SquirrellCook
Forum Member
This is what I’ll do, but with 12 volts charging 24 Volts. I think I’ll also try some foldable solar panels hanging on the side of the bus into a dedicated mppt. Should work for a few hours if the sun is out.
Not a Self-build, but a Tweaker
- Thread starter wildebus
- Start date
st3v3
Forum Member
I have 24V engine and 12V hab. What can I use to keep the starter topped up? I'm using a mains charger through the inverter at the moment - not ideal.
wildebus
Forum Member
You could use something like this maybe if just used for a trickle?
DC to DC Voltage Regulator Step Up Converter Power Unit Module 3-35V to 5V-45V 5A
I used a very similar device to provide a set 15V for an Amazon Echo and seemed pretty solid. dial in the voltage output you want with the blue pot. could combine it with a timer device to provide a pulsing trickle if you wanted to get funky?
The "best" way would probably be a 12V-24V B2B working in the reverse way to the regular 24V-12V B2B you may have fitted for charging when driving but a definate expense . depends how much energy you are ok to waste in the various voltage conversions
st3v3
Forum Member
You could use something like this maybe if just used for a trickle?
DC to DC Voltage Regulator Step Up Converter Power Unit Module 3-35V to 5V-45V 5A
I used a very similar device to provide a set 15V for an Amazon Echo and seemed pretty solid. dial in the voltage output you want with the blue pot. could combine it with a timer device to provide a pulsing trickle if you wanted to get funky?
The "best" way would probably be a 12V-24V B2B working in the reverse way to the regular 24V-12V B2B you may have fitted for charging when driving but a definate expense . depends how much energy you are ok to waste in the various voltage conversions
Ta. I wonder how that board will fare with over the set voltage on it's output, with no input. Would probably have to disconnect that with another relay I guess.
wildebus
Forum Member
You mean if there was a energy source on the output so some reverse voltage? that is a fair point and in my case not something I tried. You would need to check if 24V sitting on the output would bump the input voltage up as well (I would hope not but who knows with this kind of cheap kit?).
Ablemail make a range of 12v-24V converters that can be used as Chargers - there is a lowish current (6A) version.... https://ablemail.co.uk/dc-dc-voltag...tage_value=12V&field_output_voltage_value=24V
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SquirrellCook
Forum Member
Using the Victron DC DC charger it should virtually go to sleep once it's happy the 24 volt battery is charged.
I found if I left the victron 24 volt mains charger on all the time it did not hit the 12 volt batteries as hard as turning on the charger in the morning.
I have the 12 volt victron inverter running all the time for the fridge. Though if the 24 volt charger is on bulk, the 12 volt batteries loose amps like there is a hole in the bottom.
I found if I left the victron 24 volt mains charger on all the time it did not hit the 12 volt batteries as hard as turning on the charger in the morning.
I have the 12 volt victron inverter running all the time for the fridge. Though if the 24 volt charger is on bulk, the 12 volt batteries loose amps like there is a hole in the bottom.
st3v3
Forum Member
Yea, that's what I was saying. Can't see a price for ablemail, any idea roughly?
wildebus
Forum Member
I know the costs for the 30A units. not sure on the smaller ones. I can find out, but I would say looking at around £150 ballpark
st3v3
Forum Member
Ok. The victron is probably going to work out cheaper as we can get 0 VAT. And that's Bluetooth lol
wildebus
Forum Member
Been playing around with Node-Red .... I think the nodes could generally be a lot more logical and straightforward. What should (IMO) be a very simple interface involves too much back-end programming per node. Great idea but implementation .... hmmmm.
So looking at alternatives just for fun, decided to look at "Home Assistant". This looks interesting as you can bring in information from multiple sources as it is an "IoT" type of product.
With this you can apparently view and control Alexa enabled products - and possibly (not sure of this one yet) control with Alexa stuff that you have brought into Home Assistant?
That could be good if you could say bring in Victron Kit into Home Assistant and then control via Alexa? .... "Alexa, turn on the Multiplus Charger"
Minimal of work involved with the Venus OS device - just need to enable an interface protocol - I am using Modbus/TCP (MQTT is also an option you can use I believe), pull up the device addresses and make a note of everything you can interrogate. Start of the list below...
Then it is a matter of editing some setup/config files in Home Assistant to decide what you want to bring into HA. This screenshot shows some of the stuff that is in my overview screen ....
