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Multimeter reading of 17v


hackenbush

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One problem is that most of the "experts" here have smart well equipped boats and although they might know a fair bit of theory (in some cases) their advice is based upon their own experience in their own boats. NickNoman has got a Hudson with very very advanced electrics, he's even got coffee machines and electric blankets. I am bit more lo tech but still have 6 Trojan batteries, two alternators, alternator controller, 240v Travelpower, Smartguage and shunt based current display. Its actually quite hard for us to give good advice to someone living on a low tech boat with a single battery and not able to spend £1000+ on batteries and instrumentation. Maybe we should start a new thread on low cost liveaboard electrics ideas????.

 

..............Dave

 

 

This is true at the present time, but don't forget I have had plenty of experiences of more low tech boats - we have only had our Hudson just under 6 years. Before that we used a boat with a Lucas 70A alternator (lister canalstar) with split charge relay, 3 x 110AH leisure batteries, no TV, only incandescent lighting & electric fridge and absolutely zero battery monitoring except a voltmeter on the engine battery. It had wiring running along the ceiling angles with the wall and if you turned on too many lights on the same side the wiring started to overheat! The one before that (1970s) had a lister air cooled, instant gas water heater, minimal batteries and those horrendous "catalytic" gas heating panels that filled the boat with moisture.

 

So I have seen a fair few different ideas in my time!

 

But of course we have never been live aboard for more than 3 weeks, and we cruise nearly every day which is why we can be cavalier with electricity and use the electric kettle off the batteries.

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In case this helps, my boat (which I live on most of the time) has a Lister JP2 with single alternator and two 110a leisure batteries, of unknown age (it's possible that they were replaced in the last year, and the cost was subsumed in some giant bill, but I don't think so). After a day's cruising (10 hours) I went three days without needing to charge, having forgotten to switch off the inverter that I ran to charge my laptop and phone while cruising. Ran engine for three hours and lights/fridge freezer lasted another full day, sans inverter. I am generally either cruising long days or connected to shore power.

 

Edit: I get water from my Dickinson diesel stove or a gas-heater when not on mains, and my cabin lights are all LED.

Edited by pipistrelle
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And probably, no phone charger, no computer charging, no TV, and definitely no fridge, freezer, washing machine, tumble drier, toaster, deep fat fryer, coffee machine or electric blankets.

 

That's how they 'managed' with a single battery

That's right but the OP only talks of LED's and a pump so not much.

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Two LEDS will use not a lot, probably 0.3 amp together, or 0.6 amp if they are really bright ones.

 

If you are only using LEDs and the usual occasional water pump etc then you can get by with not much battery at all. Things that "hurt" are things that are running for a long time, fridges or a Laptop that is always on are the battery eaters.

 

Almost all liveaboards have been through the "keeping the battery charged" trauma. Do you just want more electricity or are you the sort of person who is interested in this stuff and wants to understand it better? This is a serious question as it will (hopefully) influence the advice you are given here.

 

Some old Listers can be notoriously bad at charging batteries so this might need looking at urgently. Lots of hours of engine running to put almost nowt into batteries is a waste of diesel.

 

One problem is that most of the "experts" here have smart well equipped boats and although they might know a fair bit of theory (in some cases) their advice is based upon their own experience in their own boats. NickNoman has got a Hudson with very very advanced electrics, he's even got coffee machines and electric blankets. I am bit more lo tech but still have 6 Trojan batteries, two alternators, alternator controller, 240v Travelpower, Smartguage and shunt based current display. Its actually quite hard for us to give good advice to someone living on a low tech boat with a single battery and not able to spend £1000+ on batteries and instrumentation. Maybe we should start a new thread on low cost liveaboard electrics ideas????.

 

..............Dave

 

I think it must not be forgotten, most of us cut our teeth by being in a job involving the subject. Then bought boats, many years ago, gradually progressed in the type of systems as they became commercially available. So the knowledge is there just a question of some remembering that others do not have what they have or the knowledge and the need to ask for the information needed to answer the question patiently.

Edited by Geo
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I think it must not be forgotten, most of us cut our teeth by being in a job involving the subject. Then bought boats, many years ago, gradually progressed in the type of systems as they became commercially available. So the knowledge is there just a question of some remembering that others do not have what they have or the knowledge and the need to ask for the information needed to answer the question patiently.

 

It's probably still best though to not be dismissive or disparaging of someone else's knowledge and and experience on a topic when you probably really have little idea of how much knowledge and experience they actually have!

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It's probably still best though to not be dismissive or disparaging of someone else's knowledge and and experience on a topic when you probably really have little idea of how much knowledge and experience they actually have!

 

OH I agree 100% everyone is entitled to give of their experience. It is funny how often something someone says triggers a thought which leads to the solution and it matters not who said it. What matters is the problem is solved for the poster.

