24V Van System Drawing. Get your overripe tomatoes ready!
- Thread starter HaldorEE
- Start date
I see you are running all DC loads through the MPPT load port, have you investigated the maximum current this port can handle? And if the port can still pass through current from the battery bank when the MPPT is not active.
gnubie
Solar Wizard
- Joined
- Sep 20, 2019
- Messages
- 3,847
Victron's SCCs load output, where present as terminals on the device, has the same rating as the controller in general. 20A in this case (100/20 model). The SCC has no real tolerance of over current. 20A means 20A. This could be likened to the behaviour of a fast fuse. I have seen capacitors in cheap ebay buck regulators trip a 10 amp model's load output. A thermistor took care of it but there's other ways too which I'm sure Haldor is aware of. I should test a 100/20 and see if it's as sensitive as the 10 amp models.
Battery power is available without any solar input at all.
I wasn't aware of the fast trip behavior of the Smart Solar load output. I hope when you say fast trip, that this is like a circuit breaker, not the SCC load output is damaged. Should I limit the 24V loads to a max of 15A? I can replace the 24V load switch with a 15A or 20A circuit breaker.
Power budget for loads powered by 24V Load output of Smart Solar:
- Refrigerator (Iceco GO20), 1A (24W measured)
- Ventilation Fan (Comair Rotron Patriot 24VDC), 1A (data plate)
- LED Lights, 1.5A (estimated, need to test)
- Water-pump, 1A (data plate)
- USB charger, 1A (two 2A, 5V outputs using DC-DC buck converter = 20W, 1A).
- Diesel Heater is an unknown since I have not yet purchased it. I was allowing for a 2A load.
If I determine that I am exceeding the limit of the Smart Solar load output, then I have a second 24V low voltage disconnect module I can use to power the less important 24V loads (Water-Pump, diesel heater and USB Charger).
My thinking has been that the load output of the Smart Solar is my most reliable source of DC power (the low voltage disconnect modules are unproven so far). That is why I want to put the most critical loads on on this: Refrigerator, Ventilation Fan and interior LED lights.
If I have to futz with the other loads I can deal, I really don't want the refrigerator, lights or ventilation fan to not work.
My other thinking was I will be pulling the house battery from the vehicle during the blistering hot summer months any time I am not using the van. The Smart Solar load output works from battery without solar input or from solar input without a battery. This is something I hope will help me keep the van ventilated during the summer while it is sitting idle.
I live in Phoenix AZ, so excessive heat is something I have to plan for.
I would rather just distibute the loads over more low voltage disconnect devices than add any kind of soft start circuitry to my appliances.
20A at 25.6 V is over 500W.
gnubie
Solar Wizard
- Joined
- Sep 20, 2019
- Messages
- 3,847
Yes, just fast trip, no damage. TBH this is on the 10 amp model, but I suspect it'll be the same behaviour on the 20A model though I haven't actually tested it. The steady state of that stuff won't be an issue. If anything was to cause a problem I'd put it at the USB charger but since it's a 20A Victron it'd need unusual amounts of capacitance to be a problem but at least you'll know what's going on if it does trip the over current.
Added BMV-712 Battery Temperature Sensor
Added BMV-712 relay output to provide low temperature charging disable to Orion TR DC-DC charger and Multiplus Inverter/Charger.
BMV-712 VE.Bus to Smart_Solar will be used for low temperature charging disable (VE.Bus cable not shown on wiring diagram).
Added BMV-712 relay output to provide low temperature charging disable to Orion TR DC-DC charger and Multiplus Inverter/Charger.
BMV-712 VE.Bus to Smart_Solar will be used for low temperature charging disable (VE.Bus cable not shown on wiring diagram).
Getting too deep for me. I only have 400W solar. No shore. No alternator. I do recommend connecting the green shore earth-ground to the chassis closer to the plug instead or in addition to the far side of the Victron. Just a safety thing to avoid "hot skin" condition on the van.
It has certainly grown. I am an EE and absolutely intend to do everything in a professional, safe and code compliant manner.
I see what you mean, I was assuming the PE input to the Multiplus is hardwired to the Multiplus Chassis GND, but that is not sufficient. I have updated the drawing to show proper chassis grounding for shore power. I also now show the Chassis ground connections for each of the components that have a Chassis ground lug.
I also show DC negatives going to what looks like local grounds all over the place when in reality each DC return is going to be routed in parallel with its associated positive conductor and terminated at a single DC negative bus bar (I am a firm believer in the value of star wiring). The drawing is complicated enough, that I didn't want to double the number of traces by showing all of the DC return paths. I did add a note to the drawing to make this assumption explicit.
Thanks for the input.
