Lithium Battery Image

Lithium Battery

Victron 48v Quattro & Tesla

Has anyone used Tesla S Modules in series to power the Quattro 5K? I am using this system in a mobile application and will be adding pairs of Teslas. My goal is to have 6-Teslas in a Series-Parallel 48v configuration to power the Quattro and a Dual-Zone Mini-Split.

Will the Quattro handle the slightly goofy Tesla voltage requirements better than the Multiplus?

It is hard to beat the energy density of Teslas.

murphyslaw asked
CappyJax commented ·

6 Answers

Solar System for 4s 16.4v NMC Lithium Ion Batteries

Hi all,

I am designing a custom solar system setup and want to be sure it will work.


Here's details on all components

Solar Panels - Two 12v panels at 115 W each (already owned)

Charge Controller - Victron BlueSolar MPPT 100/30

Batteries with BMS - Nissan Leaf Generation 2 Battery Module Lithium Ion NMC

Inverter - Victron Phoenix 12V 500W

Wall Charger - 54.6V 9A YALANCHA

My goal is to disconnect the solar panels and connect the wall charger (powered by generator) on cloudy days. The reason I chose a 48v charger is because I will eventually get a 48v battery for an electric bike so I'd need it anyway. I calculate that I can plug this charger into the inverter to charge the bike battery from the Nissan Leaf batteries. What do you think my potential issues are? Thanks a ton!

Cedar asked
WKirby answered ·

1 Answer

Second Controller Increased LiFePO Battery Bank Temperature

We just installed a second MPPT 150/85 controller to work with our solar wall of 6x 190w panels. The first controller is also an MPPT 150/85 and it handles our roof's 6x 180w + 2x 190w panels.

For both controllers, we set up the BMV 712 settings to match. Both are running the adaptive absorption setting, and 13.4v for float and 14.5v absorption.

We're incurring two issues ....

  1. The batteries hit 108°F on an 89°F day. Is that ok? We've never gone above 92°F with the first controller at a max v of 35v.
  2. The BMV app displays the second controller accumulating wattage, averaging 60v, when in float mode.

We're just concerned about the lack of syncing between the two controllers and the increased temps. :) Eric

BRBRV asked
adev commented ·

4 Answers

BMV-712 charge voltage for 2x 12v lithium in series for 24v

I have two 12v lithium batteries hooked up in series for a 24v system. On my BMV-712 what do I set my charged voltage at?

JohnH asked
Justin Cook - Bay Marine Supply USA commented ·

2 Answers

Why is disabling the Lithium Smart batteries Bluetooth Connection permanent?

Catching up on reading and come across this in Help for Victron Connect. Anyone know why it is irreversible?

Lithium Smart batteries

The product page can be found here.
Once Bluetooth is disabled, it is disabled permanently and is irreversible. This means that VictronConnect will ask for a confirmation code displayed in the dialogue; if you are sure that you want to permanently disable Bluetooth, enter the code displayed and choose “Ok”.

AllanD asked
adev edited ·

1 Answer

SmartSolar lithium battery storage settings?

I have a solar setup with 2x100Ah lithium batteries and two solar panels about 120w each, connected in parallell. 5-6 months of the year (wintertime in Norway) the system/cabin is not in use. Temperatures are well below zero parts of the winter, see temp. chart. In summertime and clear conditions, batteries are generally fully recharged in less than 2 hours the next day with perhaps an average 300Wh charge.

I am pretty sure the batteries (data sheet attached to this post) where delivered to me at storage voltage 13,17v each. The batteries are supposed to have a "Under temperature charge protection" (0C/32F).

What are the best SmartSolar 100/20 settings for "storing" the lithium batteries over the winter under these conditions?

MERITSUN LFP100-12.8.pdf


Tom56 asked
Fideri commented ·

5 Answers

Multiplus 1200/12/50 can I set a low battery cutout?

Hi all

I have a Multiplus 1200/12/50 connected to a BlueNova 4KWH LifeYPO4 battery.

