Battery charging

[soldthehouse]

I will in the coming months be setting up an older engine into the boat and will be starting from scratch installing an electrical system. While I have been hands on for my entire life and can wire three phase machines into a suitable supply and have charged an electric forkilift for years that requires an equalising charge. I dont really understand automotive charging and what the set up should include. Basically I have the knowledge to know how to link up 12v batteries to get 24v and the requirements of providing for voltage drop etc but the problem is that the grey areas are huge and wondered if anyone could advise on the best system for someone who doesnt need to say they have an all sing and dancing system. I will not be needing a multi megawatt system that would run a small village. I would envisage Lighting and a supply for tv/audio, Thanks in anticipation.

 

I realise this area has probably had pages of coverage but most folk are after a small power station from what I can gather whereas We only need the basics.

[Tony Brooks]

I will in the coming months be setting up an older engine into the boat and will be starting from scratch installing an electrical system. While I have been hands on for my entire life and can wire three phase machines into a suitable supply and have charged an electric forkilift for years that requires an equalising charge. I dont really understand automotive charging and what the set up should include. Basically I have the knowledge to know how to link up 12v batteries to get 24v and the requirements of providing for voltage drop etc but the problem is that the grey areas are huge and wondered if anyone could advise on the best system for someone who doesnt need to say they have an all sing and dancing system. I will not be needing a multi megawatt system that would run a small village. I would envisage Lighting and a supply for tv/audio, Thanks in anticipation.

 

I realise this area has probably had pages of coverage but most folk are after a small power station from what I can gather whereas We only need the basics.

 

2 x 12v batteries wired pos on one to neg on the other (series) will give 24v across the remaining two terminals. However you will then require 24v charging. If your engine is only equipped with 12v charging and electrical systems my advice would be to stick with 12v.

 

In my opinion you treat the boat batteries just as you would fork lift batteries except you often have far from optimum charging facilitates, but if you know how and why you do what you do to forklift batteries do as much as you can to the boat batteries. Even with modest electrical loads engine charging will usually be far from optimum for maximum battery life.

 

I suggest you have a look at the Electrical Course Notes on my website - print them out of you want - and if they do not help there are a number of books.

[nb Innisfree]

I will in the coming months be setting up an older engine into the boat and will be starting from scratch installing an electrical system. While I have been hands on for my entire life and can wire three phase machines into a suitable supply and have charged an electric forkilift for years that requires an equalising charge. I dont really understand automotive charging and what the set up should include. Basically I have the knowledge to know how to link up 12v batteries to get 24v and the requirements of providing for voltage drop etc but the problem is that the grey areas are huge and wondered if anyone could advise on the best system for someone who doesnt need to say they have an all sing and dancing system. I will not be needing a multi megawatt system that would run a small village. I would envisage Lighting and a supply for tv/audio, Thanks in anticipation.

 

I realise this area has probably had pages of coverage but most folk are after a small power station from what I can gather whereas We only need the basics.

 

According to Graham Booth in his narrowboat builders book the average nb uses between 125 and 175 ah per day. We are 24v, well equipped, but no microwave and use approx 65ah so his figures seem about right to me. Staying basic but using lighting, a TV and water pumps etc won't reduce that figure a great deal, assuming you won't have a fridge that will knock approx 18ah off which leaves 47ah. So though you say you want a basic system I think you need to do some calculations and arrive at a realistic level of usage and from that design a system that can deliver with a decent margin for error. Off the top of my head I would say you will have difficulty keeping it under 50ah. It's so easy to underestimate what you will use though the most anyone will use is just over 2kW occasionally.

[soldthehouse]

2 x 12v batteries wired pos on one to neg on the other (series) will give 24v across the remaining two terminals. However you will then require 24v charging. If your engine is only equipped with 12v charging and electrical systems my advice would be to stick with 12v.

 

In my opinion you treat the boat batteries just as you would fork lift batteries except you often have far from optimum charging facilitates, but if you know how and why you do what you do to forklift batteries do as much as you can to the boat batteries. Even with modest electrical loads engine charging will usually be far from optimum for maximum battery life.

 

I suggest you have a look at the Electrical Course Notes on my website - print them out of you want - and if they do not help there are a number of books.

