This sounds correct
Electrodacus Design-Adding Alternator and Inverter/Charger
- Thread starter APhoton
- Start date
Agreed and to make a long story even longer.
In general we don't want to use the vehicle chassis to carry current. Doing so leads to corrosion and weird electrical behavior. To ensure this can't happen we use a negative bus system and only connect that negative bus to chassis ground at a single point.
If you don't have alternator charging, then we are done. However, when we add alternator charging we now have to deal with the fact that the vehicle maker connected their negative to chassis ground in the engine compartment. Our options then are to either disconnect the house negative bus from chassis ground or use an isolated DC-DC charger that breaks the galvanic connection to the alternator DC system. Either solution will work.
If the house system is installed in a trailer and you want to use alternator charging then you must use an isolated DC-DC charger so that the house system can be connected to the trailer's chassis ground without creating a ground loop when connected to the alternator.
I hope I said that clearly. It is more than a bit complicated (I am leaving out lots of techie details that don't usually apply to power systems) and EE's don't always have total clarity on grounding. I took a 3 day seminar from a Dr. Tom Van Doren on this exact subject and I think only half the EE's in the class where really keeping up with him. The rest just pushed their "I Believe" buttons.
Here is a link to the on-line version of the course. It was a lot more expensive to take in person. Yes I am one of the 19,000 engineers who have taken this course.
In general we don't want to use the vehicle chassis to carry current. Doing so leads to corrosion and weird electrical behavior. To ensure this can't happen we use a negative bus system and only connect that negative bus to chassis ground at a single point.
If you don't have alternator charging, then we are done. However, when we add alternator charging we now have to deal with the fact that the vehicle maker connected their negative to chassis ground in the engine compartment. Our options then are to either disconnect the house negative bus from chassis ground or use an isolated DC-DC charger that breaks the galvanic connection to the alternator DC system. Either solution will work.
If the house system is installed in a trailer and you want to use alternator charging then you must use an isolated DC-DC charger so that the house system can be connected to the trailer's chassis ground without creating a ground loop when connected to the alternator.
I hope I said that clearly. It is more than a bit complicated (I am leaving out lots of techie details that don't usually apply to power systems) and EE's don't always have total clarity on grounding. I took a 3 day seminar from a Dr. Tom Van Doren on this exact subject and I think only half the EE's in the class where really keeping up with him. The rest just pushed their "I Believe" buttons.
Here is a link to the on-line version of the course. It was a lot more expensive to take in person. Yes I am one of the 19,000 engineers who have taken this course.
I think I have a firm-ish grasp of the benefits of only bonding neutral and ground or negative and ground in one place.
I suppose what I'm struggling with is understanding how the isolated DC-DC actually prevents there from being multiple negative-ground bonds.
But I think it just finally clicked for me (or maybe I'm about to discover I'm still not understanding it correctly. Even if there are multiple negative-ground bonds (at least one on the vehicle electrical side, and one on the house side) and even if bonding both sides of the system to chassis means it is not truly isolated(?), because the internal isolation of the DC-DC charger prevents ground loops.
Is the kindergarten level diagram (now you will be subjected to my drawings
) I'm picturing in my mind accurate-ish on a conceptual level:
That is exactly correct.I think I have a firm-ish grasp of the benefits of only bonding neutral and ground or negative and ground in one place.
I suppose what I'm struggling with is understanding how the isolated DC-DC actually prevents there from being multiple negative-ground bonds.
But I think it just finally clicked for me (or maybe I'm about to discover I'm still not understanding it correctly. Even if there are multiple negative-ground bonds (at least one on the vehicle electrical side, and one on the house side) and even if bonding both sides of the system to chassis means it is not truly isolated(?), because the internal isolation of the DC-DC charger prevents ground loops.
Is the kindergarten level diagram (now you will be subjected to my drawings
View attachment 25963
Ah, I think that I got it. Isolated DC-DC charger mean that charger isolates ground from alternator/engine battery so that your house electical does not make a loop! Why don't the they just call it an isolating ground DC-DC Charger-LOLAgreed and to make a long story even longer.
In general we don't want to use the vehicle chassis to carry current. Doing so leads to corrosion and weird electrical behavior. To ensure this can't happen we use a negative bus system and only connect that negative bus to chassis ground at a single point.
If you don't have alternator charging, then we are done. However, when we add alternator charging we now have to deal with the fact that the vehicle maker connected their negative to chassis ground in the engine compartment. Our options then are to either disconnect the house negative bus from chassis ground or use an isolated DC-DC charger that breaks the galvanic connection to the alternator DC system. Either solution will work.
