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I’ve got three leisure batteries which I charge for 45 minutes to and 1hr each day using a 40 amp charger and generator. My power consumption is very low. X10 12 volt led lights, inverter for tv 2 hours per day, charging phone and internet dongle. I’ve not got a fridge. I charge my batteries up until 14.7 volts. I’ve noticed that my boat has gradually getting been getting darker in the evenings. All the connections seem good. Is it time to replace the batteries? I bought a 12 volt light that has an internal battery for a bit of extra light but it’s a horrid bright white light which doesn’t seem natural. Any  recommendations for rechargeable lights that are natural? 

Edited by MrBoater2021
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21 minutes ago, MrBoater2021 said:

I bought a 12 volt light that has an internal battery for a bit of extra light but it’s a horrid bright white light which doesn’t seem natural. Any  recommendations for rechargeable lights that are natural? 

What you should look for is what is described as a warm white LED, rather than a cool white so as to not get that stark dentists surgery vibe. A warm white will be more yellow, rather than the stark blueish light from a cool white LED. Alternatively, look for a lower colour temperature. of around 3000K. Cool white will be 4000K or more.

How are you planning to recharge your rechargeable lights? If they are being recharged off the boat batteries, then you might as well use those batteries to run the lights directly, without a built in battery in the lights.

Edited by Jen-in-Wellies
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7 minutes ago, MrBoater2021 said:

Oooh really. What voltage am I supposed to charge them up to?

If you havnt fully charged them properly they will soon shoot up to a high voltage but the capacity will be so reduced that they run out of juice very quickly hence dim lights very quickly. As consumables you need to bin them and replace them and charge them fully every day. Take them up to about 14.4 with ish 4 amps going in for about an hour before switching off on an average sized battery bank of 3 or 4 batteries. You have been massively under charging them and they will be knackered.

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10 minutes ago, MrBoater2021 said:

Oooh really. What voltage am I supposed to charge them up to?

 

If you must use voltage then after stopping all charging and after few minutes with something like the water pump running, then with no electrical loads about 12.7 to 12.8 volts. That will take many hours, possibly 10 or more via the engine alternator.

 

Ideally, use charging current (Amps). When the charging current has stopped dropping over an hour or so and with a current flow of 1 to 2% of battery capacity at 14.4 volts (ish) you can consider them fully charged.

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1 hour ago, matty40s said:

The sun sets 2 minutes earlier each day at this time of year.😎

 

Is that really the case? I though it was closer to 8 minutes earlier (and rising 8 minutes later) around equinox, i.e. today! 

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If you stop charging as soon as you reach 14.7 Volts then the batteries will only be approx 85% full. If you have 3 x 100Ah batteries, then you need 1 hour to recharge you have used approx 40Ah or 13%. Therefore you are cycling your batteries between say 70% full to 83% full. This is called partial state of charge (PSOC) use and is very damaging to lead acid batteries and results in the capacity dropping so your 300Ah batteries may now only be equal to 100Ah or less.

 

It takes a lot of time to fully charge a battery. Once you first reach 14.7V that is called bulk charge and can be quick, but to get the charge completed you need to hold the 14.7V for 3, 4 or perhaps more hours, this is the absorption stage and the charge current falls from the 40Amp down to 3Amp, the charger throttling back. It takes so long because it follows a law of diminishing returns.

 

On my boat I am typically using only 10 to 15% of the battery capacity per day so similar to yourself, but it takes me 3 to 4 hours charging every day to get back to 100% charged and keep the batteries in good condition.

 

have a look at this thread Battery charging primer

Edited by PeterF
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When the batteries reach 14.4/14.7 is when the majority of the charging starts not finishes.

3-4 hrs charging after reaching 14.4/14.7 may be enough but may not be.😉

 

Edited by Loddon
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Horrible things batteries. Takes a huge amount of energy going in to store up a bit coming out. (I know that is not scientific but its how it seems) Its one of the reasons that some solar is a Really Good Thing. Solar will keep putting something in for as long as there is some daylight. Batteries are full of witchcraft. The witches inside can be forced to do 8 hours work in 4 hours but they don't do it very well and after a few months they are knackered and won't do any work at all and then you need a new battery and new witches.

