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Charnging LFP from two alternators

Hi everybody. I need to charge a Li battery bank from 2 different alternators. System configuration is as follow:

Engine 1 24V 60A alternator with internal regulation connected to its start lead battery

Engine 2 24V 60A alternator with internal regulation connected to its start lead battery

House battery back is 2 x 25,6V LPF Smart 200Ah with Ve.BUS BMS.

The idea is to send two alternator positive to the busbar and put a cyrix Li-charge between them and the lithium battery bank. is there any synchro issues?

Boat owner would like to use Buckboost but I have no knowledge ho to manage with two alternators. Do you have any advise?

bocas-uflex asked
safiery answered ·

2 Answers

Dc to dc Orion-Tr Smart DC-DC charger isolated


i have install today the new Dc-Dc isolated 30 amp

here's my setup

Truck battery - guage2 wire 25' - breaker 80amp - , gauge 8 wire 2 ' - battelborn 2x100

i purchase this unit to increase the voltage and have 30 amp to recharge the Battleborn

Lipo battery need more than 13.6 to charge

so far i was not able to get good voltage on the camper batteries

- the Bluetooth signal is not good. Compare to my other unit (all at the same place)

- what setting should be done to get higher voltage?


truck alternator is at 14.5

output is a 13.3


link to Lipo battery

How to Find Happiness With LiFePO4 (Lithium-Ion) Batteries - Solacity Inc.


fenix asked
fenix answered ·

2 Answers

Tr 12/12-9A cutting out at 10 volts not 7 volts

Hi, I have a Tr 12/12-9A (110W) isolated DC-DC converter and the unit is shutting off just below 10 volts. The specs say this shouldn't happen until 7 volts. Is there a way to fix this or is the unit faulty? I want to deep cycle my battery to about 8 volts so I get more useable capacity

binburra asked

0 Answers

Considering an Orion TR smart on the battery isolator output for a Li bank

I was considering using an Orion TR-smart between my battery isolator and my 4x100Ah LiFePO4 bank. The isolator has 5 connections 2 alternator inputs and 3 battery outputs. The application is on a a catamaran where my solar PV panels charge my Li batteries very well most of the time, The isolator is connected to the Hitachi 80A alternators on my port and starboard engines, and the outputs are connected to two 100Ah AGM starter batteries (outputs 1 and 2) and the 400Ah LiFePO4 house bank (output 3). I was concerned that if I were to run an engine or two, and my Li bank was not nearly charged I could end up overheating my alternator(s) by drawing too much current. With the batteries nearly fully charged I still saw the Li bank draw 50A from an alternator when one engine was running. Would the 30A Orion TR smart not only provide a current limit of 30A being drawn for the output #3, while also providing the optimal charging voltage for the Li bank at the same time the AGMs were charging at the appropriate voltage?

lacadienne asked

0 Answers

what is "DC POWER" on VRM Dashboard?

On the VRM Dashboard there is a "DC Power data" linked to the battery .

Presently -55W with PV charger at 46W, charging at 101W, load at 0W (multiplus off).

5 minutes later -49W, 46W, -4W, 67W (multiplus inverting)

How is thar value calculated and what does it mean?

Lionel SEYDOUX asked
Lionel SEYDOUX answered ·

2 Answers

Charging 48V batteries from alternator


It's been some time now that I'm trying to find a solution for my next van installation.

I first came with this diagram with 2 victron 12V LifePo4 (24v): https://community.victronenergy.com/questions/65042/wiring-diagram-for-a-van-install-with-multiplus-ii.html

Now I would like to use the Pylontech 48 V batteries and a Multiplus II 48V/3000 for efficiency, price, form factor, ...

I searched for a 48V buck/boost around 50/100Amps and found nothing affordable and easily available. I do not want to install a second 48V alternator... At least not at first, I have a strong 250A 12V alternator.

The basic schematic would be as follow:

- A "small" inverter under the hood would allow to feed the Multiplus at the rear of the van without needing big wires (and losses).

- The inverter would be activated with a D+ signal to avoid discharging the start battery

- The installation would be very simple

- I could easily "tune" the amps drawn from the inverter with the AC input current limiter of the Multiplus

Is it possible ? do you see any problems with this kind of setup ?

Thanks !


Basic diagram without solar, Cerbo GX etc etc etc.




sebcbien asked
danhig answered ·

3 Answers

Orion TR disable charge from VictronConnect

Is it fine to turn Orion TR 12/12 30 on/off in VictronConnect from disable charger toggle in settings? The app prompts a message stating it’s for workshop or system maintenance purpose only? Thanks

vanish asked
Alexandra answered ·

1 Answer

Cyrix ct-li

Has anyone used a Cyrix ct-li to connect a high-power 12V vehicle charging system with lead-acid batteries to a 400AH (non-Victron) battery system (Battleborn, 4x100AH parallel connected, built-in BMS)?