If the house system is installed in a trailer and you want to use alternator charging then you must use an isolated DC-DC charger so that the house system can be connected to the trailer's chassis ground without creating a ground loop when connected to the alternator.
I hope I said that clearly. It is more than a bit complicated (I am leaving out lots of techie details that don't usually apply to power systems) and EE's don't always have total clarity on grounding. I took a 3 day seminar from a Dr. Tom Van Doren on this exact subject and I think only half the EE's in the class where really keeping up with him. The rest just pushed their "I Believe" buttons.
Here is a link to the on-line version of the course. It was a lot more expensive to take in person. Yes I am one of the 19,000 engineers who have taken this course.
Isolation is actually a pretty big deal. Isolated power supplies on a PCB often costs twice what a non-isolated power supply does. At higher power levels the cost delta must not be as bad.
HardorEE and Dzi thanks for that...
Looking over my diagram and thinking of replacing Voltage Converter Regulator DC 24V to DC 12V 40A 480W and Victron BP65 with Victron Energy Orion 24/12-40 DC-DC Converter with 40 Amp Output p/n ORI241240021.
The only reason the I added BP65 is so SBMS0 can be connected to turn converter on/off
Looking over my diagram and thinking of replacing Voltage Converter Regulator DC 24V to DC 12V 40A 480W and Victron BP65 with Victron Energy Orion 24/12-40 DC-DC Converter with 40 Amp Output p/n ORI241240021.
The only reason the I added BP65 is so SBMS0 can be connected to turn converter on/off
I think this would be a sensible replacement. For one you are switching out a decent but no-name component for a quality Victron component, and two you can potentially eliminate the BP-65, so it might wind up being both cheaper and simpler. Do you have a link to the model of DC-DC converter you are looking at, there are some differences (in efficiency and in connectivity between models)
I decided to go with VictronMulti Plus 24/3000/70-50. It did increase cost by $650 but over all quality and simplicity of use with Electrodacus makes it worth it. I attached my latest diagram with changes. Now I just need to go through with a fine tooth comb and make sure all wires, fuses, and breakers are sized correctly. Make sure everything is connected correctly, etc.
I certainly appreciate everyones help on this forum; it's been great. question-How would I go about getting a qualified person to look over my plan in detail checking compatibility of components, wire sizes, fuse/breaker sizes, connections, busbar sizes, etc?
Don't get me wrong I'm sure you as well as many other people on this forum are more than qualified but I don't know if anyone is looking at all the details or if they look and comment on things that stand out.
I certainly appreciate everyones help on this forum; it's been great. question-How would I go about getting a qualified person to look over my plan in detail checking compatibility of components, wire sizes, fuse/breaker sizes, connections, busbar sizes, etc?
Don't get me wrong I'm sure you as well as many other people on this forum are more than qualified but I don't know if anyone is looking at all the details or if they look and comment on things that stand out.
Reach out to Bay Marine supply, they offer consultations and design review for a reasonable price. They are a marine electrical shop in San Diego area, Justin Cook is their lead tech I think, he is a forum member (@Justin Laureltec) and is quite knowledgeable about Victron products specifically. I believe they charge by the hour, and I recall the rate being semi-reasonable. MarineHowTo would be another option to look into, but might be a bit pricier.
F.Y.I. I am posting updates to my system diagram here if you are interested.
diysolarforum.com
I have updated my drawing to add battery temperature sensing to the BMV-712. The BMV-712 has a charging disable function to protect against freezing temperatures. The second BMV-712 input can use a thermal probe and it has two methods of controlling external devices. A relay contact closure output, plus the VictronConnect protocol over a VE.Bus port.
The Orion TR Smart Chargers only support a contact closure input for external charge control, so I am going to use the BMV-712 relay output in series with the ignition switch input to the Orion TR.
Both the SmartSolar and the Multiplus VE.Bus support VictronConnect over VE.Bus and I believe the Multiplus has a pass through function for the VE.Bus. If so, I will connect the BMV-712 VE.Bus to the Multiplus first then pass the VE.Bus through to the Smart Solar. In the event this pass through doesn't work, I will use the VE.Bus directl to the Smart Solar and use the contact closure input on the Multiplus to disable charging.
I would like to be able to stop battery charging for the following reasons without the BMS having to get involved:
The BMS will basically only be used to protect against cell imbalances and as a last backstop in event of a charging or discharging malfunction.
