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LondonRascal

Trixie (Rascal's Fleet)

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Not related but Hi from the table opposite you in the Sutton Staithe Hotel today.. I was going to say hello but you were on the phone, then your food came, then our food came and then you were gone!

Ships in the night... :default_biggrin:

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Hi Ray.. Small world eh? I’m sorry we did not get to talk a little. I’m sure our paths will cross again

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:407_beer: :407_beer: Next time! :default_biggrin:

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Currently sat in Osasis (Stalham) waiting for my Curry and reading up on here.

I have been looking at the Stirling stuff today and it looks okay. I know their stuff works well but it always comes over from the design to the manual and how they are written as home brew kit that somehow is on the mass market. 

Mastervolt do an all in one fancy Alternator with duel fans and a more compact overall size that has a charge booster unit all in. Of course this costs double the Stirling product but I guess you are getting a new Alternator with a big increase in capcity. ‭I’ve also had a look at some seriously cool water cooled Alternators usually found in high end cars. 

Then I remembered this is meant to be budget boating.

what puzzles me is how I will have a good amperage going in to the battery as expected after an evenings discharge but this seems to fall off pretty quickly because my voltage is rising too. By the time the battery has got to 13.2v the Alternator is in trickle charge mode. That is fine, but it gets to 13.2v in my view very quickly and so you think to yourself “maybe less amps were taken out the battery after all”.

But after a short time of stopping the engine the battery voltage falls off - quickly falling to 12.6v - an hour or two later it will be at 12.4v and by morning 12.2v. This is why I find it surprising how rapidly it regains back to 13.v+ after I start the engine and the regulator steps in and eases down the amps going in to recharge.

We are all different and want different things. I personally would not take a lead acid battery down below 50% depth of discharge, and would replace them every four years regardless because by then they will no longer be performing as well as when new. 

It seems maybe I don’t have much of an actual issue just my expectations (Curry has arrived) are a little too high. I think I will just calm down a little and worry a little less. Forgive any spelling mistakes but was in an unusual setting to talk batteries lol  

 

 

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Currently sat in Osasis (Stalham) waiting for my Curry and reading up on here.

I have been looking at the Stirling stuff today and it looks okay. I know their stuff works well but it always comes over from the design to the manual and how they are written as home brew kit that somehow is on the mass market. 

Mastervolt do an all in one fancy Alternator with duel fans and a more compact overall size that has a charge booster unit all in. Of course this costs double the Stirling product but I guess you are getting a new Alternator with a big increase in capcity. ‭I’ve also had a look at some seriously cool water cooled Alternators usually found in high end cars. 

Then I remembered this is meant to be budget boating.

what puzzles me is how I will have a good amperage going in to the battery as expected after an evenings discharge but this seems to fall off pretty quickly because my voltage is rising too. By the time the battery has got to 13.2v the Alternator is in trickle charge mode. That is fine, but it gets to 13.2v in my view very quickly and so you think to yourself “maybe less amps were taken out the battery after all”.

But after a short time of stopping the engine the battery voltage falls off - quickly falling to 12.6v - an hour or two later it will be at 12.4v and by morning 12.2v. This is why I find it surprising how rapidly it regains back to 13.v+ after I start the engine and the regulator steps in and eases down the amps going in to recharge.

We are all different and want different things. I personally would not take a lead acid battery down below 50% depth of discharge, and would replace them every four years regardless because by then they will no longer be performing as well as when new. 

It seems maybe I don’t have much of an actual issue just my expectations (Curry has arrived) are a little too high. I think I will just calm down a little and worry a little less. Forgive any spelling mistakes but was in an unusual setting to talk batteries lol  

 

 

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You should wait at least 4 to 6 hours after stopping the engine to measure the battery voltage as before this you will just be measuring the surface charge.

Your voltmeter will read 13.2v very quickly but it takes time for the battery to absorb the charge  and store the power as it is a reaction between the lead plates and the acid. It takes hours of this process to recharge a battery from 50% discharge.

