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Parallel DC-DC Chargers 30A

Is there an end all be all guide to doing two Orion TR Smart DC to DC 12|12 30 in parallel?

Current setup consists of 1 charger, but when on the phone with Nomadic Cooling they mentioned a few issues with the electrical system. The first one being instead of using the Victron Manual recommended 6 AWG I should be using 1/0.

However I'd like to add another charger into the mix to and curious on best wiring and fusing options.

My first thought of wiring it would be run a single wire from the battery to a 2 stud bus bar and then branch it to each of the chargers. Is this the best idea?

To fuse this I figure a 100 amp fuse on the main cable and then two 60 amp fuses on the split cables?

Please let me know your thoughts.

william-moriarty asked

0 Answers

Buck-Boost 100A - No OUT LED (Green IN LED)

I have installed a 100A Victron buckboost essentially as per the below diagram from the manual. The only difference in my install is that there is a transfer switch between the buckboost and the LiFePo4 service batteries. I am not using the green/purple pin wires. My service batteries have built-in BMS.

I am using engine vibration detection only to turn on the converter. When I turn on the engine/alternator I get an IN LED = GREEN, which is the desired status. However, I get no OUT LED. No OUT LED is not described in the manual.

My service battery monitor shows the battery is at 99.5% charge so I would expect the OUT LED = GREEN or PURPLE. If there was no connection to the service battery (because my transfer switch was installed incorrectly) then I would expect OUT LED = RED (no connection to battery as per manual).

TSConfig is showing correct input voltage (1) and output voltage (3) but no output current (4) except occasionally .1 or .2A (but mostly zero). I will screenshot TSConfig tomorrow when I am able to.


bigdumbmik asked
bigdumbmik edited ·

0 Answers

12/24v Buck Boost Converter into Orion 24/48 Converter into MPPT to get 33V charging capability

Is this combination of components possible to utilize for the desired outcome of a 33v charge?

I've currently got the 12/24v buck boost converter in use but it can only charge my batteries to 30v. (my batteries are 28-33v operational)

I want to take that 30v and boost it to 33v and it seems the only way would be to use the Orion converter then send that into an MPPT.

Is this possible?



thirdeyesamuel asked
thirdeyesamuel answered ·

1 Answer

Multiple battery strings with DC-DC converters and example component diagrams and converter configurations ?

Hi Forum. I'm in communication with BMS manufacturers about how best to configure 32 prismatic cells for a marine application. System voltage of 48 although the vast majority of loads are 12. Redundancy is important so we are thinking about qty. 2 16S1P strings with DC-DC converters isolating each string. Are there any examples of such Victron configurations in the wild that I can study ?

sven-nurber asked
shaneyake commented ·

3 Answers

Isolated Orion-Tr negative wire thickness with both batteries grounded to chassis


The starter battery negative terminal is connected to my van's chassis (as per usual) and my leisure battery negative terminal is connected to the chassis via a 20mm2 wire. I have just ordered an Orion-Tr Smart 12/12-18 Isolated DC/DC Charger; I didn't need the isolated version as my batteries are already bonded via the chassis but it was cheaper than the 30A non-isolated version. I will connect the starter and leisure batterie's positive terminals to the Orion-Tr via 20mm2 wire.

My question is, given that the two batteries negative terminals are already connected via 20mm2 wire and the vehicle chassis, can I connect the negative input and output of the Orion-Tr to the chassis/battery negative with thinner wire (say 6mm2 or even 2.5mm2)?

From my limited understanding of electrics, I would think that the Orion-Tr just needs the negative wire to be able to power itself and sense the voltage of the two batteries and the current path will be through the vehicle chassis as that will be lower resistance.

I have attached a Wiring Diagram.jpg for clarity.


OutdoorAcorn asked
OutdoorAcorn commented ·

1 Answer

input 12 v lead acid starter battery output 24 v electric motor lithium battery

Looking for a dc to dc charger to charge my 280 ah 24 v / 6800wh lifepo4 electric trolling motor drive battery from my 200 ah 12 v starter battery. (50 Amp 12V alternator on main engine)

Can you give me an advice what kind of dc to dc charger would suit my needs ?

something like a orion tr smart 12/24-15a (360w) isolated dc-dc charger should work ?

mikewh asked
justmurph commented ·

4 Answers

Orion smart charger not charging correctly

Running version 1.06

Charging from AGMs to lithiums does 30 amps for the first few seconds, then tapers to absorption charge quickly. Using solar panels with victron mppts for each bank. The AGMs show -5 amps on the victron bms and are getting about 12 amps from the panels.

