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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

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
jwfrary commented ·

2 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

Product request - Smart BMS CL 24/100

Lately we have many requests for installing big RVs with big 24V alternators (100A or more) and also more than 400Ah or more of lithium batteries.

With lithium batteries you should use a DCDC-charger but if you want to (or have to) charge the batteries from the alternator as fast as possible you have to install 2, 3 or more Orion-TR Smart or use 2 BuckBoost 100A (which is way to expensive).

So it would be great to have an easy way to limit the current like it is possible in 12V vehicles with the Smart BMS CL 12/100.

Matthias Lange - DE asked

0 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
48v-on-56north commented ·

3 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
siemcio commented ·

1 Answer

Monitoring alternator temperature with CERBO GX to regulate a Buck/Boost charger


Here is the main idea, not sure if it's possible.

I have a 180A alternator on my sprinter 2020 and I want to install two DC-DC Sterling 12->48V of 70A each to charge 6Kw of Lithium batteries.

I want the Cerbo GX to monitor the alternator temperature and disconnect one of the two sterling when there is too much heat.

Is that feasible ?

Thanks !

sebcbien asked
sebcbien edited ·

3 Answers

Relay recommendation for BMS to shut down alternator regulator

I have an alternator that charges a Victron LIFePO4 house battery bank. The alternator is regulated by a Balmar 614 external regulator.

My understanding is that the recommended method for shutting down the regulator is to have the BMS charge disconnect trigger a relay that will open the connection between ignition and the Balmar regulator.

I'm looking for specific recommendations for a relay that works for this purpose, or other known good solutions to this problem.

What I've found are other threads referencing problems activating common relays given the very low 10ma current sourced by the BMS charge disconnect, which is also being relied on to disconnect a Cyrix Li Charge that the charge load goes through (sources are 3 solar panel controllers and the alternator). Hard to find a relay that is triggered at, say less than 5mA. Or is it? What's your favorite relay for this purpose?

Then I thought maybe use a MOSFET or a transistor in front of the relay to boost the charge disconnect current up to where it would trigger a relay. But that seems to be going a bit off-script, and this isn't an area where I want to "innovate" but would rather "stand on the shoulders of giants" who have already implemented a proven solution. If you've got one, please share!

I have also seen references to a solution where instead of the BMS charge disconnect, someone used the BMS pre-alarm to trigger the relay. Although I can't find a spec for its current, presumably it is higher than 10mA if it is expected to trigger a light or buzzer.

And I've seen solutions that just throw more Victron products at the problem. I'm OK with that if it is the best answer, but it seems pretty heavy handed for the meager ignition circuit. Either another Cyrix Li Charge solely for the ignition wire (seems like 1000% overkill but should work?) or a Victron Battery Protect wired up in reverse. Again seems awfully beefy for the measly current going through the ingition wire. Also raises the question of how many relays can you successfully hook up to one charge disconnect terminal on the BMS and still have them all trigger from its 10mA current.

svaeolus asked
Stefanie commented ·

1 Answer

A DC-DC charger that participates in DVCC?

I stumbled upon the Buck-Boost DC-DC Converter and thought it would be great for my hybrid RV setup (12V OE alternator and battery, 24V auxiliary alternator and house LFP bank). But then I was very surprised to learn that it is not integrated into the beautiful Victron CAN ecosystem and thus cannot participate in DVCC.

In my dreams, I would have this device work bidirectionally: use up to 40A of current from the OE system to charge the 24V LFP bank and keep the OE 12V system topped up from the 24V bank when the engine is not running. Both being controlled by the REC Q BMS.

Is there any way to achieve even a portion of this?



Adam Sherman asked

0 Answers

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

Alternator charging -- Orion-Tr vs. Pheonix VE Direct to Multiplus -- to large lithium bank

In a setup with solar, generator, shore power, and alternator charging using Smart Solar and a MultiPlus or Quattro for the generator and shore power ... will it make more sense to use the Orion-Tr for the alternator charging or use a Pheonix Inverter to the Multiplus and then to the batteries?

The reason that this comes up for me is the Multiplus and the SmartSolar can have their charge profiles synchronized, but it seems like the Orion-Tr does not have this function, so it can be on a different voltage than the Multiplus and SmartSolar, potentially "fooling" them as to the charge state of the battery.

Happy to read up on this issue if there is a white paper available.

jkmann asked
Justin Cook - Bay Marine Supply USA commented ·

1 Answer

Same remote switch for Orion 12/24-20 and Battery Protect 65

I have two charging sources for my battery. One is the Orion from alternator one should be a grid charger connected over the BP65. The BMS should shut down the charging when Battery is full via the remote contacts.

