rookie doubts
- Thread starter Dexron
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the BMS is a Daly 250a common port, I bought it from aliexpress.
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The isolated is used when you need to keep your vehicle electrical system, and 'house' battery system separate, and you will not be grounding your house battery system. The non-isolated will be used if both sides of your system are grounded.
Thanks for that explanation. The Victron Wiring Unlimited document doesn't go into enough depth on this topic. At least not enough for me to understand what has to happen when I have two 12v systems in my trailer. In theory, the two systems aren't going to crossover. There is no logical connection between them. Neither side charges or draws from the other. However, the negative lead from the existing battery (Trojan dual 6v) on the tongue goes directly to the trailer frame. This system will be limited to providing 12v power to the generator, tongue jack and breakaway brake system. I'm thinking that the new/additional battery system (LiFePO4 12v) will also need to ground to the chassis. This side will power the interior lights, furnace, etc (everything else that the existing system won't).
Can you suggest a source that provides more information? I would like to get a better understanding of the isolation issues.
Its hard to find good information on this, Victron, in my opinion, has done a very poor job of articulating the distinction in their documentation. They don't really address it directly.
I've pieced together bits and pieces of information here and there, and only have a very partial understanding.
You can see the beginnings of my inquiry and thought process here and some additional related info here
I read those threads a while back and just reread them. They make a little more sense to me. They also worry me. The question I end up asking myself is, "Should I be isolating my two systems?" They're both 12v and all they'll share in common is the negative ground. Since I don't plan to charge/draw between the two, I don't think I need to worry about it.
The vague impression I have is that isolating the two sides of the system is not the default, and not necessary unless you have sensitive electronics (which might be more common in the marine world).
Also, if you did have sensitive electronics, you could use a DC-DC converter that is regulated and isolated for those circuits specifically.
But honestly, I still don't deeply understand the implications of one method or another.
Grounding includes connecting the battery negative to the van frame or chassis. Is this something you will do?
ianganderton
Auckland, NZ
I think there is a problem with the same terms being used for completely different things in low voltage dc systems and mains/grid voltage AC systems. The problem is in vans and other off grid vehicles we are mixing the 2 electrical types and therefore the terminology doesnt work
Grounding in a low voltage dc enviroment (below 48V) is a way of saving on wiring. It allows the metal vehicle shell to be used as the return wire so saving 50% on wiring and complexity. It does cause plenty of problems in modern vehicles where the connections between differnet body panels might not be as conductive as first might appear. Add moisture into the mix and you end up with weird flashing lights on trailers.
Grounding in a mains/grid 240V or similar system is literally running a cable to the ground and is used to prevent device electrical problems killing people. In a house/grid/mains environment any device/appliance that has a metal outer should be grounded. The aim of this is if an appliance is damaged in some way and internal wires are connected to the outer shell the ground provides a short circuit route for the electricity to blow the fuse or trip the breakers so rendering things safe
So actually completely the opposite aims. This is because dc voltages below 48V are relatively safe and mains/grid AC voltages are deadly
I haven't looked at the specs but I'd hazard a guess that 240V/110V victron products designed for in-vehicle use and therefore impossible to ground unless mains connected are insulated differently from those designed for an environment where a ground to earth connection can be made
Hope this is what you guys were talking about and helps
Grounding in a low voltage dc enviroment (below 48V) is a way of saving on wiring. It allows the metal vehicle shell to be used as the return wire so saving 50% on wiring and complexity. It does cause plenty of problems in modern vehicles where the connections between differnet body panels might not be as conductive as first might appear. Add moisture into the mix and you end up with weird flashing lights on trailers.
Grounding in a mains/grid 240V or similar system is literally running a cable to the ground and is used to prevent device electrical problems killing people. In a house/grid/mains environment any device/appliance that has a metal outer should be grounded. The aim of this is if an appliance is damaged in some way and internal wires are connected to the outer shell the ground provides a short circuit route for the electricity to blow the fuse or trip the breakers so rendering things safe
So actually completely the opposite aims. This is because dc voltages below 48V are relatively safe and mains/grid AC voltages are deadly
I haven't looked at the specs but I'd hazard a guess that 240V/110V victron products designed for in-vehicle use and therefore impossible to ground unless mains connected are insulated differently from those designed for an environment where a ground to earth connection can be made
Hope this is what you guys were talking about and helps
I get it.
the installation of the van, lights, water pump, usb sockets and heating go to 12v.
the induction hob, the hot water boiler and the refrigerator are connected to the inverter at 220v.
The inverter is only connected to the bsm output and battery positive.
for this installation I do not think a ground connection is necessary and I would need an isolated Orion charger.
I don't know if I'm wrong about something.
the installation of the van, lights, water pump, usb sockets and heating go to 12v.
the induction hob, the hot water boiler and the refrigerator are connected to the inverter at 220v.
The inverter is only connected to the bsm output and battery positive.
for this installation I do not think a ground connection is necessary and I would need an isolated Orion charger.
I don't know if I'm wrong about something.
ianganderton
Auckland, NZ
For what you are planning with a priority on both Ac power and shore power charging I would go for one of the charger inverter units. They combine all the AC power very neatly including transfer switch (when you plug your van into a mains plug say at a campsite the unit will automatically switch from batter inverter power to shore/mains power) and charge the house battery
with a house battery as big as you are planning there is no point in alternator charging. Just won’t be enough
in the UK and Europe there are ooddles of campsites with electric mains hookups. easy to pop to one for a night to refresh your batteries.
with a house battery as big as you are planning there is no point in alternator charging. Just won’t be enough
in the UK and Europe there are ooddles of campsites with electric mains hookups. easy to pop to one for a night to refresh your batteries.
I would like to mount separate components, not a complete unit, in case one fails I don't have to change the assembly.
The idea is to be as self-sufficient as possible and not stop while camping, that's why I need to charge from the alternator and the plate.
The idea is to be as self-sufficient as possible and not stop while camping, that's why I need to charge from the alternator and the plate.
If you get the isolated and don't need it then you have just paid a bit more.
If you get the nonisolated and need to be isolated then you will be replacing it.
I don't see any reason to isolate grounds between my 12V and 24V systems. I will be using an Orion Smart Charger non-isolated with my van conversion. It is about $40 cheaper than the isolated version.
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Victron Energy ORI122436120 - Inverter Supply
Shop for Victron Energy ORI122436120 at Inverter Supply for best prices online. Victron Energy ORI122436120, Victron Energy, ORI122436120, Orion-Tr Smart 12/24-15A (360W) Isolated DC-DC charger, Victron DC-DC Converters
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And to be clear. The isolated version just means you can leave the output floating (no need to tie ground to the vehicle ground). The positive output is in fact isolated at least as far as protecting your starter battery and alternator are concerned with either version. That is the entire point to prevent damage to your alternator and avoid running your starter battery dead. Unless you are doing something a lot more complicated than I think you are.
Notice that the non-isolated version has 3 terminals to wire to while the isolated version has 4.
Notice that the non-isolated version has 3 terminals to wire to while the isolated version has 4.
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