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Lithium Battery

PV system (MPPT + LiFepo4) + AGM - how combine for standby operation


I set up tiny pv system with victron MPPT solar charger + victron lifepo4.

System work great day charge - noon discharge but i”m lacking ability to have emergency power (like ups) that will allow me work offline in case power outage (lifepo4) is in constant charge or discharge so i can’t rely on power stored inside when i have couple days of shade - lifepo4 is discharged and i”m working from grid -and this is what i want .

I would like have separated battery just for storage power only to use in case real outage. I make decision - now we have serious condition - i remove all non esential dc load and switch to backup

battery to power my computer.

I bought for that victron agm 110ah.

What will be the best way to combine this AGM as backup so it will be keep fully charged but wont be discharged until I decide?

first part is easy - i just buy isolated dc/dc charger and make it constantly recharge my AGM from that liion battery that is tied to solar but how to connect inverter / dc load?

hardware changing wires to agm seems like bad idea.

i saw boat switch but all of they have mode For combine both batteries - Im afraid how they respond when fully charged agm is connected to fully depleted 100ah lifepo4.

I seen victron have something like diode combiner - does this will be good for my use case?

or buy two isolated dc-dc chargers and hook one of them in way it recharge agm from lithium and second lithium from agm and then just add double throw switch?

in normal mode it will be charging agm - in reverse it charge lithium - that way i left all my load connected to lithium.

any ideas?

opzsgu asked
Mike Dorsett answered ·

1 Answer

"Lithium Batteries" option won't stay checked in Victron Connect App?

I'm using the VictronConnect app to program my MultiPlus 12/2000. Under the charger settings, there's a "Lithium Batteries" option that I want enabled. I am able to toggle the switch on, but each time I exit the app, the switch by this option reverts to 'off'.

Jon Schroeder asked
scott-2 edited ·

3 Answers

Orion TR Smart and Euro 6 Engines

Hi the collective hive of information.

I am in the middle of commissioning an Orion TR Smart 12/12-30A on a VW T6 Camper van. The system doesn't seem to be triggering that often, and even after a couple of hours driving the Lithium batteries are not full.

All default settings have been used, but the start battery is regularly at 12.3-12.5v.

Are the default settings too aggressive, do they need to be dropped. If so any recomendations. I have done various searches and running second battery charging with Euro 6 engines seems to be a dark art with little information about what a good set of settings should be.

My instincts as opposed to science or knowledge is to:

Drop Input Voltage Lockout to be 12.1v / 12.3v. After starting the engine and idling the starter battery is regularly at 12.2v, so restarting shouldn't be an issue at 12.1v.

Setting Start Voltage to 13.2v

Setting Delayed start to 12.8v

Setting shutdown voltage to 12.7v

Any guidance, are these values too low?

Many Thanks



bathnm asked
kevgermany answered ·

4 Answers

Smart BMS 12/200 with Smart lithium

Good morning All

I have an issue that i don't seem to be able to get around an i was wondering if i could use the Smart BMS 12/200 to do it.

I have a unit that takes power via a single 35mm battery cable but also gives charge back when plugged into the mains via the same cable.

Can i use the Smart BMS 12/200 system + side to control this so that the batteries are happy and wont over charge or go low voltage?

I have a working setup with the cyrix relays plus a battery protect controlled via the VE.bus BMS and two diodes to stop reverse current.

smithie1623 asked
klim8skeptic commented ·

0 Answers

Charging lithium to 100% SOC

In my Airstream travel trailer I have two 300ah 12v Victron Smart Lithium batteries in parallel, BMV 712, 800w of solar, Victron 150/70 MPPT controller and MultiPlus for shore power / genset power for charging.... and CCGX for system coordination.

I also own a Telsa, and the best practice, generally speaking, is to run the lithium pack between 30% and 70% SOC to maximize longevity. We only ever charge to 100% ever 2-3 months when needed for extended use. It has active cell balancing, of course.

The Victron batteries have passive cell balancing, which of course means you must charge and float at 100% SOC to balance the cells.

My question is - does charging the Victron 12v Lithium batteries to 100%, over and over again (on a daily basis) degrade the performance of the Victron lithium cells at an accelerated rate? Or... should I manage the batteries like I do the Tesla cells - between say 30 and 70% SOC, and only fully charge / balance on, say, a monthly basis?

In other words, what are the best practices for yielding the longest lifespan / longevity from Victron 12v Lithium batteries aside from caring for them with low charge / discharge currents?

Thank you Victron community :)

wulfraat asked
friaras answered ·

3 Answers

How to store Victron Lithium Batteries

I have three 200ah batteries that have never been used. I have been storing them in a climate controlled storage. Should I be charging them periodically or are they okay to continue without any additional upkeep? What could I charge them with if that is needed? Thank you!

a3x5fan asked
Stefanie answered ·

2 Answers

LiFePO4 200Ah 25.6v v1.27 to v1.28 firmware update failed at 4%

Yesterday tried to access my batteries, which I check regularly while on board, in order to monitor if the cells are balanced, and whether the temperature is appropriate

Had a notification of obligation to upgrade, which I started, and 2 out of the 6 batteries I did upgrade [remains 4 I didn't dare to go on], failed to update when reaching 4%, and had the BMS shut down all systems.

