Engine rewire, wiring diagram ?

[xeitosaphil]

Now looking at it more closely in response to your specific question I begin to see the snags, if snags is the right word.

As you have drawn it ( nice big clear diagram on my computer BTW) with the house battery charger negative connected directly to the battery negative the ammeter will not see the charging current from the house battery charger .... BUT ... here comes the hiccup ... if the VSR is a dual sensing one, and I think you said it is, as the battery becomes charged the VSR will close and the engine battery will also be connected to the charger. The engine battery charging current will then be seen by the ammeter as a discharge.

Moving the charger negative connection to the other side of the shunt ( to the negative stud) will solve both issues.

If you use the engine battery charger instead, although you now have no ammeter to show the current going to the engine battery, when the VSR closes the current going to the house battery will be shown correctly by the house battery ammeter.

On the fuses issue. Don't fit fuses larger than necessary to supply the current to circuits connected to them....... that may mean you can reduce the size of the fuse in the feed to the distribution panel possibly also in the winch circuit but the winch maker may reccommend a fuse size large enough to carry a high initial current

As far as wire sizes go they should always have a max safe working rating greater than the fuse supplying them ... so that in the event of a fault the fuse will blow before the wire overheats and sets fire to your boat.

In all but the shortest of cable runs the wire size will probably have to be greater, much greater even, than the max safe working rating in order to control voltage drop. The longer the cable run the heavier the wire will have to be.

Vic,

Have amended my diagram as suggested for the house charging negative.

One thought - if using both the mains chargers to charge the different batteries at the same time, and the VSR being bi-directional , will that mean I will have to isolate the VSR as the chargers will be in conflict with each other! I would probably have to turn off the ammeter as well as it would register both combined charge rates would it?

If this is necessary if I put the switch back in the VSR negative will it isolate the VSR when using the mains chargers? I might in that situation forget to turn it back on again as someone previously said.

It might be better for me to loose the engine charger all together as it seems it is causing some trouble. What do you think?

On fuse issues- all noted, ------ all circuits on distribution panel are correctly individually fused for equipment anyway.

On Cable runs- can I just run this past you

My house batteries to isolator- engine starter and return negative to battery is 8.2mtrs.

My engine start battery to isolator – starter and return negative to battery is 6.5mtrs.

My Lofrans Windlass is fed from engine battery – winch and return negative battery is 14.5mtrs

The winch cable at present is 35mm2 and all battery cables are 25mm2

I thought I would change all the starter battery cables for 50mm2 which I thought would be ok?

The windlass seems to be ok cruising last year but I only use it when the engine is running, and only in short burst not continuously.

 

[pvb]

If this is necessary if I put the switch back in the VSR negative will it isolate the VSR when using the mains chargers? I might in that situation forget to turn it back on again as someone previously said.

It might be better for me to loose the engine charger all together as it seems it is causing some trouble.

I've tried to emphasise the advantages of not having switches which can be set wrongly or forgotten about! You don't need a switch in the VSR negative, but you do need to dispense with one charger. However, as I suggested earlier, your charger should be connected to the engine start battery, to give it priority. The VSR will automatically take care of the house batteries.

 

[xeitosaphil]

You could try here:

http://bluesea.com/productline/overview/430

or here:

http://bluesea.com/products/5143

Normally, a fuse is rated as continuous current but will pass a peak current (in-rush current) for a limited time.


.

pvb

Mega fuses have a very useful slow-blow characteristic, to avoid nuisance failures. Here's the current/time chart...






Thank you Both your help is much appreciated - Philip

 

[VicS]

Vic,

Have amended my diagram as suggested for the house charging negative.

One thought - if using both the mains chargers to charge the different batteries at the same time, and the VSR being bi-directional , will that mean I will have to isolate the VSR as the chargers will be in conflict with each other! I would probably have to turn off the ammeter as well as it would register both combined charge rates would it?

If this is necessary if I put the switch back in the VSR negative will it isolate the VSR when using the mains chargers? I might in that situation forget to turn it back on again as someone previously said.

