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Charging LiFePO4 with Alternator and Diode

I have an existing system with a starter battery (12V AGM 100Ah), a bow thuster battery (12V AGM 280Ah) and a new service battery bank (12V LiFePO4 560Ah with REC Smart BMS). Additionally this will be charged via Victron Multiplus using shore power or a VICTRON MPPT solar charge controller (only for the service battery bank) or it all can be charged by an alternator, which is connected via a diode (VICTRON ARGOFET 200-3) to all three batteries.

The old system was quite simple as usual in yachts, as the alternator just charges as the service battery tells him, how much more can be charged.

Now with LiFePO4 I read this should be charged via DC-DC charger from the starter battery.

Is this really necessary or cannot the ARGOFET still make sure the LiFePO4 batteries are charged by the alternator, especially since the SmartBMS will shut down the loading process, as soon as there is bad voltage/current coming to the system?

DC-DC chargers only deliver up to 30A and charging a 560Ah battery bank from a 100Ah starter battery seems unlogical, especially using a 130Ah alternator.

Is there something to make sure, if I want to charge the LiFePO4 directly from the ARGOFET?

Thanks for the feedback...


Marcus asked
bathnm commented ·

5 Answers

How to measure two DC Inputs On CCGX

I am looking to install a Victron system on my RV that will be using a third-party DC-DC charger to charge 48v house batteries from the vehicle's 12v alternator. If I were to connect this charger through a dedicated BMV battery monitor (with a second one for the system's DC loads), is there any way to have one show up as an "alternator" input on the CCGX display screen?

I know I could connect it through the BMV-700 and presumably just have the CCGX show it as power flowing from the "DC loads" box to the battery. My primary concern is ease-of-use for the end user, so I would greatly appreciate any way to configure thte CCGX for this display.

chase-martin asked
Sam Salwei answered ·

4 Answers

Outboard alternator charging lithium


To charge a 12V LiFePO4 from an outboard alternator charging coil, what product is suitable to regulate the charging?

System Components

Outboard: Manual start, Honda BF6, 12V 6A charging coil
Battery: Lithium (LiFePO4), 12Ah, max charging rate 0.8C (9.6A)

Research Done

Watched the Victron Q&A Webinar 1 - Using an Alternator to charge Lithium video, and understand that since the battery has a larger C rating than the alternator, alternator current must be restricted using a Smart Orion or similar.

Options Found

Using the VictronConnect app to check the interfaces via the demo mode. Nothing appears suitable:

- Phoenix Smart Charger IP43 12|30 has "maximum charge current" settings of 7.5A, 15A and 30A, the minimum is too high for the alternator.

- Orion Smart 12V|14V-18A Isolated has a LiFePO4 battery preset but no current limit settings (just voltage), and it isn't clear if it's ok with the variable output from an outboard.

- Blue Smart Charger 12|5 can limit charging to 2A or 7A, but is mains powered, and the 2A lower limit loses 4A of potential charging, while the 7A upper limit is too high for the alternator.

- SmartSolar Charger 100|15 can limit charging on a variable scale in 1A increments, but it's inputs are designed for panels only(?), not an alternator.

Which Victron product will allow the charge to be limited to a safe current for the alternator?


I am in a 3m open-top inflatable boat so the system needs to be compact, light, and simple.

neepsandtatties asked
neepsandtatties commented ·

6 Answers

12/24 Buck Boost --> 3x 24/48 *Isolated* Converter --> MPPT SCC --> 33v Charging [Now wired and sort of working]


I've got a very particular DIY Nissan Leaf 24v battery configuration and their operational voltage is about 28-33v and I'd love to get more out of my Victron 100/50 12/24 Buck Boost Converter instead of only being able to charge them to 30v (buck boost limit).

-- I do also have a 900W solar array and MPPT which provides the desired 33v charge but during the winter it is not enough to keep the 8kWh battery above 50%.

If I run the buck boost output through a step up converter then through an MPPT do you think it's possible these components will work in a way which will allow me to output the desired 33v charge output via the MPPT?

- in this configuration, will the buck boost endlessly provide output of 50 amps if programmed at 30v output charge in it's software?


1x Victron 100/50a 12/24v Buck Boost Converter

3x Victron 24/48v 8.5a DC to DC Converter (to achieve approx 50a @ 24v)

1x Victron 150/60 MPPT SCC

As I understand it, because the Orion DC DC Converters are isolated and do not have a current path between the input and output, as long as I set the buck boost to below 30v (it's max) it should not be able to see any voltage higher than the input side of the Orions, and therefor should continue to output a constant desired voltage <30v.

Pictures below to get an idea of what this will look like. I'll be doing a test wire and config before the final mounting of the board happens.

This is an "upgrade" to my system that is already working perfectly and runs a 240v mini split AC, 120v induction cooktop and water heater, as well as all 12v devices.

If this does not end up working I will be moving in the Safiery Scotty device direction.

I'm really enjoying playing around with this very unique system, it's been a fantastic learning experience, much more learning to be done for this humble DIYer.