Wondering if there’s a way to remove the firmware then reinstall? Or how do I fix this @Daniël Boekel (Victron Energy Staff)

josehoya asked

0 Answers

Orion-Tr 12/24-20 installation

Hi again

In a previous post I shared the scheme of my Van electrical system. It is almost set now, but I have some small doubts...


Mostly about Negative / Ground

here I share a scheme with three options on how to connect Orion 12/24 to the negative busbar
which one is more correct?


many thanks

pepvan asked
pepvan answered ·

3 Answers

Charging my campers’ leisure batteries both via the alternator and solar.

Hi there, community!

I wanna charge my campers’ leisure batteries both via the alternator (Orion-Tr Smart DC-DC Charger Isolated) and solar (SmartSolar 100 / 20 20A MPPT). Can I use both products simultaneously? Thanks!

leoalm asked
pepvan answered ·

3 Answers

Can I use an Orion 24/48 Converter After my 12/24 Victron Buck Boost Converter Then into an MPPT All to get 33V charge output? ⭐️

I'm collecting info on my options outside of solar to reach a charge voltage of 33v for my Nissan Leaf house batteries in my camper van.

Perhaps I can use multiple Orion 24/48 8.5amp converters in parallel, fed by my 12/24 100/50amp Victron buck boost converter then run through an MPPT to perfectly dial in the charge output to 33v.

I know it's not the simplest solution, but I've already got the buck boost converter running, however it can only output 30v, so im losing the bulk of my batteries charge by not going up to at the very least 32v.



thirdeyesamuel asked
thirdeyesamuel edited ·

0 Answers

Not Turning On - Victron Orion-Tr Smart DC-DC Charger (12/12-30 isolated)

Hi there, thanks in advance for any help you can provide.

I've just finished my solar setup in our small van and turned everything on. Everything appears to be working properly except the DC Charger is not powering on. My MPPT solar charge controller right next to it powered on just fine. Any tips from the community on how I can check what the problem might be?


  • 2 x 100ah 12v LiFePO4 batteries wired in parallel
  • Negative from Batteries run through Victron's BMV712 Smart Shunt, and then to Blue sea systems Safety Hub 150 fuse block, and from the fuse block I run a ground to the van chassis
  • Positive from batteries run through a fuse, then through a cutoff switch, and then finally over to the positive side of the Safety Hub 150
  • DC charger is wired from Alternator
    • DC Charger is not yet connected to the alternator, as I need to power off my starter battery from what I have read
    • and yes, it is actually more convenient and shorter to run 6AWG cable from my alternator, about 6-8ft, than it is from my starter battery 10+ feet and more difficult
  • Wire from Alternator is ran through a fuse, and then to a cutoff switch, finally ending in the DC charger
  • DC Charger to Safety Hub Fuseblock is very close, less than a foot, and the wire is 8AWG
  • Voltemeter test says there are 17-20 volts on the output posts

Does this sound like the unit itself malfunctioned somehow, or did I set something up wrong? I shouldn't need to connect the charger itself to the Starter Battery or the Alternator for this to work, as long as I have it connected to the battery bank, correct?

trevoraaron asked
Matthias Lange - DE answered ·

1 Answer

Orion 24/12 -25 dc to dc converter dangerous over current

Orion 24/12 -25 dc to dc converter as a backup to charge my 12 volt battery from my 24volt battery bank when smaller 12 volt solar supply can’t keep up with charging requirement. I have an older 24/12-20 model I use to charge my generator start AGM battery and it has worked without a problem.

Both the 24 v battery bank and the 12 volt battery are lithium. Connected the both systems as per instruction. Fused the system given the output and input as indicated on the unit. Energised the system and turned on the remote switch I installed. Output 12 volt fuse immediately blew. De energised system and checked all connections and found no problem. Installed BMV on 12 volt battery and safely increased fuse and wiring size to accommodate much more current than the rated 35 amps that can be supplied. Re energised the system and noted on the BMV on 12 volt battery indicated over 45 amps being put out by the converter. I allowed the charge to continue for around 3 minutes until the unit heated to a point where the smell of paint over heating on the unit.

Removed unit and had the unit replaced under warranty. Service agent/seller could not understand how the unit could output so much current above specification.

After the muck around posting the faulty unit back I finally received the new replacement. Same process of installation making extra sure of a strong negative connection I fired the systems up again with the same result again but this time the current hit 50 amps 12 volt with over 25 amp draw on the 24 volt side! Informed the victron service agent again. Weeks went by and all I got was crickets! Contacted service agent again, they have no idea. I thought it may have been a bad batch so in an effort to try and get on the road I purchased another one. Same results!!!

