8 x 200ah batteries die after 18 months

[MedMilo]

Have you thought about solar panels?
Thats my favored route - can't see the point of another (smaller) genset.

I like the idea of solar panels but would need to consider carefully where to put them - perhaps time to get a hard top fitted as per Match's recent addition! In any case, I'm pretty sure that my issue isn't really to do with charging per se (or lack thereof) but more to do with the installation, cable lengths and/or possibly even the batteries themselves.

 

[MedMilo]

I am away so on phone and just a brief comment. This design does not look great and I am not sure fairline have covered themselves in glory ( the same people who built it are still building the ones coming off the line now ).

Splitting batteries all over the place in a hot engine room ( how are they vented if some are in the bilge). What is in your lazarette??

Have you asked fairline for help given they built it ( different company i accept but same people !)

Thanks Jeremy. I haven't contacted Fairline and am thus far only working with BUK to resolve the issue. We plan to talk to Fairline next week and it'll be interesting to see how helpful they are. Will keep you posted...

 

[Hurricane]

Yes I realise two sets
The issue is the no of banks it's more than two per set which rely on "interconnects "
You have a charger / set. But each set consist of more than one bank .let's disregard the engine bank as you report no issues .
The whole set up of the house set three banks of two is dependant on the interconnects and the relative impedance differences -likely between the the three sets .
How does the single charger accurately apply to right phase of the 3 of its "smart " phases at the right time for each of the three pairs ?
Due to the interconnects each one of the three sets of the house might at some point be getting the wrong phase ,or not enough time @ the right phase ?
Bulk , absorption or float at wrong time could arguably shorten bat life ---therein lies one prob , as well as
The usage in / out calc s
It all depends how the 2x3pairs of house are interconnected

That what I was mearning by 5 sets and two chargers .
Ideally you need a charger per set -so that each one can be personally looked after .
This can be achieved by cutting down the no of batts ie 2xmuch bigger where space applies
2x for 24 V
Eg for 600 ah 2x300 is such exists for 24 v with one charger
Instead of 6 x 100ah with 3sets of 200 - relying on interconnects and potential impedance differences leading the three groups to be in different states .Poor interconnecting can lead to imbalance .
This potential interconnect imbalance is not there with a simple 2x12v set up .So the "smart "charger can read it correctly .
If you stay with the 3 banks of house
I think it may be possible via diodes to charge the 3x200 banks seperately ,but that will take 3 charge outlets working independently .
Ideally each set - house and start for 24 V should have two 12v bats each with a "smart "charger .
Realise bats need to be man handle able and bigger boats need more capacity --so they rely on interconnects .

Med milo in the other thread is exposed to 8 bats of house so 3 interconnects for 24 v -- one charger for these 4 sets
And from I can tell the arrangement is they are in two groups of 4 -so straight away the interconnect between the two 4 sets must be a different L to the ones between the pairs in the 4,s -if you get what I mean .
The proposal seems to be - get rid of one set of 4 and it's Loooong interconnect .
As it stands it seems to me a doomed set up re bat life .

Your point is valid for every cell in the bank (in fact every cell in a single battery).
Don't some battery chargers incorporate an Equalisation strategy where, from time to time, they overcharge the system to ensure all cells get to the same voltage?

 

[Hurricane]

I like the idea of solar panels but would need to consider carefully where to put them - perhaps time to get a hard top fitted as per Match's recent addition! In any case, I'm pretty sure that my issue isn't really to do with charging per se (or lack thereof) but more to do with the installation, cable lengths and/or possibly even the batteries themselves.

On top of a hard top would be a great place to put them if you didn't have an opening roof - don't you think.
I'm thinking that the flybridge eyebrow might be a good place for solar panels.
The more I think about it, panels on the eyebrow wouldn't look too bad.
I'm thinking that it should be possible to fit about 600w which (even after allowing for poor efficiency) should overcome the power that all my fridges and my electronics draw plus there should be some left to top the batteries up during the day.
My problem doesn't materialise until after about 5 or 6 days at anchor - the total battery capacity gradually "drops off" until they need a full day to recharge them.
They get this, of course, when we go into a marina and plug in.

The idea of the solar panels is to attempt to get the batteries back to a proper full charge by the end of a sunny day.
It won't actually matter if it isn't the best sunny day as long as there is a good sunny day in (say) five days.
I would start every day with a couple of hours with the generator (as we do now).
BTW, generally speaking, we run the generator just before bed to cool the cabins down etc - once in bed, the generator goes off and we use fans (very little load) over each bed.