There is no way to find the battery through Bluetooth anymore, as if it's system shut down or is offline,

Tried deleting it from paired list,

Tried using other phone, and still the same.

No way to find these 2 batteries in the victron connect app or through BT.

As I am a floating boat, I cannot stay without power, had to skip the BMS cables of these 2 batteries until I find what shall be done.

Any way to reset the Bluetooth processor of the batteries to default or factory so I could communicate again and restart the firmware update?

Or shall I remove the batteries from the banks and send them for service? (Which is a big mess btw)

Your help is highly appreciated

sydasssy asked
Stefanie commented ·

2 Answers

Battery size for MultiPlus II 12/3000/120-32

I would like to confirm my thoughts on battery size for the MultiPlus II 12/3000/120-32

I am new to Victron and the Victron community. I will be doing a full Victron GX setup for a Van with Lynx Smart BMS 500, Cerbo GX, Lynx Distributor, DC to DC Orion-Tr Smart 12/12-30A and SmartSolar MPPT 100/20. With 460 Watts solar on the roof. DC to DC as the main re charge source, solar as the top up, and shore power only as a backup if needed.

I chose to go Victron and the eye watering price of Victron batteries and eco system as I wanted an off grid van system that would "look after itself". Be able to hook up Victron batteries in parallel knowing zero issues with the whole multiple batteries and BMS shutdowns etc. Finally a 3Kva rather than 2Kva so was not running the inverter to its capacity every time a large draw was used, toaster, induction and the ability when needed to run 2 large loads, like short use of roof air con (inverter air con) while being able to cook etc.

My question: I would love be able to grab a couple of 200Ah Victron Smart batteries for a 400Ah system, a 3rd battery later for 600Ah.

But looking at the max current draw on the 200Ah Victron smart battery, MAX does say 400Ah BUT recommended max says < 200ah. ( 200Ah x 12V = 2,400 Watts)

This means with the 3,000 watt Multiplus II max performance of 3,000watts, the recommended max battery draw is a good 600 Watts below inverter capacity. If we were using the system to its full capacity of 3,000 watts thats a 250 Amp draw on the batteries. Within max battery draw but above the recommended 200Ah draw.

If we were running the roof air con Dometic IBIS 4 ( for short periods on low) by itself its a max draw of 1,600 watts, 600-900 watts on low, and why I was looking at a 3Kva inverter rather than the 2Kva. Didn't want to be in the scenario where your limited to one big draw appliance and no capacity left.

Therefore I though that to allow full use of the MultiPlus II, I have no choice but to use the Victron 300Ah or 300Ah - leaning to the 330Ah as its 20kg lighter and smaller in size.

Am I being too OCD going with the 330Ah battery ? or would 2 or 3 200Ah be fine with the view that up to 2,400 Watts inverter power would be within the 80% normal usage and 2,400 - 3,000 watts (250 Amp draw which is 50 amps above battery recommenced but within the max 400Ah ) would be a 20% use case for a few hours at a time occasionally.

Russell Brown asked
Russell Brown commented ·

2 Answers

BMV relay controlling charge sources based on SOC? Victron lithium system.

I'm working on a customers narrowboat in the UK which has had a Victron lithium system fitted by another installer a few months ago. I've attached the orginal installers diagram which is how it's all been installed.

I've been asked to sort out alternator charging - Removing the CL 12/100 (which doesn't work and installer saying the latest version isn't like previous ones they used) and fitting a Mastervolt Alpha Pro external regulator to the Beta 43 175A alternator (using BMS charge disconnect signal to control).

I'm questioning how the state of charge relay is being used to break the Charge Disconnect signal from the VE.Bus BMS. As soon as the BMV hits 100% the allow to charge signal is broken and turns solar and alternator charging off so there's no real length of time in absorption. The cells in the 3* 160AH Smarth Lithium batteries are balanced according to the app.

Is it recommended that the BMV relay be used like this? Can't see it on any of the official schematics.. edit.. just spotted this one here

Wonder what other people think and if there's an official recommendation?

1. I could leave BMV relay as it is controlling the Mastervolt Alpha Pro and SmartSolar.

2. BMV relay just controlling Alpha Pro. Smartsolar left with standard lithium profile with fixed absorption time to ensure cell balancing.

3. Remove the BMV relay control completely.

Thanks for any advice, Ed



fc-marine asked
fc-marine edited ·

0 Answers

Has anyone found how to disable "Repeated absorption" with Blue Smart IP22 12 | 30 chargers with Lithium batteries?

I have Battle Born LiFePO4 batteries. They do not require repeated absorption. In fact, unnecessary absorption it is detrimental to all LiFePO4 batteries. Reabsorption is a lead-acid battery requirement to prevent sulfation.

