New Victron MPPT Firmware

[noelex 77]

Originally Posted by FlyingScot

I just upgraded all 4 of my 100/30's from 1.39 to 1.42. I see the change of settings.
I'll watch and see how they perform. I saw the default is 2 amps. I left it there for now. One of my controllers already dropped to float. My house bank is 100% SOC right now.

Be aware that the switch to 1.42 makes the effective absorption time longer. Previously the Victron controllers simply counted the time after the absorption voltage set point was first reached. If the battery voltage dropped below the set point the time was still counted down.

1.42 introduces a more sophisticated absorption timer. After this software update only the time at (or very close to) the absorption voltage is now counted.

So the absorption time will need to be reduced to achieve the same effect. Note this my view only. Victron have not suggested this, as far as I am aware.

Absorption time is something that needs to evaluated for every installation anyway so it does not hurt to re-check the correct value for this parameter. As this software change is new, I have only observed the solar performance for a small number of cycles, but my current impression is that my absorption time will needed to be set at around 1/2 the previous value in my case, so the change is quite significant.

Incidentally, there was a subsequent software (not firmware) version released yesterday, but I suspect it is a very minor tweak to address reported conflicts.

[john61ct]

Originally Posted by noelex 77

If the battery voltage dropped below the set point the time was still counted down.



1.42 introduces a more sophisticated absorption timer. After this software update only the time at (or very close to) the absorption voltage is now counted.

Excellent, thanks for nailing that (major) change down.

> Absorption time is something that needs to evaluated for every installation anyway so it does not hurt to re-check the correct value for this parameter.

If trying to be precise about reaching endAmps "most cycles" but avoiding overcharging, AHT may well need to be adjusted regularly anyway, as usage patterns change (cruise cycling vs at the dock) or with the seasons.

Just assuming all is well without checking the BM logs, pretty much guarantees sub-optimal results.

Until the stop-charge / Float transition is based directly off the battery acceptance rate.

[admiralslater]

Originally Posted by john61ct

Yes C-rate is proportional to Ah capacity so for 500Ah endAmps is 7.5

So I would set my tail current to 7.5 on all 3 of my controllers as they all charge the same bank if I understand correctly

[FlyingScot]

Originally Posted by noelex 77

Be aware that the switch to 1.42 makes the effective absorption time longer. Previously the Victron controllers simply counted the time after the absorption voltage set point was first reached. If the battery voltage dropped below the set point the time was still counted down.

1.42 introduces a more sophisticated absorption timer. After this software update only the time at (or very close to) the absorption voltage is now counted.

So the absorption time will need to be reduced to achieve the same effect. Note this my view only. Victron have not suggested this, as far as I am aware.

Absorption time is something that needs to evaluated for every installation anyway so it does not hurt to re-check the correct value for this parameter. As this software change is new, I have only observed the solar performance for a small number of cycles, but my current impression is that my absorption time will needed to be set at around 1/2 the previous value in my case, so the change is quite significant.

Incidentally, there was a subsequent software (not firmware) version released yesterday, but I suspect it is a very minor tweak to address reported conflicts.

I updated my VictronConnect app to 5.11 on all my iDevices.

Last night I spent more time on the new settings and updated a few things.
First I upped the tail current to 6 amps per Firefly Oasis manual. I also updated temperature compensation to 24 mv/F, except it won't take 24. It changes to 23.99? Weird bug I presume. It will also accept 24.01 mv/F. I have my ABS set to Fixed - 6 hours. Victron specifically says the tail current still applies to drop to float.

Can you tell me more about absorption time? This is one area that I either don't fully understand or it doesn't apply to my situation.

Why would I limit absorption time at all? Shouldn't I bulk charge until the setpoint is reached then absorption charge until the tail current setting is met?

I have three L15+ Firefly Oasis batteries for the house bank. 450ah@12v nominal. 99%+ of charging done by solar (360wp x 4). I'm at 12N so the solar harvest day is roughly 09:00 - 17:00.

I don't see any risk of overcharging the batteries. Even it this was hooked to shore power, I don't understand why we would limit the absorption phase as long as we have the settings correct.

