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2 hours ago, Alan de Enfield said:

I had a new battery "professionally fitted" on my DiL car.

It is a Renault and requires plugging into a 'diagnostics computer' to keep the electronics and memories 'live' whilst removing the old battery.

(I could have jiggled about with jump-leads but if one of them had pinged off whilst moving batteries it would have been serious - so - not worth it)

 

I was there when the garage did the change over - they did exactly as I requested - 'supply and fit a new battery' nothing else expected or offered.

 

 

When I worked as a Daganite battery agent and also as a boatyard engineer it was standard practice to check the charging voltage after fitting the battery. This was to protect the company against claims for a faulty battery when really the basic problem was a charging system fault. It is perfectly possible that when they connected Alan's car to the computer the memory had no charging faults stored so maybe it  is reasonable to assume the charging was OK but on our type of boats I don't think so.

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1 minute ago, Tony Brooks said:

When I worked as a Daganite battery agent and also as a boatyard engineer it was standard practice to check the charging voltage after fitting the battery. This was to protect the company against claims for a faulty battery when really the basic problem was a charging system fault. It is perfectly possible that when they connected Alan's car to the computer the memory had no charging faults stored so maybe it  is reasonable to assume the charging was OK but on our type of boats I don't think so.

I remember being taught, when learning to be a mechanic, that you only do the work requested by the customer, as anything extra that you do, you theoretically cannot charge for. You do the asked for work, then see more that has to be done, so you phone the customer to ok it.

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Just now, Stilllearning said:

I remember being taught, when learning to be a mechanic, that you only do the work requested by the customer, as anything extra that you do, you theoretically cannot charge for. You do the asked for work, then see more that has to be done, so you phone the customer to ok it.

Yes but the cost of sticking a voltmeter on the battery and revving the engine is far less than having to replace what was a perfectly good battery that was ruined by insufficient or excess charging voltage. It is really just doing a professional job. If you had your brakes overhauled would you be happy for the mechanic to try the pedal and return the car with out a road test? Even today I trust the road test time would be built into the job's price.

 

How about changing the engine oil and filter and not running the engine and checking for oil leaks?

 

I agree that if while changing a battery you notice a battery clamp terminal is cracking up or a cable chaffing you should not simply change it without permission but how would you feel if a terminal was covered in corrosion and it was not cleaned off. In fact ensuring the terminals were clean and dressed was considered part of the job.

 

 

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5 minutes ago, Tony Brooks said:

Yes but the cost of sticking a voltmeter on the battery and revving the engine is far less than having to replace what was a perfectly good battery that was ruined by insufficient or excess charging voltage. It is really just doing a professional job. If you had your brakes overhauled would you be happy for the mechanic to try the pedal and return the car with out a road test? Even today I trust the road test time would be built into the job's price.

 

How about changing the engine oil and filter and not running the engine and checking for oil leaks?

 

I agree that if while changing a battery you notice a battery clamp terminal is cracking up or a cable chaffing you should not simply change it without permission but how would you feel if a terminal was covered in corrosion and it was not cleaned off. In fact ensuring the terminals were clean and dressed was considered part of the job.

 

 

I agree, it was a cautionary tale about workshop practices and why sometimes things that seem obvious don’t get done.

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39 minutes ago, andrewbridget said:

Yes it is. 12v starter 24v domestic. 1 alternator. Engine is a perkins prima. I don't know the alternator make. I will find out. When I checked it with a voltmeter is was only dishing out 17v. So possibly alt cattle trucked ! . 

Andrew,

there are still a lot of unanswered questions.

You say you damaged your previous set of batteries by using your inverter. How long have you had the boat and did those original batteries charge ok? Have you had a number of years good use out of the batteries and charging system?

Why do you think the inverter wrecked them? .......or was it just the inverter used a lot of the power and your charging system wasnt up to recharging?

Did anything else get changed either before you wrecked the first set or since fitting the new ones?

I too cant see how a single alternator can feed both 12V and a 24V battery banks at the same time.

 

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As you cant charge a 12V battery with 24 volts and you cant charge a 24 volt battery with 12 volts it seems to me that the system never worked or there is an extra component/box in it that takes 24 volt input and delivers 12v or the other way round but in that case I suspect it would be an inverter driving a battery charger to give whatever  voltage the alternator is not. There is no way of knowing so I think you need professional or a VERY electrically knowledges boater to have a look and see what you actually have.

 

What is the output voltage of the alternator - measured, not off the label?