I tried setting repeated absorption to "0" days, and the setting reverted to "1" day. Then I tried "999" days and found the setting reverts to "45" days. Victron forces 45 days as the maximum setting. I could set the absorption voltage to some low value, but then I would have to reconfigure the charger every time I actually wanted to charge to a higher SOC.

Repeated absorption should be set to "disabled" in the "Li-ion" factory profile (caveat: that factory profile is set at 7 days!). This looks to me to be a software oversight.

Suggestion to other users: to prevent these chargers from cooking your lithium batteries, set the tail current (disabled in the profile) to 7.5 amps (the maximum) so the charger at least diminishes the overcharging damage by terminating charging quickly (provided there are no parasite loads) of an already-fully-charged battery.

cpt-pat asked
cpt-pat edited ·

8 Answers

Absorption voltage LiFePo4

Hi everyone

I read that the max voltage for a 3S LiFePo4 battery is defined at 12.60 volts. (Absolute maximum is set to 4.20 volts per cell)

So I wonder, why is the default absorption voltage in the SmartSolar MPPT 75/10 Charger for a 12.0 V battery, while choosing the Smart Lithium battery preset, set o 14.20 volts?

Even the float voltage is set at 13.50 volts which is also higher than the recommended max voltage of 12.60 volts.

Will these settings not damage the LiFePo4 battery?

Thank you,


martin-haemmerli asked
Stefanie commented ·

4 Answers

MultiPlus-II sudden low battery alarm while battery is full (BSL stubby)

Update 25/11

The battery once again gave a low voltage alarm while about 80% SoC, causing the inverter to restart. There is clearly something wrong. My best guess (based on many informed opinions) is a serious BMS firmware bug or design flaw. It could also be severely unbalanced cells, or a faulty cell. BSL is apparently working on improving the firmware (they're aware something is wrong).

I'm working with the installer to have the battery exchanged for something that actually works reliably. I would not recommend buying a BSL stubby for the time being, at least not until they sort the BMS issues out.



Hardware details:

Setup details:

  • Grid connected to AC-IN
    • Grid feed-in is disabled.
  • AC-OUT-1 is feeding essential loads (no more than 2000W, average about 300W-700W)
  • AC-OUT-2 is feeding geyser (on timer 10:00-15:00) and stove.
  • ESS mode: Optimised (with BatteryLife)
  • The system is less than a week old and has been running perfectly up until a few hours ago.

Issue description:

The inverter suddenly shut down and started up on its own after a minute or two. The battery was about 99% SOC when this happened.

The following alarms occurred:


On VRM I can also see there was a "High DC ripple" warning at the same time.

The system ran fine after that for a while after which the same thing occurred again, but this time it coincided with a grid failure (load shedding). The same alarms occurred:


During both occurrences, the load on the inverter was at most 500W (nothing was switched on additionally when it happened).

Does anyone have an idea what the cause could be? I'd appreciate any input.

VRM images (please let me know if other log data could be useful):





I did also notice on the MPPT daily history, the minimum voltage for the battery today was 44.72V, which seems very wrong:


Usually it discharges to about 45% throughout the evening, and then the minimum voltage hasn't fallen below 51V before today:


anrich asked
nickdb commented ·

5 Answers

Smart BMS CL not charging

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


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

mik asked
james-ward answered ·

1 Answer

Victron ESS battery compatibility Pylontech US5000(B)

Hello, I've found some threads regarding compatibility of the Pylontech US5000 battery (not the UP) with the Victron ESS system but a lot of them seem to be mixing up the UP and the US version.

The exact battery type (US5000 or US5000B, see ) is currently not listed on the battery compatibility list of Victron (

At this point, I'm assuming it's compatible, but I'd prefer a formal confirmation of this.

Even better: would it be possible to update the documentation page with compatible battery types? During certification of the electrical system by a notified body, some inspectors are pretty specific about the compatibility, certified by the vendor of the ESS, between a BMS and the ESS system.

At this point, I don't have the documentation (or certificates) ready to back this up.

axl1988 asked
Guy Stewart (Victron Community Manager) answered ·

3 Answers

Orion Tr Smart 12/12-30a isolated starts absorption charging too soon

On my yacht i have just fitted an Orion Smart 12/12-30 isolated B2B charger charging a new 150AH lithium battery with a built in BMS for my Domestic power. This is fed by a new 100Ah AGM start battery supplied by a regular 100 Amp alternator. The problem I have is that the Orion charger enters Absoprtion charge too soon (3-5amps) with the Lithium battery at about 55% when it should still be in bulk mode. I have ensured that the charge voltages are as per specification for the battery (14.4v charge, 13.8v float), the charger is close to the start and domestic batteries (50cm) and the cabling is oversized 6mm2 I also have a new Victron Smart Solar 20 amp charger that is connected to the same battery which is in bulk (engine off) mode while the Orion was in Absorption mode. I also have a new victron 30amp 240v mains charger which was bulk charging 20-30amps I would like the Orion to Bulk charge to at least 80%, is the smart solar confusing the Orion? can yo help?

jason-t asked
jason-t commented ·

1 Answer

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