I bought a 12 year old Autotrail Cheyenne Motorhome in 2020. It was in great condition, but the electrics would have been regarded as a little dated even in 2008. The following series of posts discussed the various upgrades carried out. Some of the changes mentioned I later changed further in fact, so this is pretty much a Journel of Adaption
Part Eight. Relocating the Victron Kit 2.
In Part Two I described the installation of the Victron EasyPlus and other components under the bench seat. I later decided to relocate to both tidy up the electrics and free up space under the seat.
Step 2 – Fitting the Electrics Sled
Step 2 is to fit the prepared Electrics Sled in place ready for cabling up ….
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!?).
[INFORMATION NOTE: These are different connections to the ones I had on earlier posts]
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 (AC out 1 to AC out 3) are all full-service EHU and Inverter supplied.
Working backwards, MCB 3 goes to the standard Sargent EC325 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 and are a lot more convenient there for the VE.Direct cabling to the Cerbo GX.
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).
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?
And the Locker with the auto light on at night…
Locker Fan
The locker is quite a small area and when the Multiplus is running at a fairly high level for either Charging or Inverting, it generates a fair amount of heat. The Multiplus can run pretty hot without an issue, but the output is derated as the temp increases so the lower the temperature the better for that reason as well as better for the Device components itself.
Here is a chart of the temperature in the locker as the Multiplus (EasyPlus Compact in this case) is charging the battery at an average rate of 42.5A for two hours …
In that two hour period, the locker temp went from 22C upto 37C. Still well within the operating temperature, but a fair old increase, and I wanted to address that.
So I took the locker door and changed its appearance a little ….
Added an extraction fan to the door for some forced cooling. This is controlled by a temperature controller that turns on and off depending on the temperature.
And set it up so the fan would come on when the EasyPlus hit a certain temperature by using a little programmable temp relay controller.
Once this was wired up, I put the charger on again (and actually upped the max charge rate from 45A to 52A now I have better cooling potential). And logged what happened…
Here the stating temp was 20C (before – 22C) and went up to 31C (before – 37C) so quite a difference there despite the Multiplus running harder and for 50% longer (3 Hrs rather than 2 Hrs)
You may notice the initial increase in temperature is similar to before? that is because the fan had not kicked in at that stage – you can probably predict the time the fan came out by the extended time between changes.
And as soon as the fan started operation, it made a key impact.
Initially had not quite worked out the right point to have the fan kick on yet, but this will come!
The next shot shows the Temperature against the fan running or stopped.
It cuts out earlier then I would expect and later on in the period I set the “ON” to be 25C instead of 27.5C – after which the fan stayed on for longer – and very effectively – until the temp dropped and we started to repeat the pattern to a degree.
So the vent & fan in the door is working well, but needs a bit of fine tuning so it is not just blowing for no reason (e.g. on a hot day when the Multiplus is not doing anything anyway). I think got this sussed now
Did a 50A level charge on the EasyPlus. Temperature clicks up a degree every 5 minutes or so until it hits 28C. The Fan starts up and the temperature increase slows down to 1 degree in 40 minutes.
The Lithium batteries are fully charged in a little under 2 hours, at which point the EasyPlus ‘relaxs’ a bit as it carries on to top up the Lead Carbons, albeit at a much lower rate (typical Lead Acid charge behaviour, of course) and the temperature starts to fall naturally as well as from the fan extraction.
And at 24C the fan shuts off (I set the temp controller to have a 4 degree hysteresis, so it will go off 4 degrees lower than it turns on).
So we don’t have the regular on-off like initially seen, and the on-temp is at a good compromise level – high enough so it will not (or very rarely anyway) be kicked off by ambient temperatures, and stays on long enough to have a good effect.
Going to call this a result!