What is the charging voltage across the 12V battery/bank and ditto the 24 volt one.

 

If it is only a Prima engine and if its 24 volt engine electrics I would think t would be more satisfactory to convert the engine to 12v or the domestics to 24volts.

 

It is just possible you have a Mercedes type 12/24 volt relay think that uses one voltage for starting and another for charging but usually they only have one bank with the relay thing (big box) altering the battery configuration from series to parallel to suit thes tarting and charging.

 

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Hi again.

So I bought the boat on 23rd December. Rugby Boats.  I drove off and the inverter was on as it ran the 240v fridge. I didn't know.

The volt meter was bang in the middle of the green section. Then on day 2. Whilst cruising the meter went high in the red at the end of dial basically. And it was jumping left and right. And so was the rev counter. I thought wtf. 

Then as the next 2 days went the meter steadied out but gradually went in yellow zone.  Then red .and slowly down to empty.

I checked the batts and 2 of them were dead.  The other 2 were 7v. So dead as well. I managed without power for a few days until I got new batteries thinking that it was my nievety with the inverter that caused it. But something else must have happened. I do not use inverter any more. 

I sort of understand the quotes with 12v starter and 24v leisure. Seems daft to me also. 

Could I re adjust the batterys to 12v and see if they charge that way. I know my cables may be affected with the ampage drop etc but worth a try. So yeah. I've been a boat Owner for 6 weeks so please go easy. Ha. 

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I am going to make a guess now

24 volt alternator and domestic batteries

12 volt starter and 12 volt battery charger running from the inverter on the 24 volt system

so inverter flattened domestic batteries keeping the engine battery fully charged. The 24 volt bank has not been charged since they were fitted. 

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10 minutes ago, ditchcrawler said:

I am going to make a guess now

24 volt alternator and domestic batteries

12 volt starter and 12 volt battery charger running from the inverter on the 24 volt system

so inverter flattened domestic batteries keeping the engine battery fully charged. The 24 volt bank has not been charged since they were fitted. 

 

I'd go similar EXCEPT a 24v step down to 12v .

no body would be stupid enough to run a a battery charger off a battery.

 

I suggested early in the thread that he really needs to get some proper help, waiting until the weekend will ensure that those £600 batteries are truly dead.

12 hours ago, Alan de Enfield said:

Andrew - may I suggest that as you appear to have possibly killed another £600 of batteries in 3 days that you get someone in to sort it out for you, it will be cheaper in the long run.

 

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Maybe one of the relays connects the 12 volt start battery positive to the midpoint of the 24 volt domestic bank, with the relay coil wired in “normal” split charge fashion from the ind terminal of the alternator. Yes I have seen this before, with 48, 24 and 12 volt batteries all charged from a single 48. volt charger! Far from ideal, but simple; the charging demands of the start battery being  relitively minor. I would also expect to see a parallel link at the mid point of the 24 volt bank to further mitigate the effect of charging the starter in this way. At the end of the day a 24 volt starter would be the simplest solution, as converting the domestic to 12 volt would involve a rewire.

 

Edited by Eeyore
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I would first check to see that the equipment on the domestic side is actually 24v rather than 12v. Check a bulb for voltage designation on the domestic side and the engine panel this will show you the voltage in each system. If the domestic batteries were connected up to look as if they were 24v (ie all in series) they may have been shot and just rewired to boost the voltage(unlikely).

A split charge relay will only work if both battery banks are the same voltage .

The single alternator would have to be 24v to charge a 24v bank unless there is change over system which reconfiqures the 24v bank into 2x 12v for charging (unlikely).

Maybe there was a second 24v alternator to charge the domestic set which has been removed.

An engine is unlikely to be fitted with a different voltage alternator to the engine electrics.

Hope this helps

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Still looking like the supposed 24V alternator is goosed. As we have already said it is imperitive that the new batteries get some charge shoved into them ASAP, probably off the boat.  I would be taking th alternator to be tested.
 

3 minutes ago, Eeyore said:

Maybe one of the relays connects the 12 volt start battery positive to the midpoint of the 24 volt domestic bank, with the relay coil wired in “normal” split charge fashion from the ind terminal of the alternator

This occured to me as a possible explanantion but I wasn't sure it would work.

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1 hour ago, Eeyore said:

(snip). At the end of the day a 24 volt starter would be the simplest solution, as converting the domestic to 12 volt would involve a rewire.

 

Maybe not : if the engine is a 12V system, with a 24V domestic system, what voltage do the instruments, instrument lighting and possibly horn and tunnel light run off?