What prevents the 400AH of LIFePO4 batteries sucking down very high charge currents (perhaps 400A) and overloading the vehicle alternator (rated 250Apeak, but reports suggest better run at <150A for extended duration to avoid overheating).

What cuts off overcharging the LiFePO4 batteries?

Any better suggestions for charging the house batteries? The rest of the system is basically a Victron MultiPlus 12/3000/120 and downstream 12V and 120V loads.

neilhunt asked
neilhunt answered ·

2 Answers

Van solar electric scheme 24v and 12v

Dear forum:

I have been exploring the web and seeing a lot of electrical diagrams for a Solar installation in a camper van, but non with the idea I had in mind, so I'm sharing my scheme.

My idea is to have 2 x 180W Solar panels serial conected to have 24v output connected to a MPPT solar controler to charge two 12v batteries (115Ah each, serial conected 24v total). I would like to be able to charge those batteries also with the van alternator, and someone in the forum suggested me to try the Orion DC to DC high power 12v to 24v 450W.

From there, control de batteries level witht he BMV 712 Smart, and some other components (see int the scheme) to have a 12v power line, an inverter to have 220v, etc.

I would appreciate a lot if anybody could comment on this, give me his/her opinion, It is my first electrical scheme, I know there might be some basic error (I'm not sure how to wire the Orion 12v to 24v to the alternator/starter battery and bank batteries), things to be corrected or improved.

All fuses and wire diameters still in process




pepvan asked
pepvan answered ·

3 Answers

DC / DC Converter or Charger, Low Volt Alarms.

Is there an Alarm setting that will Alert me when for Example a 24/12 DC/DC faults and stops supplying on the Output, i.e. will i be Alerted if the 12V Outlet that is maintaining a battery is sensing a low volt condition? & If so how would i be Alerted?

mal-l asked

0 Answers

Buck Boost connection to ground always necessary?

I need some help.
I just wanna install my buck boost in my truck.
24V Car-batterie --> 24 lithium in the Cabin.

In the manual is written, that I should connect at first the ground to both systems (before they are not connected via ground (-).

So no problem, after it connecting the both plus- cable to each battery.

What is when I want do disconnect on of the battery-circle? I will have a main switch on the car-batterie on the minus-side. In this case I would disconnect one of the ground cable from the buck boost..... is this possible? Would be the same, if I had to change a battery. Normally always the ground connection is disconnected first from the battery, for any kind of work.

Even the cabin can taken of from the car. so I have to disconnect the buck boost completely with an connector (minus and plus from car-circle at the same time) ....possible or not? I will i destroy the buck boost?

Out from the Manual:

First connect all GND cables to the converter, the battery and the chassis, and then only the positive (+) cable. This is important because in the converter everything refers to GND.

When the two plus (+) cables are connected without GND, the potential difference between the plus (+) connections ensures uncontrolled and unsecured currents!
Always check that the GND connection on the middle M8 connection is correctly connected.

The converter has no reverse polarity protection!

Thanks for an advice or experience.

Best greetings

piemuth asked

0 Answers

Buck Boost charger

I am about to install the above device in my motorhome. What I want to confirm is whether the vehicle battery will also be charged via my PV once the "house" batteries are charged?? Or does it only work the other way and charge the house batteries from the alternator?

griffo1962 asked
Justin Cook - Bay Marine Supply USA answered ·

1 Answer

DC-DC converter parallel setup

Hi, I have just received my Victron 24/12 70 amp DC-DC chargers x 3
I can't find anywhere any instructions on how to parallel the 3 together.
A diagram would be great, can anyone help please.

martin61 asked
Paul B edited ·

1 Answer

Buck-Boost 26v at input terminal

I set up a new 50A Buck-Boost in my MB Sprinter RV to charge 12v LFP batteries from the alternator. If I test the line-in cable at the alternator/starter battery end, it reads 13.1v. When I test it at the Buck-Boost input terminal, it reads 26v. Can someone help me understand why this is happening and what's wrong with my installation?

usmc-mustang asked
usmc-mustang answered ·

2 Answers

Can Two Different Types of Isolated DC-DC Chargers Work in Parallel?

For example can a Buck Boost and Orion-Tr isolated version work together in parallel? I assume so if both are isolated; is anyone sure?

ecowhale asked
ecowhale commented ·

1 Answer

Orion-Tr DC-DC Converter Settings

I just got my Orion-Tr DC-DC Converter Isolated 12/24 V 15A charger, and what to configure setting for my environment.