I would say they are not fit for purpose when it comes to lithium batteries. One would think the unit would have some form of protection built in to prevent over current output and possibly avoid a severe overheating/ fire situation?

If anyone has some clue on this I would love to be enlightened



Brad Dull asked

0 Answers

DC-DC Converter Emissions

My house is off grid using all Victron components. My battery system is 48V. I have a Ham (Amateur Radio) room which requires a 13.8V power supply for some of the components. It is located about 30 feet away from the solar system components (batteries, charge controllers, inverters). I am thinking about using a Victron Energy ORI481240110 Orion-Tr 48/12-30A Isolated DC-DC converter and placing it in same area as my Ham equipment. I would run a 48V line from the solar system to the DC-DC converter (30 feet away). I would then use the 13.8V output to power my Ham equipment.

In the US, I typically look for electronic components that meet FCC Part 15(b) standards for emissions. For emissions, this product is rated for EN 61000-6-3, EN 55014-1 (European standards). Is this similar, or equivalent, to FCC Part 15(b)?

tbratten asked
Paul B answered ·

1 Answer

How to Charge a Battery to 33v from Alternator

I am currently using a Victron MPPT and 12/24 100/50 Buck Boost Converter in my 8S4P Nissan Leaf van house battery system and would love to know if I can safely increase the charging voltage of the buck boost converter from 30 to 33v.

My operational voltage is 28-33v.


thirdeyesamuel asked
thirdeyesamuel commented ·

1 Answer

Orion DC DC Charger - when will it be networkable?

Hi All, I have a camper that runs solar on the roof, and via a Smart DC DC Orion 24/24 - 17 charger in my truck camper. Currently these are not networked as I am driving along which does cause them to sometimes be in different charging states.

Posts on here have asked the question but have not been updated recently - when will the Orion DC DC chargers join the Victron Networked family?

I am very keen to have all devices working on the same charging algorithm. Is there a workaround with the Victron Dongle?

Does anyone know when these will be networkable?



trollan asked
lorin answered ·

1 Answer

Buck Boost Converter Remote On/Off with Victron Connect App

Is it possible to create a remote on/off using the Victron connect app for the buck boost converter?

I’m using a REC Q BMS, smart BMV 712, smart MPPT 250/60 and Cerbo GX.

REC BMS because I’m using 8kwh Nissan Leaf battery.

I’ve currently got the pin 1 purple wire shorted to pos terminal of buck boost as an always on workaround and I use tsconfig to turn it off when Vehicle is off but I’d love to have control from my phone instead.

Similar to the Victron vw van, I’ve got the buck boost and mppt feeding in through a single 220A smart battery protect otherwise I’d just use that device as an in app on/off.

I suppose if needed I could buy a separate SBP just for buck boost but I’d rather keep it going through the one I’ve got.

Alternatively I’d love it to be full automatic based on the starter battery voltage when vehicle is on but I don’t yet fully understand how to wire it.

dragon-wagon asked
dragon-wagon edited ·

2 Answers

Can you parallel Orion Smart 12/24-15 DC-DC Charger in charge mode?


I'm about to purchase 2 off 12-24V Smart DC-DC charger. The dealer I'm buying from advises they can only be connected in parallel for power supply mode, not as a charger. I want to use them to charge a lithium battery bank from the Engine battery/alternator on a Euro 6 engine. doubling up as I'd like more than 15amp of charge current.


marting asked
Mike Dorsett answered ·

1 Answer

DC chargers/converters to charge lithium on boat and current

I want to charge my 24v lithium house bank on my boat from my 12v start battery. First I was thinking of Sterling b2b, but heard bad things about it (too hot, plastics melting, remote expensive etc).
So I was thinking about Orion Tr Smart, or normal Orion dc-dc converter . But then I realized that since my bank is HUGE they will blow up? Or will they limit themselves to their max output and work just fine? (or work fine but very hot)

Left is the DC to DC buck converter, which as I understand has a current limiter also.
Am I thinking right?

2nd, regardless of which one, if my lithiums has max charge at let's say 28,8 (14,4x2) I could set the output voltage at 28,4, and they would never overcharge?

clubbers asked
Mike Dorsett answered ·

1 Answer

Differnte MPPT vs Orion

If I have a 2nd aux 12v battery in my car that I need charged with the correct characteristics (Li-ion) I can choose to pick the MPPT (12v) and connect solar OR orion (12-12) and connect it to alternator DC 12~14.4V.