Got Weather info brought in from an external source; Info on the quality of power on the RPi Supply (Installed Home Assistant on a Raspberry Pi); Ink Levels on an HP Printer that is on the network; plus the state of charge on the three Victron BMVs in the Motorhome.
Quite an electic mix of stuf there
Of course, a key reason of setting up a Home Assistant install is to get Motorhome Info, so I have initially created a "Battery Info" Dashboard page as a trial, looking at the Battery Banks and power demands. From this I can see the draws and how the different Banks are providing their side of the demand in a nice graphical view.
The Graphs are also configured with Green/Amber/Red sections applicable to each Battery Bank and their technologies, as well as the Load mix.
Going to also look at Grafana which I think has some very nice design features when it comes to graphing and presentation and has an interface to Home Assistant.
What is also key is that using Home Assistant to draw in information from the Victron kit has no impact on what you do currently, so you can continue to use any tools that are in place, so for example, I can view Battery Info in Home Assistant, Node-Red, VRM, the Cerbo GX Screen or VE.Connect (and the physical displays as well of course), so a super-flexible setup there.
So looking at alternatives just for fun, decided to look at "Home Assistant". This looks interesting as you can bring in information from multiple sources as it is an "IoT" type of product.
With this you can apparently view and control Alexa enabled products - and possibly (not sure of this one yet) control with Alexa stuff that you have brought into Home Assistant?
That could be good if you could say bring in Victron Kit into Home Assistant and then control via Alexa? .... "Alexa, turn on the Multiplus Charger"
Minimal of work involved with the Venus OS device - just need to enable an interface protocol - I am using Modbus/TCP (MQTT is also an option you can use I believe), pull up the device addresses and make a note of everything you can interrogate. Start of the list below...
Then it is a matter of editing some setup/config files in Home Assistant to decide what you want to bring into HA. This screenshot shows some of the stuff that is in my overview screen ....
Got Weather info brought in from an external source; Info on the quality of power on the RPi Supply (Installed Home Assistant on a Raspberry Pi); Ink Levels on an HP Printer that is on the network; plus the state of charge on the three Victron BMVs in the Motorhome.
Quite an electic mix of stuf there
Of course, a key reason of setting up a Home Assistant install is to get Motorhome Info, so I have initially created a "Battery Info" Dashboard page as a trial, looking at the Battery Banks and power demands. From this I can see the draws and how the different Banks are providing their side of the demand in a nice graphical view.
The Graphs are also configured with Green/Amber/Red sections applicable to each Battery Bank and their technologies, as well as the Load mix.
Going to also look at Grafana which I think has some very nice design features when it comes to graphing and presentation and has an interface to Home Assistant.
What is also key is that using Home Assistant to draw in information from the Victron kit has no impact on what you do currently, so you can continue to use any tools that are in place, so for example, I can view Battery Info in Home Assistant, Node-Red, VRM, the Cerbo GX Screen or VE.Connect (and the physical displays as well of course), so a super-flexible setup there.
SquirrellCook
Forum Member
It seems like another world to where I am. I’m failing a three pin polarity checking plug. Live and neutral crossed and live on the earth. Sounds like I have some wiring the wrong way round. Though I have had a thought. If the Multiplus has never seen the mains, how would it know what is correct?
xsilvergs
Forum Member
My Phoenix Inverter has an internal link which can be changed to tie the Earth to Neutral or not.
From previous experience here, I'm afraid to say much...
wildebus
Forum Member
My 240V AC domestic Fridge/Freezer is operating in the same way as a typical domestic fridge/freezer I have found .... It is not really keen on being in the equivalent of an unheated garage or shed. The fridge section carries on working but the freezer part turns off
I think I will try and add some insulation at the rear as currently got the Thetford vents top and bottom that let out any built-up heat from the compressor running so the rear compartment is always very cold this time of year.
I might even try just plugging an old-fashioned incandescent light in there which will warm up the compartment. Could run this via a temp sensor so it only comes on when the temp drops below a certain (TBC) temperature.
Not a problem generally as most of the year we are not down to the 'problem' temp and don't really go camping in proper wintertime so fridge is not used at those really low temps, but I do always tend to use the campervan fridges as extra storage over Christmas.
I think I will try and add some insulation at the rear as currently got the Thetford vents top and bottom that let out any built-up heat from the compressor running so the rear compartment is always very cold this time of year.