 

[Portofino]

Your point is valid for every cell in the bank (in fact every cell in a single battery).
Don't some battery chargers incorporate an Equalisation strategy where, from time to time, they overcharge the system to ensure all cells get to the same voltage?

In theory they do-That just shoots through 14 V or so at a predetermined time say every 2weeks for 2hrs if the bats have not been used ,or 20 mins / 14 hours ,or what ever it's programmed to do
It does not detect an imbalance then act ---
Even if they could pick up an imbalance between pairs ---they can,t over come the original poor potential interconecting problem in the first place of linking 2,3,4 or more of pairs of series linked 12v to get 24 v in parallel to increase total Ah capacity in a big boat battery house bank .
With wires of diff Lenghs and poor ish maintained contacts ,leading to various resistance differences between each pair in the bank .Especially if the various pairs are mounted all over the place necessitating diff length leads .

To over come this you need one of these wired up seperately ,the crappier the interconnects the busier this will be .
Get the interconnects right then this could be redundant .
https://www.victronenergy.com/upload/documents/Datasheet-Battery-Balancer-EN.pdf

 

[HelgeA]

I wonder why nobody considers a fuel cell. Solar panels deliver little to nothing most time of the day. The look is at least questionable. A fuel cell delivers 24h, is easy to install, fuel supply not difficult to handle. Just my 2c....

 

[Portofino]

I wonder why nobody considers a fuel cell. Solar panels deliver little to nothing most time of the day. The look is at least questionable. A fuel cell delivers 24h, is easy to install, fuel supply not difficult to handle. Just my 2c....

Good call ---from memory there was a guy on here who took del of a new big boat build .
I think ( correct me if wrong ) it was that big Jeaneau which went to the Amalfi coast ,had it wrapped in blue .
Spends a lot of time @ anchor compared to run time and his hobby was cooking .

Any how how who ever it was I recall the builder ( no a UK one )fitting a fuel cell to get over the very prob of topping up silently mid afternoon /early evening , sans Geny .

Seem popular with racing Yachts .
Googling them seem to get rapid start ethanol low temp 80 oC up to 20kW -smallish and light .

We are Problem solving for a minority of boat owners who basically for what ever reason -noise mostly -won,t run there generators @ anchor ,especially extended periods -@anchor -long enough-to manage the house batts .
Some seem to have a poor charge per capacity ratio combined with trad lead acid ,wet plated batts ( not AGM) .
Batts get hammered taken down to well below 80 -% --- far too often .
Coupled with various potential interconecting issues whereby the middle bats die first or get wounded early -eventually taking down the other pairs in the 24 v bank necessitating replacement in 18 months .

 

[MedMilo]

Did not realise you had two 100ah if they work correctly then that's a1-4 charge /cap ratio in theory -but they never really put in what's on the label only a % of 100 each .
How ever with a cut down from 800 house to 400 house then that ratio is looking better -if I understand correctly the proposed plan is to 1/2 house bat cap?
Here's a link from Dolphin see pages 22-26 re install and wire size and L
http://www.dolphin-charger.com/en/p...es/produits/pdf/user-manual-dol-pro-fr-en.pdf
I know yours are different ,but I think the basic principles apply .
(ABS brakes work the same in Audi ,BMW and Merc for example )

Slightly confused re bat spec -there basic and cheap Lead acid ,which take ages to ram charge in -that's the point .
Then gel and AGM ,-the AGMs are actually best for really deep cranking ,big stuff it's the choise for heavey plant etc which share the 12-30 L diesel engines our boats have ---I think .
AGM s allow more rapid -stuffing of charge ,but are temp sensitive and the suggestion is to link temp sensors to charger or if poss as per JFM -relocate in a cooler place - which is not an option .
The charge -stuff rate only decrease marginally anyhow if in the E-Room ,but one has to accept ATBE they will last longer
Say guess 7y in a cooler spot than 5y in a hotter place -there's so many other variables like number of deep discharges and being left off float -that ultimately override bat life -rarther than where they are in real world use .