Thanks Tony Ive had a look. Ive always said thatI would leave gaining some advanced knowledge on electrics for my retirement, Seems I need to grasp the basics first.I may enrol on one of your courses, do you have a couse aimed at electrical installations. Stuart

 

According to Graham Booth in his narrowboat builders book the average nb uses between 125 and 175 ah per day. We are 24v, well equipped, but no microwave and use approx 65ah so his figures seem about right to me. Staying basic but using lighting, a TV and water pumps etc won't reduce that figure a great deal, assuming you won't have a fridge that will knock approx 18ah off which leaves 47ah. So though you say you want a basic system I think you need to do some calculations and arrive at a realistic level of usage and from that design a system that can deliver with a decent margin for error. Off the top of my head I would say you will have difficulty keeping it under 50ah. It's so easy to underestimate what you will use though the most anyone will use is just over 2kW occasionally.

Thanks for that where would we be without Graham Booths Bible.

[Tony Brooks]

Thanks Tony Ive had a look. Ive always said thatI would leave gaining some advanced knowledge on electrics for my retirement, Seems I need to grasp the basics first.I may enrol on one of your courses, do you have a couse aimed at electrical installations. Stuart

 

Details of the electrical course are under the "Public Maintenance & Electrical Courses" link on the site. Have a look at the typical programme and see if you think it will answer your needs.

 

They are also on the RCR website but theirs is not updated as often as mine, but you do book with RCR, not me.

[John Orentas]

I owned a boat for 30+ years and never once suffered a a flat battery but I never suffered fools either, those who say "Buy one of my Acme controllers and never worry about batteries again"..

 

Mr Lucas and Mr Bosch are not idiots, they manufacture alternators with all the necessary regulators and controllers built into them, and they work very well, when did your car battery ever discharge itself..

 

Don't go adding silly gizmo's into your electrical system and you won't have too much trouble..

[soldthehouse]

I owned a boat for 30+ years and never once suffered a a flat battery but I never suffered fools either, those who say "Buy one of my Acme controllers and never worry about batteries again"..

 

Mr Lucas and Mr Bosch are not idiots, they manufacture alternators with all the necessary regulators and controllers built into them, and they work very well, when did your car battery ever discharge itself..

 

Don't go adding silly gizmo's into your electrical system and you won't have too much trouble..

Thanks John I thought I was missing something.

[journeyperson]

I owned a boat for 30+ years and never once suffered a a flat battery but I never suffered fools either, those who say "Buy one of my Acme controllers and never worry about batteries again"..

 

Mr Lucas and Mr Bosch are not idiots, they manufacture alternators with all the necessary regulators and controllers built into them, and they work very well, when did your car battery ever discharge itself..

 

Don't go adding silly gizmo's into your electrical system and you won't have too much trouble..

 

That's refreshing to read. I sometimes try to follow the battery charging debates/arguments and end up thinking that it is all black magic and wizardry. There are so many different views, all strongly held and they can't all be right. So far as I can tell my boat has an alternator (one of Mr M. Marelli's) and a split charge relay and between them they seem to do the job of providing me with all the electricity I need. If I'm not using the engine I connect a charger between a generator and the batteries for an hour or three to get the electricity I need. I don't know how old the batteries are, I've had the boat a couple of years and they seem to work better now than when I got it. I do look after them and check the electrolyte regularly. If they get to the point where they don't hold a charge long enough I'll replace them.

[soldthehouse]

That's refreshing to read. I sometimes try to follow the battery charging debates/arguments and end up thinking that it is all black magic and wizardry. There are so many different views, all strongly held and they can't all be right. So far as I can tell my boat has an alternator (one of Mr M. Marelli's) and a split charge relay and between them they seem to do the job of providing me with all the electricity I need. If I'm not using the engine I connect a charger between a generator and the batteries for an hour or three to get the electricity I need. I don't know how old the batteries are, I've had the boat a couple of years and they seem to work better now than when I got it. I do look after them and check the electrolyte regularly. If they get to the point where they don't hold a charge long enough I'll replace them.

Hello what does a split charge relay do exactly is it a device for separaring the charge to starter and day batteries.[ PS dont mention the miners strike]

[nb Innisfree]

Hello what does a split charge relay do exactly is it a device for separaring the charge to starter and day batteries.[ PS dont mention the miners strike]

 

It disconnects starter batts from domestics when engine stops so that starter batt doesn't discharge along with the domestics.

