question

remibggx avatar image
remibggx asked

At what voltage is a Victron Lithium battery at 100%?

Hi Everyone,


At what voltage is a Victron Lithium battery at 100%?

I have a 160Ah LifePo4 Victron battery, and I am trying to understand to what % of the battery my voltage corresponds.

I am struggling to get it charged at more than 13.3V - 3.33V/Cell with the Orion 12/24V non-isolated - 30A.


Don't feel like buying and installing a BMV and find it a ridiculous that we don't get this information on the battery information on the app. This seems fairly basic information.

I did not find much informaiton in the manual and my only references are:

  • 14.0V = 100% - 3.5V/cell (last time I saw my battery fully charged after I installed it)
  • 11.2V = 3% - 2.8V/cell (information provided on the user manual)


But, I am not an expert and there might be some technical limitations.


Would anyone know or have an idea.


Thanks in advance,

Rémi

battery chargingLithium Battery
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7 Answers
Sarah avatar image
Sarah answered ·

Hi @Remibggx a good question but unfortunately voltage is not really the full answer - this is especially true with lithium which will often sit between 13.2 and 13.3 volts regardless of charge. BMV’s are used because they measure current which is a better indicator of charge (fully charged when battery is above 14 volts and current is negligible).

That said. I would be more concerned that you are not getting the battery fully charged and the opportunity for cells balancing which occurs at 14.4 volts. You quoted the 12/24 Orion and 12 volt charge settings - is this the correct product or do you have a 24 volt system? Next what are the setting on the Orion - the default settings will not charge Lithium particularly well. Lastly how long is your available charge cycle and what is the source and what sort of load do you have (this is where a BMV or smart shunt would be helpful). With a bit of troubleshooting we should be able to get you up to a full charge. Also assuming you have a superpack with internal BMS - if not what sort of BMS are you using?

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remibggx avatar image
remibggx answered ·

Hi Sarah,


Thanks for your reply :).


So here are my answers to your questions:

  • My model is the Orion Non-Isolated 12/12 - 30A (I made a mistake above).
  • I do have a 12V system in my motor home.
  • I am attaching below the screenshots of my settings. As alternator type, I selected Regular Alternator, as I have a Fiat Ducato from 2010. In my recollection, it is not yet a smart alternator.
  • My charge cycle is about 1 to 2 hours driving every day or every two days.
  • Regarding my loads, for the most energy intensive, I have a MacBook 16 plugged with 2 external hard drives plugged to a 600W converter from Giandel (not Victron). The second most intensive is my diesel heater from Eberspächer, which requires lots of power when starting it. I am a photographer, and I am charging camera/drone batteries too, every couple of days. Beyond this I have the usual lighting (leds) and phone chargers about once a day.


I think that's pretty much it.

Thanks fr your help.

screenshot-20230125-193523.jpgscreenshot-20230125-193545.jpgscreenshot-20230125-193553.jpg



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kevgermany avatar image
kevgermany answered ·

You don't tell us what voltage you see at the battery, or if it's increasing or decreasing over time.

Fact is that voltage, as @Sarah said, doesn't tell you an accurate state of charge. To get this from the BMS in the battery means extra circuitry, and with many installations having multiple batteries the extra cost is high. It's why the BMVs are available. One piece of kit for the installation. Sorry but it's the best way. Although some batteries give SOC readouts based on voltage, they're very inaccurate and we often see questions here about why the BMV and battery readings don't match.

Suggest you increase absorption voltage to the max for your battery, which I think is 14.4V. As long as the system switches to float, that batteries are being fully charged.

I've found that driving as little as you do doesn't provide enough charge through an Orion.

If float isn't happening, consider adding a second Orion in parallel, same settings. This will potentially double your charge rate, but make sure the alternator is up to it. Drawing 60A from the alternator, driving with lights on is going to put a continuous load of about 80A on the alternator. There's a good video on the Victron YouTube channel about problems with overloading alternators and how to prevent it, but the cost is high.

You might also consider putting a decent sized solar installation on the camper(my solution). But in winter you may still need a mains hookup.

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Sarah avatar image Sarah commented ·
Hi @Remibggx i agree with @kevgermany comments and If you can, some additional charge ( 2nd Orion or solar panels). Unfortunately for good management a smart shunt or similar is a must - I hope your question has been resolved.
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seb71 avatar image
seb71 answered ·

My charge cycle is about 1 to 2 hours driving every day or every two days.

At 30A, that means maximum 60Ah (if there are no loads powered at the same time). You have a 160Ah battery. So it depends on how much you discharge it. Keep in mind that there are also loses.


What is the lenght and the cross section of the wires from the Orion output to the charged battery?

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dc4me avatar image
dc4me answered ·

I would lower your start voltage to 13.2v and your shutdown to 13.0v. Without being able to monitor your alternator output you have not idea what it is doing. It could be dropping below 13.5v during your 1-2 hrs run time.

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kevgermany avatar image kevgermany ♦♦ commented ·
Unlikely, unless it's smart.
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dc4me avatar image dc4me kevgermany ♦♦ commented ·
Not if the alternator is getting hot. Volts as well as amps decrease. Why have settings so high. If volts get lower than 13.5v charger shuts down. No idea what other loads are affecting the charging system ie. cooling fans, radios, etc. Just a thought. Without having accurate monitoring of output?


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remibggx avatar image
remibggx answered ·

Hi, I am guessing that I have just been over optimistic with my battery capacity and the load I put on it.

After getting really scared with the battery putting itself in security and the charge never being completed, I managed to plug my MH to a 220V plug for few hours and then drove for about 40 minutes and got into the absorption mode soon followed by the float mode.


So, I am grateful for your answers, as they helped me foresee if I want to get a BMV or not in the future. As of now, I'll be more careful with the charging of my battery and might even consider purchasing a second one to ensure sufficient capacity for my activity.


Thanks again for all your replies.

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May I suggest turning off adaptive absorption and setting a fixed absorption time of 2 hours instead? Reason: at least once a month your battery wants to be properly balanced. This happens in absorption mode, roughly above 14V, and should last 2 hours. And once fully charged, you can turn adaptive absorption back on.

Adaptive absorption unfortunately shortens the time for proper balancing too much, so that the cells eventually diverge.

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kevgermany avatar image kevgermany ♦♦ commented ·
Adding an extra battery may help. But it doesn't solve the problem of too little charging. Probably better to spend the money sorting that out first.

In some ways adding an extra battery will make things worse, as you're going to have two batteries not charged enough for the internal balancing to work.


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rdcat avatar image
rdcat answered ·

Over 3.45 volts / cell is 100% with enough time.
see Offgridgarage for video proofs


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remibggx avatar image remibggx commented ·
Thanks for your reply! So I can confirm that I struggle to get my battery to 100% with my current settings. I am trying now a lower Absorption Voltage as the preset one is rarely reached, apparently. I am going to try the next time I am driving long enough to fully charge the battery.
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