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51 minutes ago, LondonRascal said:

Currently sat in Osasis (Stalham) waiting for my Curry and reading up on here.

I have been looking at the Stirling stuff today and it looks okay. I know their stuff works well but it always comes over from the design to the manual and how they are written as home brew kit that somehow is on the mass market. 

Mastervolt do an all in one fancy Alternator with duel fans and a more compact overall size that has a charge booster unit all in. Of course this costs double the Stirling product but I guess you are getting a new Alternator with a big increase in capcity. ‭I’ve also had a look at some seriously cool water cooled Alternators usually found in high end cars. 

Then I remembered this is meant to be budget boating.

what puzzles me is how I will have a good amperage going in to the battery as expected after an evenings discharge but this seems to fall off pretty quickly because my voltage is rising too. By the time the battery has got to 13.2v the Alternator is in trickle charge mode. That is fine, but it gets to 13.2v in my view very quickly and so you think to yourself “maybe less amps were taken out the battery after all”.

But after a short time of stopping the engine the battery voltage falls off - quickly falling to 12.6v - an hour or two later it will be at 12.4v and by morning 12.2v. This is why I find it surprising how rapidly it regains back to 13.v+ after I start the engine and the regulator steps in and eases down the amps going in to recharge.

We are all different and want different things. I personally would not take a lead acid battery down below 50% depth of discharge, and would replace them every four years regardless because by then they will no longer be performing as well as when new. 

It seems maybe I don’t have much of an actual issue just my expectations (Curry has arrived) are a little too high. I think I will just calm down a little and worry a little less. Forgive any spelling mistakes but was in an unusual setting to talk batteries lol  

 

 

Are any of your batteries made by Multicell?

I had a very similar problem when I replaced some batteries with Multicell ones. I had 2 x banks of 24V made up of 2 x batteries in series. One bank would go flat very quickly, but likewise charge very quickly. After some fault finding I found that one of the batteries would read 10.5V, but within a minute of charging would quickly rise and stay at 12.6V. This fooled the charger into going in float mode and no real charge was put back into the battery. At the first sign of any current drain it would quickly drop off to 10.5V Lead acid batteries are made of 6 x 2.1V cells. It was as if one of the cells was acting more like a capacitor rather than a full blown cell. It took a bit of convincing for Multicell to acknowledge the fault and replace it under warranty. The replacement failed in the same way just out of warranty.

I have since replaced all four Multicells and purely based on my own experience with them, wouldn't use them again. They do have a trade outlet in Norwich and because of this, a few chandlers and no doubt hire yards around The Broads are likely to be selling, or running them.

The problem with having 2 or 3 batteries in parallel is that if you get a battery behaving in the manner I have described it will fool your alternator, or charger into going into float mode and none of the batteries then get a deep charge. It can only be diagnosed by separating the batteries and doing a full charge and then load test and see how long each one lasts under the same load after a full charge.

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The first set of Batteries were Multicell Marine, they cost me £79.00 each. They came with a 2 year warranty. When these were ruined in less than 3 months by overcharging, I was told that they are sold all over the Broads but are bought for around £50.00 at trade prices and are not that well made up (the amount of Lead in them and thickness of the plates).  The batteries I have now are Vetus branded, and are a lot more robust, They have a lower capacity (105Ah) but have considerable thicker plates and a 5 year warranty. They are also sealed lead-calcium based and cost a lot more than the Multicell's.