It might be better for me to loose the engine charger all together as it seems it is causing some trouble. What do you think?

On fuse issues- all noted, ------ all circuits on distribution panel are correctly individually fused for equipment anyway.

On Cable runs- can I just run this past you

My house batteries to isolator- engine starter and return negative to battery is 8.2mtrs.

My engine start battery to isolator – starter and return negative to battery is 6.5mtrs.

My Lofrans Windlass is fed from engine battery – winch and return negative battery is 14.5mtrs

The winch cable at present is 35mm2 and all battery cables are 25mm2

I thought I would change all the starter battery cables for 50mm2 which I thought would be ok?

The windlass seems to be ok cruising last year but I only use it when the engine is running, and only in short burst not continuously.

Sorry detailed reply lost by frigging forum!

In brief
ammeter will show the current in or out of the house battery.. Fine so long as you realise that is does not show specifically output from either charrger, alternator or the dist panel

I dont know what conflict there will be, if any, between two chargers connected in parallel when the VSR closes. Ask the manufacturer perhaps.
If any problem ditch one charger or disable the VSR with the switch Brian suggested

Calculations confirm cable size for Windlass Ok assuming 70 amps.

25mm² a bit on the small side for the longish battery cable runs you have. 50mm² more than heavy enough.

Connect charger to starter battery on the basis that engine starting is the main concern ... but the alternator should always leave it adequately charged anyway
OR
Connect cahrger to house battery because that will be the one most depleted after a couple of nights away from a shore power supply.
Also the M300 is suitable for use as a power supply... to run or your 12 volt stuff from it while keeping the battery topped up. Not all are apparently ... mine is not.
Your call on this one

 

[xeitosaphil]

I've tried to emphasise the advantages of not having switches which can be set wrongly or forgotten about! You don't need a switch in the VSR negative, but you do need to dispense with one charger. However, as I suggested earlier, your charger should be connected to the engine start battery, to give it priority. The VSR will automatically take care of the house batteries.

I think I had come to the decision to remove the engine charger earlier in my letter to Vic, as the result of your suggestion in a previous post and also all the hassle of trying to accommodate its use.

With regards to the chargers position in the charging sequence, my thoughts and layout are base on a few things.

First of all the boat is not on a mains 240v based pontoon and electric is only available once the boat is moved to where it is installed. Hence the engine battery needs to be charged by other means to be able to start and to be able to get access the electric supply. Also there is a current drain with the battery charger permanantly installed - not much but it would create a disharge where now there isn't one.

Second when the boat is first started, the engine is automatically charged by the alternator as it has priority over the house battery anyway, and as you have said previously there is not much taken out of the engine battery at start up and is replaced within a short time by the alternator.

Another thing is the house battery usually takes more discharge than the engine battery and usually takes longer to charge so it would take even longer if the engine battery was charged first.
This coupled with the fact that it is already installed I thought I would leave it as it is.

There is a Solar panel which at present is adding charge to the house battery, which usually takes more of a discharge because it is supplying a permanent Gas Monitor, but it could be rewired so it puts additional charge to the engine battery instead, if thought necessary.

 

[xeitosaphil]

Sorry detailed reply lost by frigging forum!

In brief
ammeter will show the current in or out of the house battery.. Fine so long as you realise that is does not show specifically output from either charrger, alternator or the dist panel

I dont know what conflict there will be, if any, between two chargers connected in parallel when the VSR closes. Ask the manufacturer perhaps.
If any problem ditch one charger or disable the VSR with the switch Brian suggested

Calculations confirm cable size for Windlass Ok assuming 70 amps.

25mm² a bit on the small side for the longish battery cable runs you have. 50mm² more than heavy enough.