I forgot to turn off the inverter so the battery got drained to the point of the battery shutting itself down, fortunately it has this protection built in. As a belt and braces approach, is it possible to set a low battery cutout on the Multiplus as well so that it can shut down before the battery reaches its internal shut off voltage?

P.S. From what I read so far, trying to charge a heavily discharged LifeYPO4 battery with too high amps can damage the battery. Does the Multiplus compensate for this, does it start off charging at low amps if a batteries voltage is very low?

Thanks, Nick

bigboy529 asked
Harmodio answered ·

3 Answers

Orion-Tr Smart 12|12 18 continuously outputting 25A


I just fitted an Orion-Tr Smart 12|12 18 in my old campervan. It sits between the alternator and a Liontron 150Ah LiFePO4 battery.

I noticed in the batteriy's iPhone app that the battery receives 25.5A continuously. For way longer than the 10 second peak that the manual specifies. I've configured the output voltage to be 14.4V, which is what the battery manual specifies as charing voltage. There's nothing else charing the battery, when turning charging off in the Victron App the battery says 0A input.

I also noticed that the alternator got very hot. Tbh I don't know if this is normal or not in my van as I've never checked it before. But reading up online it shouldn't be that hot. I'm not sure if it's related to the Orion pulling too much current or the fan belt which I've yet to check.

The Orion is fitted like this:

+ on starter battery > alternator > 30A fuse > Orion

- on start battery > chassi > cable > Orion

I know the manual has the battery and the alternator in a different order. But the place I bought the items from said it didn't matter (I already have cables in the engine bay to hook things up that way from my old setup).

Cables are 6mm² and should be short enough to handle that current.

Any need for worry?


- Simon

simme asked
Stefanie commented ·

1 Answer

48V Multiplus II with 16s lithium-ion battery bank?

Hi all, I've got a Multiplus II 48/3000 which I intended to run with a 14S lithium-ion battery bank.
This will however be a bit of a challenge with the battery bank physical layout and super messy wiring.
Not sure why I didn't discover the max input voltage rating of 66V on the MP2 before today, but moving from 14S to 16S will really help a lot. I do not plan on running the lithium cells higher than 4.0-4.1 volts anyway - which means I'll stay within the 66V max.

Is there any reason you could think of that suggest I should stick to the plan and go with 14S?
Both 14 and 16S allows me to stay within a nice range for the lithium-ion cells (3.2-4.1V)

The only two issues I can think of, are that I have to run triple solar panels to stay above the system voltage and that I may be pushing the spec of some standard fuses?


Pokerfjes asked
John poul answered ·

1 Answer

BMV 712 temperature sensor and MPPT charge controller

I am installing some LiFePO4 batteries (not Victron ones, sorry!) in my van which will be charged by solar power. I have a BMV 712 installed with the optional temperature sensor. I also have a Smartsolar 100/50 MPPT charge controller installed. What I want to know is do the two Victron products talk to each other? With LiFePO4 batteries, temperature is very important so I want to know whether the BMV tells the MPPT charger what the temperature of the batteries are so that it knows when to stop charging?

brassmonkey001 asked
erutan commented ·

3 Answers

End of absorption with tail current

Hello. I wonder if I am thinking this right... I am trying to end the absorption phase solely based on the tail current, but it seems system is ignoring that.

Scenario is: Charging LiFEPO4 bank with 8 cells (25.6V) with integrated BMS just for protection (no communication with Victron)

- Multiplus 24/ 3000

- 3x MPPT in parallel charging

- Venus GX

Customised charge profile:

- Absorption voltage: 27.6 V (I can monitor cells, and no cell is above 3.6V)

- Absorption time: Fixed, 1hour 30 minutes

- Tail current: 9 amps, battery capacity is ~180Ah

- Float voltage: 27.1 V

It ignored the tail current and the absorption time was exactly 1,5 hours. I would like to stop absorption when current decreases past 9A.

I didn't feel adaptive time was ok for lifepo4, as if bulk takes longer, absorption may not need so much time. I would like to make the criteria to stop Abs be solely the Tail Current (system!, not individually each MPPT)

How can I do this?

