wildebus
Forum Member
I think it looks "proper"
I am think maybe pull off the "LEC" badge as Motorhome fridges seem to have no branding on them nowadays?(PS - old 3-Way picked up today
)
Not a Self-build, but a Tweaker
- Thread starter wildebus
- Start date
I am think maybe pull off the "LEC" badge as Motorhome fridges seem to have no branding on them nowadays?(PS - old 3-Way picked up today
)Markd
Forum Member
You may find that there is a manifold with a valve for the fridge pipe so you can belt and brace the supply cut off?
Screenshot of Cheyenne Handbook below
Attachments
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wildebus
Forum Member
Thanks
I had already turned the Fridge Supply off at the valve (in my case, one of three located behind the fire).
FYI for anyone wondering, the Fridge Gas Supply is indicated by the 'snowflake' symbol (like the one on the far left in the photo).
On my Cheyenne I do as mentioned have two sets as well - Fridge, Space Heater and BBQ valves one side, with Boiler and Cooker valves on the other side under the seat.
wildebus
Forum Member
Brackets arrived today so completed the securing of the fridge at the rear now on the top side.
Used VHB tape on the fridge housing, and some extemely short self-tappers into the case to add some mechanical security so nicely locked into place.
And Fridge trim cut to size and offered into place ready for final securing once the new top door-lock mount arrives.
Sits nicely in the old Thetford hole.
Used VHB tape on the fridge housing, and some extemely short self-tappers into the case to add some mechanical security so nicely locked into place.
And Fridge trim cut to size and offered into place ready for final securing once the new top door-lock mount arrives.
Sits nicely in the old Thetford hole.
wildebus
Forum Member
The top and middle hinges arrived to modify into locks
Unfortunately they were both for a different fridge
Modified the top hinge fitting enough to work I think (it better! seller won't want to take it back with various holes drilled into it ) . But the middle one is going to have to go back so need to make one myself I think.
Unfortunately they were both for a different fridge
Modified the top hinge fitting enough to work I think (it better! seller won't want to take it back with various holes drilled into it
) . But the middle one is going to have to go back so need to make one myself I think.wildebus
Forum Member
Got the locks sorted out, even if at least temporarily for the bottom door.
Got limited clearance in the gap between the two doors and had a play with some knock-off "meccano" from B&M Bargains ....
It turned out to work very well so at least I have a template to work with for something permenant
Got limited clearance in the gap between the two doors and had a play with some knock-off "meccano" from B&M Bargains ....
It turned out to work very well so at least I have a template to work with for something permenant
wildebus
Forum Member
Reworked some electrics following the changeover from the 3-Way to the Compressor Fridge ...
I had installed a couple of AC Spurs a few months ago - one for the Water Boiler and one for the Fridge
These are controlled by the Cerbo GX and have power to them based on various conditions (EHU Present, SOC and AC load levels). I then turned on each spur (top to Boiler, bottom to Fridge) depending on what load I wanted to run off Electric (rather than Gas).
Now I have a 240V Compressor Fridge I want power to that to be always available, so rerouted the Fridge line to connect back to the default Supply out the Sargent unit - but with a slight twist ... still routed through an SSR (Solid State Relay), but for the fridge I control the SSR via the BMV-712 Relay. I don't intend to use any programming to switch the Fridge supply on and off, but it is just a way to be able to remotely turn the fridge off and on if I find I won't be using it for a while, or if off and I decide to I am going out in the van the next day I can turn it off or on from the house using VE.Connect via VRM
Maybe a bit of a gimmick, but the wiring and options were there so thought "why not"
The Water Boiler I still want to have the orginal level of control, but if I am specifically controlling the Fridge On and Off via the BMV Relay, I don't want the Switched Spur so removed it.
That left a hole so would to do with it? Well, thought may as well fit an 13A Socket
This outlet is controlled in the same way as the AC Spur above, with the various Cerbo GX conditions coming into play, which is fine.