Can the two devices be connected to the same switch/relais in parallel?

sponk asked

0 Answers

Battery Isolator & Alternator Sense Terminal

I have installed an Argo Fet Battery Isolator. It works well, but when the batteries are full, I am getting a reading of around 15.1 volts at the battery, which I understand to be too high. When I installed the battery isolator, I removed the wire from the sense terminal of the alternator. Should I reconnect that? and if so, to where?

kyleolmstead asked

0 Answers

Cerbo GX, DVCC and combined charging from Multi, MPPTs and alternator. How measured?

Hello all.

I have some curly questions on using a Cerbo GX and Distributed Voltage and Current Control (DVCC) to manage the system described below.

The yacht installation I’m preparing will have four Victron 12.8V 300Ah Smart LiFePO4 batteries, arranged in parallel. Their overall voltage will be sensed by a SmartShunt, connected to the Cerbo by VE.Direct. The batteries’ 3 Pole Balance Temperature & Voltage (BTV) cables will be daisy-chained to a Smart BMS CL 12-100. This BMS will control a Smart Battery-Protect 220 via its Load Disconnect terminal. The BMS will also control a Cyrix-Li-Charge 120 via its Charge Disconnect terminal. Three Smart MPPT 100/50 solar charge controllers will send current from 1200W of solar panels to the batteries through the Cyrix. The MPPTs will connect to the Cerbo by VE.Direct-to-USB adapters, into a USB hub and then to one of the Cerbo’s USB ports. Another job the BMS will do is regulate battery charging from a 115A alternator.

The system will include a MultiPlus 12/3000/120-50 inverter/charger, connected to the Cerbo by VE.Bus. Current from the MultiPlus will not be routed through either the Smart Battery Protect 220 or the Cyrix-Li-Charge 120, to avoid damaging those with flow in both directions.

I’ve read Victron’s explanations of DVCC, along with relevant discussions here in the Community. I’m satisfied it will work. What I think will happen (and not happen) is:

- the Cerbo will take the battery voltage sensed by the shunt and assess this in terms of what it was told the batteries are, during setup;

- it will look up its program library of how these batteries like to be treated and will instruct the MPPTs and the MultiPlus how they should serve up amps for charging, or draw on them for inverting;

- when the Cerbo assesses that the battery voltage reported by the shunt is getting low, it will tell the MultiPlus to stop inverting;

- the Cerbo will not be able to stop the DC loads from drawing upon the batteries, as it has no data connection to the BMS or the battery-protect. These two will use their load-disconnect linkage to cut the loads when one of the batteries says ‘Stop!’;

- if something goes wrong and the Cerbo doesn’t succeed in stopping the MPPTs from charging, the BMS will step in when the batteries ask it to and stop the charging via its charge-disconnect link to the Cyrix;

- however, if something goes wrong and the Cerbo doesn’t succeed in stopping the MultiPlus from charging, there’s nothing in the system or the setup to cut it off. I assume that the MultiPlus will not stop itself from charging, given it’s been told to be dumb and work under DVCC rules. Perhaps I could add a Cerbo controlled relay as a back-up, to switch off the MultiPlus if it goes feral?

Please set me straight if any of the above is off-beam.


Some aspects I’m less clear on are:

- will the shunt report the overall charging current from the MPPTs, the MultiPlus and the alternator, such that the Cerbo might instruct the MultiPlus and the MPPTs to ease-off or stop?

- if the batteries are full, does the BMS have the ability to throttle the current from the alternator? Checking … . Yes, it does.

- and last but not least …

… the Cerbo GX has a second pair of CAN-bus ports, called BMS.Can. Little is written about these, other than how they can be used to hook up other-brand CAN-bus BMS equipped batteries or BMSs. So how good would it be to have Victron lithium batteries that can talk directly to a Cerbo over CAN-bus? :-D Has Victron said these are on the way, or ruled them out for some reason?

valden asked
bathnm commented ·

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
dano71 answered ·

3 Answers

Practicality of using two parallel connected Orion TR Smart 12/12 -30 to speed up charging.

Practicality of using two parallel connected Orion TR Smart 12/12 -30 to speed up charging of two parallel connected 100 Ah LiFePO4 batteries. Alternator of our van is not smart, 105 amp. Concerns: 1) Will this amount of load on the alternator overwork it too much? 2) Will the alternator only be able to deliver such a small additional amperage with a second Orion that the addition of a second unit is not worth it? 3) Is there a way to know how much charging amperage is available from an alternator without over-stressing it? 4) Would it be smarter to install a larger capacity alternator?

yeknom asked
ernesto 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

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
Stephen Otto commented ·

2 Answers

Multipass 24/3000 shuts down when disconnected from shore power

My Multipass 24/3000 was installed this past summer. Everything has been great until two weeks ago.