I know all the batteries are charging okay, having checked each individually. Previously only my cranking battery was taking charge and my domestics were left not getting any charge at all from the Alternator. They remained at 12.4v after 3 days of use which proved they are good.  I then had things looked at again and it was then everything was begun over from Alternator back - new wire, regulator on Alternator (which had been found to be melted in areas) and this then feeds into a Victron combiner. Victron state:

Quote

" The Cyrix Battery Combiner is a microprocessor controlled heavy duty relay that automatically connects batteries in parallel when one of them has reached a pre-set voltage (indicating that the battery is being charged), and disconnects when the voltage decreases below float level (indicating that one or more batteries are being discharged). Cyrix Battery Combiners are an excellent replacement for diode isolators. The main feature is that there is virtually no voltage loss so that the output voltage of alternators or battery chargers does not need to be increased. "

So really the issue is myself, I have not had any issues with power like the fridge going off, or lights being dull etc. I think I haev been fussing over something that was not really there but I perceived to be there based on lack of patience.

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I've had a Stirling Alternator Regulator and was impressed with its performance. Batteries were always in a good state of charge. I was even more impressed with their customer service. Charles Stirling himself spent a long time talking me through the instalation and wiring needed.

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I have Multi cell batteries four in parale now four plus years old never had to top up the electilite level yet (i do check) But i do have a  extractor fan that runs while engine is running and has a timed delay that continues to run after engine is switched off this has reduced my engine room temp by 45 degrees. John

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Learning and new ideas...

Thank you everyone who contributes on this thread. I have been doing a little more than the You Tube/Google thing and been reading actual books about DC Electrics and wiring. What a rabbit hole this is once you get into it deeply, but fascinating stuff all the same. 

I have had a look at my Alternator on Trixie, and boy is it in a tight place. Most of these little boats in hire and that I have previously seen for sale privately have engines between 28Hp and 33Hp.  The model for sale through Richardson's, for example, has bags of room around the engine when I looked into buying that boat. On Trixie with her larger 43Hp engine it has been pushed as far forward as one can to make room for the gear box and prop shaft (which also has a a flexible shaft coupling which reduces vibration/noise). So far as the Alternator - and indeed things like raw water pump are concerned, these are less than 5cm away from the sound insulation that is on the underside of the wooden steps that lead down into the cabin accommodation. Even when you have removed the steps it is a real squeeze, not dissimilar to the layout you might find on a sailing boat where the engine is partially under the steps from the cockpit.

The adjuster for the Alternator belt tension seems to have had better days, and some areas are showing signs or corrosion - anyway this is all leading up to me looking at the different options to boost the charging to my battery bank - especially if I am to enlarge such capacity. I was wondering how you would get to the Alternator and remove the same - make the relevant changes and replace. 

Some systems on the market do need you to remove the Alternator and make a couple of simple changes to the wiring, others replace the Regulator on the rear of the Alternator entirely but they generally all make a change at the point of power generation and then connect to the main unit which houses the brains of the operation.  

I have now found several manufactures offering an 'all in one' solution that requires nothing changing to the Alternator at all and act not only as a multi-stage DC to DC battery charger but an MPPT Solar Charge Controller. I have seen some pretty fancy stuff for over  £800.00, some mid-range at about £300.00 but I am tempted for a 'cheap' solution coming in at £175.00 from Ring Automotive. I am pretty sure despite the well known name this is a generic product badged 'Ring' but at least there is the back up from a well known brand and an instruction manual that is written in real English. Regardless of make, they all work on much the same principle however:

You connect the unit to your start battery at one end and your output from the unit heads off to your leisure batteries. A second input shares the common earth but has a separate positive input from a Solar Panel. The Solar Panel input can be used at the same time as the rest of the unit to further increase charge and so does not 'fight' any other inputs. The Alternator begins power generation and heads off to the start battery - only when the voltage passes 14v does the system engage, taking power from the start battery and boosting it to up to 30Amps at 14.4v onward to your domestic batteries. From here on it it is monitored both for temperature of the batteries and also goes through multi stage  charging process (just as most mains powered battery charger would). This means your domestic battery bank is charged more rapidly and completely than an Alternator alone could, and so the thinking goes, a multi stage charge and a battery bank that is kept at or close to full charge lasts longer.

