Boat Electrician & Batteries....

[chris w]

All that is really needed on a boat is a 'push to start' button and another 'push to pre-heat' button if the engine needs this added complication.

But you're missing the point that the buzzer is a warning device that will alert you should your oil pressure, temperature limit or alternator fail whilst the engine is running.

I have an electric fuel pump which one is advised to run for 60 seconds (on ignition only) first thing in the day to purge any air from the fuel system. Having the buzzer running for this amount of time is indeed irritating which is why I fitted the bypass switch.

 

Chris

[Sir Nibble]

The buzzer is an "attention getter" an oil pressure warning lamp could glow for some time without being noticed with expensive results. Try wiring the buzzer from D+ to oil switch, this can be done behind the instrument panel without running extra cables.

[Malabar]

Hi Bones

 

Have a read of this from Charles Sterling

 

http://www.sterling-power.com/support-faq-2.htm

 

Alex

 

 

What a super informative read for anyone trying to get their head around all the questions about battery types, uses, terminology etc. It answered more than a few of my questions and uncertainties very adequately. Many thanks to Alex for the posting.

 

Regards to all

 

Malabar

[bottle]

Malabar

 

If you thought that was good, you should try http://www.smartgauge.co.uk/, click on 'technical info'.

[Gibbo]

Hi Bones

 

Have a read of this from Charles Sterling

 

http://www.sterling-power.com/support-faq-2.htm

 

The biggest problem with that article is that a whole dollop of it is completely wrong.

 

Gibbo

[Smelly]

I hate that system. Every time you switch on the ignition to start the engine, this bl**dy buzzer goes off.

 

I still hate it, especially when it's a lovely peaceful morning and the hire boat next to you disturbs the peace with 10 secinds of buzzig while the plugs heat up.

 

I had my buzzer disconnected for a while, then I developed an oil leak... These days I'd like to know about the oil pressure dropping as soon as possible.

[Guest]

The biggest problem with that article is that a whole dollop of it is completely wrong.

 

Gibbo

Do you mean the charging voltages etc. They are of course justifying the battery boiler?

[Gibbo]

Do you mean the charging voltages etc. They are of course justifying the battery boiler?

 

 

That's just part of it.

 

There are many more.

 

From the article....

 

"100 amp hour Gel = £265.59" ...... odd, the first one I got was £125.00 - so that is half what the article says.

 

"Do they charge 3 – 5 times faster to reduce your engine running hours? (Only in their dreams)"..... well, they're actually upto to 2.5 times the price (not 5 times the price), so the question becomes "do they charge 2.5 times faster?"............. er, the answer is: yes, they do

 

"For cost and performance open lead acid batteries are king"............. That's a mere opinion until it is proven or at least agreements are cited along with references. I note there are none.

 

"“Most expensive is best” This is so not even close to being true. In fact I would say the reverse is true in the marine leisure market.".... Total cr*p. He's telling us the cheapest is best? Read the sentence again, because that is indeed what it says.

 

"They claim weird things including longer shelf life and that you can turn them upside down and have your dinner under them."..... Errrr.... longer shelf life is extremely important (longer shelf life = less internal self drain - it's the same thing) when boats get left for months on end with no charge. The ability to turn them upside down is a silly statement, but the ability to heel them to 45 degrees (which you can't do with a wet cell in one direction) is seriously important in a yacht.

 

"There is no such thing as maintenance-free, all batteries are basically the same. A Gel, sealed lead acid and AGM are all only maintenance-free because of the reduced charging performance curves".......... Complete and utter sh*t. Modern AGM can handle a higher charge voltage than wet cells, don't sulfate up as badly, can handle a higher charge current, and still don't lose electrolyte.

 

"if you want to charge you batteries fast, don't touch a Sealed/Gel/AGM etc with a barge pole.".... Perhaps true 15 years ago. No longer the case.

 

"If the battery is sealed the water loss cannot be replaced"............. Errrr...... some batteries simply do not lose water. Including modern AGM, They recombine the normally lost hydrogen and oxygen into water.

