alternator Image


How to charge a starter battery from leisure battery?

Goal : I want to use my vehicle's indoor lights and ventilation during the night (3A 12V).

Setup : I currently have an independant solar and battery setup (700W solar 160AH of usable LiFePO4 battery)

Proposed solution : I think I could use an Orion-TR 12/12-9 converter taking power from my leisure battery and use the cigarette lighter circuit to charge the starter battery (15A fuse so everything seem alright). (The vehicule manufacturer said it's ok to let the car at "on" for long periods if I charge the battery.)

- Will it work?

- If I start the engine and the alternator is working at the same time as the converter, will it cause problem? (alternator and converter in parallel, seems ok from the manual from the possibility of paralleling multiple converters)

- Have I other solutions?


mathieu-dubuc asked
mathieu-dubuc edited ·

0 Answers

Orion TR smart 12-12-30 working in parallel ie. twice as productive - Is this actually possible Victron?

I have bought 3 x Orion 12-12-30's but if they are not made to work in parallel, please let me know so I can get a refund before my return receipt expires.

eg. Do the software/hardware allow without conflict? etc

(Mercedes Sprinter 200amp alternator, multiplus 3000W, 300ah Victron battery etc)

(Or is a different alternator required?)

Kind regards


mike-thornton asked
arghhh40k answered ·

1 Answer

twin motor boat with two alternator how it use for charge battery


I need to know, how I must connect two alternators, charger, and battery.

I have two battery - single starter battery for both engines and single service battery.

I want to use battery isolator (smart relay) for isolate starter battery from service battery but what I must do with alternators? I think I can use simple parallel connection without any diodes.

But may be You can tell me best practice for twin engine boats?

Thank You!

olegpowerc asked
olegpowerc answered ·

4 Answers

Catamaran without generator possible? ORION-TR a solution?


on my catamaran I would like to get rid of the generator.

I will intall 2000W of solar, 1200 AH LiFePo4 batteries and two MultiPlus 3000 in parallel. But this is not sufficient for two reasons:

1) redundancy

2) weather impact (no sun)

As a backup I would like to be able to charge my batteries FAST!! with the two 57 HP Yanmar diesel engines. How do I do that?

Thank you + kind regards,


phe asked
michael859 answered ·

6 Answers

Non-Isolated vs Isolated Orion-Tr

Can anyone kindly give me a straight forward explantion to what is the difference between Non-Isolated vs Isolated Orion-Tr. I am trying to regulate the current coming from the starter battery/alternator to charge my 720AH 12v battery bank. at the moment they are connected via VSR which is not healthy i think :)

Many thanks

vanlifer007 asked
jhickok answered ·

3 Answers

Optimal B2B charger amperage

I am renovating a 1992 Ford RV, and I was wondering what amperage I need for my B2B charger. The alternator is rated at 70A. I am planning to put one 220Ah AGM battery, with a max charge current of 0.2C (translating to 44A).

Would a 30A B2B charger wear down my alternator too quickly? What about 20A or 15A?

Any help would be much appreciated:)

Kind regards


jadmeest asked
basil katakuzinos answered ·

1 Answer

Alternator charging of your battery storage

Today, we see many vehicles with second alternators that can be used to charge your coach/rv batteries while driving. This is great to augment what solar can provide to keep the LiFePo4 batteries topped off.

The vehicle I have is 120 amps on the alternator.

Is there a way to limit the current from the alternator going into the inverter?

Is this a software setting?

Seems like you wouldn't want to push the alternator too hard to charge the batteries.

Thanks, everyone!


electrichi01 asked
electrichi01 commented ·

2 Answers

Alternator Visual Input GX device. DVCC compensation for alternator charge.

Hi, I am looking for a very visual input for the alternator power source,

I am considering buying an Orion smart charger for the alternator, to have everything compensated and properly measured, but to my surprise DVCC can't include the alternator charge, neither with the "smart" charger that I thought was meant for this use.