Normal arrangement re starters
We have two sets of AGM s in the E room only 2x 185ah bank -out board to the engines -the charger incidentally is less than 1/2 M away from the house bats above them .
It has 3 outlets -two are used ,one for each bank .
Port is dedicated engines st ,Stb the house .
The port start both engines -2x185 ah for MAN 13 L straight 6's .Assume v8, and v 12,s need more oomph to turn
There is a x-over switch called "Parallel " on the dash -this will connect the house bats (stb) temporarily to the starter( port)
It works I know as see another thread from Deleted User we had a charger issue and on a short trip the bats were struggling -they relied on a long alternator /cruise .
You could have your engines with two sep Bats for each side -but now 3 groups instead of two --why ??-more potential hassle re wire size /L issues --me thinks
I guess a x-over switch from each either way incase one fails ( for what ever reason ) Or a x-over from house ,so you can grab some of that ,.
You defo need some sort of x-over function .Are you sure there is not one ?
We also have a v small bosch dedicated Geny bat charger for 45 ah lead acid -car shop type -but we have a tiny 400cc Yanmar 3-5 Kv
Both chargers have seperate breakers on the pannal ---and there's a x -over switch in the E -room by the Geny to grab 12 v from the 24 V system ,should the Geny bat no work .
Sod law and boats go hand in hand ----I know that works .(left if diconected once )

So if you go down the smaller donkey Geny route -

--get them to fit a 24 to 12 x over ( cos Geny willbe 12 v ) for it .

Get then to fit a dedicated 12v bat and charger /float /conditioner €100 tops each

Do what Barts done fit a V sensor that auto starts it -to mitigate deeper than normal discharges -they recover,but you have shortened there life more than necessary .

Finally get or repair a main engines x-over .

Looking at the pic re little Geny install to min resonance they do not like being put on a flat surface .
Mines Mase - us in a gage rubber mounts fixed to bearers .Inside that gage is the Geny agian rubber mouted to the gage -kinda twin mounted .it's hollow underneath -as aircooled are the windings -so needs air from the bilge which v shape and thick GRP --I hope!-then sea
It works no vib of resonance -whole thing on the other sides and top has a sound proof box ,which I have installed extra lead self adhesive sound proofing .
In the previous boat the Fischer Panda was stud on a flat surface in its box this flat surface just acted as a resonator .
Sunseeker need a slap on the wrist for that .
There's also a super silent exhaust kit too as an extra and consideration should be given to positioning the water and gas outlets .
What ,iam trying to say here is that there's instal and "instal " of tiny genys .
As another layer of sound proofing I have thought about making a tea cosy out of something to drape over it to really kill off those last few decibels ?

Thanks very much for all this Portofino.

Yes, the current suggestion from BUK is to halve the domestic capacity from 8 x 200ah to 4 x 200ah. These would be housed in the port stern quarter which is accessed through the crew cabin heads and is a pretty large, cool area and where currently half the domestic bank is anyway (see my second pic). The thought is that these would be AGM's rather than gels so that the starter batteries can be AGM's too (because AGM's are apparently much better starter batteries than gels) - we can't have a mixed bank because of charging. That said, maybe one of my 100 amp chargers could be pointed at the domestics and be set to gel and the other charger could be pointed at the starter bank and be set to AGM/Lead acid - though it sounds as though you and others think that 2 x 100 amp chargers charging the whole bank as one bank would be desirable? Not sure…

There is definitely no crossover switch which is IMHO ridiculous. I'm actually fitting a crossover capability this winter as it was pretty scary not being able to start one of the engines this summer when the wind picked up in an anchorage in Sardinia in August!

Thank you for the 'donkey genny' suggestions - BUK are I think following this thread so will take on board the suggestions re float charger and 24/12v crossover etc...

 

[Hurricane]

In theory they do-That just shoots through 14 V or so at a predetermined time say every 2weeks for 2hrs if the bats have not been used ,or 20 mins / 14 hours ,or what ever it's programmed to do
It does not detect an imbalance then act ---
Even if they could pick up an imbalance between pairs ---they can,t over come the original poor potential interconecting problem in the first place of linking 2,3,4 or more of pairs of series linked 12v to get 24 v in parallel to increase total Ah capacity in a big boat battery house bank .
With wires of diff Lenghs and poor ish maintained contacts ,leading to various resistance differences between each pair in the bank .Especially if the various pairs are mounted all over the place necessitating diff length leads .

To over come this you need one of these wired up seperately ,the crappier the interconnects the busier this will be .
Get the interconnects right then this could be redundant .
https://www.victronenergy.com/upload/documents/Datasheet-Battery-Balancer-EN.pdf

Am I correct in thinking that we are only talking about the middle bank in my set of batteries.
My system feeds the positive into one end of the bank and the negative into the other end.
All the interconnects are the same length.
I would have thought that the impedance of the first bank would be much that same as the last bank.
Anyway, I'm not sure that balance is my problem.