You are not able to discharge the starter battery as the unit does not take any power until the start battery itself is 'full' - and also only once the Alternator is outputting peak voltage, so anything under 14v won't trigger the charging unit. Once the engine is off it also is disengages so power cannot be removed from the starter battery and trickle into the domestic batteries.  All seems pretty good, the only issue I can see is effectively you are constantly 'jumping' the domestic batteries from and through the starter battery. I'd imagine that over a period of time the increased load and use is put on the starter battery  may shorten its service life verses a system that takes a higher current from the Alternator directly and then feeds this to all batteries - starter and domestic equally.

However what I do like is the ease the unit can put put in and equally removed if you changed boats and once the wiring is put back the boat will operate in 'default charging mode' if you want to call it that, meaning you can easily install the unit in a new boat without the hassle of an Alternator needing to be played with. Furthermore, this system seems to have the start battery acting as a balancer so the voltage going to your domestic batteries is constant and smooth - which also means the voltage to appliances when underway will be smooth and not subject to spikes.

Now, I could me walking into a right boobie here so any thoughts would be welcome. I attach the manual for the unit I am interested in and link to buy in case I have missed anything obvious that will end up cocking up more than it might fix.

RSCDC30 Instructions.pdf     Link to buy

In other news...

I thought I might as well disassemble half the cockpit to see how on earth you could ever get to the heater and back end of the boat around the Transom area.   Turns out once the seating is all removed (and the locker tops too) the storage lockers are GRP and effectively just very large boxes. These lift out and are over 3 feet deep, once that is out the way you can easily get to the rudder cable, greaser and bolts that hold the swim platform to the transom.  On the port side is the heater controller and heater itself. It is, as expected, an old 1990's D2 model.

What bothers me is the air intake for the heater (not the combustion air intake but the air intake for heating) draws directly from the engine bay. Normally this is not an issue, after all when the engine is off there no risk of fumes from a leaking exhaust or blow by from the engine getting sucking into the cabin, but what did cause me concern is the battery box vents into the engine space (which itself vents to the outside). Having had batteries boil and deal with that horrible smell (not to mention any Hydrogen Sulfide in the air) I'd really prefer that any risk of this being sucked into the cabin space be minimized.

I am therefore going to get some suitable heater hose and either have the air brought in from the outside through a new vent which would then cause positive air pressure in the cabin space, or re-cycle previous warmed cabin air which would cause neutral air pressure in the cabin space. This is what happens on Independence, where air is sucked in from under the sofa and sent back to the heater to be heated, thus also making the heating a more efficient process. Doing this on Trixie though would need some careful thought of ducting and running it in a confined space, so I am going more towards the less efficient method of outside air being drawn in.

I also found two large bags of sand which act as ballast - that is nice to know as this can be removed when my new batteries go in and the batteries therefore won't add too much extra weight and things should be balanced. If she lists just a little to port, I can use those sand bags on the starboard side to help even the distribution of weight.

The most strange thing I found was an old, plastic watering can by the rudder stock. It only holds a litre of water but I've kept it as I guess it might come in handy someday like topping up coolant or watering a small herb garden lol.

 

 

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A little knowledge is a dangerous thing, far better to leave it to those that know what they are doing, also there seems to be a lot of overkill going on for a rather small boat.

Fred

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You could be right Fred re a little knowledge and Robin has confessed to making mistakes, but it is his money and his enjoyment and his choice. We all start somewhere. I first started by my fathers side as he fixed his cars. At a very young age I would be the one volunteered to keep him company as he did not like to work alone. Problem was he never ever read a manual or instructions and had a fierce temper when it went wrong. I now read everything possible and always the instructions, there is not much that I have not been able to do with engines, that is until they got more electronically dependent and I earned enough to pay someone else to do it. Robin is doing what he enjoys and doing it his way. Who are we to criticise?

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Not a criticism just an observation, batteries can be dangerous things with an incorrect installation.