I might even try just plugging an old-fashioned incandescent light in there which will warm up the compartment. Could run this via a temp sensor so it only comes on when the temp drops below a certain (TBC) temperature.
Not a problem generally as most of the year we are not down to the 'problem' temp and don't really go camping in proper wintertime so fridge is not used at those really low temps, but I do always tend to use the campervan fridges as extra storage over Christmas.
SquirrellCook
Forum Member
I made sure I purchased a SN T freezer that lives outside. The documents said it was unsuitable for a garage / shed. It’s a good job it’s outside then. No problems.
wildebus
Forum Member
Been doing some work on the Fridge/Freezer to try and make it more effective in the Motorhome (as mentioned above, the Freezer was defrosting because, I think, the rear was too cold).
The other issue I have in this area is I get a cold draft coming through from the rear compartment through the sides of the Fridge and top and through the little gap openings I have for the hinges.
First thing was to move the Temp Sensor from the Top Fridge Section to the Bottom Freezer Section. When the Freezer goes to its defrost mode, the Fridge temp doesn't go up for a long while so you don't get to know about the Freezer until too late So now with the Sensor in the Freezer, I can set a system alarm if the Freezer goes above say -12C (exact number to be determined) and catch the issue before food gets spoiled.
The Graph shows the Sensor while it was in the Fridge until shortly before Noon, then about half an hour later, after repositioning it in the Freezer and turning the Fridge back on, the temp falls rapidly and the freezer is back to its working temp within 2 hours. (I need to relabel the sensor as well now )
Updated the Alarm as well. Right now set to -10 to alarm and -14 to clear. Probably tweak that once I have a days worth of monitoring and can see what kind of temp variation there is (usually have some kind of cycling on the temp and don't want an alarm due to a normal cycle increase).
To fix the Cold Drafts, put some insulation on the sides and top at the back.
When I fitted the Fridge originally, the instructions were to not insulate around it, so I left it totally open. Didn't consider the draft issue though and heat loss so adding the insulation but only at the rear of the sides and top to prevent the drafting coming through without enclosing the whole side area. I think this will also help the rear of the fridge compartment stay warmer as well and help with the defrost situation. Time will tell
I used the Diall Loft insulation from B&Q. Find it very good generally (used on camper conversions) and is made from recycled Plastic Bottles and holds zero moisture.
Still have the fan kit at the bottom of course which is for summertime use
and I haven't blocked the flow from bottom to top vents to allow heat to escape - although currently I have covered the vent with cardboard (bit like you used to do with Radiators in the winter in the old days. An cheaper alternative to getting Winter Vents (but would not be a good idea on a gas fridge with potential flame and sparks mind!)
Can't see either the cardboard or the fan kit once the covers are back on
So next is to keep an eye on how the freezer is going and if I need to doing anything else. I was thinking of maybe adding a slight heat source if the temp drops, but I could also use some of the leftover insulation to add a temporary insulation batt above the lower vent in the cooler months to enclose the area around the compressor and retain generated heat. (Need to remember it is fitted, mind!)
The other issue I have in this area is I get a cold draft coming through from the rear compartment through the sides of the Fridge and top and through the little gap openings I have for the hinges.
First thing was to move the Temp Sensor from the Top Fridge Section to the Bottom Freezer Section. When the Freezer goes to its defrost mode, the Fridge temp doesn't go up for a long while so you don't get to know about the Freezer until too late
So now with the Sensor in the Freezer, I can set a system alarm if the Freezer goes above say -12C (exact number to be determined) and catch the issue before food gets spoiled.The Graph shows the Sensor while it was in the Fridge until shortly before Noon, then about half an hour later, after repositioning it in the Freezer and turning the Fridge back on, the temp falls rapidly and the freezer is back to its working temp within 2 hours. (I need to relabel the sensor as well now
)Updated the Alarm as well. Right now set to -10 to alarm and -14 to clear. Probably tweak that once I have a days worth of monitoring and can see what kind of temp variation there is (usually have some kind of cycling on the temp and don't want an alarm due to a normal cycle increase).
To fix the Cold Drafts, put some insulation on the sides and top at the back.
When I fitted the Fridge originally, the instructions were to not insulate around it, so I left it totally open. Didn't consider the draft issue though and heat loss so adding the insulation but only at the rear of the sides and top to prevent the drafting coming through without enclosing the whole side area. I think this will also help the rear of the fridge compartment stay warmer as well and help with the defrost situation. Time will tell
I used the Diall Loft insulation from B&Q. Find it very good generally (used on camper conversions) and is made from recycled Plastic Bottles and holds zero moisture.