 

E.t.a. One method of running such a system would be a 24V alternator, with a battery charger run off the invertor to charge the starter battery. That would require two relays, one to put 24V onto the alternator D+, and one to connect the charger only when the engine was running. Much neater and more efficient with two alternators, though!

 

Furher thought : A similar system could, I suppose, be done with a 12V alternator and 24V charger, but would need a dedicated 12V invertor for the charger.

 

We really need pictures or diagrams of how the syatem is actually put together!

Edited by Iain_S
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1 hour ago, Iain_S said:

Maybe not : if the engine is a 12V system, with a 24V domestic system, what voltage do the instruments, instrument lighting and possibly horn and tunnel light run off?

 

E.t.a. One method of running such a system would be a 24V alternator, with a battery charger run off the invertor to charge the starter battery. That would require two relays, one to put 24V onto the alternator D+, and one to connect the charger only when the engine was running. Much neater and more efficient with two alternators, though!

 

Furher thought : A similar system could, I suppose, be done with a 12V alternator and 24V charger, but would need a dedicated 12V invertor for the charger.

 

We really need pictures or diagrams of how the syatem is actually put together!

So if the panel is 12 volt then maybe the second relay is energised by a 12 volt feed from the key switch and the contacts connect the 24 volt battery to one side of the alternator indicator light? This is basically the same as the wiring for the second indicator light on a dual alternator setup.

 

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10 hours ago, andrewbridget said:

So I bought the boat on 23rd December. Rugby Boats.  I drove off and the inverter was on as it ran the 240v fridge. I didn't know.

The volt meter was bang in the middle of the green section. Then on day 2. Whilst cruising the meter went high in the red at the end of dial basically. And it was jumping left and right. And so was the rev counter. I thought wtf. 

Then as the next 2 days went the meter steadied out but gradually went in yellow zone.  Then red .and slowly down to empty.

Have you spoken to Rugby Boats?  You've sailed from there either without a brief or with a fault.  As a broker, it isn't their boat you bought so I'm not sure where you stand re  guarantee or consumer rights (I suspect you have none), but I'd be surprised if they intentionally let you go off to suffer catastrophic failure. 

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Oh yeah I agree. They were really good and did help as much as they could (rugby boats ) . I did contact the original owner but he had no idea of anything.  I know he paid out lots of wedge for alternator and engine overhaul etc. He also was in a marina with the boat as it has all hook up stuff and tons of 230 v sockets. 

I'm taking batts out today. And taking pics. 

Thank's for your comments.  

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Did you have a full survey on the boat?

 

If so what, if anything, did the surveyor say about the fact you have a 12 volt starter and 24 volt domestic electrics, but only a single alternator?

 

Whilst some of the putative arrangements that people have described could work, frankly none are ideal, and I would class all as bodges.

 

You really do need someone very reliable and good to look at this, but someone reliable and good will I fear declare that what you currently have is well less than satisfactory.

 

I can't imagine there is any really ideal arrangement where a single alternator can charge both systems.

Edited by alan_fincher
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The BIG question.......................... How do you know you have a 24v system? Exactly what is running off 24v? Engine?  cabin lights?  pumps? Battery charger? Inverter?

Could you be mistaken and its all 12v and a muppet has paired the batteries to give 24v?

Edited by Boater Sam
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4 minutes ago, Boater Sam said:

The BIG question.......................... How do you know you have a 24v system? Exactly what is running off 24v? Engine?  cabin lights?  pumps?

Its all speculation until we get some pictures of how the batteries are wired, the ACTUAL voltage of the starter motor and the boat domestics.

 

Is the boat really 24v and the engine 12v ?

If so how are the batteries charged from 1 alternator outputting 17v ?

Is the boat really 24v and the engine 24v  and the alternator is broken (should be outputting 28v) ?

Did the "professional" make a mistake and wire the domestic bank up as 24v (when it should be 12v), if so what damage has been done to the various electrical items ?

Is the domestic bank actually wired up for 12v, but the OP is confusing the wiring and thinks its 24 v ?

 

The OP really either needs to provide information (which may be beyond his experience levels) or get a suitably experienced sparky in to sort it. (Not just a 'mate' who has an hour to spare on Saturday)

On ‎11‎/‎02‎/‎2019 at 23:18, andrewbridget said:

Oh yeah when the last lot of batteries died my voltmeter shot up into the red zone as I reved the engine. Thank's. 

Wonder if that's when the alternator regulator failed and boiled the batteries ?

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