[journeyperson]

Hello what does a split charge relay do exactly is it a device for separaring the charge to starter and day batteries.[ PS dont mention the miners strike]

 

Well, I'm not really the person to ask because I know very little about electrics, but there is a little black cube which has wires going into it from somewhere and wires going from it to the batteries. I believe it controls the charge between the starter battery and the leisure batteries - but I might be wrong.

 

It disconnects starter batts from domestics when engine stops so that starter batt doesn't discharge along with the domestics.

 

So I was wrong. That explains why, when my charger is connected across the leisure batteries and not actually charging and I turn on the ignition, the charge level indicator jumps up, because it is then getting juice from the starter battery.

[soldthehouse]

Well, I'm not really the person to ask because I know very little about electrics, but there is a little black cube which has wires going into it from somewhere and wires going from it to the batteries. I believe it controls the charge between the starter battery and the leisure batteries - but I might be wrong.

 

 

 

So I was wrong. That explains why, when my charger is connected across the leisure batteries and not actually charging and I turn on the ignition, the charge level indicator jumps up, because it is then getting juice from the starter battery.

I would have presumed it would have been to do with charging as its in the name. Perhaps it does do something while charging and also disconnects the starter battery when the engine isnt running aswell.

[bottle]

Split charge relay.

 

This is used when only one alternator is fitted.

 

Think of a 'normal' set up with an engine and a start battery then add the split charge relay that is energised (closed) when the engine runs and connects the alternator to both the start and domestic batteries, so charging them both from one alternator.

 

When the engine is stopped the split charge relay is de-energised (open) so disconnecting the start and domestic batteries from each other, this stops the start battery being discharged.

 

A 'split charge relay' is only a normal relay (of correct size).

[soldthehouse]

Split charge relay.

 

This is used when only one alternator is fitted.

 

Think of a 'normal' set up with an engine and a start battery then add the split charge relay that is energised (closed) when the engine runs and connects the alternator to both the start and domestic batteries, so charging them both from one alternator.

 

When the engine is stopped the split charge relay is de-energised (open) so disconnecting the start and domestic batteries from each other, this stops the start battery being discharged.

 

A 'split charge relay' is only a normal relay (of correct size).

In language I understand well done that man. If I opt for rigging up a relay to do this what determines the rating of the relay.

[bottle]

Personally I would fit one that is equal to or of higher rating than the stated size of the alternator.

 

Bigger is better in my opinion.

 

ps. not qualified to tell you this is correct, just what I would do.

[soldthehouse]

Personally I would fit one that is equal to or of higher rating than the stated size of the alternator.

 

Bigger is better in my opinion.

 

ps. not qualified to tell you this is correct, just what I would do.

That will do. Am I right in thinking that the gizmos that people talk about ie state if the art charging aids just overide the premature shutdown of the alternator, I'm working from memory and things keep coming back .

[mchancox]

That will do. Am I right in thinking that the gizmos that people talk about ie state if the art charging aids just overide the premature shutdown of the alternator, I'm working from memory and things keep coming back .

Hi,

I have been reading the replies and agree with most if not all. Stick with 12volt if that is your current alternator output (To go to 24volt would mean more expense). Keep it simple, if you have only one alternator then the Split charging relay is good (it as good as makes your charging of both batteries automatic).

 

There are lots of fancy gizmo's and monitors out there but again keep to a basic system. One thing I would advise is if you are near shorepower (and you have 230v onboard) is to have a mains powered charger (one of reasonable calibre) that will save you running your engine all the while.

 

Final thing to remember is that what you take out of the batteries you have to put it back in. Keep them charged up.

 

Good Luck.

[soldthehouse]

Hi,

I have been reading the replies and agree with most if not all. Stick with 12volt if that is your current alternator output (To go to 24volt would mean more expense). Keep it simple, if you have only one alternator then the Split charging relay is good (it as good as makes your charging of both batteries automatic).

 

There are lots of fancy gizmo's and monitors out there but again keep to a basic system. One thing I would advise is if you are near shorepower (and you have 230v onboard) is to have a mains powered charger (one of reasonable calibre) that will save you running your engine all the while.

 

Final thing to remember is that what you take out of the batteries you have to put it back in. Keep them charged up.

 

Good Luck.