 

I could go on but I see little point.

 

There is a lot of truth in the article. But there is also a lot of b*ll*x.

 

Gibbo

[Night Hawk]

I'm going to have to start replacing my batteries soon - they've been in the boat for a decade and Chas Harden had them all out and on charge in his workshop - he put his meter on them and suggested they didn't have much life left in them after he charged them up and topped them up....Reading thru Gibbo's extensive post I wonder what to replace them with? I'm thinking of something fairly decent (whatever that means) for the engine batteries..and something 'inexpensive' for the rest... What make to choose?

[Guest]

Speaking for myself I am using ex back up batteries to very good effect at the moment which I got for buttons. If these are unavailable at the next change, I will use truck size starter batteries for the domestic bank. Better than "leisure"batteries and cheaper. They guy at the local truck chandlers said he would do me a good discount on five.

[Gibbo]

I'm going to have to start replacing my batteries soon - they've been in the boat for a decade and Chas Harden had them all out and on charge in his workshop - he put his meter on them and suggested they didn't have much life left in them after he charged them up and topped them up....Reading thru Gibbo's extensive post I wonder what to replace them with? I'm thinking of something fairly decent (whatever that means) for the engine batteries..and something 'inexpensive' for the rest... What make to choose?

 

 

I'll now mirror what Charlie says but for different reasons

 

Put cheap semi-crap batteries on. Try to find a battery that (at today's price - it might be different in 3 months time) costs about 50 to 60 quid per 100Ahr. But accept that they are a consumeable. They are not an assett. Think of them as a long lasting tank of diesel. It will run out if you use it more.

 

By all means put dead expensive wet cell deep cycles on, but be prepared to waste lots of your time monitoring them, checking them etc etc etc. If you don't they will die as quickly as a cheap set. Most people have better things to do with their time. If you look after them properly they will cost you 5 times more but last ten times longer. But can you be bothered? Remember most batteries don't die of old age, they are murdered in their prime.

 

Gel cells and AGMs score where time is important. Given the same treatement they will cost twice as much and last 1.5 times longer than wet cells. This is important in fleet vehicles, ambulances etc where time is money. This is your time. It costs nothing, but get a grip on life!

 

It's a personal choice. My own is for cheap sh*t and I replace them every 18 months to 3 years depending upon how hard they've been used. Think of battery replacement cost as one of the running costs of the boat.

 

You can increase the replacement period up to double by spending 3 times as much on batteries. That makes no sense. See the 50% rule on my webpage.

 

 

Gibbo

 

Speaking for myself I am using ex back up batteries to very good effect at the moment which I got for buttons. If these are unavailable at the next change, I will use truck size starter batteries for the domestic bank. Better than "leisure"batteries and cheaper. They guy at the local truck chandlers said he would do me a good discount on five.

 

They're probably one of the best buys around at the momnent. The biggest problem is that they're usually (not always) an odd size that never fits where they need to go. But pound for pound (due to economoy of scale in manufacturing) they're a good buy considering amp.hours per quid.

 

Gibbo

[NB Alnwick]

It's a personal choice. My own is for cheap sh*t and I replace them every 18 months to 3 years depending upon how hard they've been used. Think of battery replacement cost as one of the running costs of the boat.

 

That does seem to make a lot of sense . . .

[nb Innisfree]

Hi Everyone,

 

Turned off our battery charger yesterday morning whilst having some work carried out on the boat.

 

It was switched back on in the afternoon around 3pm, and remained switched on until roughly midnight.

 

So over that time, the batteries should have hopefully received a full charge.

 

However the low charge alarm sounded at 7.30am this morning.

 

We were having similar problems whilst out cruising last summer, but thought it was just a glitch that had seemed to sort itself out since we have been back on our mooring.

 

We really need to get it checked and sorted before we head off again.

 

So, firstly, can anyone recommend an electrician in the Stourport area who is used to working on boat systems and is reasonable on cost?

 

Second question is regards using starter batteries as leisure batteries.