Fred

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Robin,

A couple of comments, the Ring battery to battery charger is only 30A output, which is less than your alternator is able to provide, so assuming your batteries were really flat, it will take longer to charge via the Ring B2B charger than direct, although with prolonged running the B2B would more than likely put in more charge.

Have you considered the Sterling alternator to battery charger. Works very similar to an advanced alternator regulator, but without the need to modify the alternator wiring, and is very simple to fit. Just place it between the alternator output and the split diode. It fools the alternator into thinking the battery is flat and draws maximum current from the alternator. It then provides four step charging to the split diode and thus onto your engine and domestic batteries. All the benefits of the advanced regulator, and four step charging and simplicity of installation.

https://sterling-power.com/collections/alternator-to-battery-chargers/products/alternator-to-battery-chargers-up-to-130a

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Hi Robin The post from IPA is what i have fitted to my boat, covers temp control and max amps control no need to touch alternator or alter it.   Ref heating recycling the air in Independence from under the seat i would guess is for air con, Cars can recycle air from interia when outside dust /smells ect or fresh from outside that is (pure).  getting air from engine bay i would expect it to  be smelly even if engine is of.   air from outside would be better BUT the intake needs to be positioned so no fumes from adjacent boats aren't sucked in or indead your own exhaust should you be static running,  also the noise of air being drawn in through grill. John

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@IPA: Yes I have looked at this (we have one on Broad Ambition) so I know they work well and without fault. 

The Ring unit (C-Teak do something too) operates on a different principle so far as I can see where the residual power from the Alternator is stepped up - both in terms of voltage and then on amperage to 30Amps.  But this is taken through the start battery first.

That does not seem (in my eyes at least) to put any additional strain on the Alternator. The Sterling unit fools the Alternator to work at maximum capacity however. In so doing that makes more heat and more heat reduces the efficiency and output of an Alternator. Since my Alternator is so confined and the engine bay gets very hot, running it hard seems a bit of a bad idea. 

Now the Ring unit may itself prematurely wear out the starting battery but a new battery is far cheaper and easy to put in than a new Alternator. 

My battery charger is only 20Amps but will recharge the batteries in about 3 hours to full. I am currently running engine for upwards of 7 hours to complete the same task. Last fill up at Southgates took 83 litres and cost me £103.00. The less time I can run for and complete a full battery charge in a day the better!

@Annv: Reference heating. The return feed (under the Sofa I mentioned on Independence) is for the Diesel warm air heating system. Many new boats have their heating system set up in this way as is does two things:

1) It means the heater is heating already warmed air and an input temperature sensor works with the digital thermostat and regulates the output air volume (fan speed) and burner between high and low. It means you will burn less fuel as the heater can reach the desired temperature and fall back to low or medium mode to maintain it. 

2) Since you are not drawing in cold outside air the heater is not having to constantly heat that cold air - the resultant output air will get hotter, faster. The burner can only heat air by so many degrees and if the incoming air is, for example 3c on a cold day,  it will not output at the same temperature as if the incoming air was 14c for example. Of course there is a limit and why you have the input temperature sensor to stop the heater outputting air that is too hot  

3) Finally you are not creating positive air pressure if you don’t draw in air from the outside. This is important because if you draw in outside air it must escape. It will do this though gaps and vents in the boat - and what is lost will be warm air you’ve just spent to heat up - even more loss of efficiency.  If you are heating cabin air drawn in you don’t create positive air pressure - it’s neutral,  just the same as if the heater was not in operation as no new air is being drawn in from outside.  

Now, on Trixie to run the extra ducting to the cabin space to re-cycle air and make a neutral air pressure will be tricky so I am opting for a vent, perhaps on my transom away from the heater exhaust outlet in my port side. I’m not worried about fumes being drawn in from other boats since the volume of air the heater sucks in is impressively high. This currently comes from the engine bay but this air must come into the engine bay from the ventilation already there (e.g if fumes are about outside I’m already going to draw them in to my cabin space) it is just the fact they have passed first into my engine bay.

