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Orion on alternator without starter battery

Hi everyone !
I am writing to you to know if some people have already connected an isolated Orion tr smart to a vehicle alternator without a starter battery? and if it worked and charged proprely?
I explain the vehicle contains 2 alternators, the second alternator was mounted specifically to take advantage of charging a large auxiliary lithium park (mechanical assembly + belt, no electrical wiring).
The excitation of the alternator is given by the starter battery.
I have a problem concerning the output voltage of the alternator which is 8.7V at no load (belt tightened everything is ok). The wiring is quite classical (+ and - input on + and - alternator). The negatives, alternator housing, are well connected to the truck chassis, R=1 ohm. Then I tried to connect to the input of the Orion and there my multimeter shows me 32 V DC (and the Victron application too)!
I wonder if the alternator has a defect because according to me the alternator is supposed to provide a stable voltage and therefore the Orion should work quite normally. I wanted to know if some people have already done this type of assembly with an isolated Orion on an alternator without starting battery and if it worked.
I would like to specify that this is not the first Orion I have installed.
Thank you all for your help.
Sorry for my english i'm not native.

mathiasotf asked

0 Answers

Orion Smart DC-DC Charger Settings for Connection to 2018 Ford F250 Upfitter Switches

Summary of Issue:

Not always getting charge to my batteries, when I do, the VictronConnect app doesn't reflect the charging state or battery levels.

Details of Issue:

I have a truck camper on my 2018 Ford F250 with the heavy duty alternator and auxiliary upfitter switches. I've got everything running off of upfitter/AUX switch 1 which is rated for 25amps. Cabling is marine-grade 10/2 all the way to the Orion Smart 20amp DC-DC charge controller. I'm consistently always getting 14.7V input at the Charge Controller, but have different results/scenarios on the output voltage:

  1. I do not get output voltage to my batteries: this is after starting truck with AUX1-switch enabled, or, having truck run for a few minutes before enabling AUX1-switch. This is with Engine Shutdown Detection enabled and Input Voltage Lock-Out enabled.
  2. I get output voltage to my batteries, but app does not reflect charging state and reports that charging is disabled: sometimes I can have AUX1-switch enabled when I start the truck and will very soon after will have output voltage to batteries. Or, after having truck running, I enable AUX1-switch and shortly after have output voltage to batteries. This is with Engine Shutdown Detection disabled and Input Voltage Lockout disabled.
  3. I get output voltage to my batteries, and the app reflects the charging state (bulk, float, etc): I've tried about every combination of settings in the VictronConnect app I can and the times I've seen the app report the charging state have been just about random. The times I've adjusted VictronConnect app settings and it has reported 'bulk' charging state, it does not continue to do so after turning truck off and back on. I've also only been able to get app to relfect 'bulk' charging state while truck has been running (and AUX1-switch enabled) and I've made changes in the charge controller settings, I've yet to see a 'bulk' charging state on startup without changing app settings.

Installation notes:

  1. From upfitter/AUX switch 1 (rated for 25amps), I've run marine-grade 10/2 to the terminal/junction box I installed on camper (so that I can disconnect cabling in the event I remove the camper or sell it). 25' of cabling at most.
  2. From the terminal box, the marine-grade 10/2 runs through the interior of camper to the Orion Smart DC-DC charger input terminals. 25' of cabling at most.
  3. From the Orion Smart DC-DC charger output terminals, marine-grade 10/2 cabling to battery compartment, connecting to 2 Dakota Lithium 54ah batteries connected in parallel. 9' of cabling at most.


  • I also have a 200watt 10amp solar panel array (2 panels) with 20amp charge controller connected to batteries.

1. Under the Hood Connection.jpeg

2. Terminal:Junction Box.jpeg

3. Orion Smart DC-DC Charger.jpeg

4. Camper Battery Compartment.jpeg

VictronConnect - Output Voltage with Input Voltage Detection Disabled.jpeg

VictronConnect - Getting Output Voltage but no Charging State.jpeg

VictronConnect - Output Voltage with Engine Detection Disabled .jpeg

VictronConnect - Engine Detect Enabled and Input Voltage Lockout Enabled.jpeg

VictronConnect - Output Voltage but no Charging State - Engine Detection Disabled and Input Voltage Detection Disabled.jpeg

VictronConnect - Set to Charger.jpeg

Clayton Tompkins asked
Clayton Tompkins commented ·

1 Answer

ARGOFET alternator cable fusing

Should I FUSE the cable connection between the alternator B+ output and the Argofet Input ? On which side (close to alternator or close to argofet ?)