 

 

Are they suitable or not?

 

We have 4 starter batteries, just over 12 months old, fitted on Marmaduke, but I keep getting conflicting feedback on their suitability.

 

Some say that the starter batteries are better to use than the leisure type, others say the opposite and that this is the cause of our problem!

 

Thanks in advance.

Regards,

Pav.

 

A question.

It seems one problem with wet lead acid batteries on narrowboats is inadequate mixing of electrolyte (not enough movement of batteries) resulting in stratification. Modern batts gas very little so this method of mixing is limited. I recently asked an ex submariner what they did and he said they bubbled them by pumping air through. If this could be acheived would it increase battery life usefully?

[Night Hawk]

I notice that some of the more expensive batteries offer a 3 or 5 year guarantee....what will that cover I wonder?

[nb Innisfree]

I notice that some of the more expensive batteries offer a 3 or 5 year guarantee....what will that cover I wonder?

 

Don't think you get anything in writing

[Night Hawk]

Well...if what I've got has lasted a decade, I'll try and replace like for like!

[Keeping Up]

I notice that some of the more expensive batteries offer a 3 or 5 year guarantee....what will that cover I wonder?

It doesn't mean they will last for 3 or 5 years. It usually means that they will guarantee against any manufacturing defects that are discovered within 3 or 5 years - but ordinary degradation or sulphation are not covered.

[chris w]

It doesn't mean they will last for 3 or 5 years. It usually means that they will guarantee against any manufacturing defects that are discovered within 3 or 5 years - but ordinary degradation or sulphation are not covered.

They will normally replace them if the internal resistance increases to 50millohms within the 3 years or whatever time is the guarantee. Don't tell them it's been used on a boat though!!

 

Chris

[nb Innisfree]

They will normally replace them if the internal resistance increases to 50millohms within the 3 years or whatever time is the guarantee. Don't tell them it's been used on a boat though!!

 

Chris

 

How do you measure that?

[chris w]

How do you measure that?

The simple answer is to put a load on the battery and measure the battery volts before and after the load is connected and the load current.

 

The volts drop will be i x R, where i is the load current and R is the battery internal resistance.

 

The more complex answer is that I designed and built an automatic battery internal resistance measuring circuit, which is simply clipped acros the battery and reads out on a voltmeter, with the volts (or actually millivolts) displayed actually meaning internal resistance value. I use it to monitor the health and longevity of my batteries. It alternately switches a known load across the battery at a 50Hz rate and ac couples the result of doing this to some processing circuitry. The ouput is a 50Hz squarewave with an amplitude equal to the volts drop. Some electronic processing converts this to an internal resistance figure. The reason for using 50Hz is so that I can use a normal multimeter set on its AC volts range.

 

Chris

[nb Innisfree]

The simple answer is to put a load on the battery and measure the battery volts before and after the load is connected and the load current.

 

The volts drop will be i x R, where i is the load current and R is the battery internal resistance.

 

The more complex answer is that I designed and built an automatic battery internal resistance measuring circuit, which is simply clipped acros the battery and reads out on a voltmeter, with the volts (or actually millivolts) displayed actually meaning internal resistance value. I use it to monitor the health and longevity of my batteries. It alternately switches a known load across the battery at a 50Hz rate and ac couples the result of doing this to some processing circuitry. The ouput is a 50Hz squarewave with an amplitude equal to the volts drop. Some electronic processing converts this to an internal resistance figure. The reason for using 50Hz is so that I can use a normal multimeter set on its AC volts range.

 

Chris

Thanks, just going to try and get my head round that.

[chris w]

Thanks, just going to try and get my head round that.

Let's take a simple case. Suppose you switch on all the internal lights inside your boat and you measure the current as 20 amps say. You then measure the battery volts before you switch on the lamps (say 12.6v ie: fully charged in this case) and the battery volts after you switch on the lamps. Let's say this is 12.4 volts.