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I think it must not be forgotten, most of us cut our teeth by being in a job involving the subject. Then bought boats, many years ago, gradually progressed in the type of systems as they became commercially available. So the knowledge is there just a question of some remembering that others do not have what they have or the knowledge and the need to ask for the information needed to answer the question patiently.

And then there is the breadth and depth of experience. Some people have a lot of experience of only doing the same thing over and over again, others have experience of lots of different things

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And then there is the breadth and depth of experience. Some people have a lot of experience of only doing the same thing over and over again, others have experience of lots of different things

 

Agree, and that advice can be crucial as they have done it frequently so they have met most of the problems.

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smile.png That depends on their wattage a quick idea of their ampage is W/V=A so one at 6 watts at 12 volts would be 1/2 Amp. That will be good enough for what you are doing. So ten hours of the two lamps above would be 10Ahs, not a lot in battery term but a starting point

OK, I'll see what the amp damage is tomorrow morning and cross-reference with your algorithm!

 

Two LEDS will use not a lot, probably 0.3 amp together, or 0.6 amp if they are really bright ones.

 

If you are only using LEDs and the usual occasional water pump etc then you can get by with not much battery at all. Things that "hurt" are things that are running for a long time, fridges or a Laptop that is always on are the battery eaters.

 

Almost all liveaboards have been through the "keeping the battery charged" trauma. Do you just want more electricity or are you the sort of person who is interested in this stuff and wants to understand it better? This is a serious question as it will (hopefully) influence the advice you are given here.

 

Some old Listers can be notoriously bad at charging batteries so this might need looking at urgently. Lots of hours of engine running to put almost nowt into batteries is a waste of diesel.

 

One problem is that most of the "experts" here have smart well equipped boats and although they might know a fair bit of theory (in some cases) their advice is based upon their own experience in their own boats. NickNoman has got a Hudson with very very advanced electrics, he's even got coffee machines and electric blankets. I am bit more lo tech but still have 6 Trojan batteries, two alternators, alternator controller, 240v Travelpower, Smartguage and shunt based current display. Its actually quite hard for us to give good advice to someone living on a low tech boat with a single battery and not able to spend £1000+ on batteries and instrumentation. Maybe we should start a new thread on low cost liveaboard electrics ideas????.

 

..............Dave

I'm not really after more lecky. I have a simple lighting set-up that covers my needs and I need to charge my phone. That's it. I live a simple life! It's definitely information mostly in the sense of wanting to understand how to keep batteries in good condition, especially as I only have one. I've learnt a lot already. I may upgrade to a two battery set-up just for peace of mind but I really don't need much more power.

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Until they come across something they havn'the seen before

 

We all come across things we have not seen before and have to try and guide the poster to a solution. Frequently basic fault finding is the best route and that means questions and some form of testing and a lot of patience with the poster.

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We all come across things we have not seen before and have to try and guide the poster to a solution. Frequently basic fault finding is the best route and that means questions and some form of testing and a lot of patience with the poster.

And I think some first time question askers think we are getting at them when we probe for more information.

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And I think some first time question askers think we are getting at them when we probe for more information.

 

That is where we have to use all the skill and tact we have to ask a question that does not imply a criticism of the poster. We have no way of knowing anything about the poster and should assume that they are likely to be embarrassed etc about having to ask on a public forum. For some it would be bad enough asking a person for help stood in their own homes. Care, tact are important words I think.

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OK, I'll see what the amp damage is tomorrow morning and cross-reference with your algorithm!

 

I'm not really after more lecky. I have a simple lighting set-up that covers my needs and I need to charge my phone. That's it. I live a simple life! It's definitely information mostly in the sense of wanting to understand how to keep batteries in good condition, especially as I only have one. I've learnt a lot already. I may upgrade to a two battery set-up just for peace of mind but I really don't need much more power.

 

Measuring current during charging is a big step forward. It will confirm that the alternator is working well and will also tell you when the batteries are fully charged. With a bit of skill and experience you can also spot when they are on the way out (they appear to charge faster).

Measuring volts is also important to tell you that the alternator is putting out enough voltage so as to charge the batteries as fast as you dare whilst burning that diesel. With a fair bit of skill and interpretation you can also monitor the discharge by measuring voltage.

As a first shot your voltmeter will help. Maybe you can find someone to lend you a clamp on current meter (ammeter) for a few days.

 

Having something permanently installed to do volts and amps really makes it all a whole lot easier. The little Nasa BM1 would be a good choice for you but it will cost just over £100. There are usually some much cheaper Chinese alternatives on eBay. Some people are concerned about a possible fire risk from this cheap stuff, its probably not really likely, but if you are worried you could mount it away from flammable surfaces. The only drawback with these devices is that you have to resist taking the amp-hour stuff too literally (loads of info on this forum).