I have limited understanding so my questions may be lacking. I will elaborate when needed. Also will appreciate advice and direction to concepts I missed here.

I have multiple 24V batteries in parallel all connected to busbars. Do I run the Output wires to the busbars?

I know my battery's voltage range is 21V – 29.4V. What do I set Bulk and Float to?

My alternator has a fixed voltage of 14.2V.

Absorption Voltage: 29.2?

Float Voltage: 27.6?

Caveat, I plan on limiting my driving to less that six hours a day when I do drive.

What are the Bulk time limit and Re-bulk Voltage Offset?

Oh - and Adaptive Absorption?

Lock-out I assume has to do with chassis batteries. I never want them to drop below 11V. Is it here that I input that setting? (12.3 - 12.9)

Engine shutdown detection, do I set this something like 12v - 13.8v?

Thank you.


Voltage: 24V

Voltage Range: 21V – 29.4V

Capacity: 95Ah (2.3kWh)

Power (Amp): 100A Continuous, 200A Peak

Configuration: 7S 20P


Prestolite A0014949PA

Output 270 amp

Fixed Voltage 14.2V

ajaja asked
marvs answered ·

1 Answer

12/12 30A Orion-Tr Isolated Smart in parallel fusing recommendations

I am new to 12V systems and am currently specing out / purchasing components for my 2020 4x4 sprinter conversion power system. I have purchased 2 x 12/12 30A Orion-Tr Isolated smart units since I am looking to obtain 60A charging capabilities. I am building a 12V 400Ah battery system. I see the fusing recommendations are 60A at the starter battery and 60A at the auxiliary battery side, this is however in the case of having a single 12/12 30A Isolated unit.

What would the fusing reccomendation be for two units in parallel? do I fuse / circuit breaker them separately effectively having 4 fuses configured? If not I would appreciate any documentation links or schematics I can refer to. Any input is appreciated!

So far I am using Blue Sea Systems components for Bus Bars, Battery Switches and Circuit Breakers.

karol-kozubal asked
d-winterburn answered ·

2 Answers

Charging my LifePo4 with an alternator


I am designing my setup but the only thing that is not clear to me is how to safely have my batteries charge through my alternator.

The battery will be a LiFePo4 battery, 12V 600Ah.
Inverter/charger Victron Phoenix 12/2500/120
700W of Solar through SmartSolar 100/50

I am still deciding on the BMS. My van is a 2006 Renault Master, so I'm pretty sure it's not one of the newer "smart alternators".

From what I can find online it looks like there might be a way to use either a BMS or a VE.Bus BMS to do this? I would like the alternator to be connected to my starter battery at all times, and connect a system to that that
A) Doesn't destroy my alternator
B) Doesn't drain my starter
C) Shuts off charging when battery is full

Has anyone already made a setup like this?

Thank you!!!

shivadas asked
Trina edited ·

4 Answers

Victron Orion-Tr Smart 12/12-30 cable bus bar

i am looking to add a Victron Orion-Tr Smart 12/12-30 to my system but my main cable that come from my alternator is a gauge 2

So my cable is to big to connect it to the DC-Dc....

so does that combinations look ok?

Truck Alternator - breaker 60 amp - truck batterie (AGM) - Gauge 2 25 ft long - breaker 60- Gauge 6 4 ft long - 2 x batteries (Lithium total 200 amp)

fenix asked
rodneyab answered ·

2 Answers

Wiring a Victron DC-DC charger - HELP!


I want to install an Orion DC-DC Smart 12/12/30 in my van. It would be connected to the starter battery under the driver's seat all the way to the back of the van on the opposite side (passenger side). My question is, if I run the wiring up to the ceiling, to the back, and back down, the distance would be 10m one way (2m up, 4m to the back, 2m across, 2m down), if I run it through the floor the distance would be around 6m one way (4m to the back, 2m across). Keeping in mind derating factors (running continuously for more than 20m, being in a conduit or insulation), I've calculated I need a 0awg wire (50mm), which seems way too big. I don't know if my calculations are wrong? Victron recommends a minimum cable gauge of 16mm for a 5m distance (i'm guessing this would be one way?).

I'd appreciate any help!! Thank you

palomafts asked

0 Answers

Orion Tr Smart Isolated 12|12|30 2019 Sprinter Install

Hi @Justin Cook - Bay Marine Supply USA, wondering if you have any experience in installing the Orion Tr Smart Isolated 12|12|30 in a 2019 Sprinter? From reading the manual it seems very plug and play but I don't know what I don't know. My question is it as simple as connecting the Negative and Positive to the starter battery terminals directly? Does this interfere with any of the factory computers since the onboard computers don't talk to the Victron and produce error codes?

jsmith1985 asked
Justin Cook - Bay Marine Supply USA answered ·

2 Answers

Connect a DC-DC converter to EasySolar / MultiPlus

I have an EasySolar 5000VA (=MultiPlus) connected to a 48V Lifepo4 battery. I was wondering, where or how I could connect a 48V to 24V DC-DC converter.