Recently, I went to use my boat and after unplugging from shore power, engines start etc. I noticed the breaker for the inverter was not illuminated, but the breaker was on and had not tripped. Before starting the boat, AC/DC panel showed inverter breaker operating and illuminated. The inverter is left in charge only when connected to shore. The color control GX showed no alarms or issues.

With the engines operating the port side steering was not functioning but starboard size was. (Boat uses jet drives with buckets and joystick steering). After a few minutes trying to trouble shoot, I started the generator and then the breaker switch for the inverter became illuminated and now both port and starboard steering began to work.

The alternators on both engine were replaced during the Multipass install and everything had been working without issue.

Summary: the Multipass 24/3000 only is working when connected to shore power or receiving generator power source. It does not work when the engine is running.

What am I missing that may cause this?

talaria asked
talaria 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

Orion-TR Smart 12/12 30A F-250 Alternator Charging Settings?

I am having some difficulties setting up my new Victron Orion-TR Smart 12/12 30A chargers on my 2019 Ford F-250 with a 200 amp heavy duty alternator.

Originally, I had this isolator based system:

Blue Sea System Relay

80 amp circuit breaker

House Battery (300 ah LiFEBlue LiFEPO4)

I have now wired in the two Orions between the circuit breaker and the house battery (want to test before removing the relay).

I am having some wild voltage swing looking at the units with the standard LiFEPO4 settings.

For one, can this setup only handle one Orion potentially?

Also, if I remove the remote plug does that disable the unit and allow it be bypassed even if it is still wired in currently?

Any tips or pointer from someone who has tackled a similar project would be most appreciated.

I just wanted to better protect my alternator and charge my LiFEPO4 at the optimum voltage, and I am accomplishing neither at the moment.

erstwild asked
Justin Cook - Bay Marine Supply USA answered ·

2 Answers

How to limit the current in a 48V alternator?

For a project the customer has a 48V 150A alternator.

I recommended, the following solution


As the Cyrix at 48V only allows 80 A, can I put two in parallel?



The ideal to protect the alternator would be to have a current limiter. Unfortunately, victron only has current limiters for 12 and 24V.

Does anyone have a suggestion for a better 48V solution?

bite asked
marijn-achterkamp commented ·

4 Answers

My auxiliary battery died after i installed solar system, is my installation is wrong ?

Hello everybody.

6 month ago, after installation of my solar system on my camper van, I observed an unexpected phenomena on the Bluetooth monitoring : engine off, after a sunny day charging, the regulator was floating. But as soon as i turn engine on, regulator show a high charging current as the battery needed bulk charging. I could observe that the current was directly linked to the sun exposure (instantly lower when driving in tunnel or under a bridge).

At first, i thought it was normal, perhaps with engine on and engine battery + alternator entering the system, the solar controller was kind of lost.

But few weeks ago, my auxiliary battery when totally dead. It can't keep the charge.

So now i try to understand why my battery died before i replace it.

my configuration is :

- SmartSolar 75/15

- Backcontact solar panel 210W

- Pb auxiliary battery 100Ah

- Pb engine battery 110 Ah (link between the two battery is the original VW T5 system made with a simple relay the connect "on contact" or "engine running", not sure

- 12v Dometic cooler, Led lights, etc. Yet not connected to the load output but directly to the battery (planned to connect to load later because i didn't finish global wiring)

Ideas to explain battery death :

- fridge connected to battery while controller trying to charge messed up the process ?

- problem with alternator charging and messing up with controller ?

- normal end of life for the battery. Strange because i used it for one year using fridge and only charging with engine, and it didn't seemed to be damaged.

So thank you very much even if you managed to read all my message ;P and i would be glad to have your point of view on this problem.


antone asked
antone answered ·

2 Answers

12v car battery charging 24v house battery - confirming my choice.

This question has been asked, but I've read through the threads and have not found the answer I need.

I have a 24v house battery for my cargo van conversion.

Everything is designed and set up (I've done a 12v system before) without alternator charging.

I would like to add on alternator charging.

My alternator (GMC Savanna, 135 amps I believe) is 12v and my house batteries are 24v. (I can buy a new alternator that goes to 240amps and I may do that).

Is this the right product?

Victron Energy Orion-Tr Smart 12/24-Volt15 amp 360-Watt DC-DC Charger, Isolated (Bluetooth)

Is there one with greater amps output?(I could not find anything).


stevelex asked
stevelex commented ·

1 Answer

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