I have a couple of potential uses for this outlet, including for example a laptop charger (I store the laptop and charger in one of the lower cupboards and this would allow me to also charge it in situ
I had installed a couple of AC Spurs a few months ago - one for the Water Boiler and one for the Fridge
These are controlled by the Cerbo GX and have power to them based on various conditions (EHU Present, SOC and AC load levels). I then turned on each spur (top to Boiler, bottom to Fridge) depending on what load I wanted to run off Electric (rather than Gas).
Now I have a 240V Compressor Fridge I want power to that to be always available, so rerouted the Fridge line to connect back to the default Supply out the Sargent unit - but with a slight twist ... still routed through an SSR (Solid State Relay), but for the fridge I control the SSR via the BMV-712 Relay. I don't intend to use any programming to switch the Fridge supply on and off, but it is just a way to be able to remotely turn the fridge off and on if I find I won't be using it for a while, or if off and I decide to I am going out in the van the next day I can turn it off or on from the house using VE.Connect via VRM
Maybe a bit of a gimmick, but the wiring and options were there so thought "why not"
The Water Boiler I still want to have the orginal level of control, but if I am specifically controlling the Fridge On and Off via the BMV Relay, I don't want the Switched Spur so removed it.
That left a hole so would to do with it? Well, thought may as well fit an 13A Socket
This outlet is controlled in the same way as the AC Spur above, with the various Cerbo GX conditions coming into play, which is fine.
I have a couple of potential uses for this outlet, including for example a laptop charger (I store the laptop and charger in one of the lower cupboards and this would allow me to also charge it in situ
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wildebus
Forum Member
Next month will be the 1st anniversary of owning my Autotrail Cheyenne Motorhome
And I thought I would celebrate the fact by reworking my electrics now they are pretty settled in what I have fitted and future enhancements.
Step one was to rerun all the cabling in preparation ....
It may not look like it, but this is pretty well the "after" shot
There are a few more cables to relocate which will be done in a few days time.
Battery Bank location adjusted. Still using the under-sofa storage but repositioned the Lead Carbons to be both against the front and get some of the weight more in the centre (L-R centre that is).
The Lithium Battery is against the Leads but positioned lengthways. The reason for this is two-fold. It keeps the storage area to the rear a little squarer in space; and it will also let me add a potential second Lithium end on with cabling that would be very straightforward to adapt by just adding a pair of battery interconnects and moving the current -ve cable to the additional battery (cable already sized ready for this).
So the 3 PbC (Lead Carbon) Batteries are set up in parallel in a regular way. The -ve is connected to a dedicated Shunt for a BMV-700.
The LiFePO4 (Lithium) -ve is connected to its own BMV-700 Shunt and the two Shunt LOADs are then connected to a 3rd Shunt which is for a BMV-712.
The +ve's for the Batteries are setup in a slightly unusual but flexible way.
In the picture above you can see a Green cable coming off the PbC Battery Bank; and a Yellow cable of the LiFePO4 Battery. I decided to colour-code them for easy future identification when I have forgotten what I have done and can refer to the wiring diagram (that I always initially do for future reference but forget to update usually )
The Green and Yellow Cables go to a Isolation Switch that has two inputs and one output.
It is always a good idea to have an isolation switch between the Battery Bank and the Loads & Chargers. In this case, as well as having that switch in situ, using a 4-position switch meant that I could do any of the following:
OFF: disconnect all the Batteries
1: Use the LiFePO4 Battery on its own
2: Use the PbC Battery Bank on its own
1+2: Use both PbC Bank and LiFePO4 Battery as a parallel Hybrid bank. This would be the standard operating mode and also is very simple way to get the two battery types cabled up in parallel.
After the isolation switch, which is useful for maintenance purposes, I have what is referred to as a "catastrophic fuse". The purpose of this is if there is a serious malfunction of a device or physical damage to a cable resulting in a short or near-short, this fuse will blow and cut off the battery power to prevent further risk.
Size wise, these should be larger than any possible loads you are likely to have and below the amapacity (current capability) of the cabling as you don't want the cables acting as the fuse.
For info, this is the fuse setup above in more detail ...