Elimac asked
Elimac commented ·

2 Answers

Charging a Victron Lithium Smart battery with a Blue Smart IP65 12/25 - Which BMS to use?


I bought a Victron 160ah Lithium battery and a Blue Smart IP65 12/25 and I was wondering which BMS do I need to use.

My usage is extremely simple, i will charge the battery at home with the Blue Smart charger and then put the battery in my caravan to use it in my 12V system.

I spent a lot of time reading the forum but I am still not sure and afraid to make a mistake.

- Do I really need a BMS or is this charger enough for such a simple system?

- If I need a BMS, will the miniBMS be enough or do i need other equipment to charge the battery properly and safely?

Thank you very much in advance for your answer.

Paulis asked
Paulis answered ·

5 Answers

100/20 controller wont leave bulk even when bmv-712 reports 100% charge

I have 350w of solar on my sailboat with the 100/20 mppt charge controller and the bmv-712 connected to 400ah of lithium batteries. The batteries consist of 16 individual 3.2v cells grouped up into 4 12v supercells and then connected in parallel.

My issue is that my bmv-712 will read 100% and be at 13.5 with the solar charger still in bulk pushing 260w all day long without ever leaving bulk or changing the voltage of the batteries from 13.5v. Manufacturer of the batteries say it should go up to 14.6v and then drop down

Turboslice asked
Turboslice answered ·

1 Answer

SmartSolar 100/20 and GoalZero Yeti


I'm new to Victron and am looking at adding the Smart Solar 100/20 to my current setup.

My current setup is a GoalZero Yeti 1400 with their expansion module that is connected to my vehicle battery/alternator. The module interfaces as an isolater and voltage regulator since the vehicle battery is an AGM and the GoalZero is lithium.

I would like to add 200 watts of solar that would keep both batteries topped off.

I am new to solar so I wanted to run this flow by the community.

Solar>MPPT (set for AGM settings)>alternator/AGM battery.

My thinking is the MPPT can watch the V of the vehicle battery and the Yetilink module will pickup on the higher voltage and charge the GZ lithium battery.

Does this sound correct? If the alternator were to come on, would it damage the MPPT?


notfamous asked

0 Answers

Can diffrent "can-products" clash?

We have an client with an existing Victron 5kVa Quattro inverter. The client wants to replace the old batteries with lithium batteries. We intend on using BlueNova. BlueNova uses the can-port for communication. The only "possible" problem I can predict will be the existing charge controller; which is one of the older ve-can charge controllers victron has.

We will add a GX device for proper control and monitoring, but i want to be sure that the two ve-can products will not clash when communicating with the GX

Will this be a problem or can i assume that it will work? Or is it just safe to suggest a new charge controller?

schalk@solarengineering asked
ejrossouw commented ·

1 Answer

Where do I put the master switch for a battery to battery charger two battery system on a boat?

Hi everyone,

A simple question for those that know I suspect.

I'm trying to wire up a basic boat system, with a lithium house and a lead acid engine start battery. I have a Victron Orion TR Smart battery to battery charger and just want to know where the main battery isolator fits into this system. I realise both batteries must always be connected when the engine is running so that the charge has somewhere to go when the lithium battery reaches full charge. Can I continue using the traditionals 1/2/both swithch shown as per the schematic at the link below or do I need to have completely separate isolators. Can someone explain or even better draw on the schematic to complete the wiring diagram?

Many thanks for any assistance


AndrewL asked

0 Answers

BMV-712 not synchronizing with solar lithium setup

Hope this community can help. My BMV 712 detects a full charge but does not sync. I have 200ah of Renogy lithium batteries charging with a MPPT 100/20 on 300 watts of solar. The BMV-712 smart with temp sensor is connected to the MPPT with a VE network. I've configured my settings based on the recommendations from Victron for lithium and the SOC will jump to 100% but it does not register a sync. Its been a week with these settings, full charge every day but no sync, worried that its not a true SOC measurement. MPPT and BMV settings are listed below and in screenshots attached.


absorption - 13.9

float - 13.5

absorption time - 2min (fixed)

tail current - 3 amp


charged voltage - 13.6 (.3 under the absorption as recommended)

tail current - 4%

charged detection time - 3m

Peukert exponent - 1.05

efficiency factor - 99%

Thanks all!