When I looked into Lithium batteries, it is common to have each cell properly load balanced.
There doesn't seem to be the same issue with lead/acid batteries as with Lithium.
I assume because the charge/discharge line on the graph is much flatter with Lithiums than with conventional lead/acid.

 

[Portofino]

Yes it's the middle pair in a 6 or pairs in a 8 bat set up , Imbalance is a potential risk obviously diff cable L if new banks have been fitted .But any even same L as yours ,or shall I say visually by eye appear to be the same there's a risk of via poor conections between them .
You could simply next time take a voltmeter and check it all out .Easy to DIY
The two master +ve and -ve ,s at each end
Then +ve and -ve of each pair hopefully 10mv of each other?
Then +ve and -ve of each bat (12-something ?) agian are they near as dam it the same ?
Turn the charger (s) off 1st ,then repeat it all with the charger on noting what stage it's on -pay Particular attention to the middle sets ---are they getting it ,the charge ? Fully ,like the end ?
If you are real geeky do it at all three stages .
Go away use the boat as you do repeat in 6/12 ---compare data .

 

[Portofino]

Thanks very much for all this Portofino.

Yes, the current suggestion from BUK is to halve the domestic capacity from 8 x 200ah to 4 x 200ah. These would be housed in the port stern quarter which is accessed through the crew cabin heads and is a pretty large, cool area and where currently half the domestic bank is anyway (see my second pic). The thought is that these would be AGM's rather than gels so that the starter batteries can be AGM's too (because AGM's are apparently much better starter batteries than gels) - we can't have a mixed bank because of charging. That said, maybe one of my 100 amp chargers could be pointed at the domestics and be set to gel and the other charger could be pointed at the starter bank and be set to AGM/Lead acid - though it sounds as though you and others think that 2 x 100 amp chargers charging the whole bank as one bank would be desirable? Not sure…

There is definitely no crossover switch which is IMHO ridiculous. I'm actually fitting a crossover capability this winter as it was pretty scary not being able to start one of the engines this summer when the wind picked up in an anchorage in Sardinia in August!

Thank you for the 'donkey genny' suggestions - BUK are I think following this thread so will take on board the suggestions re float charger and 24/12v crossover etc...

The charger "box" unit should have more than 1 outlet .My Dolphin unit is 100ah has 3 independent outlets -we utilise two.
So a typical scenario after a good blast 4 hours @ 30 knots we anchor up for lunch ,cold buffet ,no Geny /hob or kettle -it's 30 + degrees , and the sea ,s not far behind -all roasting ,fridges /ice hammered all day .
8pm when it dusk -meal time -Geny on .
The same charger ( box ) does both engine and domestic bank
I can see the E bank is vertually full maybe charger is only giving 1-2 amps -normal batt decay for 8 hrs -so its floating this bank .
How ever flick the ah guage across to the dom bank and it's taking 40 ah or more from the charger ,so presume that bank is getting "Bulk"

Dolphin , Mastervolt , Victron - nowt in it -BMW ,Merc ,Audi
Your 100 ah chargers should have more than one outlet each ?
So it might be possible to link them ? Dunno ?
Or just keep one for each bank
Just that I noticed the E bank never really discharges much -especially obviously after a run whereby the alternator does its stuff .remember there,s no other draw ,just 5-6 seconds of starter motor twice a day .
So having a dedicated 100ah just for that ? When some of it can be also used ( somehow??) to help the other 100ah top up the fast grabbing AGM,s --kinda makes sence ---if it can be done ?

You then have redundancy -so if one charger fails -you can top your domestic ,with t,other ----AND with the X-over start up if for what ever reason engine bats fail .
Two genys as well , a choise - the big one presume will be fully functional with both chargers ?

 

[MedMilo]

Thought I'd post a quick update regarding Milo's battery conundrum.

We explored the option of fitting a small, 'slave' generator (Onan 7kw) but decided that this was noisier than we wanted pounding away all day just to charge laptops, power play stations and other AV equipment and make coffee. I'd specced an oversized battery bank and 2.5kw inverter largely because I want silent 240v power for most of the day (albeit without needing to use the inverter for high power draw applications). So fitting a small generator didn't seem like the right answer. And also the cost was also fairly prohibitive.