The Catastrophic Fuse is 225A.
This is fairly low in many ways and if you had say a big 3000W inverter you would exceed that current easily. But this is something where you choose the size based on your own system. My own regular maximum load would be from the inverter in the EasyPlus, which is 1300W, which with inverter overhead means upto 120A draw, plus upto 20A maximum on the Habitation electrics - so I need to accomodate around 150A. Potential surge on the inverter of around 60A from the fridge (lasting around 2 seconds) and so looking at around the 200A area worse case so the 225A I have should never blow in normal service but is lower than the ampacity of the cable - which is 240A constant current.
The Fuse below that is an 80A one and is there for protection on the cabling for the 60A Ablemail B2B. I have an 80A on both the input and output sides.
The final fuses are for the habitation electrics. The +ve is 30A, which is more than can actually be delivered by the source but again is within the current spec of the cable; I have a fuse on the -ve Hab electrics also, of 100A. It is not needed to fuse the -ve cable but I did so simply because it was easier and neater (and cheaper!) to just use another fuse holder rather than find a busbar.
I am relocating all the Victron kit and general 12V stuff to a new place, but I am keeping my Ablemail kit in the front in the gap between Batteries by the batteries for efficiency give the starter battery is of course at the front.
So the AMC 12-12-60 Programmable Battery-to-Battery charger is the main device (connected to the battery bank via 16mm2 cable); Next to the B2B there is an AMT12-2 Battery Maintainer; and finally there is the ABB07 Bluetooth Device that can be used to both program and read various Ablemail units. Here I am using it on the AMC B2B.
A further update showing the Victron and other kit will follow
And I thought I would celebrate the fact by reworking my electrics now they are pretty settled in what I have fitted and future enhancements.
Step one was to rerun all the cabling in preparation ....
It may not look like it, but this is pretty well the "after" shot
There are a few more cables to relocate which will be done in a few days time.
Battery Bank location adjusted. Still using the under-sofa storage but repositioned the Lead Carbons to be both against the front and get some of the weight more in the centre (L-R centre that is).
The Lithium Battery is against the Leads but positioned lengthways. The reason for this is two-fold. It keeps the storage area to the rear a little squarer in space; and it will also let me add a potential second Lithium end on with cabling that would be very straightforward to adapt by just adding a pair of battery interconnects and moving the current -ve cable to the additional battery (cable already sized ready for this).
So the 3 PbC (Lead Carbon) Batteries are set up in parallel in a regular way. The -ve is connected to a dedicated Shunt for a BMV-700.
The LiFePO4 (Lithium) -ve is connected to its own BMV-700 Shunt and the two Shunt LOADs are then connected to a 3rd Shunt which is for a BMV-712.
The +ve's for the Batteries are setup in a slightly unusual but flexible way.
In the picture above you can see a Green cable coming off the PbC Battery Bank; and a Yellow cable of the LiFePO4 Battery. I decided to colour-code them for easy future identification when I have forgotten what I have done and can refer to the wiring diagram (that I always initially do for future reference but forget to update usually
)The Green and Yellow Cables go to a Isolation Switch that has two inputs and one output.
It is always a good idea to have an isolation switch between the Battery Bank and the Loads & Chargers. In this case, as well as having that switch in situ, using a 4-position switch meant that I could do any of the following:
OFF: disconnect all the Batteries
1: Use the LiFePO4 Battery on its own
2: Use the PbC Battery Bank on its own
1+2: Use both PbC Bank and LiFePO4 Battery as a parallel Hybrid bank. This would be the standard operating mode and also is very simple way to get the two battery types cabled up in parallel.
After the isolation switch, which is useful for maintenance purposes, I have what is referred to as a "catastrophic fuse". The purpose of this is if there is a serious malfunction of a device or physical damage to a cable resulting in a short or near-short, this fuse will blow and cut off the battery power to prevent further risk.
Size wise, these should be larger than any possible loads you are likely to have and below the amapacity (current capability) of the cabling as you don't want the cables acting as the fuse.
For info, this is the fuse setup above in more detail ...