ExpressLife asked
Sailor Jerry answered ·

7 Answers

Protecting LiFePO4 batteries from all sorts of things If I connect my MPPT, DC2DC charger and a EHU charger to one side of a Battery Protect and the other side to the battery, and connect my BMV712 relay output to the Battery Protect, would that then disconnect my battery bank to prevent being charged when the temperature drops cold (as well as if it gets too hot) and disconnect in the event of low (or high) voltage events? Or is it not so simple as that?

brassmonkey001 asked
brassmonkey001 edited ·

2 Answers

Using a SmartSolar MPPT 100|30 with a Common Port BMS and LiFePo4 batteries.

I need a definitive answer from someone that really knows what they are talking about.

It’s always being bandied about that the solar panels must be disconnected before the batteries, otherwise the Victron SmartSolar MPPT Controller will be damaged. Well, I find it pretty hard to believe that this unit is designed to self-destruct if its outputs are disconnected from the battery by any means; fuse, switch or otherwise. before the solar panels are disconnected.

I want to use a common port BMS with a LiFePo4 battery setup, and from what I’ve read, the BMS will break the battery connection to the MPPT at some point which, in turn, will damage the MPPT charge controller.

I do know the manual for the SmartSolar MPPT 100|30 states “First: connect the battery. Second: connect the solar array (when connected with reverse polarity, the controller will heat up but will not charge the battery). Torque: 1,6 Nm” but, scratching around the net I found the website, and in their right-up on the Victron SmartSolar they state “You need to make the battery connections first so it knows what battery voltage you have. In the programming you can tell it the battery voltage and then in the future it won't matter what order you make the connections”. Now is this statement correct? If it is correct all this stuff about damaging the charge controller is just people talking parrot fashion, and there is no problem using a common port BMS on this charge controller; so long as one does the initial battery voltage programming of the charge controller first!

Any engineers responsible for designing these Victron charge controllers on this board??????????

FrankH asked
Anthony Sennett edited ·

2 Answers

CYRIX-LI charge and BMV 712 settings for overcharge protection

I have a 200Ah lithium battery bank connected to my starter battery/alternator via a Cyrix-Li Charge 230A controlled by the BMV 712-Smart.

It's currently configured to only connect when the starter battery is over 14.1V (indicating that the engine is on) and to cut off when the starter drops below 13.7 (when the engine turns off). I'd like to add another condition that my lithium battery bank must be below 95% to protect against overcharging. Not having luck with the state of charge. Anyone have guidance?

Desired Logic:

ENGINE ON, BANK < 95% = Closed Circuit (aka charging)

ENGINE ON, BANK > 95% = Open Circuit (aka not charging)

ENGINE OFF, BANK < 95% = Open (aka not charging)

ENGINE OFF, BANK > 95% = Open (aka not charging)

evolutionyst asked
evolutionyst edited ·

0 Answers

Orion-Tr Smart, VE.Direct and integration with GX devices?

Hey there, as I commented on the blog post,

"I'm curious if future versions will have VE.Direct or some sort of integration like that with GX devices? Currently, it seems that the MPPT and MultiPlus are able to coordinate their total charge rate with external BMS via the GX devices. But it seems that the Orion-Tr does not participate in this?"

I'm wondering if there's a way to integrate the Orion-Tr Smart chargers with the CCGX. In particular, as far as I understand, GX devices can coordinate with external BMS via CANBus to determine the charging parameters of a battery. It seems that the Victron MPPT and Victron MultiPlus can respect these limits via VE.Direct and VE.Bus respectively, which is great and a big reason why I bought this BMS and the suite of Victron product.

Now I'm considering purchasing Orion-Tr Smart chargers, however I noticed that they don't have any VE.Direct connectivity, or any other VE connectivity aside from the Bluetooth one. Is something like VE.Direct, VE.Bus or VE.Can planned? Will Orion-Tr Smart chargers integrate with GX devices?

aybabtme asked
adric answered ·

4 Answers

LifePo4 Charge Profiles

Hello, I'd love to get some input from the community regarding how they are setting their charge profiles for LifePo4 batteries across Victron equipment.