Still have the fan kit at the bottom of course which is for summertime use
and I haven't blocked the flow from bottom to top vents to allow heat to escape - although currently I have covered the vent with cardboard (bit like you used to do with Radiators in the winter in the old days. An cheaper alternative to getting Winter Vents (but would not be a good idea on a gas fridge with potential flame and sparks mind!)
Can't see either the cardboard or the fan kit once the covers are back on
So next is to keep an eye on how the freezer is going and if I need to doing anything else. I was thinking of maybe adding a slight heat source if the temp drops, but I could also use some of the leftover insulation to add a temporary insulation batt above the lower vent in the cooler months to enclose the area around the compressor and retain generated heat. (Need to remember it is fitted, mind!)
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wildebus
Forum Member
Fridge is still in need of tuning. It goes off but won't come on again - something is telling it it doesn't need to. It worked fine last time I was away on a trip last autumn and I do think it is ambient temp related.
The checking overnight ended up a bit flawed as after I put the fan kit vent back on, I turned in on to check it was ok but forgot to turn the fans off again! so they were running at full speed overnight all the time blowing in the cold external air onto the compressor. I put a smart themometer at the back of the fridge so I can check this and looking at the numbers it didn't get really really low (3.8C was the lowest) but still lower then the Fridge specs would want I think in terms of where it is housed.
I have stuffed a big wad of insulation between the rear of the fridge and the lower vent now and will see what happens. Compressor Fridges don't need venting externally (one of their big advantages) and the only reason I am keeping the venting is in the hotter months having airflow will be better, but I have had rear temps on compressors running well over 30C and no problems so blocking off the vents in the winter will not be an issue - I guess I was hoping to get a more scientific solution
PS. It is incredible how fast the temperature drops down when the Compressor is running. This is just in one hour ....
If it comes down to it, I have a "virtual hammer" solution - I can set the fridge at MAX on the dial (on this setting the compressor essentially stays on) and can use the Victron OS setup, via a couple of relays, to turn the AC power to the fridge on and off depending on the temp sensor reading in the Freezer - thereby bypassing the fridges own thermostat entirely. That method might end up being my "winter" setup, and leave the fridge to its own devices in the summertime.
The checking overnight ended up a bit flawed as after I put the fan kit vent back on, I turned in on to check it was ok but forgot to turn the fans off again! so they were running at full speed overnight all the time blowing in the cold external air onto the compressor. I put a smart themometer at the back of the fridge so I can check this and looking at the numbers it didn't get really really low (3.8C was the lowest) but still lower then the Fridge specs would want I think in terms of where it is housed.
I have stuffed a big wad of insulation between the rear of the fridge and the lower vent now and will see what happens. Compressor Fridges don't need venting externally (one of their big advantages) and the only reason I am keeping the venting is in the hotter months having airflow will be better, but I have had rear temps on compressors running well over 30C and no problems so blocking off the vents in the winter will not be an issue - I guess I was hoping to get a more scientific solution
PS. It is incredible how fast the temperature drops down when the Compressor is running. This is just in one hour ....
If it comes down to it, I have a "virtual hammer" solution - I can set the fridge at MAX on the dial (on this setting the compressor essentially stays on) and can use the Victron OS setup, via a couple of relays, to turn the AC power to the fridge on and off depending on the temp sensor reading in the Freezer - thereby bypassing the fridges own thermostat entirely. That method might end up being my "winter" setup, and leave the fridge to its own devices in the summertime.
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SquirrellCook
Forum Member
I'm still puzzled by your findings. I guess a fridge or freezer's behaviour is more down to the refrigerant. Liquid and gas temperatures at it's stored pressure.
wildebus
Forum Member
I am a little as well. My previous 240V unit was a Fridge with an Icebox (rather than a freezer compartment) and that used to go up and down as well, but i put that down to not being a proper freezer.
The question is ... is what I am seeing actually just typical and normal, and the only reason people are not aware of it is because they are not monitoring the temp as much as I am?
mistericeman
Forum Member
More down the the refrigerants ability to move heat from one place to another and the condenser coils ability to dissipate it at given temperatures....
On fan cooled condenser coils you can use head pressure control to prevent over condensing at low ambients....
Not really necessary on small domestic fridges with the time spans the compressor runs for.