The Catastrophic Fuse is 225A.
This is fairly low in many ways and if you had say a big 3000W inverter you would exceed that current easily. But this is something where you choose the size based on your own system. My own regular maximum load would be from the inverter in the EasyPlus, which is 1300W, which with inverter overhead means upto 120A draw, plus upto 20A maximum on the Habitation electrics - so I need to accomodate around 150A. Potential surge on the inverter of around 60A from the fridge (lasting around 2 seconds) and so looking at around the 200A area worse case so the 225A I have should never blow in normal service but is lower than the ampacity of the cable - which is 240A constant current.
The Fuse below that is an 80A one and is there for protection on the cabling for the 60A Ablemail B2B. I have an 80A on both the input and output sides.
The final fuses are for the habitation electrics. The +ve is 30A, which is more than can actually be delivered by the source but again is within the current spec of the cable; I have a fuse on the -ve Hab electrics also, of 100A. It is not needed to fuse the -ve cable but I did so simply because it was easier and neater (and cheaper!) to just use another fuse holder rather than find a busbar.
I am relocating all the Victron kit and general 12V stuff to a new place, but I am keeping my Ablemail kit in the front in the gap between Batteries by the batteries for efficiency give the starter battery is of course at the front.
So the AMC 12-12-60 Programmable Battery-to-Battery charger is the main device (connected to the battery bank via 16mm2 cable); Next to the B2B there is an AMT12-2 Battery Maintainer; and finally there is the ABB07 Bluetooth Device that can be used to both program and read various Ablemail units. Here I am using it on the AMC B2B.
A further update showing the Victron and other kit will follow
wildebus
Forum Member
Whilst the Motorhome has been away at the garage to get the handbrake sorted, been working on the other end of "alien resurrection" and finished the Victron 'sled' to go into the locker and attach all the cables to...
So this is my new 'control centre' - nothing actually really new in terms of devices, just now I have (I think!) finalised my electrics setup, wanted to have a tidier setup for maintenance and servicing.
Everything is mounted on a 'sled' which can be put into position with just the external connections needed to be made.
The main Battery +12V and 0V are via 16mm2 cable, which is more than adequate for the current loads possible here.
The Cerbo uses a variety of connections - VE.Direct, RJ45, HDMI, USB and Jumper Blocks
For the other various cables I am utilizing DIN-Rail mounted connectors - screw terminals for the various Power +ve and -ve connections, including all the Solar connections (excepting the Battery), and Wago-style lever conductors for the SSR and AES Control wiring.
Bit more detail below for that....
Each cable going into the screwdown terminals has a number tag on it so if I am having to do any disconnections I won't need to guess where the cable needs to go. And where there is duplication (on the two solar controllers), I have designated the Roof Array Controller "Green"and marked the cables to the connector block in Green to distinguish from the Portable Arrays controller and cabling.
Now you may wonder why I have a Input here for +12V when there is already an input with a the big cable to the left? Simply because if I disconnect the battery via the isolation switch, I probably still want power to devices such as the Cerbo GX, and to a light that I will be fitting in the locker and will want powered if I am doing any maintenance to the system (and so likely want the main power off).
I am bringing in Starter Battery +12V as well to the board, but not sure if I will be using it. There is a connection on the EasyPlus to give a 4A charge to a secondary (e.g. Starter) battery which I might connect up, but I have the AMT12 Trickle Charger which works with Solar as well as EHU so is better really. It could be handy just to be able to access it for investigation purposes or other possible options (say an alarm, which often operates by detecting a drop in Starter Battery voltage when a cab door is opened)
So this is my new 'control centre' - nothing actually really new in terms of devices, just now I have (I think!) finalised my electrics setup, wanted to have a tidier setup for maintenance and servicing.
Everything is mounted on a 'sled' which can be put into position with just the external connections needed to be made.
The main Battery +12V and 0V are via 16mm2 cable, which is more than adequate for the current loads possible here.