Thanks Mike I dont have an alternator yet so the choice is there. As I want to keep the system as simple as possible without an all singing and dancing power output would 24 volt be better. I realise that eqipment supply might be more limited or could I generate and store 24 volts and step it down to 12volts for final use,

[mchancox]

Thanks Mike I dont have an alternator yet so the choice is there. As I want to keep the system as simple as possible without an all singing and dancing power output would 24 volt be better. I realise that eqipment supply might be more limited or could I generate and store 24 volts and step it down to 12volts for final use,

Have a look at the cost of 24v alternators and the accessories that you want to power form the 24v supply. I am currently working with a customer that wants 6v cells connected in series to give 12 volt but with a higher Ah output.

I would advise you to go for 12v, get a 70A alternator and a split charge relay. Have one engine battery and two 110ah Deep cycle batteries (Going on the appliances that you listed in the earlier post). This keeps the whole thing very simple indeed and readily available.

Important thing to remember is that your installation meets the requirements of the Boat Safety Scheme.

 

Hope this helps you?

[soldthehouse]

Have a look at the cost of 24v alternators and the accessories that you want to power form the 24v supply. I am currently working with a customer that wants 6v cells connected in series to give 12 volt but with a higher Ah output.

I would advise you to go for 12v, get a 70A alternator and a split charge relay. Have one engine battery and two 110ah Deep cycle batteries (Going on the appliances that you listed in the earlier post). This keeps the whole thing very simple indeed and readily available.

Important thing to remember is that your installation meets the requirements of the Boat Safety Scheme.

 

Hope this helps you?

Thanks for that..

[bottle]

If you are only going to have one alternator then stick with 12v, the starter on the engine will be 12v.

 

ps. it can be 24v but that would be on large commercial vehicle engines not those we fit to narrowboats.

 

If you by a new alternator, from what I have picked up on here you do not need any gizmo's to change what the alternator can do by itself.

[Sir Nibble]

Battery charging = can of worms.

Righto, plenty of advice, some contradictory. If I don't add my ha'porth then half the forum will think I am dead!

There is no advantage in 24V that is not balanced by disadvantages, 12V is standard and gives you a better range of available equipment. Vehicle alternators are NOT designed for charging batteries, they are designed to power a vehicles electrical system and hold the battery at around 75%. Regulation is usually at 14.2V, lifting that voltage a little can make a massive difference to charging times and the state of charge the batteries reach. I consider 14.6 to be a good compromise. That is my professional opinion. There is no need to spend a fortune on "gizmos", I suggest you use a lucas A127 alternator, they are cheaply available (check e-bay) very reliable, long lived and lend themselves readily to easy diy modification with a 15p diode to lift the voltage a little.

I've spent 35 years up to my elbows in alternators and frankly, I'm happy not to be doing that any more but it would be churlish to ignore a fellow boater's enquiry when I have specialist knowledge.

[soldthehouse]

If you are only going to have one alternator then stick with 12v, the starter on the engine will be 12v.

 

ps. it can be 24v but that would be on large commercial vehicle engines not those we fit to narrowboats.

 

If you by a new alternator, from what I have picked up on here you do not need any gizmo's to change what the alternator can do by itself.

Just to tip everything on its head I,ve just remembered the starter is 24v, where do we go now.

 

Battery charging = can of worms.

Righto, plenty of advice, some contradictory. If I don't add my ha'porth then half the forum will think I am dead!

There is no advantage in 24V that is not balanced by disadvantages, 12V is standard and gives you a better range of available equipment. Vehicle alternators are NOT designed for charging batteries, they are designed to power a vehicles electrical system and hold the battery at around 75%. Regulation is usually at 14.2V, lifting that voltage a little can make a massive difference to charging times and the state of charge the batteries reach. I consider 14.6 to be a good compromise. That is my professional opinion. There is no need to spend a fortune on "gizmos", I suggest you use a lucas A127 alternator, they are cheaply available (check e-bay) very reliable, long lived and lend themselves readily to easy diy modification with a 15p diode to lift the voltage a little.

I've spent 35 years up to my elbows in alternators and frankly, I'm happy not to be doing that any more but it would be churlish to ignore a fellow boater's enquiry when I have specialist knowledge.

Thanks for that see above please keep advice coming..

[mchancox]

Just to tip everything on its head I,ve just remembered the starter is 24v, where do we go now.

 

 

Thanks for that see above please keep advice coming..

What engine do you have?????

[soldthehouse]

This is the engine.