I am still researching all of this. If it turns out I need the Cerbo GX to do what I want, I will add it, but for now it is looking like I can do what I want with just the the BMV-712 wired to the other Victron devices.
24V Van System Drawing. Get your overripe tomatoes ready!
After months of pontificating, I have finally pulled together the electrical design for my RV conversion. Let me know what you think. This is my first version and I would much rather fix as many problems at the pixels on a screen stage as I can.
diysolarforum.com
I have updated my drawing to add battery temperature sensing to the BMV-712. The BMV-712 has a charging disable function to protect against freezing temperatures. The second BMV-712 input can use a thermal probe and it has two methods of controlling external devices. A relay contact closure output, plus the VictronConnect protocol over a VE.Bus port.
The Orion TR Smart Chargers only support a contact closure input for external charge control, so I am going to use the BMV-712 relay output in series with the ignition switch input to the Orion TR.
Both the SmartSolar and the Multiplus VE.Bus support VictronConnect over VE.Bus and I believe the Multiplus has a pass through function for the VE.Bus. If so, I will connect the BMV-712 VE.Bus to the Multiplus first then pass the VE.Bus through to the Smart Solar. In the event this pass through doesn't work, I will use the VE.Bus directl to the Smart Solar and use the contact closure input on the Multiplus to disable charging.
I would like to be able to stop battery charging for the following reasons without the BMS having to get involved:
- Over Temperature Alarm
- Freezing Temperature Alarm
- Battery has reached a programmed state of charge
The BMS will basically only be used to protect against cell imbalances and as a last backstop in event of a charging or discharging malfunction.
I am still researching all of this. If it turns out I need the Cerbo GX to do what I want, I will add it, but for now it is looking like I can do what I want with just the the BMV-712 wired to the other Victron devices.
Last edited:
Another resource is Peter Kennedy at PKYS in Annapolis MD. He is a Victron and Blue Sea dealer as well as a certified marine electrician. He has excellent prices from what I can tell.
I really like his circuit breaker and switch gear panels. Top notch equipment. I am happy with what I ordered from him.
Last edited:
Thanks!
F.Y.I. I am posting updates to my system diagram here if you are interested.
24V Van System Drawing. Get your overripe tomatoes ready!
After months of pontificating, I have finally pulled together the electrical design for my RV conversion. Let me know what you think. This is my first version and I would much rather fix as many problems at the pixels on a screen stage as I can.
I have updated my drawing to add battery temperature sensing to the BMV-712. The BMV-712 has a charging disable function to protect against freezing temperatures. The second BMV-712 input can use a thermal probe and it has two methods of controlling external devices. A relay contact closure output, plus the VictronConnect protocol over a VE.Bus port.
The Orion TR Smart Chargers only support a contact closure input for external charge control, so I am going to use the BMV-712 relay output in series with the ignition switch input to the Orion TR.
Both the SmartSolar and the Multiplus VE.Bus support VictronConnect over VE.Bus and I believe the Multiplus has a pass through function for the VE.Bus. If so, I will connect the BMV-712 VE.Bus to the Multiplus first then pass the VE.Bus through to the Smart Solar. In the event this pass through doesn't work, I will use the VE.Bus directl to the Smart Solar and use the contact closure input on the Multiplus to disable charging.
I would like to be able to stop battery charging for the following reasons without the BMS having to get involved:
If I can daisy chain the VE.Bus ports I am hopeful that I can use the BMV-712 to disable discharge based on reaching a minimum state of charge. If not then I will use the low voltage disconnect functions built into the Multiplus and the Smart Solar (I am using the load output of the Smart Solar to power my 24VDC loads). I have an external low voltage disconnect circuit that is used for 12V (non-critical) loads and I will configure this to disconnect at a high enough voltage level that I am sure I am not over discharge the battery.
- Over Temperature Alarm
- Freezing Temperature Alarm
- Battery has reached a programmed state of charge
The BMS will basically only be used to protect against cell imbalances and as a last backstop in event of a charging or discharging malfunction.
I am still researching all of this. If it turns out I need the Cerbo GX to do what I want, I will add it, but for now it is looking like I can do what I want with just the the BMV-712 wired to the other Victron devices.
Nice, interesting idea of filter and surge protection at shore power entry. Don't believe that I've seen this on other designs. Also like the 24v appliance-no sense in converting from 24v to 12v when you can buy 24v appliances.F.Y.I. I am posting updates to my system diagram here if you are interested.