The Cerbo uses a variety of connections - VE.Direct, RJ45, HDMI, USB and Jumper Blocks
For the other various cables I am utilizing DIN-Rail mounted connectors - screw terminals for the various Power +ve and -ve connections, including all the Solar connections (excepting the Battery), and Wago-style lever conductors for the SSR and AES Control wiring.
Bit more detail below for that....
Each cable going into the screwdown terminals has a number tag on it so if I am having to do any disconnections I won't need to guess where the cable needs to go
. And where there is duplication (on the two solar controllers), I have designated the Roof Array Controller "Green"and marked the cables to the connector block in Green to distinguish from the Portable Arrays controller and cabling.Now you may wonder why I have a Input here for +12V when there is already an input with a the big cable to the left? Simply because if I disconnect the battery via the isolation switch, I probably still want power to devices such as the Cerbo GX, and to a light that I will be fitting in the locker and will want powered if I am doing any maintenance to the system (and so likely want the main power off).
I am bringing in Starter Battery +12V as well to the board, but not sure if I will be using it. There is a connection on the EasyPlus to give a 4A charge to a secondary (e.g. Starter) battery which I might connect up, but I have the AMT12 Trickle Charger which works with Solar as well as EHU so is better really. It could be handy just to be able to access it for investigation purposes or other possible options (say an alarm, which often operates by detecting a drop in Starter Battery voltage when a cab door is opened)
wildebus
Forum Member
Thanks
My old setup was quite messy as it kept changing as I adapted and tweaked it.
Then a couple of things spurred me into action ... squirrelcooks excellent system board layout looked so much easy to work with and logical; and my YouTube friend Clark with his DIY Air-Con build for his boat all laid out on a board (sled) that he can build on the bench and just push into place and make the final connections meant much less bending over an sofa frame and contorting yourself.
The colour-coding and cable tags I think will be handy going into the future when I have forgotten what is what and so will remind me what is meant to go where
Raining currently so can't finish off the connecting up, but partly completed and got the Cerbo powerered up again and all is good so far
wildebus
Forum Member
Been raining on and off (mostly on ) for the last couple of days so taken a while to get the connecting up all done.
Both MPPT Controllers PV in and Load out cable pairs installed, as are the SSR and AES switch cables, plus the +12V and Ground connections in place.
I decided to move the top enclosure box along a bit as I have another one to install for the Cerbos Digital IO inputs which would be best on the left hand side of the board.
On the right is fitted the Battery Isolation switch for the Locker, and alongside that I fitted a 13A socket which could be handy for various purposes (there is an external AC socket on the other side of the van also).
(need to do some dusting I think after a bit of wood cutting!)
Rather than a Victron Multiplus, I have the Victron EasyPlus. Essentially the same device but with the addtion of an integrated Consumer Unit. This is very useful even when there is an existing consumer unit in the Motorhome as it gives extra flexibility.
Left to Right, there is the Primary On/Off Breaker (Input).
This then supplies the RCD (Output) that feeds the various MCBs. Note that the RCD goes direct to the MCB Bank and provide protection on all the circuits however they are supplied, be it AC on Hookup or Inverter power.
I added labels to the various Breakers to remind me what I am using them for. (I know now, but in a years time? or even a month!?).
The first one - Labeled "Boiler" (and MCB 0 also) is only live when EHU is plugged in. This I have reserved for the Truma UltraHeat Room Heater as it is really only practical to run that on mains.
MCB 1 to MCB 3 are all full-service EHU and Inverter supplied.
Working backwards, MCB 3 goes to the standard Sargent EC328 which then distributes power pretty well as before (except it no longer supplies the Ultraheat, of course).
MCB 2 is the dedicated output to the External and Locker AC sockets.
MCB 1 is not connected to anything. Potentially I could move the Ultraheat from MCB 0 to MCB1 and use the Room Heater on the battery for a limited time if "caught short" with no LPG to run the heater. Not something which I plan to do, but handy to have the contingency available.
Final bit of the installation is a proper home for the two BMV-700s fitted to the different Battery types in the Hybrid Bank.
