I originally intended to parallel two Orion TR 24/12/20's to cover the almost 40A 12V DC loads I could require (w everything on all at once ... unlikely though). As I was about to purchase them, noticed that there's an Orion TR 24/12/70 but it's not isolated. Since I've recently decided to ground my NEG bus bar to avoid having to break both NEG and POS circuits everywhere I have a breaker, wondering now if it doesn't simplify my system (and give me a little more breathing room, going to 70A) if I just went with the non-isolated converter since the rest of my system is no longer isolated. Any other PROs CONs with either of these options?
24V to 12V Converter Options: Isolated vs Non-isolated
- Thread starter Dhowman
- Start date
Since your system isn't floating anymore and everything use the same ground you can use a non-isolated converter if you want. I don't see any downside electrically speaking, then I don't know about price, etc... but a non-isolated one should be less expensive so go for it 
Yeah, was just reading up on this. A couple downsides w non-isolated systems (which I'm grasping a little better now that I'm looking into this for the converter) are 1) Ground Loops (my AC inverter would now share ground w my 12V DC side), 2) Transients on the source passing through to 12V appliances (don't think I'll ever be connected to grid, but that could change in the future ... also not sure how variable V on my 24V side given PV charging and LFP charge states might impact ability of a non-isolated converter to regulate output ... or not).
Also, wouldn't a ground short on my 24V side turn my 12V side into MINUS 12V, if breifly?
[EDITED>>] The 70A non-isolated converter costs about the same as ONE of the 2 20A isolated converters. It's also about 1/4 the weight and 1/2 the space ... no small things in my setup. [<<EDITED]
Hmmm ... may rethink whether or not I want to ground the NEG side of my system and just add breakers to NEG wires in my system, especially given that all this is riding around on 4 rubber tires and is isolated from Earth anyway. Not sure it doesn't make sense to isolate the individual circuits w/i my system. Maybe it's safer (fewer short scenarios).
Also, wouldn't a ground short on my 24V side turn my 12V side into MINUS 12V, if breifly?
[EDITED>>] The 70A non-isolated converter costs about the same as ONE of the 2 20A isolated converters. It's also about 1/4 the weight and 1/2 the space ... no small things in my setup. [<<EDITED]
Hmmm ... may rethink whether or not I want to ground the NEG side of my system and just add breakers to NEG wires in my system, especially given that all this is riding around on 4 rubber tires and is isolated from Earth anyway. Not sure it doesn't make sense to isolate the individual circuits w/i my system. Maybe it's safer (fewer short scenarios).
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It shouldn't, or else someone didn't do his job on the converter design.
Justin Laureltec
Bay Marine Supply Tech Support Manager
I don't see any problem with going to the non-isolated 24/12-70; the buggest concern I'd have (so long as everything is connected and working properly, which I do question with that Xantrex in the mix, but eh) is that you may experience RF noise with the non-isolated due to, as you mentioned, the increased chance of ground loops. The odds are in your favor though.
As a side note, I see a lot of wireless or bluetooth signals around that schematic... you're aware that the Orion-Tr is not bluetooth-enabled, yes? The only bt-enabled Orions are the Orion-Tr Smart DC-DC Chargers, which are an entirely different product in any case... though, as a note, they do have a configurable power-supply mode, so an Orion-Tr Smart 24/12-30A would work for you in this scenario, but depending on the totals of those loads you still might need two and that starts adding up quickly.
As a side note, I see a lot of wireless or bluetooth signals around that schematic... you're aware that the Orion-Tr is not bluetooth-enabled, yes? The only bt-enabled Orions are the Orion-Tr Smart DC-DC Chargers, which are an entirely different product in any case... though, as a note, they do have a configurable power-supply mode, so an Orion-Tr Smart 24/12-30A would work for you in this scenario, but depending on the totals of those loads you still might need two and that starts adding up quickly.
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Hmmm ... kinda good news. That Xantrex will only be on maybe an hour a day. I may just give it a go. Wouldn't be that much trouble to reset everything back to isolated if I did run into issues. I'd be out $140, but if it works, well, I get more space, 4 pounds of GVWR back, and about 100 bucks and 30A to spend somewhere else. That reward might just be worth the risk. ;-)
Yeah, my bad on that Orion WiFi icon (copy/paste error). I think at one point I did think it was BT but, yes, was looking at the charger, not the converter. Everywhere else I have that is correct.
The chargers are intriguing, but yes, the Amps/$$ ratio is going the wrong way and I only need to convert.
Thank you Sir!
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@Justin Laureltec Quick question that might make me rethink that though ... that Orion-Tr Smart 24/12-30A only passes current from 24 to 12, yes? If it was bidirectional, might consider it for setting up alternator charging too, but alas, I think I know what the answer to that question is. ;-/
Justin Laureltec
Bay Marine Supply Tech Support Manager
Yeaahhhh you do know what the answer is, strictly one-way operation. I mean, there's a 12-24 model too, so you could have a 12-24 for charging and a 24-12 for discharging, but again that starts adding up...