Thanks in advance!





Update -- I wired everything up and was able to get the buck boost to send current through the Orions and MPPT however it keeps cycling after about 20 seconds of current.

Example is 20 seconds current then off for 20 seconds then back on for 20 seconds etc...

Also, 1 of the Orions is about 10 degrees hotter than the others. All of the output and input voltages are the same, or at least within 0.1v.

I'm enjoying the experiment and would love to know if anyone has best practices for having 3x Orion 24/48 dc dc converters wired/configured to share the load equally.


Below is screenshot of all (or some) of the converters and mppt (Alternator’s MPPT) working up to 700+W (desired is closer to 1200W though, which the 3 Orions should be able to provide, unless the inefficiencies stack and then perhaps I’m at limit)


I can hear the converters "tick" when they switch on and they aren't quite in synchrony, I imagine this causes problems with load sharing or even one or 2 of them not activating.

Can I wire them in some way with the remote switch to all come on at the same time?

Should I wire them all directly to one another instead of using bus bars? i.e. wire positive to positive and neg to neg?



I raised the output voltage via the rotary switch on one of the devices from base of 40v to about 42v to start various tests and the buck boost is now constantly delivering around 20 amps current at 30v.

I also have been testing temperature differences and it seems that whichever Orion is set to the highest output voltage, it is the unit that "does more of the work" (gets the hottest).

I ended the test for the night by maxing out the output voltage dial for all 3 Orions to about 60v, which led to still consistent current but a higher level that any previous tests.

The tests concluded with an output of 885W. I'd still love to figure out how to utilize the full current of the 50a buck boost though. (1200+W ***update***if the efficiency losses dont stack)


A DC current clamp meter shows the buck boost outputting about 45 amps but the MPPT after the 3x Orions only outputting about 30a.

More testing to come tomorrow.

Update *** i’ve got the system now operating at a consistent level with an output between 700-800W.

Does each Orion converter have a 11% efficiency loss which would be 33% cumulative loss which is why I’m seeing about a 30%-40% drop in output across the system?

thirdeyesamuel asked
kevgermany answered ·

2 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
nicetrip commented ·

3 Answers

Orion Smart compatible charging of starter battery

We’re using an Orion Smart 30A to charge the leisure batteries while the engine is running in our van. However, we also have 500w of solar (real world output up to 30A) connected to a SmartSolar.

We’re finding after long periods stationary, particularly with use of vehicle accessories like the radio, that the starter battery can be a little low. Despite having completely full leisure batteries thanks to the solar. And had even failed to start the engine once (fixed by manually connecting leisure to starter to get engine on).

Is there a way to trickle charge the starter, with any excess power but without allowing any leisure accessories to drain the starter? And without “waking up” the Orion and creating a loop?

pezmc asked
kevgermany answered ·

1 Answer

Alternator Current Limiter without Smart BMS CL 12/200

Hi everyone, I am currently planning to replace the existing electricity system on my 34ft sail boat and have 2 questions that I was unable to answer despite extensive googling / forum reading. Would appreciate your help.

Goal: I am trying to figure out an alternative to the Smart BMS CL 12/200 that will allow me to limit the current drawn on my alternator when charging my 160Ah lithium house battery.

Rationale: While the Smart BMS CL seems to be perfect for this job, it does not have a VE.bus port that would allow me to connect it to a Cerbo GX which I need to display energy system data on my B&G/Navico chart plotter.

My planned setup: sail boat with onboard diesel engine and solar cells as sole sources of electricity (decidedly no allowance for shore power as it lives on a mooring). 12v circuit. Lead acid starter battery and victron smart lithium as hope battery. SmartSolar MPPT and 2 BatteryProtects currently by the Smart BMS CL. Phoenix VE inverter. This is still in planning phase so I could change it all up if necessary.

Second question: if I keep the current planned setup with the Smart BMS CL, how can I make sure the solar charger also charges the start battery?

white-russsian asked
hjohnson answered ·

2 Answers

when batteries being charged from alternator the volts jump up to 14.1 but the battery % continues to decrease

I have a multi plus 12/3000,connected to a BMV battery monitor and a CCGX colour screen - when on shore line the batteries charge normally and the CCGX shows 100% charge batteries full. However when I disconnect the shoreline and run the engine over a four hour period the batteries are going down as well as the percentage - have had the alternator checked and the cables from the batteries to the shunt have been tested with a clamp meter for the amps and voltage but the equipment is not detecting any amps volts etc - any ideas?

mbase asked
drlbradley commented ·

0 Answers

Positioning the alternator input with the lynx modular system

I’m using a lynx shunt, power-in and distribution panel. I’ve a balmar alternator with MC-618 regulator. If I follow the balmar instructions I connect the alternator power out directly to the house bank positive. How will this current flow, with the alternator on register with the cerbo GX ? I guess it will totally mess up the battery discharge calculation. If I wire the alternator into the distribution side there are significant issues in the battery’s disconnect with the alternator still charging?

rupez1 asked
hjohnson commented ·

1 Answer

With the Smart BMS CL 12V 100A, is a VE.Bus BMS still needed?