THe alternator has a rated output of 55A (Hitachi LR 155-20 for Yanmar) and the cable is 35mmq, than can carry all of the current. I don't believe there can be a fire risk on the cable, if there is a short on either side of the cable. May be the alternator can burn if it sees a short at the output, but I cant fuse less than 55A, and If I use a larger fuse I don't think there is much more short circuit current enough to blow a say 70A slow fuse.

ANy recommendation ?



abuonocore asked

0 Answers

Orion 12/30 with 60a alternator

I'm considering connecting my lead acid starter battery (100 ah) to my agm house bank (400 ah) with a Victron Orion tr smart 12/30, charge the starter battery with the alternator (non regulated 60 amp Hitachi) and the house bank indirectly through the orion when engine battery is full.

  1. Is this an ok situation for the alternator?
  2. I have read that there is an efficiency loss from the orion. Is this bigger than the efficiency gain from having the alternator output regulated for agm batteries?


the-white-whale asked
the-white-whale edited ·

0 Answers

Smartshunt DC energy meter for case grounded alternator

I have a Smartshunt ready to install as a DC energy meter on my boats domestic alternator, but this has the negative via the grounded case and engine. I also have a separate engine battery and alternator but they share the common negative return via the engine. This will add to the existing BMV702 on the domestic batteries. I have seen many comments that in this case, you need to have a shunt in the positive cable.

Thinking about this, I believe that I can wire it up in the negative cabling per the attached sketch. The negative return from both alternators splits at the new Smartshunt to separate out the current from the two alternators so it will only measure the domestic alternator. In the existing wiring, the alternator negative, the ground and the engine battery -ve all connect to the -ve bus and this works OK with the BMV. The boat is steel hulled and it is not used for any negative returns, everything is fully wired to the -ve buses.

The sketch ignores fusing, isolation switches, minor wiring to the shunts.

Am I missing something in my wiring layout.


pwfarnell asked
pwfarnell commented ·

1 Answer

Control Orion with temperature sensor

Is it possible for a temperature sensor connected to engine alternator from cerbo GX to turn off Orion DC-DC charger when alternator reaches to high of temperature?

blackbird asked
blackbird answered ·

3 Answers

Connexion prise ATS contact sec


Je recherche quel sont les 2 pin de la prise ATS à connecter au relais contact sec sur mon onduleur chargeur Victron

Sur une prise 3 pin je sais que c'est le pin 2 et 3

Mais ici sur ma prise ATS il y 6 pin d'où ma question ?

Merci d'avance à vous




benj Gaïa asked
Thierry Cortassa (Victron Energy Staff) answered ·

10 Answers

Smart BMS CL not charging

We have the same issue with multiple Smart BMS CL: They are not letting significant charge to the Lithium batteries even though the alternator is running at high speeds.
Screenshot attached - we have a 100A alternator, engine running at 2000rpm, the device shows 5% load and no significant current flows towards the battery. We had the same / similar issues on multiple boats and caravans.


Any idea what the reason could be? It can not really be linked to the batteries - we have tried bridging the M8 connectors with a BMS cable, still the same behavior..

mik asked
philiplyra answered ·

3 Answers

Smart BMS 12/100 low charge rate

I have a victron lifepo4 90ah battery connected to my smart bms 12/100 and a smart victron shunt. I am using the bms to charge the house battery from the vehicle alternator. The vehicle has a temperature controlled alternator (new hilux) I have fitted 2 x 30amp fuses and set the bms to charge 40amps. This is a new set up and the most charge I can see from the shunt is 12amps when the engine is cold, and drops down to 5amps when hot. The house battery is at 40%. Why can I not get any more charge ? My friend has same car and enerdrive dcdc and he can get 40amps. I have triple checked wiring and all is good.

thanks Luke

luke4140 asked
ell249 edited ·

1 Answer

Smart BMS 12/200 voltage difference

I'm scratching my head with the Smart BMS 12/200, and hoping someone can shed some light for me.

The voltage on the alternator terminal appears to be 0.2V higher than the voltage on the System+ terminal when the absorption voltage of the charging is reached. Eg, when absorbtion voltage of 14.2V is reached on the alternator terminal, the System+ terminal reads 14.0V. I have resorted to installing a DC-DC charger to the alternator terminal and set the absorption voltage to 14.4V, this brings the System+ (battery) voltage to around 14.2V. In the BMS I've set the battery charge limit voltage to 14.5V to keep the DC-DC charger alive in order to provide power to loads like a 12V fridge - otherwise the BMS cuts the alternator charging and the fridge draws down the batteries until the alternator charging kicks back in (lots of micro cycles)

Does anyone have any idea why this is?