 

This looks like it might do (but do check the details)...............

http://www.ebay.co.uk/itm/Programmable-90V-100A-Combo-Meter-Volt-Amp-Power-Ah-Hour-Battery-Capacity-Tester-/181821824407?hash=item2a556cdd97:g:VYkAAOSwgQ9V4xwJ

 

These are shunt based devices so you will need to fit them into your thick battery cable which will involve a little effort and expense.

 

The Smartgage is a lovely instrument, it gives an instant and believable readout of state of charge (but no charging amps) but is well over £100 so probably not suited to your low tech life.

 

................Dave

  • Greenie 1
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Measuring current during charging is a big step forward. It will confirm that the alternator is working well and will also tell you when the batteries are fully charged. With a bit of skill and experience you can also spot when they are on the way out (they appear to charge faster).

Measuring volts is also important to tell you that the alternator is putting out enough voltage so as to charge the batteries as fast as you dare whilst burning that diesel. With a fair bit of skill and interpretation you can also monitor the discharge by measuring voltage.

As a first shot your voltmeter will help. Maybe you can find someone to lend you a clamp on current meter (ammeter) for a few days.

 

Having something permanently installed to do volts and amps really makes it all a whole lot easier. The little Nasa BM1 would be a good choice for you but it will cost just over £100. There are usually some much cheaper Chinese alternatives on eBay. Some people are concerned about a possible fire risk from this cheap stuff, its probably not really likely, but if you are worried you could mount it away from flammable surfaces. The only drawback with these devices is that you have to resist taking the amp-hour stuff too literally (loads of info on this forum).

 

This looks like it might do (but do check the details)...............

http://www.ebay.co.uk/itm/Programmable-90V-100A-Combo-Meter-Volt-Amp-Power-Ah-Hour-Battery-Capacity-Tester-/181821824407?hash=item2a556cdd97:g:VYkAAOSwgQ9V4xwJ

 

These are shunt based devices so you will need to fit them into your thick battery cable which will involve a little effort and expense.

 

The Smartgage is a lovely instrument, it gives an instant and believable readout of state of charge (but no charging amps) but is well over £100 so probably not suited to your low tech life.

 

................Dave

 

I think in this case charging amps could be one of the most important things.

But first lets see where the OP is. Things have moved forward to a battery with goodish charge in it from virtually nothing. Step at a time.

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Measuring current during charging is a big step forward. It will confirm that the alternator is working well and will also tell you when the batteries are fully charged. With a bit of skill and experience you can also spot when they are on the way out (they appear to charge faster).

Measuring volts is also important to tell you that the alternator is putting out enough voltage so as to charge the batteries as fast as you dare whilst burning that diesel. With a fair bit of skill and interpretation you can also monitor the discharge by measuring voltage.

As a first shot your voltmeter will help. Maybe you can find someone to lend you a clamp on current meter (ammeter) for a few days.

 

 

I think this can lead to confusion because one or more shorting cells will appear to lengthen charging times.

 

When compared with charging and discharging times with a new battery under a similar load :-

 

A faster charge and faster discharge = serviceable but sulphated batteries (loss of capacity).

A slower charge and faster discharge = unserviceable battery with shorting cells.

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We all come across things we have not seen before and have to try and guide the poster to a solution. Frequently basic fault finding is the best route and that means questions and some form of testing and a lot of patience with the poster.

Yup, plenty of experience of this from my time in technical support.

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We all come across things we have not seen before and have to try and guide the poster to a solution. Frequently basic fault finding is the best route and that means questions and some form of testing and a lot of patience with the poster.

 

 

This highlights a shortcoming of this board when providing technical support.

 

A new poster (or poster inexperienced with fault finding) tends to explain their their problem and be met with a series of questions instead of the answers they hoped for. Battery threads especially illustrate this. The shortcoming is our tendency to offer no explanation of why these (so many!) questions need answering.

 

Often the poster rolls up their sleeves and sets about answering but other times, it looks to me as though they take the board as just being obtuse and awkward.

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This highlights a shortcoming of this board when providing technical support.

 

A new poster (or poster inexperienced with fault finding) tends to explain their their problem and be met with a series of questions instead of the answers they hoped for. Battery threads especially illustrate this. The shortcoming is our tendency to offer no explanation of why these (so many!) questions need answering.

 

Often the poster rolls up their sleeves and sets about answering but other times, it looks to me as though they take the board as just being obtuse and awkward.

 

Unfortunately the written word is not the greatest way of conveying a friendly smile as one does in person. Hence we need to exercise care in what we write particularly that first request for information. We can but try harder

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Unfortunately the written word is not the greatest way of conveying a friendly smile as one does in person. Hence we need to exercise care in what we write particularly that first request for information. We can but try harder

 

 

Or... we can offer explanations for the questions we ask!

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