Also, In my case, I share the boat with my father (67 y/o) and my brother, and they don't have that big technical knowledge, would be great to be able to see the alternator charge as another "device" in the bubbles graphs, to be easier to see at a glance the alternator charge.

Same applies for VRM Portal.

Victorn has gone very far to make this great products that we love, and can't leave it there, It's just a very little step in the natural direction to integrate this and make the perfect combo.





alnavasa asked
sarahb edited ·

2 Answers

How to monitor Alternator in CerboGX?

I have a CerboGX with Touchdisplay, a 500A smart shunt monitoring the service battery and the power draw and a ARGO FET for the alternator.

The display showing the system, shows how much amps are going into the batteries or are drawn from the batteries. I have a MPPT for my solar which is shown there as well and in the winter I possibly will upgrade the shore 230V loader to a VICTRON model.

But how can I display and monitor the alternator in my system?

obione asked
sarahb edited ·

2 Answers

Has Anyone Actually Destroyed an Alternator?

I would like to know if anyone out there has actually managed to destroy their alternator by using a Cyrix LI CT and a lithium battery bank?

(I do know about 'the video' and why a DC/DC converter is the 'correct' solution. However, this is expensive in comparison to Cyrix and one loses some nice functions such as bidirectional charging and start assist).

If it's such a no no to use a Cyrix, why does Victron sell it?

Looking forward to hearing some real world experience.


davidq asked
batak answered ·

3 Answers

Configuring a blue smart ip67 12/17A for use as external charger in parralel to a somewhat faulty alternator


would anybody have any suggestions how to configure the blue smart ip67 12/17 to use in parallel to a somewhat faulty alternator to keep my automative starter battery (sealed lead/acid) charged? It needs to be “tricked” so as not to get confused by the inconsistent alternator/regulator feed. I will exchange or repair the alternator as soon as possible but need an intermediate solution.booth the alternator and charger are now connected to this independent starter battery.

jstrom asked

0 Answers

Lithium batteries on a 250hp Outboard motor, how to protect alternator (start and house batteries)

I need to increase the capacity of the house batteries for my boat. At the same time I need to keep or preferrably reduce the weight of the boat (I'm at the weight limit when trailering the boat).

Preferrably I would like to replace 2x Tudor 115Ah Dual Marine (60kg) with 1x Li starter battery and 2x Li house batteries (100Ah starter and 2x100Ah House).

Alternator puts out max 46A.

What is needed to ensure a NON overheated alternator?

See picture for separated starting and accessories batteries direcly at the alternator:


daycruiser asked
daycruiser edited ·

4 Answers

Battery Monitor on Cerbo GX not accurate when charging via alternator

I have a new Widebeam canal boat which has a complete Victron system.

Cerbo GX with screen, 2 solar chargers, inverter, smartshunt, galvanic isolator and 3 200ah Lithium batteries.

My problem is when charging from the alternator on the engine the battery indicator on the Cerbo only goes up by say 10 to 20 % after 6 or 7 hours of cruising. The voltage get to 14.2 volts and the alternator stops charging but the meter on the screen only shows 30 to 40% charged. If however I charge from a portable generator the boat fully charges in about an hour and a half and the indictator shows 100% charge

Is there a setting that needs to be changed, I have contacted my supplier several times, but having no joy.


sagascoigne asked
pwfarnell commented ·

2 Answers

Managing a dual alternator system

We have a two alternator 12V system, 1 for traction (capacity unsure) and one for leisure/house batteries (500Ah). For clarity this is a narrowboat fitted with a Nanni 43hp diesel. Both alternators are run off the crankshaft, via different pulleys.

Historically we have had battery charging issues and are considering a DC-DC connection (Orion) to allow the traction alternator output to be made available to the leisure batteries.

Does anybody have any dual alternator schematics? All the standard Victron offerings are for single alternator systems.