Connect charger to starter battery on the basis that engine starting is the main concern ... but the alternator should always leave it adequately charged anyway
OR
Connect cahrger to house battery because that will be the one most depleted after a couple of nights away from a shore power supply.
Also the M300 is suitable for use as a power supply... to run or your 12 volt stuff from it while keeping the battery topped up. Not all are apparently ... mine is not.
Your call on this one

Thanks once again Vic for your contribution, as per my previous post I‘ve decided it better to not use the engine charger for all the fore mentioned problems.
Charger will be to house bank for the fore mentioned reasons, but I think I will re-wire existing Solar panel to engine start battery for maintenance charge, or purchase another one for the same purpose.
Ammeter monitoring - My assumption was, it would monitor total input from chargers /alternators minus all discharges form house bank showing net current input or discharge. To monitor individual discharges on items, I would have to look at each in turn on their own.

Thanks for taking time to check my cable sizes- good to know they will be ok

 

[xeitosaphil]

Thanks once again Vic for your contribution, as per my previous post I‘ve decided it better to not use the engine charger for all the fore mentioned problems.
Charger will be to house bank for the fore mentioned reasons, but I think I will re-wire existing Solar panel to engine start battery for maintenance charge, or purchase another one for the same purpose.
Ammeter monitoring - My assumption was, it would monitor total input from chargers /alternators minus all discharges form house bank showing net current input or discharge. To monitor individual discharges on items, I would have to look at each in turn on their own.

Thanks for taking time to check my cable sizes- good to know they will be ok

MORE ELECT-E-R-I-K-E-R-Y

Now Digital Ammeter
http://www.ebay.co.uk/itm/New-Handy...-/120998831429?ssPageName=ADME:X:eRTM:GB:1123
has arrived from China, and I have fitted it as per attached diagram, I find the alternator is not being monitored by the ammeter when charging the house batteries through the VSR?

Question - is it possible that when the VSR is closed, when the engine battery is up to Voltage and the positive feed is charging house battery, that the return to the engine battery is going from house to engine battery in the wrong direction through the shunt, or even missing the shunt all together?
Would it make any difference if I took the alternator earth ground wire off the engine, and extended the wire to pass through one side of the shunt? Not sure which side?
Alternator is not an isolated earth return but earths through the case and mounting bolts, so not sure if this would make any difference?

One other thing, as distance from House Bat to ammeter is 2 1/2 mts , I may need to re- calibrate it due to voltage drop. Has anybody ever done this or have any experience of doing this? there is an adjuster on the back of gauge so wondered if I find a discharge of say 1amp maybe a light, and adjust the gauge till gauge reads 1amp discharge would this be ok - does it sound feasible.

As always grateful for any comments or advise.

 

[VicS]

Difficult to read such a small diagram but I have cranked up the browser magnifier a bit and I think:


If wired as shown the ammeter should be measuring the net current flow into or out of the house battery.

Not sure of your concerns about the distance from house battery to ammeter.

The shunt can be positioned anywhere along the cable leading to the battery its position is not important. You will drop volts if the cable from alteranator to battery is excessively long and/or too small a gauge for its length and current flow.

The length of the connections from shunt to meter should not cause any problems as the current flow along then should be small.
If you want to check/adjust the meter calibration do so with a good quality ammeter, not by comparing with a bulb which could take 1 amp +/- a considerable margin

 

[kmakk]

MORE ELECT-E-R-I-K-E-R-Y

Now Digital Ammeter
http://www.ebay.co.uk/itm/New-Handy...-/120998831429?ssPageName=ADME:X:eRTM:GB:1123
has arrived from China, and I have fitted it as per attached diagram, I find the alternator is not being monitored by the ammeter when charging the house batteries through the VSR?

Question - is it possible that when the VSR is closed, when the engine battery is up to Voltage and the positive feed is charging house battery, that the return to the engine battery is going from house to engine battery in the wrong direction through the shunt, or even missing the shunt all together?
Would it make any difference if I took the alternator earth ground wire off the engine, and extended the wire to pass through one side of the shunt? Not sure which side?
Alternator is not an isolated earth return but earths through the case and mounting bolts, so not sure if this would make any difference?