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If you still feel that rechargeable lights will be of some help after you've sorted out the underlying issue of battery charging, I would recommend these: 

 

https://www.amazon.co.uk/dp/B07V5VCSZN/ref=sspa_dk_detail_4?psc=1&pd_rd_i=B07V5VCSZN&pd_rd_w=OBDOg&pf_rd_p=828203ef-618e-4303-a028-460d6b615038&pd_rd_wg=yzGtj&pf_rd_r=XGHD4QFQJ0C8GRTEAR2W&pd_rd_r=4a8683c2-79e5-40ac-b69d-b08db4921cf8&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzUFQyUDFBSE5MQVo5JmVuY3J5cHRlZElkPUEwNjUxNTY0MjE0STdPSTBPNjgxWiZlbmNyeXB0ZWRBZElkPUEwNDQyNDkxM0g0RDc1MEg4RFQ4VSZ3aWRnZXROYW1lPXNwX2RldGFpbCZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

 

They have a really good battery life and will stay on all evening if you want/need, they are dimmable if you want less light, there are three colour options (only one is really useable to be fair), and they use an opaque cover so there is no harsh glare from the light itself. You can even take off the glass cover to reduce the 'shine' of them further. 

I bought half a dozen of them and hung them from the ceiling in two rows of three, in an effort to provide softer and dimmer light in my lounge lighting during the evenings (and backup lighting if the electrics ever fail), and I'm very pleased with them I must say. 

 

But these things are subject to our very personal tastes, and you might not like the particular light colour of any given lamp (or it might not suit your interior), so my strong advice would be to buy one, and if you like it, then get a couple more as needed. 

 

 

Edited by Tony1
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11 hours ago, MrBoater2021 said:

I’ve got three leisure batteries which I charge for 45 minutes to and 1hr each day using a 40 amp charger and generator. My power consumption is very low. X10 12 volt led lights, inverter for tv 2 hours per day, charging phone and internet dongle. I’ve not got a fridge. I charge my batteries up until 14.7 volts. I’ve noticed that my boat has gradually getting been getting darker in the evenings. All the connections seem good. Is it time to replace the batteries? I bought a 12 volt light that has an internal battery for a bit of extra light but it’s a horrid bright white light which doesn’t seem natural. Any  recommendations for rechargeable lights that are natural? 

Please read.  It's the best info on battery charging I've seen.

 

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Its worth bearing in mind that lots and lots of boaters kill a set of batteries before they start to pick up the info about how to manage them. 

 

I'm sure I contributed to the demise of my lead acid batteries last year, and just last week I had a knock on the boat from a lovely woman moored a few boats down, who said her 240v electrics had started to fail, and asking if I knew anything about electrics. 

 

The people moored around were all hire boaters, and not massively well-informed, so whilst admitting to her that I knew almost nothing useful about diagnosing electrical problems, I offered to do what little I could until professional help could be sought. 

 

My first question was whether she was sure it was only the 240v that was affected, and she recalled that the 12v had also had some issues, and in fact she'd needed a jump start a few days earlier. So I went over with my multimeter (which lends me an air of expertise that is comically undeserved). 

My next question was about her battery voltage. She looked a bit puzzled but opened a phone app (Victron of course), and I could see her domestic batteries were at 12.17 volts. 

 

She asked what that meant, and I said that it seemed like her batteries were a bit less than half full, and that if they fell much lower (and if this was happening regularly), they would be damaged. She had only bought the batteries six months ago, so this was rotten news to hear.

 

I was shocked that someone could have been living aboard for 6 months or so and not be aware of the importance of battery voltage, and how to check it.

But then I remembered it took me a few days to even start to get to grips with it, and I'd been keen on a bit of researching, and had even read threads about it here beforehand.

But somehow, when I was finally aboard, this info had been lost in the welter of info and tasks that I was dealing with- at least for a while.  

I think there is so much new info to take on board when you first move into a boat that the electrics dont always figure in your thoughts as prominently as they really should.

 

Anyway, apart from the unlikely eventuality of finding a boater who knew less about electrics then myself, it was a sad realisation that many boaters (myself included) have to learn this expensive lesson about how important it is to know at least something about battery charging. 

 

 

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17 hours ago, mrsmelly said:

If you havnt fully charged them properly they will soon shoot up to a high voltage but the capacity will be so reduced that they run out of juice very quickly hence dim lights very quickly. As consumables you need to bin them and replace them and charge them fully every day. Take them up to about 14.4 with ish 4 amps going in for about an hour before switching off on an average sized battery bank of 3 or 4 batteries. You have been massively under charging them and they will be knackered.