For completeness we are also considering solar panels with MPPT charge control.


thebounder asked

0 Answers

2 alternators and 2 Orion-Tr Smart 12/12-18A Lead Acid bank

Hi, thanks for looking at this. I have a boat with 2 x 6 cylinder diesel engines. I believe the alternators are around 40A each. I have a bank of 2 110Ah lead acid batteries. I'm thinking of getting 2 Orion-Tr Smart isolated 12/12-18A units, one for each engine and then have the outputs both going to the battery bank in parallel. Will they work okay together like this or is there anything else I need to consider? Cheers.

teekay asked
Mike Dorsett answered ·

1 Answer

Is my alternator sufficient for DCDC Charger?

I see SMART alternator mentioned in the Victron DC DC Charger overview but don't know if my original alternator is adequate.

Sprinter 2005 413cdi

2 house batteries @ 125 DC.

Regulator is MPPT 40amp.

I just need help to charge my batteries when solar is lacking. And, which model suits?

Any advice appreciated please.

johna asked
wanek commented ·

2 Answers

Charging Battle Born (LiFePO4) batteries from a Delco Remy 50dn (24v 270amp) alternator

Hello Victron Community,

For a few weeks now I've been struggling to find the right solution to charge my LiFePO4 batteries from my bus alternator. Here are the relevant technical details:

  • Delco Remy 50dn heavy duty alternator (24v 270amps); oil cooled, belt driven, externally regulated
  • 2x3 Battle Born batteries (12v 100ah) in seriesxparallel for 300ah at 24v (internal BMS)
  • Cyrix-li-ct relay connecting start batteries (2x group8 lead acid)

I consulted Battle Born and a few others in the industry and was told that this setup should work. The alternator is rated for heavy continous use and the Battle Born batteries can take charge from the alternator with the normal caveats (i.e. the alternator voltage will not be able to take the batteries to full SoC, etc.)

In practice, however, what I'm seeing is unworkable and I'm concerned I may actually damage my alternator/system. With the engine on and the relay engaged (solid blue light), I see a cycle that lasts 3-4 seconds and repeats ad infinitum. For a few seconds there is no current flow. Then, for a split second, a large in-rush of current (160+ amps) and a voltage spike of over 30 volts. Followed by no current and a return to 28 volts.

I've recorded the behaviour on video here:

Does anyone at Victron or in the community have an idea as to why this is happening? In the video you can hear the relay making a noise that is a bit disturbing as well.

Thanks in advance for any advice.

Micah Quinn asked
Micah Quinn commented ·

3 Answers

Charging the Lithiums using a DC-DC charger, Connected to AGM batteries connected to Shorepower Charger?

Hi Community,

From the factory, the boat was originally equipped with AGM only, and the house was powered from one of the starter banks (dual purpose AGM). This will only allow my appliances to run for 12 to 24hr, so I have ordered an upgrade to Lithium. The original shore-power charger is connected to 3 independent AGM banks (Starter 1, 2 and thruster). The charger does not have any more independent outputs.

The yard is currently fitting the boat with 2 x Orion Smart DC-DC charges (+ MPPT 100/30, Cerbo GX, smartshunt +++), that will be connected from each Starter-banks and to the new Lithium house bank.

So my question is; if I use Volt sensing on the DC-DC, will the DC-DC charge the Lithium's when the Shore-power charger is charging the Starte-batteries (@14,4v)?

Will this work? Any major issues with this idea?

I know this is not the best set-up, but I would like to leave the original set-up as original as possible and rather add a Multi-plus inverter/charger for the Lithium bank next year.

PS!! the original shore power charger is a 20A Cristec Y-power 5-step charger.

thomas-hamre asked

0 Answers

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
Dosheimer commented ·

1 Answer

Orion TR Smart draining starter battery when engine is running at low RPM

Q: How to use the Orion TR Smart 12/30 when running at low RPM and the alternator cannot supply enough current?


I have recently upgraded to a lithium housebank, and just installed the Orion TR Smart 12/30 for alternator overheating protection and a better charging algorithm for my 'not so smart' Hitachti 80A alternator on my Yanmar engine.