24V Van System Drawing. Get your overripe tomatoes ready!
After months of pontificating, I have finally pulled together the electrical design for my RV conversion. Let me know what you think. This is my first version and I would much rather fix as many problems at the pixels on a screen stage as I can.
I have updated my drawing to add battery temperature sensing to the BMV-712. The BMV-712 has a charging disable function to protect against freezing temperatures. The second BMV-712 input can use a thermal probe and it has two methods of controlling external devices. A relay contact closure output, plus the VictronConnect protocol over a VE.Bus port.
The Orion TR Smart Chargers only support a contact closure input for external charge control, so I am going to use the BMV-712 relay output in series with the ignition switch input to the Orion TR.
Both the SmartSolar and the Multiplus VE.Bus support VictronConnect over VE.Bus and I believe the Multiplus has a pass through function for the VE.Bus. If so, I will connect the BMV-712 VE.Bus to the Multiplus first then pass the VE.Bus through to the Smart Solar. In the event this pass through doesn't work, I will use the VE.Bus directl to the Smart Solar and use the contact closure input on the Multiplus to disable charging.
I would like to be able to stop battery charging for the following reasons without the BMS having to get involved:
If I can daisy chain the VE.Bus ports I am hopeful that I can use the BMV-712 to disable discharge based on reaching a minimum state of charge. If not then I will use the low voltage disconnect functions built into the Multiplus and the Smart Solar (I am using the load output of the Smart Solar to power my 24VDC loads). I have an external low voltage disconnect circuit that is used for 12V (non-critical) loads and I will configure this to disconnect at a high enough voltage level that I am sure I am not over discharge the battery.
- Over Temperature Alarm
- Freezing Temperature Alarm
- Battery has reached a programmed state of charge
The BMS will basically only be used to protect against cell imbalances and as a last backstop in event of a charging or discharging malfunction.
I am still researching all of this. If it turns out I need the Cerbo GX to do what I want, I will add it, but for now it is looking like I can do what I want with just the the BMV-712 wired to the other Victron devices.
Last edited:
Looks like one of wires not connected
I decided to add 24v connections for appliances as you did. It was not as straight forward as I first thought since SBMS0 needs to be able to turn them on/off when batteries are discharged to certain level. For this reason I added Victron Energy Battery Protect 12/24-Volt 65 amp and run EXTI5 through 4-Channel Optocoupler. I hope this makes sensesF.Y.I. I am posting updates to my system diagram here if you are interested.
24V Van System Drawing. Get your overripe tomatoes ready!
After months of pontificating, I have finally pulled together the electrical design for my RV conversion. Let me know what you think. This is my first version and I would much rather fix as many problems at the pixels on a screen stage as I can.
I have updated my drawing to add battery temperature sensing to the BMV-712. The BMV-712 has a charging disable function to protect against freezing temperatures. The second BMV-712 input can use a thermal probe and it has two methods of controlling external devices. A relay contact closure output, plus the VictronConnect protocol over a VE.Bus port.
The Orion TR Smart Chargers only support a contact closure input for external charge control, so I am going to use the BMV-712 relay output in series with the ignition switch input to the Orion TR.
Both the SmartSolar and the Multiplus VE.Bus support VictronConnect over VE.Bus and I believe the Multiplus has a pass through function for the VE.Bus. If so, I will connect the BMV-712 VE.Bus to the Multiplus first then pass the VE.Bus through to the Smart Solar. In the event this pass through doesn't work, I will use the VE.Bus directl to the Smart Solar and use the contact closure input on the Multiplus to disable charging.
I would like to be able to stop battery charging for the following reasons without the BMS having to get involved:
If I can daisy chain the VE.Bus ports I am hopeful that I can use the BMV-712 to disable discharge based on reaching a minimum state of charge. If not then I will use the low voltage disconnect functions built into the Multiplus and the Smart Solar (I am using the load output of the Smart Solar to power my 24VDC loads). I have an external low voltage disconnect circuit that is used for 12V (non-critical) loads and I will configure this to disconnect at a high enough voltage level that I am sure I am not over discharge the battery.
- Over Temperature Alarm
- Freezing Temperature Alarm
- Battery has reached a programmed state of charge
The BMS will basically only be used to protect against cell imbalances and as a last backstop in event of a charging or discharging malfunction.
I am still researching all of this. If it turns out I need the Cerbo GX to do what I want, I will add it, but for now it is looking like I can do what I want with just the the BMV-712 wired to the other Victron devices.
got it!