Not really sure how you intend to wire them but, if you intend to parallel multiple smaller ones to provide output to a common bus for further distribution, would recommend going the Single Big one route.
Tried doing something similar with multiple non-isolated ones and hit the road block on 2 fronts:
1) Its almost impossible to regulate equal load distribution between the parallel units because load is a function of voltage - which would fluctuate just a little bit all the time. Even the slightest ever higher voltage would avalanche all the load to one side while other would sit idle.
2) Non-Isolated ones would not be able to work in a string fashion, they would short their negatives and render useless if you ever wish to use them in series.
Quite some money put to waste, I am now contemplating getting a Bigger single unit to keep system clean and one less thing to worry about.
You can read more about it here: Non-Isolated chargers
This was my previous design using 2 isolated Orion TR 24/12/20's in parallel. This is my current design that replaces those with a single non-isolated Orion 24/12/70. Much simpler and more DC amps at my disposal (trying to get everything I can off of AC and on to DC).
I read the Non-Isolated chargers thread. Victron states that both of these converters (isolated and non-isolated) can be paralleled:
- Isolated 24/12/20: Short circuit proof and can be paralleled to increase output current. An unlimited number of units can be connected in parallel.
- Non-isolated 24/12/70: Can be paralleled to increase output current. Up to five units can be connected in parallel.
Or am I mis-reading what you were trying to accomplish and/or your set up there?
Okey, in simple terms I meant to imply that always go with Single Larger DC converter instead of paralleling smaller ones.
Parallel or redundant power supplies have inherent load balancing issues, unless there is special feedback mechanism which
regulates their equal participation in the group.
I am not sure if Orion TR 24/12/20 has such mechanism - at least the product data sheet on their website is silent on this.
But if they say unlimited number of those could be paralleled, there must be some truth to it.
We can clarify their redundant load sharing mechanism - that should be all.
Good that you already chose the single 70Amp unit route
Second, from the experiment on the thread - those were actually non-isloated converters (identified later) which lead to
them shorting each other. It would have worked well with Isolated types - so it just emphasizes that Isolated ones have their
advantages on certain specific application. If you don't wish to mix-n-match yours with others, non-isolated should be fine.
Parallel or redundant power supplies have inherent load balancing issues, unless there is special feedback mechanism which
regulates their equal participation in the group.
I am not sure if Orion TR 24/12/20 has such mechanism - at least the product data sheet on their website is silent on this.
But if they say unlimited number of those could be paralleled, there must be some truth to it.
We can clarify their redundant load sharing mechanism - that should be all.
Good that you already chose the single 70Amp unit route
Second, from the experiment on the thread - those were actually non-isloated converters (identified later) which lead to
them shorting each other. It would have worked well with Isolated types - so it just emphasizes that Isolated ones have their
advantages on certain specific application. If you don't wish to mix-n-match yours with others, non-isolated should be fine.
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Okay, I believe I'm stepping into dumb question territory again, but doesn't a lot of what y'all are discussing re: isolated vs non-isolated converters not apply to Dhowman's situation. Everything you are saying makes sense to me in relation to a dc-dc charger/converter bridging the 12v vehicle electrical system and the 'house' battery bank, using a non-isolated charge/converter, but I don't see how it applies to Dhowman's use case. What am I missing?
The converter in question will convert 24v from the batteries to 12v for the DC consumers. Whether or not the converter is isolated or non-isolated is a completely separate issue from whether the system is 'floating' (isolated from chassis-ground) or not isn't it? The effect of using an isolated converter would isolate the 12v from the 24v system, but the system as a whole could still be 'isolated/floating' or 'non-isolated' right?
The converter in question will convert 24v from the batteries to 12v for the DC consumers. Whether or not the converter is isolated or non-isolated is a completely separate issue from whether the system is 'floating' (isolated from chassis-ground) or not isn't it? The effect of using an isolated converter would isolate the 12v from the 24v system, but the system as a whole could still be 'isolated/floating' or 'non-isolated' right?
Hopefully this won't add to the confusion. Say you have 3 power sources: 24V and a 12V house batteries and a 12V car battery. If any of them share a ground reference, they're not isolated from each other. If 2 of them do and one of them doesn't, those 2 are "floating" with respect to 3rd (and vice versa). Isolated and Floating (Grounds) are interchangeable terms. (Hopefully I haven't totally mucked that up.)
No you didn't add to the confusion at all, you cleared it up (I think we are on the same page here).
What was confusing me was that in the beginning of the thread you and Bidule seemed to be discussing pros/cons of isolation between the vehicle electrical system and house system, but this converter would be between the 12v and 24v sides of your house system. I couldn't (still can't) understand why the decision to float or chassis-ground your house system was relevant to whether to isolate the 12v side of your house system from the 24v side. I supect I'm missing something obvious, or maybe not so obvious, but missing something nonetheless.
DerpsyDoodler
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