I look at the info on them via Victrons VRM system and the Cerbo GX Console, but never on the displays themselves unless working on the setup, so having them in the locker should work well
Got the Digital IO side to finish off and that should be it
) for the last couple of days so taken a while to get the connecting up all done.Both MPPT Controllers PV in and Load out cable pairs installed, as are the SSR and AES switch cables, plus the +12V and Ground connections in place.
I decided to move the top enclosure box along a bit as I have another one to install for the Cerbos Digital IO inputs which would be best on the left hand side of the board.
On the right is fitted the Battery Isolation switch for the Locker, and alongside that I fitted a 13A socket which could be handy for various purposes (there is an external AC socket on the other side of the van also).
(need to do some dusting I think after a bit of wood cutting!)
Rather than a Victron Multiplus, I have the Victron EasyPlus. Essentially the same device but with the addtion of an integrated Consumer Unit. This is very useful even when there is an existing consumer unit in the Motorhome as it gives extra flexibility.
Left to Right, there is the Primary On/Off Breaker (Input).
This then supplies the RCD (Output) that feeds the various MCBs. Note that the RCD goes direct to the MCB Bank and provide protection on all the circuits however they are supplied, be it AC on Hookup or Inverter power.
I added labels to the various Breakers to remind me what I am using them for. (I know now, but in a years time? or even a month!?).
The first one - Labeled "Boiler" (and MCB 0 also) is only live when EHU is plugged in. This I have reserved for the Truma UltraHeat Room Heater as it is really only practical to run that on mains.
MCB 1 to MCB 3 are all full-service EHU and Inverter supplied.
Working backwards, MCB 3 goes to the standard Sargent EC328 which then distributes power pretty well as before (except it no longer supplies the Ultraheat, of course).
MCB 2 is the dedicated output to the External and Locker AC sockets.
MCB 1 is not connected to anything. Potentially I could move the Ultraheat from MCB 0 to MCB1 and use the Room Heater on the battery for a limited time if "caught short" with no LPG to run the heater. Not something which I plan to do, but handy to have the contingency available.
Final bit of the installation is a proper home for the two BMV-700s fitted to the different Battery types in the Hybrid Bank.
I look at the info on them via Victrons VRM system and the Cerbo GX Console, but never on the displays themselves unless working on the setup, so having them in the locker should work well
Got the Digital IO side to finish off and that should be it
wildebus
Forum Member
I sold an Easy Solar a couple of weeks ago to go into a Hymer. That's an EasyPlus with extr height to accomodate an MPPT 100/50.Very organised - if that's the "compact" Easy Plus I wouldn't like to have to be fitting the standard size
wildebus
Forum Member
Fitted the Digital IO Box for the Cerbo GX now.
Bit of background on the Victron Cerbo GX Digital IO ports ... The Cerbo has 4 IO Ports (which as far as I can tell are not really IO (In/Out) but just IN) and the unit detects for the presence of a high or low signal and reports the status of the port on the Console, or VRM or can send an alarm.
A key thing ... these ports have a maximum of 5V - you cannot connect a 12V level wire (which is what the typical motorhome or campervan will provide). So the usual way to connect to these is using an opto-isolator - such as the one on the photo above. This detects a high on the input and then sets the output to match, but at the different voltage. In the board above, it accepts a 12V input and sends out a 3.3V output (The Cerbo has a max of 5V but is fine with the lower 3.3V)
You need to supply the output side with DC Power matching the output, and the little board at the top is a regulator dropping a 12V supply down to 3.3V
The board is a tight fit in the box I am using so I decided to run the 4 input +ve's to 2-wire Wagos for ease of connecting. The 4 input -ve's are all connected together and goes to the -ve line from the power lead in (the -ve will be common on everything so grouping them will work fine).
Right now I have two inputs connected (and you see 2 pairs of red LEDs lit).
One is the connection to a door switch I fitted to the locker door opening - This is set up so some lights come on when the door is opened (handy for maintenance) and I also get a flag and alarm set when the door is opened (handy for security).
The Second tells me when the engine is running (pretty obvious you may think, but it means you actually have a log of the time and can use it to analyse charging info maybe?