 

So the volts drop is 12.6 - 12.4 = 0.2v and this is equal to the current x the internal resistance

 

So, in this case, 0.2 = 20 x R

 

So R, the internal resistance = 0.2/20 = 0.01 ohms or 10 milliohms which would be a good battery.

 

However, if the volts drop were say close to a volt, your battery is in bad shape.

 

Chris

Edited March 23, 2009 by chris w

[Colin Smith]

Interesting…..It seems to me that there are myriad opinions when it comes to batteries and even more when it comes to charging them! In my (very humble) opinion, it really does depend on individual circumstances and application ie. A live-aboard will have a different requirement to a ‘leisure’ user; the equipment being used; the type of charging (engine, genset, wind, solar etc. etc.). So, what may be ideal for one individual may be wildly different to another.

 

Batteries are a consumable – maybe a long-term one but a consumable never the less and as with any consumable, the cost/lifecycle is the calculation to start with. When I started looking into the whole power issue for my new barge, I had the benefit of being able to design-in a suitable space to take almost any size/quantity of batteries. This isn’t the case for many especially on a narrowboat where space and access is a major limiting factor. So compromise creeps in sometimes although I do believe where there’s a will there’s a way!

 

My barge will be a live-aboard so this meant daily use for most of the year. Leisure type batteries would be a waste of time/money unless I wanted to change them regularly – which I don’t. So I talked to businesses using heavy plant such as access equipment, fork-trucks, road sweepers etc. These things are used daily and charged either every night or every 2 days or so. Without exception, the only things that will take this sort of ‘work’ are deep-cycle, lead-acid battery ‘packs’ usually made up from 2volt or 6volt cells. Yes, they require looking after (watering) and you need to vent them properly to get rid of the gas.

 

I seriously considered 2volt cells to give me a 12volt 500Ah (@20hrs) ‘pack’ but the cost was around £680 and the cells were about 500m high! Cutting a long story short, I’ve opted for 4 x 6volt deep-cycle 283Ah batteries to give me 566Ah (12volts). I know that these batteries are used by some organisations in the US for heavy plant and have personal experience of them through work. The specs are very good and so is the curve – out-performing similar Trojan batteries.

 

The ventilation is not a problem. I’ve commissioned the production of a simple fan controller that runs when the batteries are under charge and then runs on for a period after to evacuate the battery box – which is vented to outside. Watering is also a doddle. There is a warning light to show when the water level is below optimum and an automatic watering system to top them up. This also has the added benefit of flame arrester for each cell so some added safety. This setup occupies a space 600mm long x 370mm deep x 300mm high and weighs in at 141kgs. All fine and dandy for me but would it fit in a narrowboat?

 

The cost is under £600 for the lot so if they last me 5 years, that’s £119.50/year. A cost that is fine by me and cheaper than shoving in leisure batteries that I might have to replace every year. I really can’t see the point of using something that hasn’t been designed for the job (truck starter batteries etc) even if they are “cheap”!

 

Colin

[chris w]

I really can’t see the point of using something that hasn’t been designed for the job (truck starter batteries etc) even if they are “cheap”!

 

Colin

I agree with you wholeheartedly on this. I used to be involved just as heavily in a particular sports car forum and the philosophy on there, in general, was always to go for the best quality. It has always struck me on this forum, in counterpoise, that the overriding consideration is most often cheapness at the expense of quality and length of service. Many do not consider the "whole life" cost of an item.

 

Chris

[nb Innisfree]

Let's take a simple case. Suppose you switch on all the internal lights inside your boat and you measure the current as 20 amps say. You then measure the battery volts before you switch on the lamps (say 12.6v ie: fully charged in this case) and the battery volts after you switch on the lamps. Let's say this is 12.4 volts.

 

So the volts drop is 12.6 - 12.4 = 0.2v and this is equal to the current x the internal resistance

 

So, in this case, 0.2 = 20 x R

 

So R, the internal resistance = 0.2/20 = 0.01 ohms or 10 milliohms which would be a good battery.

 

However, if the volts drop were say close to a volt, your battery is in bad shape.

 

Chris

 

Thanks. All clear now