Hello everyone.

For the lithium battery system on my yacht I've been planning to use a VE.Bus BMS to manage and protect the batteries. Now that I've been made aware of the Smart BMS CL 12V 100A, which I will use to protect the diesel engine's alternator from having the life sucked out of it by four big lithium batteries, I'm wondering if the VE.Bus BMS is still needed?

The Smart BMS CL 12V 100A has the same three control outputs as the VE.Bus BMS; load-disconnect, charge-disconnect and pre-alarm. So it can handle those jobs. But it doesn't have the VE.Bus BMS' mains detect cable connector. Perhaps this function isn't needed?

Does the MultiPlus inverter/charger need the mains detection connection?

Does the Cerbo GX need the mains detection connection, via the MultiPlus?

It's looking like I can adopt the new Smart BMS CL 12V 100A, drop the VE.Bus BMS and also drop the mains detector.


This Smart BMS CL 12V 100A could well be the best thing since sliced bread. :-)

valden asked
lostandfoundadventures commented ·

1 Answer

Smart BMS 12/200 with Balmar MC-612 cutting alternator input

Hello, firstly the setup.

Smart BMS 12/200

X3 Smart 200ah lithium

X2 100/30 smart mppt

X2 410 watt panels

X1 smart battery protect 100a for mppt charge

X1 smart battery protect 220a for load

Super AGM 110ah start battery

105 amp alternator

Balmar MC-612 regulator

(Balmar settings)

Bulk voltage 14.4

Bulk time .3 (factory)

Absorption voltage 14.4

Absorption time 2hrs

Float voltage 13.5

Float time .3 (factory)

Alt temp 108c

Positive voltage sense connected to starter battery. (Not lithium side)

Engine is running at 1200 RPM at the dock. I started charging via alt at 82% as seen in video the BMS % drops down as starter batt voltage reaches 13.92v. Slowly starts applying amperage until nearly 55amps (100amp fuse on alternator side of BMS) this only lasts until starter voltage climbs back up and repeat. The BMS doesn’t have charge settings so how do I get this issue solved

How do I stop this cut off?
The link for the video is below because the file format is not acceptable on this site for some reason.

I have attached a pic of my wiring diagram and video of the problem.


Image Caption



svgemini asked
svgemini answered ·

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
Sam Salwei answered ·

1 Answer

12/200 alternator shut off

Trying to get my head around how the 12/200 operates and would appreciate any help to educate me ;)

The 12/200 datasheet shows that the 12/200 has a shutoff voltage of 11V which makes sense, but I am missing something in my understanding of how it works to stop overcharging of a lithium.

I also understand the purpose of the fuse to set the current limiting from the alternator (not sure how it achieves this though) - but again, am missing something to see how/when it shuts off the charge to the lithiums (and uses the lead-acid to dump into).

Anybody able to fill the missing gaps for me ?

moiuk asked
luis-gomezcala commented ·

1 Answer

Alternator & argodiode - where is the reference voltage?

I have a Volvo Penta D6 which includes a 150 amp VP alternator. This feeds a Argodiode 180-3AC. A recent voltage measurement showed 14.77V on the input side and 14.45V out to the 3 battery banks. Clearly the compensation is working.

My question is this. Who in the system is responsible for regulating the voltage? I presume the Argodiode is only monitoring the voltage drop. This implies the alternator has a voltage it is working to, perhaps 14.4V, but is designed so it can be 'influenced' to go a little higher by the compensation terminal. Do I have this correct? Is 14.4V a standard output?


steves asked
Mike Dorsett answered ·

1 Answer

Sources combined exceeding max charge current - solutions?

I am putting together the electrics for a camper van. I currently have the following items:

- Multiplus 12/1200/50
- SmartSolar 100/30 with a 350 Wp solar panel
- BMV-712
- SOK 206 Ah Lithium Battery (Max charge current 50A, max discharge 100A)

I have two points that I need some help figuring out:

(1) I realized that the max theoretical charging current (shore power + full solar) would be 80A, exceeding the battery's charge current of 50A. Would this be a problem? I found that a Cerbo device can be used to limit the charge current to the battery. I feel like this a relatively advanced device for my simple system (and it adds to the costs as well). Would it be highly recommended to get one, or are there other options?

(2) I would also like to be able to charge via the (smart) alternator. Initially I thought I could use a cyrix-ct, but with the 120A rating this would not work with my battery, correct? (Even disregarding the fact that solar charging wile driving would even add more current). I am trying to figure out a solution that could charge my batteries without killing them, and prioritizes solar over alternator. I came across the Orion DC-DC charger, but because it does not connect with a Cerbo device I would not be able to prioritize solar, correct? Any other methods?


0xana asked
kevgermany edited ·

6 Answers

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
scraggs edited ·

2 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

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
Sarah 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?

Marcus asked
Sarah 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

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


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