I have the "dumb" older version of the BMS 12/200 and the voltage readings on the AB and LB terminals are the same...

cuanb asked
cuanb commented ·

1 Answer

Buck Boost vs Lynx Smart BMS for alternator charging

Hi, I am in the planning stages of my camper van conversion. 2023 Ford transit AWD LWB. I plan to have an all victron system: one 24v Victron 100ah battery, and charge it with shore power and alternator power (no solar). I won’t have a lot of access to shore power so alternator charging is my main charging source. For alternator charger, I am debating between buck boost 50a plus VE.Bus BMS or Lynx smart BMS. I saw from Van Land YouTube channel that they are charging their batteries using Lynx smart BMS. What’s the pros and cons of each approach? The prices are similar. Thanks for your help!

angeljia asked
angeljia commented ·

1 Answer

Which should I use - Smart BMS 12/100, BMS 12/200 or Orion-Tr charger????

I am having a lot of trouble finding a direct answer to the question of what is the recommended way to charge a Victron Smart 12,8/200-a lithium battery from an alternator.

Which should I use and why?

craigp asked
codefoster commented ·

1 Answer

Orion 12|12-30 not charging

I have just installed an Orion 12|12-30 into my 2012 sprinter van. I’m running 3 206Ah LiFePo4 batteries (eventually plan on getting a second alternator). I am not getting a current output while driving which I believe should be around 30A. I’ve adjusted my settings but still seem to be having issues. Start voltage: 14, delayed start voltage: 13.8, delayed start voltage delay: 120s, shutdown voltage: 13.5 input voltage lockout: 12.5V / 12.8V

klf93 asked
kevgermany commented ·

2 Answers

Dual Output Alternator from Single Alternator

I am interested in upgrading my house bank from AGM to Lithium. I have a sailboat with four (4) 100AH group 27 AGM batteries for the house bank (12Volt System) and a separate AGM engine start battery. The engine is equipped with a 100 amp Balmar dual output alternator (50 A per leg, one lead to the house bank and the second lead to the start battery) with a MAX charge regulator. The boat has both shore power and an onboard 120v output diesel generator. There is a battery charger aboard that is connected to shore power and generator and this will be replaced with a 2000W inverter / charger). The wire size is 1/0 AWG copper for the line and load side of the battery bank and the connections from the alternator are also 1/0 AWG. I will eventually add solar, but for now I wish to use shore power, generator, and engine alternator to charge the house bank.

* I am keeping the lead acid AGM starter battery for the engine and generator. I believe I need a DC-DC charger for the house bank, which one would normally connect the alternator and regulator to the AGM starter battery, then from the starter battery to the DC-DC charger, then from DC-DC charger to the lithium house bank. However, what do I do with the existing second 1/0 AWG lead from the alternator to the house bank? Is the lead abandoned and the I just use ½ of the alternator? Is there an alternative to a DC-DC charger for dual output alternators?

Any advice is appreciated.

Thank you


tsanders2017 asked
Mike Dorsett answered ·

1 Answer

Alternator and solar charging system problem

I have recently added a Victron BlueSolar MPPT 75 /15 and Victron 140W 12V Mono Solar panel to my existing campervan installation. Unfortunately the system appears to have some problems with the leisure battery not charging fully and then performing erratically. I am unclear as to what is happening, what I have done wrong and how to correct it. Help would be appreciated please!

It's a simple, relatively cheap installation as shown below in the schematic. The leisure battery (Expedition AGM 115Ah) is charged from the starter battery using a Votronic VCC 1212-30 battery to battery charger. The loads include a 48W fridge, diesel heater, LED lights, USB chargers and 12v outputs. I calculate the maximum daily load at about 55Ah.

I have recently added solar to allow me to power the system without starting the engine. I calculated that 140W should be sufficient.

I am now finding the following problems:

- the leisure battery never seems to get fully charged - the voltage fluctuates greatly when only a light is turned on. This never happened previously.

- the battery seems to discharge quickly.

I have not used the 'Load terminals', is this a problem? Is it possible that the B2B charger and MPPT chargers 'confuse' eachother as each thinks the battery voltage is higher than reality due to the other charge source? Is it possible that my battery is damaged and is the problem, how do I check this?

Sorry if this is all very obvious and basic but it's all voodoo magic to me. Thanks for your help


ryan-mulligan asked
kevgermany answered ·

2 Answers


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