I’m just going to connect them up to the generator and maybe the inverter later on to top them up. 

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13 minutes ago, MrBoater2021 said:

I’m just going to connect them up to the generator and maybe the inverter later on to top them up. 

 

If you are talking about using the battery charger output on the generator, my advice is, don't bother. They normally have a derisory output, so use the generator to power a battery charger or inverter-charger and get a far higher charge rate.

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7 hours ago, Tony1 said:

Its worth bearing in mind that lots and lots of boaters kill a set of batteries before they start to pick up the info about how to manage them. 

 

I'm sure I contributed to the demise of my lead acid batteries last year, and just last week I had a knock on the boat from a lovely woman moored a few boats down, who said her 240v electrics had started to fail, and asking if I knew anything about electrics. 

 

The people moored around were all hire boaters, and not massively well-informed, so whilst admitting to her that I knew almost nothing useful about diagnosing electrical problems, I offered to do what little I could until professional help could be sought. 

 

My first question was whether she was sure it was only the 240v that was affected, and she recalled that the 12v had also had some issues, and in fact she'd needed a jump start a few days earlier. So I went over with my multimeter (which lends me an air of expertise that is comically undeserved). 

My next question was about her battery voltage. She looked a bit puzzled but opened a phone app (Victron of course), and I could see her domestic batteries were at 12.17 volts. 

 

She asked what that meant, and I said that it seemed like her batteries were a bit less than half full, and that if they fell much lower (and if this was happening regularly), they would be damaged. She had only bought the batteries six months ago, so this was rotten news to hear.

 

I was shocked that someone could have been living aboard for 6 months or so and not be aware of the importance of battery voltage, and how to check it.

But then I remembered it took me a few days to even start to get to grips with it, and I'd been keen on a bit of researching, and had even read threads about it here beforehand.

But somehow, when I was finally aboard, this info had been lost in the welter of info and tasks that I was dealing with- at least for a while.  

I think there is so much new info to take on board when you first move into a boat that the electrics dont always figure in your thoughts as prominently as they really should.

 

Anyway, apart from the unlikely eventuality of finding a boater who knew less about electrics then myself, it was a sad realisation that many boaters (myself included) have to learn this expensive lesson about how important it is to know at least something about battery charging. 

 

 

I'm not an expert at all but on a number of threads 12.7v is shown as what you might expect for fully charged batteries at rest. Am I missing something?

I just noticed it was 12.17v not 12.7v. 

Edited by Ianws
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23 hours ago, PeterF said:

If you stop charging as soon as you reach 14.7 Volts then the batteries will only be approx 85% full. If you have 3 x 100Ah batteries, then you need 1 hour to recharge you have used approx 40Ah or 13%. Therefore you are cycling your batteries between say 70% full to 83% full. This is called partial state of charge (PSOC) use and is very damaging to lead acid batteries and results in the capacity dropping so your 300Ah batteries may now only be equal to 100Ah or less.

 

It takes a lot of time to fully charge a battery. Once you first reach 14.7V that is called bulk charge and can be quick, but to get the charge completed you need to hold the 14.7V for 3, 4 or perhaps more hours, this is the absorption stage and the charge current falls from the 40Amp down to 3Amp, the charger throttling back. It takes so long because it follows a law of diminishing returns.

 

On my boat I am typically using only 10 to 15% of the battery capacity per day so similar to yourself, but it takes me 3 to 4 hours charging every day to get back to 100% charged and keep the batteries in good condition.

 

have a look at this thread Battery charging primer

Is it fair to assume running the engine for 4 hours costs £3 in fuel (let's ignore the additional servicing cost for now)? If you're a liveaboard this means you're spending almost £1100 a year to keep your batteries charged. You could replace them all every 4 months for that.

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21 minutes ago, George and Dragon said:

Is it fair to assume running the engine for 4 hours costs £3 in fuel (let's ignore the additional servicing cost for now)? If you're a liveaboard this means you're spending almost £1100 a year to keep your batteries charged. You could replace them all every 4 months for that.

 

Well yes, but you wouldn't have working lights or water except for the first two days on a new set of batteries.