Haldor, hi there, I'm following this in the background and I'm at a similar stage to you as in design. We're going slightly separate ways with power distribution but essentially on the same page. I've noticed your inclusion of a 12v relay (R12V) and a push to make run switch. Then you have a switch (12V on) which i assume is an enable system switch. What is the function of the device you've marked as (R12V) that looks like a capacitor symbol...??? Where is your 'holding in' contact and what is the stop/disconnect method or am i thinking to conventionally from a system automation point of view...??? I'm not trying to be a smartarse here because i think you've done a cracking job of the diagram and as an electrician myself i do like to scrutinise a drawing, can't help it as I'm sure you do the same...!!!
That is a momentary contact push to start circuit. The toggle switch upstream is how you turn it off. The capacitor looking things are normally open relay contacts.
The idea is the 12V loads are not critical and if the low voltage cutoff engages, I don't want these to turn themselves back on automatically when the battery voltage recovers.
100% got you, under voltage shunt drops the load and R12V coil de-energises opening R12V N/O contacts, easy peasy automation..!!
Where or rather what app you using for the drawings..?? I'm a dinosaur with CAD so hopefully it's idiot friendly...!!
I am using Visio. I find it to be very easy to use.
I use Solid Works PBC (Altium) at work, but no way am I paying for that for home use. If you are not designing a PCB, I find Visio to be faster to sketch out a concept.
Updated the drawing to include the water cooling system for the battery.
The LiNMC cells I am using are the vent with fire chemistry and I need a way to pull heat out of the cells without ventilation fans.
Found some bitcoin miner cold plates that are a perfect fit for my battery pack. They will fit inside the 40mm ammo can on either side of the cells. A pair of PC-CPU radiators with fans and water pumps should do the job. I found a fireplace fan thermal switch that automatically turn the pumps and the radiator fans on and off.
The LiNMC cells I am using are the vent with fire chemistry and I need a way to pull heat out of the cells without ventilation fans.
Found some bitcoin miner cold plates that are a perfect fit for my battery pack. They will fit inside the 40mm ammo can on either side of the cells. A pair of PC-CPU radiators with fans and water pumps should do the job. I found a fireplace fan thermal switch that automatically turn the pumps and the radiator fans on and off.
To avoid further polluting the Electrodacus thread https://diysolarforum.com/threads/e...and-inverter-charger.13860/page-5#post-161692
I am moving the discussion DZL and I were having about appropriate ground symbols to here.
Here is my understanding of correct electrical grounding symbols.
Above image is from: https://www.ni.com/en-us/support/do...ignal-grounding--terminology-and-symbols.html
The subject of earth ground vs chassis ground is complicated by the commonly used convention of indicating an electrical control enclosure chassis ground connection point with an Earth Ground symbol (like in the pic below). This is not technically correct, the box is not earth ground, the ground rod driven into the earth somewhere else is earth ground. If the box is installed correctly, then that enclosure chassis ground gets connected to earth ground by the incoming AC wiring, but the one is not the other.
That is why I use ground symbols the way I do in my schematic. The Chassis Ground symbol is used to indicate connection to the vehicle's metal body and frame and the down pointed triangle is used for everything else related to DC negative. This is a vehicle, there is no earth grounding in my van except when we are plugged into shore power and then only if the shore power outlet is properly wired. I am only showing the wiring for what is physically in my system.
I am moving the discussion DZL and I were having about appropriate ground symbols to here.
Here is my understanding of correct electrical grounding symbols.
Above image is from: https://www.ni.com/en-us/support/do...ignal-grounding--terminology-and-symbols.html
The subject of earth ground vs chassis ground is complicated by the commonly used convention of indicating an electrical control enclosure chassis ground connection point with an Earth Ground symbol (like in the pic below). This is not technically correct, the box is not earth ground, the ground rod driven into the earth somewhere else is earth ground. If the box is installed correctly, then that enclosure chassis ground gets connected to earth ground by the incoming AC wiring, but the one is not the other.
That is why I use ground symbols the way I do in my schematic. The Chassis Ground symbol is used to indicate connection to the vehicle's metal body and frame and the down pointed triangle is used for everything else related to DC negative. This is a vehicle, there is no earth grounding in my van except when we are plugged into shore power and then only if the shore power outlet is properly wired. I am only showing the wiring for what is physically in my system.
This is my understanding as well
(with the acknowledgement that in practice the second symbol "earth ground" is often used a generic symbol for 'ground' as well as the symbol for earth-ground)
If you refer back to the original image posted, it got earth and chassis confused I think. As for 'signal ground' and 'power ground' I'm unfamiliar with these terms. From context (your schematic) I take signal ground to mean 'negative return' or 'grounded conductor'?
Yup. I have two grounds in my system. The van chassis ground and the negative house system busbar. I have them as separate symbols so I can explicitly show what is connected to each as well as where the two ground systems are connected together.This is my understanding as well
(with the acknowledgement that in practice the second symbol "earth ground" is often used a generic symbol for 'ground' as well as the symbol for earth-ground)
If you refer back to the original image posted, it got earth and chassis confused I think. As for 'signal ground' and 'power ground' I'm unfamiliar with these terms. From context (your schematic) I take signal ground to mean 'negative return' or 'grounded conductor'?