We got expert advice on the original Fairline battery installation and learned the following;
- battery cables many different lengths
- battery boxes inadequately vented
- no meaningful over-discharge warning (I thought that the inverter automatically tripped when batteries got too low - WRONG!)
- no shore power cut out warning
- gel batteries not good for short bursts of heavy discharge (engine start, kettles! etc)

So, very much in layman's terms, our plan is in early January to do the following;
- install 4x dedicated starter batteries (http://www.odysseybatteries.com/batteries/pc2250.htm)
- install 8x dedicated domestic batteries (http://www.odysseybatteries.com/batteries/pc1800.htm)
- install various crossover rocker switches to connect port/starboard engine banks and domestic banks so each engine and/or generator can be started from either of the various battery banks
- build a custom, adequately vented, battery box
- rewire so all cables are uniform length
- install an audible low voltage alarm
- install a shore-power fail texting system
- individual battery temp sensors throughout

So we've gone away from Mastervolt gels in favour of high quality lead acid AGM's which are, apparently, more robust and forgiving. And are certainly a bit cheaper and more readily available!

Will post a quick pic when the installation is complete!

 

[ph321]

Thought I'd post a quick update regarding Milo's battery conundrum.

We explored the option of fitting a small, 'slave' generator (Onan 7kw) but decided that this was noisier than we wanted pounding away all day just to charge laptops, power play stations and other AV equipment and make coffee. I'd specced an oversized battery bank and 2.5kw inverter largely because I want silent 240v power for most of the day (albeit without needing to use the inverter for high power draw applications). So fitting a small generator didn't seem like the right answer. And also the cost was also fairly prohibitive.

We got expert advice on the original Fairline battery installation and learned the following;
- battery cables many different lengths
- battery boxes inadequately vented
- no meaningful over-discharge warning (I thought that the inverter automatically tripped when batteries got too low - WRONG!)
- no shore power cut out warning
- gel batteries not good for short bursts of heavy discharge (engine start, kettles! etc)

So, very much in layman's terms, our plan is in early January to do the following;
- install 4x dedicated starter batteries (http://www.odysseybatteries.com/batteries/pc2250.htm)
- install 8x dedicated domestic batteries (http://www.odysseybatteries.com/batteries/pc1800.htm)
- install various crossover rocker switches to connect port/starboard engine banks and domestic banks so each engine and/or generator can be started from either of the various battery banks
- build a custom, adequately vented, battery box
- rewire so all cables are uniform length
- install an audible low voltage alarm
- install a shore-power fail texting system
- individual battery temp sensors throughout

So we've gone away from Mastervolt gels in favour of high quality lead acid AGM's which are, apparently, more robust and forgiving. And are certainly a bit cheaper and more readily available!

Will post a quick pic when the installation is complete!

Sounds like a good plan. Just thought I would share my budget "shore-power fail texting system" in case it may work for you. I've got an older Android phone plugged into a point with the Power Outage Alarm Pro app installed. The phone will instantly SMS me when the power is disrupted or restored. Very handy and a much cheaper option than some of the other monitoring options in Australia.

Paul

 

[Hurricane]

Personally, I don't think this will solve the problem of running quietly - if that is your goal.
IMHO it is the charging part of the cycle that is the issue.
In order to "put back" the power that you have taken from your batteries after running (say) overnight, you need to run the generator for a long time.
Initially, the batteries will charge quickly but to fill them back to the same level that they were before you left a marina will take many hours charging with the generator (or engines).

In my case, we only give them a couple of hours in the morning and again in the evening.
This has turned out - not to be enough.
Generally it is OK for a few days but gradually they start to discharge overal so that after about a week they are at serious risk of damage.
I suppose your low voltage alarm will tell you when they are getting low (probably at five o'clock in the morning after you have been away from your marina for about 6 or 7 days).
But, IMO you will need to give them a really good charge about every 5 days - IMO a good charge will mean 8 hours or so with the generator running.
This is why I'm considering solar panels which will "finish off" charging the batteries after an hour or so from the generator in the morning and evening. I would expect a good day's sunlight sometime during that crucial 5 or 6 days when we currently (please excuse the pun) cant completely "refill" the battefies.

 

[BartW]

- install an audible low voltage alarm

insist the installer not only to install a low voltage alarm,
but a real "battery monitor"

when you discharge a (in good condition) 12V battery for 40...50%
the voltage of that battery should still reed approx 12,3V or above.
but no voltage alarm, and that is the moment when you should stop draining the batt's any further !

if the battery's are drained below 12V, actual damage is done !!!
so a low voltage alarm will useably be too late !

