significant and important.

 

Similarly for the 13.<something> value.

[Robbo]

Yes it was a sailaway - with additions - fully working bathroom and wc and all the wiring tails in.

I'm afraid a 240v fridge was all I had available to start with, so yes the inverter is on 24/7 and I know the self consumption of the inverter is over 1/2a. 12v fridge - yet another on my list of stuff to get and things to do. To be honest, If I'd gotten 18 months out of the first set of batteries, well by then everything else would have been in place (hopefully). Was hoping to buy a bit of time and I certainly can't do without a fridge on board

Again, without a microwave my food choices are limited to what I can boil up

If it's a decent fridge I wouldn't bother with a 12v one, if it's a poor fridge question yourself if yourself if you can be bothered to turn it off when not needed. There's not that much difference between a decent 240v fridge and bog standard 12v fridge.

 

Me personally also wouldn't bother with a genny unless it's built in and deisel. As you already have a decent alternator and inverter I would put the money into a battery monitor and solar.

 

Also try and charge your batteries around the time your using the microwave.

Edited August 30, 2016 by Robbo

[Dinz]

I like MTBs analogy

'Charging a battery is like filling a lock. The closer to full it gets, the slower it fills.'

If you have lost capacity it's a bit like a smaller lock.

Will still require the length of time to get the final bit in.

 

If you are doing power tool work then a genny may be of more use.

When linked thru the Victron [assuming Multi or Quattro]

Then at least you can charge up with some form of indication.

Even the LED'S [bulk, absorb, float]will at least give some idea of where you are.

Also the genny will run your tools.

Then some form of monitoring?

[Justme]

If the fridge is using 2 amps at 240v thats around 500 watts which is what you mentioned previously, that sort of power from a 12v battery is in the order of 40 amps plus at least another 10 or more amps lost in the inverter. Your poor batteries have only 200 useful amps no wonder they are dying/dead. You need real forklift batteries and 2 alternators if you want to live like that.

 

 

Mains fridges dont use that much.

 

I think our larger one has a draw of about 120watts IE 0.5 amps on mains or 10 amps on 12v.

 

Its total daily usage is 0.4kWh.

 

It therefore has a duty cycle of about 1/7th.

[WotEver]

While we're talking about voltages it's worth pointing out that 11.x volts is effectively completely flat. Considering that you should try to keep the voltage above 12.2V as an absolute minimum then not only have these batteries been undercharged they've also been hammered.

[Alan de Enfield]

While we're talking about voltages it's worth pointing out that 11.x volts is effectively completely flat. Considering that you should try to keep the voltage above 12.2V as an absolute minimum then not only have these batteries been undercharged they've also been hammered.

 

And they are now probably in a long term coma with the prognosis of waking up - "unlikely"

 

11v is a battery killing voltage.

[WotEver]

 

And they are now probably in a long term coma with the prognosis of waking up - "unlikely"

 

11v is a battery killing voltage.

I recall some tests that Gibbo did where with one make of supposedly leisure batteries a single discharge to 10V or thereabouts killed them completely. A single (abusive) use and they were dead!

 

Tony

[MtB]

I recall some tests that Gibbo did where with one make of supposedly leisure batteries a single discharge to 10V or thereabouts killed them completely. A single (abusive) use and they were dead!

 

Tony

 

 

Swerving slightly off topic, are there any brand of leisure battery that doesn't do this?

 

Or rather, which brand of ordinary leisure battery stands up best to being occasionally discharged to below 12.0v?

[WotEver]

Swerving slightly off topic, are there any brand of leisure battery that doesn't do this?

 

Or rather, which brand of ordinary leisure battery stands up best to being occasionally discharged to below 12.0v?

Yes. In the same test he was unable to break a Rolls battery. He repeatedly took it down to 0V and it just refused to die.

 

I suspect that Trojan would perform similarly to the Rolls.

[MtB]

Yes. In the same test he was unable to break a Rolls battery. He repeatedly took it down to 0V and it just refused to die.

 

I suspect that Trojan would perform similarly to the Rolls.

 

But Rolls and Trojans are expensive 'semi-traction' batteries aren't they?

 

By ordinary leisure battery I meant the run-of-the-mill type of leisure battery places like Midland Chandeliers sells for about £80.

[Tony Brooks]

 

 

Swerving slightly off topic, are there any brand of leisure battery that doesn't do this?

 

Or rather, which brand of ordinary leisure battery stands up best to being occasionally discharged to below 12.0v?

 

Because my ignition switch is a bit worn so the key can be pulled out when its in the stop position, the yard seem to run the boat's radio while blacking and do not turn the master switches off after use (despite finding them off when they get to the boat) my Exide wet open cell batteries (maybe £20 more expensive that cheapies) plus a start battery with a German sounding name were all flattened to a very few volts in the spring for up to a week. A jump start and several hours charging seems to have brought them back to life for this season although the domestics might have lost a bit of capacity. The domestic batteries were four years old in June.

 

There is a 65 watt solar panel charging the domestic bank but no mains charging. I am a bit carefully about only topping when the tail current is down to about 2 to 3% of battery capacity though - the solar will do the rest when we leave the boat. I note that the tail current seems to be higher than it once was but the batteries are four years old so I am expecting it - hence the 3%

 

I think I paid £270 for three.

Edited August 30, 2016 by Tony Brooks

[Paul C]

 

 

 

There is a 65 watt solar anal charging the domestic bank

 

Great to see you've gotten that much power out of it!

[Tony Brooks]

 

Great to see you've gotten that much power out of it!

 

Thanks - sorted in case I get banned. It did say panal but the autocorrect seems to have slipped up, this time with a degree of humour.

 

PS, it might have been a wind turbine.

Edited August 30, 2016 by Tony Brooks

[Richard10002]

But Rolls and Trojans are expensive 'semi-traction' batteries aren't they?

 

By ordinary leisure battery I meant the run-of-the-mill type of leisure battery places like Midland Chandeliers sells for about £80.

T105s are only about twenty quid more these days, although you have to buy in pairs to get 12V.

[WotEver]

T105s are only about twenty quid more these days, although you have to buy in pairs to get 12V.

But they're twice the capacity so that evens out

 

Tayna are selling them at £108 right now.