If I wanted both, would I need both? What stops me from feeding alternator power to the solar in on the MPPT? Aren't these the same chargers with another name?

xychiux asked
xychiux answered ·

1 Answer

Buck Boost, MacBook Pro, Boot camp Windows 10 coms port issues.

Morning, I’m hoping someone out there has gone through the pain already of configuring the settings to a buck boost from a MacBook Pro using boot camp windows system.
The problem being is the windows system gives me that reassuring double gong when I plug in the USB detecting an external device however no coms ports are visible in the TS software. Am I loosing a fighting battle?

Many thanks in advance.


whick89 asked

0 Answers

Best option for charging a secondary 12V battery bank from a primary 48V battery bank


I have a 48V, 440Amp battery bank for the electric engine in my sailboat. I also have a 12V, 200Amp buffer battery for my house bank.

I own the following Victron equipment:

12/12-30 DC-DC Smart Charger

48/12-30 DC-DC Converter

Before I connect this and possibly damage the equipment and battery banks, I thought I would check with the forum. Should I connect the 48V bank to the converter, the converter to the charger, and then the charger to the house bank?



ftlsailor asked
hoeken commented ·

1 Answer

DC/DC - 48v to 24v conversion + buffer battery?

I am in the process of spec'ing out the power electronics for a large sailboat. For various reasons, it will have a 48v LiFePo4 bank where the majority of charging sources come in, as well as the inverter/charger, and then a 24v buffer battery where most of the DC loads will draw from. It looks like the total 24v DC power usage will be around 10kwh per day, but with loads like electric winches or windlass potentially spiking temporarily to 3.6kw (~150A)

My first question is this - what is the proper way to handle this conversion? The only 48/24v dc/dc converters I see on the site are the 'dumb' Orion DC/DC chargers that go up to 400W. It looks like we'll need about 500W/hr of charging to keep up with demands, and an extra converter for redundancy (absolutely cannot have this fail at sea!) So it looks like 3 x Orion 48/24v converters in parallel?

Secondly - the buffer battery will be a Victron 24v 200ah LiFePo4 smart battery. The DC/DC converters seem to be configured to just output a steady voltage. Does this buffer battery need to be supplied with a 'smart' charger to give it exactly the right voltage to fully charge, or can the converters be set to a safe voltage and just keep it mostly charged?

hoeken asked
hoeken commented ·

3 Answers

BMS or 12/12 DC charger?
I am just about to spend a lot of money on loads of lovely little blue boxes and just wondered if you could help me choose between a couple of them?
I am a boater I’m afraid. My curse is that I am simply tied to a soap on a rope in the middle if a river all season. This means I have no shore power and have to take advantage of all the elements to charge my LiFePo4 battery. Wind and solar is comprehensively taken care of due to charge controllers however I’m left in some doubt over the engine charging:

I have a 230ah LiFePo4 battery bank (not Victron I’m afraid) managed by a simple Chinese BMS. My starting battery is a small 16ah lead acid. My charging source is a 15hp Honda outboard with 12a charge coil (not really an alternator)
As I see it, the simple solution is a dc-dc 18a(?) charger connected between starter and LiFePo4 but I wondered if the BMS 12/100 unit might be an alternative? I appreciate that without a Victron smart battery a significant amount of its functionality is lost but in principle, it looks like I would benefit from a higher charge rate, should I need it in the future, adjustable charge rate and a battery protect cut off with a remote control circuit. Am I correct in this or will this not work without the combination of smart batteries?
Do Victron have or ever plan to develop a battery BMS for non Victron batteries that would allow connection to the Victron BMS bus?
I also have a 50a mains to 12v charger which I hope to use for the winter lay-up months but it is not designed to be used with LiFePo4 batteries. Would running this charger to the starter battery and hence through the 12/100 bms manage the charge to the LiFePo4 bank?

Thanks in advance,


jimmerbee asked
raphael answered ·

1 Answer

100/20 MPPT + 12-12/30 DCDC + Control Box Wiring Diagram

Hey all!

I’ve gotten myself into a little bit of a spaghetti of a mess trying to rely on my memory with everything coming in and out of the control box for my setup...

basically, all wiring and devices are mounted and wired in and out of the control box, making itself and the device easily removable if required because, both my 100ah deep cycle and the control box will be in the wheel well in the back of my Outback.

I’m hoping someone who is kind enough to help me out with putting together a diagram with the appropriate midi holders in place with what I’m trying to achieve here, I’ll be posting up photos shortly also with how far I’ve gotten so far.