To get this input I am using the Starter Battery +12V I brought into the Locker (I knew I would have some used for it ) and run it through a TEC3M, which is a basic VSR (Voltage Sensing Relay) that turns on automatically when the engine starts and Starter Battery voltage rises.
These are generally used for Towing Electrics and sometimes 3-Way Fridges when switching to the 12V supply avoiding the use of the D+ Alternator line. They are also pretty cheap (around £10) and reliable, and I happened to have one kicking around
This "engine running" function is probably more typically used for a Generator so you can log running hours (schedule oil changes, say?). I could use one of the other IO inputs for just this purpose as my Generator has no run-counter on it.
Something I will be using one of the inputs for is to monitor an extraction fan I will be fitting in the locker to help cooling (High current chargers and inverters generate a fair bit of heat and the Victron Multipluses are no exception).
The screen grab below shows the IO ports and the definition of each.
Now got the covers on the two control boxes and labelled up so I will remember what they are for down the line!
And apart from the Vent & Fan that will be fitted in next couple of weeks, the electrics revamp is pretty well done!
I didn't count up just so many +ve connections to a "control 12V" when I planned the board. The in-line glass fuse holders work fine but I could have fitted a 10-Way Blade Fuse holder with -ve Busbar instead which might have looked neater?
Bit of background on the Victron Cerbo GX Digital IO ports ... The Cerbo has 4 IO Ports (which as far as I can tell are not really IO (In/Out) but just IN) and the unit detects for the presence of a high or low signal and reports the status of the port on the Console, or VRM or can send an alarm.
A key thing ... these ports have a maximum of 5V - you cannot connect a 12V level wire (which is what the typical motorhome or campervan will provide). So the usual way to connect to these is using an opto-isolator - such as the one on the photo above. This detects a high on the input and then sets the output to match, but at the different voltage. In the board above, it accepts a 12V input and sends out a 3.3V output (The Cerbo has a max of 5V but is fine with the lower 3.3V)
You need to supply the output side with DC Power matching the output, and the little board at the top is a regulator dropping a 12V supply down to 3.3V
The board is a tight fit in the box I am using so I decided to run the 4 input +ve's to 2-wire Wagos for ease of connecting. The 4 input -ve's are all connected together and goes to the -ve line from the power lead in (the -ve will be common on everything so grouping them will work fine).
Right now I have two inputs connected (and you see 2 pairs of red LEDs lit).
One is the connection to a door switch I fitted to the locker door opening - This is set up so some lights come on when the door is opened (handy for maintenance) and I also get a flag and alarm set when the door is opened (handy for security).
The Second tells me when the engine is running (pretty obvious you may think, but it means you actually have a log of the time and can use it to analyse charging info maybe?
To get this input I am using the Starter Battery +12V I brought into the Locker (I knew I would have some used for it
) and run it through a TEC3M, which is a basic VSR (Voltage Sensing Relay) that turns on automatically when the engine starts and Starter Battery voltage rises.These are generally used for Towing Electrics and sometimes 3-Way Fridges when switching to the 12V supply avoiding the use of the D+ Alternator line. They are also pretty cheap (around £10) and reliable, and I happened to have one kicking around
This "engine running" function is probably more typically used for a Generator so you can log running hours (schedule oil changes, say?). I could use one of the other IO inputs for just this purpose as my Generator has no run-counter on it.
Something I will be using one of the inputs for is to monitor an extraction fan I will be fitting in the locker to help cooling (High current chargers and inverters generate a fair bit of heat and the Victron Multipluses are no exception).
The screen grab below shows the IO ports and the definition of each.
Now got the covers on the two control boxes and labelled up so I will remember what they are for down the line!
And apart from the Vent & Fan that will be fitted in next couple of weeks, the electrics revamp is pretty well done!
I didn't count up just so many +ve connections to a "control 12V" when I planned the board. The in-line glass fuse holders work fine but I could have fitted a 10-Way Blade Fuse holder with -ve Busbar instead which might have looked neater?