 

If you recharge them until they die you have working services every day.

 

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2 minutes ago, George and Dragon said:

Is it fair to assume running the engine for 4 hours costs £3 in fuel (let's ignore the additional servicing cost for now)? If you're a liveaboard this means you're spending almost £1100 a year to keep your batteries charged. You could replace them all every 4 months for that.

 

I think there are a lot of boaters who dont do the math on this issue, and I regularly moor near to boats that seem to have engines running for 3 or 4 hours each day.

My engine needs a service every 200 hours. My very first one was was mid-Sept last year, and for that I paid a boatyard £150. 

The next service was due by mid Nov. That was when it hit me that on that basis, I would've been doing 5 or 6 services a year, and putting many hundreds of hours on the engine. 

 

So I went for more solar, and lithium batteries (which dont need a very long charge every week or so).

Solar panels aren't aesthetically great, but from early to mid-March right through to late October, I can expect my panels to keep my batteries fully charged on 90% of the days, unless I moor in one of those 'green tunnels' that are heavily overlooked by tall trees (which did actually happen after I came out of the Chirk tunnel a couple of months ago).

As long as only one bank is overlooked, even on an overcast day I'll get enough charge to get up to 75% full. 

My second set of panels, rated at 750 watts, cost me over £600 including the MPPT, mountings, etc, but they will pay for themselves in saved fuel and servicing within a few years at most. 

Panels are a lot cheaper nowadays, and they can save a lot of money- I dont really get why lots more liveaboards don't go for 1000+ watt solar arrays.

 

The other thing I've been trying to address is a way to increase my measly 40-45 amp alternator charging capacity. At the moment, from Nov- Feb, with little solar, I currently need to run the engine for maybe 2-3 hours each day. 

I'm hopeful that in the next week or so I'll have an upgraded alternator and some tweaks that will bump up my total charge to around 100 amps, and that means much less diesel used in the winter. 

 

I cottoned on to this very heavy diesel usage and high engine hours as soon as my second service within 8 weeks became due, but to be fair my objectives are probably not typical. I want self-sufficiency ,and to not worry about switching the fridge off overnight because my lead acid batteries were down to 12.3 volts by 9pm, which they typically used to be.

 

 

 

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You could charge them poorly for 1 to 1.5 hours a day for £350 a year and buy a set of batteries every 4 months for £750 giving £1100 total and less noise and engine servicing.

 

Edited by PeterF
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30 minutes ago, Tony1 said:

The other thing I've been trying to address is a way to increase my measly 40-45 amp alternator charging capacity. At the moment, from Nov- Feb, with little solar, I currently need to run the engine for maybe 2-3 hours each day. 

I'm hopeful that in the next week or so I'll have an upgraded alternator and some tweaks that will bump up my total charge to around 100 amps, and that means much less diesel used in the winter. 

As has been said many times before on the forum, once you are past the initial bulk charge stage, the charging current is determined by what the batteries will accept, not what the alternator can put out. So having a larger capacity alternator will make very little difference to the overall charging time.

 

In your situation, in winter you would be better off getting your engine charging of the battery done early in the day to provide the bulk charge, then let the solar produce its winter output for the next few hours to do the final low current charging.

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17 minutes ago, David Mack said:

As has been said many times before on the forum, once you are past the initial bulk charge stage, the charging current is determined by what the batteries will accept, not what the alternator can put out. So having a larger capacity alternator will make very little difference to the overall charging time.

 

Surely avoiding this effect was the whole point of Tony1 installing his lithium battery bank.

 

 

 

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20 minutes ago, David Mack said:

As has been said many times before on the forum, once you are past the initial bulk charge stage, the charging current is determined by what the batteries will accept, not what the alternator can put out. So having a larger capacity alternator will make very little difference to the overall charging time.

 

In your situation, in winter you would be better off getting your engine charging of the battery done early in the day to provide the bulk charge, then let the solar produce its winter output for the next few hours to do the final low current charging.

 

I suspect it might be a different approach with lithiums, because I'm finding they will accept almost any level of current (that I can deliver), and this carries on up to about 95% SoC. 

 

I'm finding that in reality, they very rarely get as far as float mode, because most days my automatic 85% SoC cutoff kicks in whilst the bulk charging is still in progress, and that stops the charging from solar and alternator.. 

 

 

 

Edited by Tony1
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