Ultimate goal is to have it looking simple but, fully functional with the ability to show customers what’s possible as well as easy access to its fuses if required.

cheers and thanks all!





I’ll note that -

A. Yes I’ll have ventilation added through the box for the MPPT via a Load controlled fan.

B. I haven’t added a Anderson for the Auxiliary Battery as of yet to the box, however - it will be located on the opposite side to the Fridge output

Rick asked
Rick edited ·

0 Answers

Upgrading boat to AGM Starter and LiFePO4 House batteries

I am planning to upgrade the old Lead Acid batteries on my power boat this year. The current configuration looks like this;


My plan is to replace the starter battery with a dual-purpose AGM battery and replace the house batteries with a pair of LiFePO4 batteries. My understanding is that I will need to install a DC-DC charger between the starter & house batteries to adjust for the higher charging voltage for the Lithium batteries, but I wanted to confirm this. It seems like the DC-DC charger should be installed next to, or in place of the battery combiner (between the starter and house batteries), is this correct? Thanks for any guidance.

rob-crawford asked
rob-crawford answered ·

2 Answers

DC-DC converter with outboard engine alternator

My sailboat’s electrical system is very simple.
I have a dual purpose 12V 200Ah flooded cell battery bank. I run the daily loads and also start my Honda 20hp outboard from this single bank.

The bank is charged from the outboard and from a 300W solar array connected to an MPPT 100/20.

The outboard has a starter motor and a 12A regulated alternator that reaches ultimately 14.8V,

The recommended absorption voltage for my batteries is 14.4V.
So in my understanding I should install some device such as an Orion Tr DC-DC converter to get the 14.8V brought down to 14.4V.

However, the outboard’s harness is solely a positive and a negative wire. These are connected directly to the battery bank. There’s no outside separation for the starter motor and for the alternator circuits.

I may be wrong, but it seems obvious to me that I cannot connect these two wires to a DC-DC converter, since the current would be reversed whenever the starter motor is used.

Does anyone have any suggestions on how to regulate the (already internally regulated) alternator output? Or any other solution for my system?

Thank you!


henrique-eipeldauer asked
markus commented ·

1 Answer

Orion DC-DC Converters Non-isolated, High power vs Orion IP67

I'd like to run 12V loads in a motorhome from a 24V battery bank, and the loads should not exceed 70A. Hence I could use an Orion IP67 24/12-100, or an Orion 24/12-70 (Non-isolated, High power)... Which should I choose, and why? (Basically, how are they different?)

hookem asked

0 Answers

which orion dc to DC


I am updating the leisure electrics in my VW T6 Euro 6 to a lithium system. I am replacing everything with Victron apart from the CBE Fused distribution box and the only thing I am stuck on is the DC to DC charger. I will be using a single 100AH lithium leisure battery. I am presently using a Ring RSCDC30 combined 30 Amp DC DC Charger/MPPT which has the positive out feeding to the CBE unit then from there to a busbar. Although programmable I have been advised against using it for lithium so will be replacing with a Victron MPPT and a Victron Orion unit. Can anyone advise which Orion unit is best suited for use with a VW T6 Euro 6. Also do I need isolated or non-isolated.

many thanks

tcummins857 asked
lydart commented ·

1 Answer

Orion TR Smart and Euro 6 Engines

Hi the collective hive of information.

I am in the middle of commissioning an Orion TR Smart 12/12-30A on a VW T6 Camper van. The system doesn't seem to be triggering that often, and even after a couple of hours driving the Lithium batteries are not full.

All default settings have been used, but the start battery is regularly at 12.3-12.5v.

Are the default settings too aggressive, do they need to be dropped. If so any recomendations. I have done various searches and running second battery charging with Euro 6 engines seems to be a dark art with little information about what a good set of settings should be.

My instincts as opposed to science or knowledge is to:

Drop Input Voltage Lockout to be 12.1v / 12.3v. After starting the engine and idling the starter battery is regularly at 12.2v, so restarting shouldn't be an issue at 12.1v.

Setting Start Voltage to 13.2v

Setting Delayed start to 12.8v

Setting shutdown voltage to 12.7v

Any guidance, are these values too low?

Many Thanks



bathnm asked

0 Answers

MPPT and DC-DC in parallel?


Is it OK to connect Orion-Tr (12-12-30) and MPPT (100/20) to the (second) battery in parallel or do I need to have a switch so they don't both connect at the same time?


captainmagnus asked
motorhomer commented ·

3 Answers


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