As a side note I've mentioned before, I have my controller settings turned down as not to have too high a voltage. Example: 14.15v to keep the upper voltage just over 14.4. Float is set to 13.17 to keep it around 13.2. Voltage reading are taken from my BMV-712. I verified my BMV is within .03 to my calibrated Fluke 87v. BMV has optional temp probe.

[john61ct]

Originally Posted by admiralslater

So I would set my tail current to 7.5 on all 3 of my controllers as they all charge the same bank if I understand correctly

Yes, but as discussed above, measuring at the source output does not give acceptance by the bank, so ongoing loads can result in overcharging.

Which is what the AHT maximum is for, and adjusting that requires tracking how often endAmps point is reached before the stop-charge / transition to Float.

[john61ct]

Originally Posted by FlyingScot

Why would I limit absorption time at all? Shouldn't I bulk charge until the setpoint is reached then absorption charge until the tail current setting is met?

As long as the tail current is measured by a shunt at the bank posts.

Otherwise see above, loads may mean the charge source output current never drops to endAmps.

Of course with solar, sunset arrives every night 8-)

[john61ct]

The "safe" voltage level can vary with the current rate too, but that's more relevant with LI chemistries than lead.

https://endless-sphere.com/forums/vi...98203#p1498203

[FlyingScot]

Originally Posted by john61ct

As long as the tail current is measured by a shunt at the bank posts.

Otherwise see above, loads may mean the charge source output current never drops to endAmps.

Of course with solar, sunset arrives every night 8-)

Well yes, I'm still waiting for Victron to incorporate the BMV shunt amps to the solar controllers.

Our normal house load is typically 15-20 amps during the daytime.

I'm not sure how to adjust the SC tail current amp from the current setting of 6 on each controller. Maybe I should add 4 to each one making the tail current setting 10 amps (4 x 4 = 16). This would add some wiggle room for the house loads.

Thoughts anyone?

[RickG]

Great discussion. My summary:
- Tail current = n*battery tail current, I have seven FF G31s with a 1.5amp tail current, so 10.5amps
- House bank load is a factor, may need to add average house load to tail current
- Victron BMV-712 does not feed current to solar controllers from the shunt

I'm looking forward to getting back in the water in October and running the software update on the solar controllers. Early float has been an issue for us. I have been resetting the SmartSolar controllers to get back into absorption.

Regards, Rick

[noelex 77]

Originally Posted by FlyingScot

I updated my VictronConnect app to 5.11 on all my iDevices.

Last night I spent more time on the new settings and updated a few things.
First I upped the tail current to 6 amps per Firefly Oasis manual. I also updated temperature compensation to 24 mv/F, except it won't take 24. It changes to 23.99? Weird bug I presume. It will also accept 24.01 mv/F. I have my ABS set to Fixed - 6 hours. Victron specifically says the tail current still applies to drop to float.

Can you tell me more about absorption time? This is one area that I either don't fully understand or it doesn't apply to my situation.

Why would I limit absorption time at all? Shouldn't I bulk charge until the setpoint is reached then absorption charge until the tail current setting is met?

I have three L15+ Firefly Oasis batteries for the house bank. 450ah@12v nominal. 99%+ of charging done by solar (360wp x 4). I'm at 12N so the solar harvest day is roughly 09:00 - 17:00.

I don't see any risk of overcharging the batteries. Even it this was hooked to shore power, I don't understand why we would limit the absorption phase as long as we have the settings correct.

As a side note I've mentioned before, I have my controller settings turned down as not to have too high a voltage. Example: 14.15v to keep the upper voltage just over 14.4. Float is set to 13.17 to keep it around 13.2. Voltage reading are taken from my BMV-712. I verified my BMV is within .03 to my calibrated Fluke 87v.

Chris, the Firefly batteries are very different to conventional lead acid batteries. I have no experience with this type of battery so I can only offer advice relevant to conventional lead acid batteries. I hope the following helps, but keep in mind your batteries have different requirements.

The tail current reported by the Victron solar controllers is not tail current in the conventional sense. The battery manufacturer’s recommendations cannot be applied to the Victron solar controller, as although confusingly the terms are the same the meaning is very different.