I rest my case, the biggest issue with domestic battery's is that users drain them too deep,
or have no clue about how much they drain them.
imo a inverter is a really nice thing to have on a boat, but you need to be aware of the power consumption / charge status of the battery's.
and then battery's have to be recharged adeaquately , which means sometimes run the genny for several hours,
and or do just as we do, navigate the boat for few hours ones or twice a day ;-)

A battery monitor, will "measure" or "count" the total current that goes in and out a battery bank
the devices that I know can be programmed to give a audible alarm, or a relay contact alarm, at a programmeable charge threshold

thanks for keeping us updated !

 

[oceanfroggie]

Another possibility is an intermittent fault in the charger could be damaging the batteries. We have an inverter too but I would never use it to run a heavy 1.5kw appliance like a kettle - too much intense short period drain. We anchor a lot too, more than we moor in marinas when cruising, but run the geni for periods to charge batteries, especially when we've gone ashore so we don't hear the noise (even though ours is super quiet).

 

[John100156]

I tend to agree with much of what Hurricane is saying, with the possible exception that I would probably not bother with the morning re-generation.

Less energy is removed from the batteries overnight, what with cooler ambient and less fridge door openings (although I believe on Jenny Wren that can extend to long into the night), the fridge loads and the like would be less; lighter evenings and use of LED lighting helps. I think PV is a very sensible solution, particularly when running through long summer days, it would put back in much of the energy used over night probably before breakfast and then meet some of the load during the day, minimising the drain on battery energy, then I would go for one good generator run (1-2hrs) after the highest loads of the day are over, to get as much energy back into the battery as possible.

We must however remember that this is not a 'one size fits all' solution, it will depend on many factors, battery type, condition, how the energy is taken over time from the batteries and the ability of any charging devices to return that energy. I am not sure if there is a smart charger available that can be coupled to a PV array, but if not I am sure they will come soon. As will far more efficient PV arrays, as they seek to harness a wider spectrum of light energy available from the sun, that many researchers are currently working on.

 

[jfm]

Sounds good. I agree 100% with BartW: you should fit a battery monitor so you know the % consumed. This needs doing carefully as you will have to re-work the negative busbar so that all relevant loads are routed through the single shunt.

I'm just replacing my batteries after 4 seasons. I'm about to buy the same ones that Fairline originally fitted: Sonneschein gel batteries. I've been very impressed by their real world ability to give a large number of cycles at 70% DoD and to accept 175Amps of charging current (in a 400Ah @24v bank).

When you switch from gel to AGM you will have to reset your chargers and your alternator charge regulators

 

[MedMilo]

Sounds good. I agree 100% with BartW: you should fit a battery monitor so you know the % consumed. This needs doing carefully as you will have to re-work the negative busbar so that all relevant loads are routed through the single shunt.

I'm just replacing my batteries after 4 seasons. I'm about to buy the same ones that Fairline originally fitted: Sonneschein gel batteries. I've been very impressed by their real world ability to give a large number of cycles at 70% DoD and to accept 175Amps of charging current (in a 400Ah @24v bank).

When you switch from gel to AGM you will have to reset your chargers and your alternator charge regulators

Thanks J. BUK are following this thread so will pick up on the monitor point I'm sure. I know one's been discussed but am not sure it's still on the work schedule - will check…

 

[jfm]

Thanks J. BUK are following this thread so will pick up on the monitor point I'm sure. I know one's been discussed but am not sure it's still on the work schedule - will check…

OK. If BUK have access to a Sq78 (which has a mastervolt battery monitor fitted as standard) then they can see how it is done there. That boat has a typical negative busbar, about 450mm long and with a series of M10 and M8 studs. The negatives from the engine start batteries and the 12v battery go directly to studs on this busbar. EVERYTHNG else needs to be connected not to the busbar, but to the shunt, which is then in turn connected to the negative busbar. You may even want to install a little busbar to the input side to the shunt, to make everything fit. After you have set it up this way, all domestic services flow through the shunt and their drain is measured by the battery monitor.

What I have described is fitting the shunt on the negative side. You can fit it on the positive side but I prefer (as do Fairline) to fit it on the negative side. Either works; it's a free choice. Usually it is physically easier on the negative side.