Now this is what happens when running stationary:

  1. Engine start
  2. Start battery (input) voltage rises
  3. Orion TR considers engine has started, and starts charging
  4. Due to low RPM the alternator does not deliver 30A. The starter battery starts to supply the other (20?A) current. And the voltage drops a lot (just a simple lead start battery).
  5. Only after quite some time at 11.8V it considers the engine has stopped and then stops the charging.
  6. The voltage starts to rise again, and the Orion considers the engine to have started again, so the proces repeats.

Is this a common issue with engines running stationary? When I go for a daysail my engine runs more stationary then actually making RPM.

The only thing that would work for me would be that the Orion lowers the charging current when the voltage is dropping. But I guess that would be quite an advanced feature and is probably not built in.

My intermediate solution now is:

- Changed the settings that the input voltage lock is at 13.8V (in case the voltage drops below this, it looks that the alternator cannot supply enough current). This is more a 'safety setting' but of course leads to constant starting and stopping of charging.

- I have a manual switch , so that I can enable the charging only when I have enough RPM

But I would prefer a fit and forget solution. I considered switching to a lower output version of the Orion, but that it would take forever to get some energy in my batteries. Maybe there is another product that could solve this?

See the alternator details in the attached image.


emarges asked
ranger-rocko commented ·

0 Answers

Orion Smart: How to controll the "engine on" function for multiple outboards??

Hi community,

I have a boat with 2 outboards connected to a AGM starter bank. From here I would like to charge my lithium bank using 2 x Orion TR smart 12/12-30.

I have read about the voltage settings for starting and stopping. All good so far.

The problem starts if I run only one of the outboards (trolling etc) both Orions will start and overload the one 50ah alternator.

Is there a signal from each outboard I can connect to the Orions on/off port? What type of signal is accepted? On / off voltage or just short cutting? Do not know what the Yamahas provide.

I also have the Cerbo Gx connected to the NMEA 2000 so maybe the relays can be used if the cerbo understands which outboard is on/off?

For info I have the following equipment;

- 2 x 100ah lithium batteries c/w bms (aio)

- 2 x Orion Smart 12/12-30

- Cerbo GX

- Smart Shunt

- Smart MPPT 100/30 + solar panels

- 2 x yamaha f225

Hope there is someone out there with the same setup that can share their setup.


thomas-hamre asked
ripper edited ·

3 Answers

How to add a lithium battery to a Boat setup

Hello, I am having some challenges trying to incorporate a LiFePO4 house battery into my boat. I would like to know will I kill my alternator/rectifier or cause other problems ie for MPPT solar controller or LiFePO4 with the setup in the attached diagram?
please not that I do not want to change out anything in that diagram now only add items where necessary

Many thanks for your expertise and suggestions


thanks Dan

dano71 asked
martins commented ·

3 Answers

Voltage too high with MPPT + Alternator

I have a SmartSolar Charger MPPT 100/30 on a boat with an alternator that does not have an external regulator. I'm seeing an issue where, when the batteries are fully charged, the solar controller is on and in float, and the engine is on, I'm seeing voltages between 15.25 - 15.45. That is definitely too high. The solar controller reports it is in float and putting no amps into the batteries, but when I turn it off, the voltage drops to 14.8, which is closer to normal. Why is the Solar Controller increasing the voltage in this situation, and is there anything I can do other than turn it off when I'm underway?

douglane asked
douglane commented ·

1 Answer

12v AGM leisure battery charging from van alternator

Hello, i have a Ford Tansit van converted into a camper and i would like to charge my leisure battery from the alternator. I was thinking of using the Orion-Tr dc to dc charger. Would this be enough, or is this even a good ideea? Or is there another way of doing it.

Thanks alot :)

buryck asked
southsideph answered ·

3 Answers

Alternator and regulator for Victron Lifepo4 smart battery.

Hi, i like to instal second alternator in mercedes sprinter , i have a 400Ah ( 600 in the future )battery bank and i like to charge it fast. I found alternator and i need your opinion is it right one for my battery ?