One other thing, as distance from House Bat to ammeter is 2 1/2 mts , I may need to re- calibrate it due to voltage drop. Has anybody ever done this or have any experience of doing this? there is an adjuster on the back of gauge so wondered if I find a discharge of say 1amp maybe a light, and adjust the gauge till gauge reads 1amp discharge would this be ok - does it sound feasible.

As always grateful for any comments or advise.

Can you upload a larger diagram? This is to small for study

 

[xeitosaphil]

A

Difficult to read such a small diagram but I have cranked up the browser magnifier a bit and I think:
The ammeter only measures the net current flow into or out of the house battery. It will not show any charge current going to the engine start battery.
Not sure of your concerns about the distance from house battery to ammeter.

The shunt can be positioned anywhere along the cable leading to the battery its position is not important.

You will drop volts if the cable from alternator to battery is excessively long and/or too small a gauge for its length and current flow.

The length of the connections from shunt to meter should not cause any problems as the current flow along then should be small

If you want to check/adjust the meter calibration do so with a good quality ammeter, not by comparing with a bulb which could take 1 amp +/- a considerable margin

" Difficult to read such a small diagram but I have cranked up the browser magnifier a bit and I think: "


Not sure how to make this diagram bigger had this problem uploading pictures of diagrams before if you recollect.

" The ammeter only measures the net current flow into or out of the house battery. It will not show any charge current going to the engine start battery. "

The problem is Vic, it doesn't - it doesn't register the alternator current at all? Or it doesn't seem too. I don't want to monitor engine battery charge rate anyway, only like to see charge rate in amps going into house battery Via VSR.

With the alternator charging house battery from 70% to 80% over the space of an hour via VSR the ammeter was only registering 00.4amp.

" Not sure of your concerns about the distance from house battery to ammeter. The shunt can be positioned anywhere along the cable leading to the battery its position is not important. "

I thought it had to go right next to the battery, and every neg return had to go to load side of shunt?

" You will drop volts if the cable from alternator to battery is excessively long and/or too small a gauge for its length and current flow. "

As previously stated in this post, alternator cable is 10mm, cable length to engine Bat 3mts, alternator 55A thought this was ok.

" The length of the connections from shunt to meter should not cause any problems as the current flow along then should be small "

That was my concern, that because the current flow is only Milli amps, length of cable at 2 1/2 mtrs could cause voltage drop which would affect gauge accuracy, hence the need to re-calibrate it to read right discharge of given quantity

" If you want to check/adjust the meter calibration do so with a good quality ammeter, not by comparing with a bulb which could take 1 amp +/- a considerable margin" [/QUOTE]

Not sure how to go about doing this, so maybe a subject for another separate post later.

 

[pvb]

With the alternator charging house battery from 70% to 80% over the space of an hour via VSR the ammeter was only registering 00.4amp.

If you've actually wired it as you've shown in the diagram, then it would seem that the ammeter is either faulty or incorrectly installed. What are you using to power the ammeter? It needs an independent 5v power supply, how have you arranged this?
.

 

[xeitosaphil]

If you've actually wired it as you've shown in the diagram, then it would seem that the ammeter is either faulty or incorrectly installed. What are you using to power the ammeter? It needs an independent 5v power supply, how have you arranged this?
.

Thanks pvb, yes I have wired it as diagram and I have also powered it by an isolated power supply

http://www.ebay.co.uk/itm/Isolated-...063?pt=LH_DefaultDomain_0&hash=item2a0e6a4967

which I had made up for my original 50A ammeter instalation.

However the ammeter supplier does state in his advert that it needs a 12v supply to work, but does not say it needs to be isolated, but I had one made up so thought I would use it.


So I don't need to worry about directional flow of the negative to shunt then ?

I thought it need to be on the outboard side of the shunt into the battery to actually measure the current flow into the battery, measured by the sensing wires to gauge.

If that is the case, where is the neg coming from into the house battery when power is coming from the VSR?

 

[pvb]

So I don't need to worry about directional flow of the negative to shunt then ?