Right, I am now off to collect my second bike in Norwich. The first had a few issues and was swapped under guarantee. It’s scary how you can spend as much on a bicycle as a used car these days! 

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4 hours ago, rightsaidfred said:

A little knowledge is a dangerous thing, far better to leave it to those that know what they are doing, also there seems to be a lot of overkill going on for a rather small boat.

Fred

I tend to agree.

Throwing lots of money and equipment at a small boat is a bit of a fools errand.

Keep it simple.

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1 hour ago, LondonRascal said:

@IPA: Yes I have looked at this (we have one on Broad Ambition) so I know they work well and without fault. 

The Ring unit (C-Teak do something too) operates on a different principle so far as I can see where the residual power from the Alternator is stepped up - both in terms of voltage and then on amperage to 30Amps.  But this is taken through the start battery first.

That does not seem (in my eyes at least) to put any additional strain on the Alternator. The Sterling unit fools the Alternator to work at maximum capacity however. In so doing that makes more heat and more heat reduces the efficiency and output of an Alternator. Since my Alternator is so confined and the engine bay gets very hot, running it hard seems a bit of a bad idea. 

Now the Ring unit may itself prematurely wear out the starting battery but a new battery is far cheaper and easy to put in than a new Alternator. 

My battery charger is only 20Amps but will recharge the batteries in about 3 hours to full. I am currently running engine for upwards of 7 hours to complete the same task. Last fill up at Southgates took 83 litres and cost me £103.00. The less time I can run for and complete a full battery charge in a day the better!

@Annv: Reference heating. The return feed (under the Sofa I mentioned on Independence) is for the Diesel warm air heating system. Many new boats have their heating system set up in this way as is does two things:

1) It means the heater is heating already warmed air and an input temperature sensor works with the digital thermostat and regulates the output air volume (fan speed) and burner between high and low. It means you will burn less fuel as the heater can reach the desired temperature and fall back to low or medium mode to maintain it. 

2) Since you are not drawing in cold outside air the heater is not having to constantly heat that cold air - the resultant output air will get hotter, faster. The burner can only heat air by so many degrees and if the incoming air is, for example 3c on a cold day,  it will not output at the same temperature as if the incoming air was 14c for example. Of course there is a limit and why you have the input temperature sensor to stop the heater outputting air that is too hot  

3) Finally you are not creating positive air pressure if you don’t draw in air from the outside. This is important because if you draw in outside air it must escape. It will do this though gaps and vents in the boat - and what is lost will be warm air you’ve just spent to heat up - even more loss of efficiency.  If you are heating cabin air drawn in you don’t create positive air pressure - it’s neutral,  just the same as if the heater was not in operation as no new air is being drawn in from outside.  

Now, on Trixie to run the extra ducting to the cabin space to re-cycle air and make a neutral air pressure will be tricky so I am opting for a vent, perhaps on my transom away from the heater exhaust outlet in my port side. I’m not worried about fumes being drawn in from other boats since the volume of air the heater sucks in is impressively high. This currently comes from the engine bay but this air must come into the engine bay from the ventilation already there (e.g if fumes are about outside I’m already going to draw them in to my cabin space) it is just the fact they have passed first into my engine bay.

Right, I am now off to collect my second bike in Norwich. The first had a few issues and was swapped under guarantee. It’s scary how you can spend as much on a bicycle as a used car these days! 

If your 20 amp battery charger is charging your batteries to full in 3 hours then there is something amiss somewhere.

During the last stages of charging,the batteries can only accept a limited number of amps regardless of the source of those amps be them from the alternator or the battery charger. So they shouldn't be accepting them any quicker from the battery charger.

What are you using to measure the SOC of the batteries?

If it is a battery monitor then they are notorious for not being all that accurate during the charging process.

A simple ammeter and voltmeter and the ability to read the data is a far more reliable method of determining when batteries have reached a full charge.