The standard profile seems to be; Absorb - 14.2V and Float 13.5V - These seems to contradict various articles and research I have done.

Any input would be appreciated.

mrdanielmh asked
klim8skeptic answered ·

2 Answers

A Victron - Mastervolt Hybrid System?

Hello everyone.

Has anyone built a Victron - Mastervolt hybrid system? Why not select the best elements from both if building a solar/lithium battery system for a boat from scratch? Victron’s open-systems approach enables this.

I’m designing a lithium battery system for a sailing yacht, currently under construction. Basic parameters are: ~1200Ah of lithium batteries; 1200W of solar panels; combined inverter/charger with shore power connection; no generator but twin alternators; worldwide sailing program including Arctic/Antarctic environments.

I’ve been looking closely at Victron and Mastervolt systems, along with batteries from other suppliers. I’ve been struggling to reconcile a few concerns.

While I’m happy with most elements of a Victron system, weaknesses are:

- integration and control of alternators. While Victron offers modules that can shield lithium batteries and alternators from each others’ damaging tendencies, it doesn’t provide a fully integrated method for controlling alternators, so that they can deliver ideal battery charging.

- the low IP22 rating of the batteries. IP22 might stop small rocks and drips of water from getting into the batteries, however, these will be installed in the bilge area of a rocking and rolling sailing yacht. Hmmm. :-/

- a Victron lithium battery warranty will be voided by any charging below 5℃. The yacht will be used in Arctic and Antarctic locations, where water temperatures down to 1 or 2℃ are higher than air temperatures. To take advantage of this the hull is uninsulated below the waterline. Keeping the batteries warm will not always be convenient, but catching what sunlight is available will always be important.

Some problems with Mastervolt's offerings are:

- solar charge controllers. Mastervolt’s range is small and performance of the best candidate is insufficient.

- system programming and monitoring. Mastervolt’s software for programming system elements is effective but is far less user friendly than Victron’s. Mastervolt’s monitoring and control displays are less convenient. Victron’s options for Bluetooth interfacing, with Apple iOS and OS X apps and software is a big plus. The ease of interpreting energy flows via Victron’s GX devices can’t be matched by Mastervolt’s presentation of discrete numbers.

I’m thinking that an ideal hybrid system for my yacht, using the best of both makers, will be to ask the builder's electrical engineer to install:

From Victron:
- Cerbo GX and GX Touch 50, for system status display including tanks and pumps and to control charging via DVCC
- MultiPlus 12/3000/120-50
- Smart Solar MPPT 100/50 (x3)
- SmartShunt 1000
- Phoenix IP43 24/25 charger, for bowthruster battery charging

From Mastervolt:
- 3 x 12/5500 MLI lithium batteries (400Ah each). IP65 protection rating! No warranty voiding by charging below 5℃. With 3 x BlueSeas ML RBS safety switches - to cut loads and charging in the one unit, which also has a manual isolation switch. Brilliant! And a Blue Seas ML ACR battery combiner - to charge both house and engine-start batteries from alternators
- 2 x AlphaPro III alternator regulators - programmable for Bulk, Absorption and Float charging. Better and easier than Balmar's offerings I think.
- MasterShunt - to send battery voltage and temperature data to the alternator regulators (might not need this if the regulators can get this data directly from the Mastervolt batteries via Masterbus)
- Masterbus to USB adapter - to enable programming via MasterAdjust software and effing Windows.

This thread advises that using two shunts will work. This will be important, so please speak up if you can see a problem.

DVCC should work. Victron's GX devices appear to be battery agnostic. I don't plan to connect the Mastervolt batteries to the Cerbo's BMSbus port, but doing so might be a future project.

Thoughts? Comments? Suggestions?

Thank you.