The DC-DC converter is supposed to power a Teltonika RUT950 4G router (9-36V) which is connected to the GX computer and gives me remote control over the EasySolar, even if its inverter (MultiPlus) is turned off.

I know, that there are several relay's from the MultiPlus and one is there at the SmartSolar charge controller. That relay can be configured when to be switched, but there was no Voltage when I measured, no matter what settings... However, is this the way to go? The router drains max 7W of power... should not be a problem I guess...?

Or could I hook the router directly to a relay without a DC-DC converter?

Or has anybody an idea, how I would power the router the right way?

Thank you!!!

andrer asked
andrer commented ·

0 Answers

Orion-Tr Smart DC-DC Charger, Yamaha generator EF1000iS.

Hi I own a Yamaha generator EF1000iS, it has the option to charge a 12V car battery via a 12v 8A output. To my understanding this is for emergencies, as the 12V 8A output does not include a pwm or mppt. My question is can I use the Orion-Tr Smart DC-DC Charger 12 | 12 30, to go between the 12V 8A generator out and charge my lead acid battery?

Thank you in advance :)


sane asked
Henk answered ·

1 Answer

How to wire MPPT and DCDC charger in same system

I am getting a 120amp LifePo4 and wanting to charge from both Victron solar and dcdc from starter battery

Will these two interfere with each other whilst driving? I have heard that they can cancel each other out.
Should I include a manual switch so I can choose to use one or the other? Or is there another way to insure that my batteries will be getting charges whilst driving.

rubytuesday asked

0 Answers

Can I use the ORION charger and MPPT SmartSolar charger at the same time?


installing a battery system to my pop top. having a VE ORION TR 12/24 30 amp 360W ISOLATED DC-DC charger and VE 100/30 MPPT SMART SOLAR CHARGER fitted. so I can run 12 v fridge when driving but also charge from solar when stopped/driving.

how will these operate when driving and connected to car alternator? will both still charge? will they conflict? will one shut off?

many thanks for any help.


robdav asked
JohnC answered ·

1 Answer

12v to 24v 70a dc-dc converter can this be left on all the time?

My camper has 24v batteries and 24v inverter. Could I run a 24v/12v70a dc to dc converter to run lights / heater and water pump (all 12v) I would need it to be on 24/7 as my heater trips in and out. Also does it consume power when no items are being used.


hex123 asked
wkirby answered ·

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

0 Answers

Can I use a Orion-Tr DC-DC converters, isolated 12 to 12 V / 18 A to charge a leisure battery from a Euro5 engine or do I need a Orion TR Smart DC-Dc converter?

I have a 2014 Citroen Relay van which I am fairly sure uses a Euro5 engine.

I currently have a Orion-Tr DC-DC converters, isolated 12 to 12 V / 18 A, but it does not appear to charge the leisure battery at all while I am driving.

declanbredin asked
philippe answered ·

1 Answer

Orion-Tr Smart DC-DC Charger Isolated (Size of Wire)

Anyone know the biggest Wire that the size Orion-Tr Smart DC-DC Charger Isolated could take?

i Have gauge 2Awg... Will that fix?


fenix asked
jhickok commented ·

2 Answers

Orion TR Smart woes. Not impressed.


I have three different Victron DC systems and had plans to add the Orion TR Smart to two of them. I purchased a 12v 30a non-isolated Orion TR for my RV and to bluntly put it.. I'm not impressed.

This device has no ve.direct connector, what is the logic behind this decision? If I've invested the money to control every aspect of my Victron system through Venus, why would this device be headless? There also seems no way to add it into the bluetooth VE networking protocol.

I have come to rely heavily on DVCC for my dynamic charging needs, so the fact that this device can only be controlled through bluetooth with an extremely limited set of configuration options is frustrating.

The bluetooth radio in this device is abysmal. I can control every other Victron Smart product meters away from them, whereas this Orion TR doesn't even broadcast outside of the vehicle it's in. I have also seen similar complains in the ratings sections of a retailer and on this forum.

Has anyone used the external relay control features of their multiplus or possibly bmv-7xx to provide at least some type of logic-based control to their dc-dc charger?

I feel like this device was rushed to market. I am struggling to see the value in the Orion TR, I am considering returning this item. Does anyone have any insight if there are firmware improvements scheduled for this product or if I'm missing something here?

teejmiller asked
alnavasa answered ·

4 Answers


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