Thank you for your help

siemcio asked

0 Answers

Smart bms cl 12/100 with non Victron lithium batteries
  • I've connected my Smart BMS Cl 12/100 into my system with my non Victron lithiums, my non Victron bms is connected to the remote switch to stop overvoltage.

The starter battery is above the voltage needed but I'm still not getting any charge into the battery. I'm getting an alert saying that undervoltage protection is activated even though its registering the Lithiums and starter above the cut off limits?

Is this because I'm using a none victron battery and the 2 bms cable aren't connected?

If so is there a workaround?

I would have used the bms 12-200 but my alternators neg goes through the engine.

chezgals asked
chezgals commented ·

1 Answer

Argofet and MPPT compatibility question

HI guys,

Can someone with expertise with the Argofet help me, I want to add an Argofet to split charge my VRSLA start battery and my LFP house bank. Easy so far. I want to connect an MPPT controller to the input of the FET and utilize the alternator energize circuit to tell the MPPT that there is voltage. The solar controller needs to see voltage at the battery terminals or it wont start charging.

This is what I had in mind, will it work?


The following is from Victron ArgoFet documentation...

Alternator energize input
Some alternators need DC voltage on the B+ output to start charging.
Obviously, DC will be present when the alternator is directly connected to
a battery. Inserting a Diode or FET splitter will however prevent any
return voltage/current from the batteries to the B+, and the alternator will
not start.
The new Argofet isolators have a special current limited energize input
that will power the B+ when the engine run/stop switch is closed.

Jafa Russell asked
pim answered ·

3 Answers

Argo FET in a dual engine installation


In my yacht I have a dual engine installation. Originally the boat builder connected both alternators to the house batteries and put a zener diode as a separator between house batteries and starter batteries. Both sense cables from the alternators are connected to the house batteries. Both engine starts from the single starter battery pack.

I am now looking att installing Argo FET for a better separation solution, but the question arises directly. Should I use one or two Argo FET, is it enough with one Argo FET and connect both alternators to it or should use one Argo FET per engine and alternator.

The goal is to have both engines charging both battery packs.

Any input here would be much appreciated!

jowi asked
jowi edited ·

0 Answers

Best setup for lithium batteries (580Amp), charging while driving, and shoreline. No Solar.

Hi everyone,

My first posting and wonderful to have such community and help! I am new to van life, and I am working on getting a Sprinter van battery house (Chinese lithium batteries: 8 cells @ 3.6V 280Amp) which will give me 560Amp 12V house bank. I would like to be able to charge my house batteries while driving (using the Sprinter alternator battery), and also while parked in my garage or campgrounds using AC plug. I don't plan on using solar. I like what i have read so far about Victron products, and I would like to know what will be the best package to order and install (there seem to be many products and options doing the same thing: i.e. the Multiplus vs EasyPlus, etc. I plan to have a small induction stove (1200W), small portable 120V air conditioner (6 Amp), and the Bosch electrical water heater (120V, so these would be my three 120V AC load. Any advise is greatly apprecaited.

esam asked
Kevin Windrem answered ·

2 Answers

How does Cyrix-Li-ct work?

I just replaced my original battery combiner with the Victron Cyrix-Li-ct. I tied the small read lead to both my dashboard wire (AUX START) and to AM Solar's AMS Lithium Control Module v4.2 to the ALT + and - connectors.

Can someone explain to me how this relay is supposed to work? I have 3 typical scenerios: (1) vehicle running (class A motorcoach) with no solar, (2) shore power and (3) dry camping with plenty of solar.

Is this a "one-way" solenoid? Are both lithium batteris and chassis batteries affected in the above scenerios?

I've included the data sheet from Victron for your refereance.


edgargw22 asked
jmccain52 commented ·

3 Answers

99 Posts
95 Users

Topic Experts

There are currently no experts identified for this topic. Can you answer questions in this topic area? Community members who provide answers that are marked as correct earn reputation and may become recognized as topic experts.