Edit on 28 Apr 2020. A thought is that I can get the great performance of the Mastervolt AlphaPro III alternator regulators without necessarily needing the Mastervolt batteries. All I need is the Mastervolt shunt, which will communicate with the regulators and keep the alternators safe, performing well and charging the batteries well. This means I can use Victron lithium batteries if desired. That's handy.

Valden asked
Valden edited ·

2 Answers

Lifepo4 Charging Profiles

Good morning Victron Gurus!

Im looking at the 100/30 Mppt, Orion 12 12 30 and Smart Charger IP22 30.

I can see that they all having lifepo4 charging profiles which is fantastic however, the ip22 cant be modified and the default settings are 13.5v and 14.2v.

My question is, i was hoping to change the charge profiles to be more in the range of 13.6v and 14.5v. Having the IP22 at a slightly different profile, will this adversely effect charging when charge is applird through the battery charger as opposed to the different settings from the mppt and b2b?

mrdanielmh asked
mrdanielmh edited ·

0 Answers

Multiple LiFePo4 banks in parallel

Hi all,

I'm currently designing a home solar system that will use Winston LiFePo batteries to store excess energy.

To keep the initial costs down, I'm going to use 16x 300Ah cells in series to make a 48V 300Ah bank. I'll be using the GWL BMS123 to manage the batteries.

This bank will be connected to a Victron Quattro inverter and 18x Solar panels via 2x Victron MPPTs. I'll also have a Colour Control GX module setup in the ESS config

I'd like to design the system in such a way so that I can add additional battery banks of the same type later in parallel to the original one to give more storage. As far as I can tell, this is possible with the BMS123 system, I'll just need additional BMS kits per bank. However there's a line from the manual which has me confused

Multiple battery packs parallel
When you have to connect multiple packs parallel, you need 1 complete BMS per pack. You can connect the signal relays on each End Board in series. For instance: with 3 packs parallel, you can run the charging signal through from the first End Board Charge relay to the second Charge relay and through the third Charge relay. This signal can switch an enable/disable or power relay. The same goes for the Load relays in series.

If anyone has any experience with this kind of setup, can you please help me figure out what they mean by connecting the relay signals in series?

Also if there's any other advice for connecting banks in parallel, I'm all ears

cruisey1987 asked
cruisey1987 commented ·

1 Answer

Orion-TR Smart DC-DC 12/12 30 and use cases with LiFePO4 on a sailboat

Hi, looking at the Orion-TR Smart component as an option to simplify things with my new lithium house bank, and got some questions..

First question:

Given that the house bank is LiFePO4, and the starter bank is lead, the Orion-Tr Smart will protect the alternator from being burned by charging the lithium only at 30 Amps. This is good, but will also waste power that could be fed to the lithium-batteries. Is it not a better solution to feed all possible power to the lithium batteries, and charge the other way? (given another solution to save the alternator from burning)?

Second question:

Is the Orion-Tr Smart DC-DC 12/12 30 usable as a LiFePO4 charging adapter for a multiple of other charging sources? E.g. wind/solar, old shore power charger and old engine alternator - as long as all initial charging goes via the start battery? Or is it usable only on an isolated alternator circuit, as pictured in the documents?

As an example, I have an old shore-power charger, providing lots of amps but with variable voltage. Seems to be ok with the lead-battery, but probably too variable voltage for my new LiFePO4 bank. Can I still use it if I add the Orion-Tr Smart between the lead-battery and the LiFePo4 bank?

Third question:

Is there a short term plan to provide a version of the Orion-Tr Smart with higher output amps? E.g. 50?


Henning S asked
Henning S commented ·

1 Answer

Lithium Assistant - Charge Settings

I am using the output from my LiFePO4 BMS to indicate when charging is complete. It is set to force the Quattro into Float and set the SOC to 100%.

I always triggers the charger to float but doesn't set the SOC to 100%

Occasionally the Quattro enters Float well before the trigger from the batteries internal BMS.

It does this even though the Charge voltage (13.2V) and the Tail current parameters (4%) haven't been achieved.