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there is a chart to correlate battery voltage to charge state, but it must be measured after the batteries have been off charge for about an hour or you will get a false reading

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On ‎08‎/‎08‎/‎2018 at 21:00, LondonRascal said:

Currently sat in Osasis (Stalham) waiting for my Curry and reading up on here.

I have been looking at the Stirling stuff today and it looks okay. I know their stuff works well but it always comes over from the design to the manual and how they are written as home brew kit that somehow is on the mass market. 

Mastervolt do an all in one fancy Alternator with duel fans and a more compact overall size that has a charge booster unit all in. Of course this costs double the Stirling product but I guess you are getting a new Alternator with a big increase in capcity. ‭I’ve also had a look at some seriously cool water cooled Alternators usually found in high end cars. 

Then I remembered this is meant to be budget boating.

what puzzles me is how I will have a good amperage going in to the battery as expected after an evenings discharge but this seems to fall off pretty quickly because my voltage is rising too. By the time the battery has got to 13.2v the Alternator is in trickle charge mode. That is fine, but it gets to 13.2v in my view very quickly and so you think to yourself “maybe less amps were taken out the battery after all”.

But after a short time of stopping the engine the battery voltage falls off - quickly falling to 12.6v - an hour or two later it will be at 12.4v and by morning 12.2v. This is why I find it surprising how rapidly it regains back to 13.v+ after I start the engine and the regulator steps in and eases down the amps going in to recharge.

We are all different and want different things. I personally would not take a lead acid battery down below 50% depth of discharge, and would replace them every four years regardless because by then they will no longer be performing as well as when new. 

It seems maybe I don’t have much of an actual issue just my expectations (Curry has arrived) are a little too high. I think I will just calm down a little and worry a little less. Forgive any spelling mistakes but was in an unusual setting to talk batteries lol  

 

 

Hi Robin,

 

was good to see you at horning last weekend.

From what you describe above I dont really think you have an issue.

The nominal voltage of a fully charged 12 volt battery is actually 12.2 volts no load. The alternator normally charges anywhere between 13 and 13.8 volts, some at 14.2.  If you are getting 12.2 in the morning with no load on the batteries, then there is still a lot of power left in them, worry if it drops to or below 12v. It is perfectly normal for the voltage to fall off over a couple of hours after stopping the engine and the readings you describe are perfectly within normal paramaters. An alternator is designed essentially for a lead acid starter battery and should blast high amps into the battery for a short time to replace the current used to start the engine, this then falls off very rapidly to just above a trickle charge to prevent battery damage.

Leisure batteries are of course a slightly different matter as they dont like being boost charged and prefer a steady high trickle charge instead. So basically I wouldnt worry too much as long as your morning voltage is around the 12.2 mark, all is fine.

cheers

trev

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A fully charged battery should read 12.7v. A reading of 12.2v is 50% discharged. (All measurements taken with no load on the battery and 4 to 6 hours after the engine has been stopped).

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Don't know if you recall Robin, but when I gave you the 'not so grand tour' of my boat, we had a conversation about the input air for the heating, the photo below is the vent I have purchased, not fitted yet but I am going to place it on the opposite side of the boat to the exhaust and once fitted I will have the option of external air or recirculated by making or breaking a hose connection.

 

scupper-vent-1.jpg

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If your 20 amp battery charger is charging your batteries to full in 3 hours then there is something amiss somewhere.

During the last stages of charging,the batteries can only accept a limited number of amps regardless of the source of those amps be them from the alternator or the battery charger. So they shouldn't be accepting them any quicker from the battery charger.

What are you using to measure the SOC of the batteries?

If it is a battery monitor then they are notorious for not being all that accurate during the charging process.

A simple ammeter and voltmeter and the ability to read the data is a far more reliable method of determining when batteries have reached a full charge.


I don't think ti is amiss if you have not taken too much power out of the batteries to begin with. Then the time to recharge to 100% and float charge would be a great deal less than if, for example charging from half discharged.

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