I thought it need to be on the outboard side of the shunt into the battery to actually measure the current flow into the battery, measured by the sensing wires to gauge.

If that is the case, where is the neg coming from into the house battery when power is coming from the VSR?

As I said before, if you've wired the shunt according to your diagram, it has to measure the current into/out of the house batteries. If it doesn't, it's either faulty, or you've installed it wrongly.

 

[VicS]

Does it show the current being used by the domestic circuits when there is no charging going on?

If it does that then maybe your charging current is by-passing the shunt ... but it cant if you have wired it as in your diagram.

Could try reversing the connections between meter and shunt to see what happens .. maybe faulty and only measuring the current in one diection.

 

[nigelmercier]

One thought - if using both the mains chargers to charge the different batteries at the same time, and the VSR being bi-directional , will that mean I will have to isolate the VSR as the chargers will be in conflict with each other!

Jumping in without reading the whole thread, but I have a relay in the ground return of my VSR so it is only active when the ignition is on.

 

[VicS]

Jumping in without reading the whole thread, but I have a relay in the ground return of my VSR so it is only active when the ignition is on.

In the OPs earlier thread the merits of fitting a switch in the negative connection, so that it could be activated or deactivated at will, were discussed IIRC. I think it was eventually one of the things that went during a simplification of what had become an overly complex system.

Not quite sure I see the point of the ignition switch controlled idea. It wont be active if the engine and alternator are not is not running anyway.

The Op may need his VSR to operate when the battery chagrer is in use but I cannot remember exactly how he eventually decided to plumb in the charger

 

[xeitosaphil]

In the OPs earlier thread the merits of fitting a switch in the negative connection, so that it could be activated or deactivated at will, were discussed IIRC. I think it was eventually one of the things that went during a simplification of what had become an overly complex system.

Not quite sure I see the point of the ignition switch controlled idea. It wont be active if the engine and alternator are not is not running anyway.

The Op may need his VSR to operate when the battery chagrer is in use but I cannot remember exactly how he eventually decided to plumb in the charger

Just to confirm things, it is wired as per posted diagram. Alternator charge feed is fed direct to engine start battery positive terminal via mega fuse, alternator earth to engine block ground via earth wire and mounting bolts. Alternator not a Yanmar insolated return, but Mitsubishi normal earth return.

All negatives - Fused Distribution board neg bus, House battery shore powered charger negative, Fridge negative, Gas monitor, all fitted to Negative stud. A short length of 50mm2 negative cable, from neg stud to shunt then a length of negative 50mm2 cable to paralleled house batteries.

VSR is bi directional and wired as diagram with sensing wire taken to distribution negative bus .Red light activates almost instantly after start up to show charging both. By the time I get from cockpit to saloon its charging both.

Ammeter does show discharge minus when nothing is turned on, but I assume it is picking up its own discharge current from switched isolated supply to power the gauge? As it reads -00.0amp I assume it’s because the discharge is less than 1amp and it cannot read it?
When I turn on the galley light and saloon lights it still reads -00.0amp but these are 3 leds replacement bulbs which only total 500mA which is also below the reading range?
If I turn on saloon internal lights and push cigarette lighter on fuse panel in it reads -2.00+ amps so it must be working on the discharge side if not accurately?

As I said it only read 00.4amp when engine running and charging both batteries through VSR @ 14.55v registering on Smart Gauge. Unfortunately I don't have a clamp on meter to check what the actual charging DC current was from the alternator . My multi meter will only read up to 10A DC current, so if charge was over that it would blow it up so didn’t chance it.

Quote " Could try reversing the connections between meter and shunt to see what happens .. maybe faulty and only measuring the current in one diection. "

Could try this as I wondered the same, but it won’t damage the gauge will it? Only sensing wires are + and – , aren’t they.

I am going over the boat later, and will take some photos will post tonight.