Something strange is going on, any help will be appreciated, ta Tony

Tony C asked
Paul B commented ·

0 Answers

Orion-TR Smart 12/12 30 Charge Disconnect Question

Hi there,

i just purchsed a Orion-TR smart 12/12 30A isolated to istall it into my Van. I would like to enable low temprature charge disconnect as my lithiums could get below 5 degrees from time to time.

The manual states that i should connect it with a "Isolated remote ON/OFF cable" to the charge discconect of the VE.Bus BMS. Unfortunately i cannot find this kind of cable anywhere, could anyone point me in to the exact cable i need? Also, could this special cable be replaced with a simple wire from the VE.Bus BMS charge disconnect to the H-Pin of the Orion-TR?

As an alternative, could i also connect the VE.Bus BMS charge disconnect to the COM Port of my BMV712 and then connect the NC relay of the BMV712 to the H-Pin of the Orion-TR in order to remotely turn of the Orion-TR in case of low temperature?

best regards,


lofy asked
lofy commented ·

1 Answer

Lithium battery charging in Arctic expedition conditions

@Ur12VMan , @Daniël Boekel (Victron Energy Staff)

Hi 12VMan (and Victron staff please). I found your thread on Lithium battery protect settings while searching, but decided my comment should be a new question.

Thanks for your answer in that thread, mentioning that Victron lithium batteries issue a temperature alert at 5C. This gets my attention. My research to date was indicating that lithium batteries are OK for charging down to around 1C (and for discharging well below 0C, as an aside). I need to pursue this, as I'm planning to use Victron LiFePO4 batteries in Arctic conditions, in an expedition yacht that will be static for days to a week or two. Water temps will be down to around 2-3C, sometimes lower depending on icing. I'm looking into the need for heating for the battery box, which will be under the insulated floorboards and so outside of the primary heated spaces. If 5C is the real deal, I need to get serious with calculations on battery energy that might be consumed in making the batteries warm enough to be chargeable. Or other heating.

So, where is this 5C figure coming from? OK, I see +5C mentioned in the 12.8V LiFePO4 battery data sheet.

This prompts a few specific and important questions, about the Victron 12.8V 300Ah variants:

1. What is the lower internal battery temperature at which the battery signals to a connected BMS that charging is not permitted?

2. If the answer to Q1 is different than +5C, what is the consequence in terms of battery health (and charging efficiency?) of charging occurring between the two temperatures?

3. Does the answer to Q2 depend on the rate of charging?

4. If the internal battery temperature is just high enough for the battery to allow itself to be charged, and in this case at a low rate of 20A per battery (80A from a normal alternator, shared between 4 batteries), will this charging slowly warm the batteries up such that a higher rate of charging can be initiated in due course?

5. At what battery temperature (measured by a sensor on the positive terminal, or is there a way to get the internal temperature?) can high rate charging at ~150A per battery be initiated, such that no appreciable damage to battery health occurs? Would it be prudent to step the charging rate up slowly as the batteries warm up?

Clearly, it will be helpful if I rig a temperature sensor for the battery box, to guide appropriate action before each charging session.

The boat will use an Integrel On-Engine Charger (basically a big and very efficient second alternator) which can charge at up to a very high rate. Or it can be turned off so that charging is via the engine's standard alternator only. I might need to raise the battery box temperature before starting to charge each week or so. Heat from the main engine during these charging events will then help.

Thank you for your help with these questions. :-)

Valden asked
Valden commented ·

3 Answers

How to regulate lithium 12v batteries

Hello everyone. I’ve recently bought 2x 100Ah lithium batteries. The problem I have is that the nominal and charged voltage (anywhere from 13.3-14.4V) of these batteries is higher than that of regular AGM or other types of batteries. This increase in voltage is causing my 12v rated LED lights to blow as they can’t handle it.

So my question is, does anyone know of anything I can use to step down the higher voltage to a useable voltage of 12v approx?
I was thinking of something like a resistor or a potentiometer, but does anyone know of anything specifically for lithium that would work and not burn out? Thanks.

Kramsy asked
jaywolfe answered ·

2 Answers

302 Posts
404 Users

Topic Experts

0 Points
Franz Voelkl
0 Points
Roberto Kruse
0 Points