 

[xeitosaphil]

Just to confirm things, it is wired as per posted diagram. Alternator charge feed is fed direct to engine start battery positive terminal via mega fuse, alternator earth to engine block ground via earth wire and mounting bolts. Alternator not a Yanmar insolated return, but Mitsubishi normal earth return.

All negatives - Fused Distribution board neg bus, House battery shore powered charger negative, Fridge negative, Gas monitor, all fitted to Negative stud. A short length of 50mm2 negative cable, from neg stud to shunt then a length of negative 50mm2 cable to paralleled house batteries.

VSR is bi directional and wired as diagram with sensing wire taken to distribution negative bus .Red light activates almost instantly after start up to show charging both. By the time I get from cockpit to saloon its charging both.

Ammeter does show discharge minus when nothing is turned on, but I assume it is picking up its own discharge current from switched isolated supply to power the gauge? As it reads -00.0amp I assume it’s because the discharge is less than 1amp and it cannot read it?
When I turn on the galley light and saloon lights it still reads -00.0amp but these are 3 leds replacement bulbs which only total 500mA which is also below the reading range?
If I turn on saloon internal lights and push cigarette lighter on fuse panel in it reads -2.00+ amps so it must be working on the discharge side if not accurately?

As I said it only read 00.4amp when engine running and charging both batteries through VSR @ 14.55v registering on Smart Gauge. Unfortunately I don't have a clamp on meter to check what the actual charging DC current was from the alternator . My multi meter will only read up to 10A DC current, so if charge was over that it would blow it up so didn’t chance it.

Quote " Could try reversing the connections between meter and shunt to see what happens .. maybe faulty and only measuring the current in one diection. "

Could try this as I wondered the same, but it won’t damage the gauge will it? Only sensing wires are + and – , aren’t they.

I am going over the boat later, and will take some photos will post tonight.

Now back with photos and more info.

Tried changing sensing wire over - gauge read plus when discharging and minus when charging so changed sensing wire sback as before so it does read right way around.

Photos confirm wiring diagram and show charge rate with engine charging both at 14.60v - 83% on house battery bank, ammeter reads 00.4Amp charge, engine 1050 RPM, same figures on engine battery but can't check SOC.

Could this be right if alternator has reduced charge by sensing voltage is up or should I see more charge?

Photos of cockpit locker electrics, Shore power Battery charger mega fuse, Shunt box, positive and negative studs and 4 way permanent fuse board, paralled House bank of batteries, wires yet to be organised and clipped

 

[pvb]

Photos confirm wiring diagram and show charge rate with engine charging both at 14.60v - 83% on house battery bank, ammeter reads 00.4Amp charge, engine 1050 RPM, same figures on engine battery but can't check SOC.

Could this be right if alternator has reduced charge by sensing voltage is up or should I see more charge?

I'd expect to see more current if the batteries are only 83% charged and the alternator is delivering 14.6v. Alternators can't "reduce charge" - they simply work at a set voltage, the charge rate is governed by the battery's ability to accept charge at that voltage.

You've spent a lot of time fiddling with what must be the cheapest ammeter on the market. Do you really not believe that the ammeter might simply be junk?

 

[VicS]

Now back with photos and more info.

Tried changing sensing wire over - gauge read plus when discharging and minus when charging so changed sensing wire sback as before so it does read right way around.

Photos confirm wiring diagram and show charge rate with engine charging both at 14.60v - 83% on house battery bank, ammeter reads 00.4Amp charge, engine 1050 RPM, same figures on engine battery but can't check SOC.

Could this be right if alternator has reduced charge by sensing voltage is up or should I see more charge?

Photos of cockpit locker electrics, Shore power Battery charger mega fuse, Shunt box, positive and negative studs and 4 way permanent fuse board, paralled House bank of batteries, wires yet to be organised and clipped

If the volts , presumably measured at the house battery, are 14.6 I would expect to see a higher charging current than 0.4 amps .

Two possible things to look at/try/check

Check both readings with a known good multimeter.

Try partly discharging the battery and then see what happens. It'll take a while to make a sizeable dent in the SOC but worth trying I think