An example might help:

The battery voltage has reached the set absorption voltage of 14.6v and one Victron solar controller is outputting 1A. Using Victron’s definition, the tail current is 1A.

However tail current really means the current entering the battery at (or close to) the absorption voltage. In the above example the battery could be receiving 10A because another charge source such as an alternator, additional solar controller, wind etc) is suppling another 9A. So the real tail current is not 1A but 10A. On the other hand, the only charge source may be the single solar controller, but there may be a load of 0.75A. So the current entering the battery is only 0.25A. So the real tail current is 0.25A.

The numbers on the above example do not matter, but they illustrate how the real tail current, which is what the battery manufacturer is referring to in their specifications, can be very different (higher or lower) than the tail current reported by the Victron controller. So setting the Victron solar controller to the tail current specified by the battery manufacturer will not I work and I would not recommend doing this.

The only time the Victron solar controller will report the correct tail current is if this is the only charge source and there is no load. This situation is not common on a boat.

Note: The above is relevant to the solar controller as a stand alone device. Victron make some devices that will communicate battery information to the solar controllers. I have not installed these, so I am not sure how they modify the above.

[FlyingScot]

Some notes about the 1.42 f/w

Include firmware v1.42 (v1.43 for some models) for BlueSolar and SmartSolar chargers:
The Lithium battery rotary switch preset has been changed. Absorption time is fixed to 2 hours, and it will not stop on low tail current.
The re-bulk voltage was lowered from 13.7V to 13.4V (for all battery types).
Added four new settings:
Adjustable tail current (changeover from absorption to float).
Adjustable re-bulk offset voltage (changeover from float to bulk).
Adjustable automatic equalization parameters (current / duration).
Choose between adaptive- and fixed- absorption time. The adaptive mode is the method that has always been in the algorithm. It adapts the time to the battery voltage as seen in the morning. The fixed absorption time is what it says it is: a fixed time. No multipliers related to voltage in the morning. Setting absorption time to fixed does not disable the tail current mechanism: disable that too to get a 100% fixed absorption time. Note that we advise to not use fixed absorption times for lead batteries.


And look what's coming with 1.44
***Add synchronized charging through VE.Smart Network for SmartSolars

[FlyingScot]

Somethings I've noticed today. I had the controllers set to 10 amps for trailing current. One dropped to float way too soon. I've pushed that number down to 3 amps for now on all four.

Also, FF Oasis recommends 12v for 'reset to bulk' charging. The new f/w allows a voltage setting offset. I have put in 1.17v to offset my 13.17v float to 12v. The default was 0.1v so this is a huge change. I'll keep an eye on this to see if it works as expected.

[noelex 77]

A few other significant changes that I have noticed with 1.42:

Second absorption cycle:

The previous Victron algorithm expected to frequently drop down to float before 100% SOC was achieved. It therefore initiated a second absorption phase of around 10 min whenever a new bulk cycle was reached.

With the 1.42 firmware upgrade the absorption time is now only counted down when the voltage set point is maintained. As a consequence, the second absorption cycle will no longer be initiated. If a second bulk cycle is initiated the controller will immediately drop to float. This is another significant change that will hopefully work well. There is a risk with a significant power drain (for example electric cooking) that the SOC may still be significantly down at the end of the second bulk cycle. The algorithm may have a trigger point where a second absorption cycle is initiated, but if it does I have not hit this criteria so far with my system.

[noelex 77]

Equalisation:

The equalisation cycle has been significantly changed in 1.42. The first difference is like the absorption cycle, the controller now looks at voltage and if the voltage set point is not met then the timer does not count down. There is also significant extra control available for the equalisation cycle.
The time is now variable.
The maximum current can be programmed.
The time can be fixed or based on voltage.

These are all very welcome additions. My batteries do not need an equalisation cycle so I use the equalisation cycle to apply an extended absorption time when this is warranted. The extra control works well in this application.

[TxCoastSailor]

Originally Posted by RickG

As the battery completes charging internal resistance slows the current that the battery can accept. Battery manufactures define what that tail current for the transition from absorption to float. On my Firefly batteries the tail current is 1.5amps. Without the ability to set tail current my Fireflies have been flipping to float early. There is more to it. You can read the posts in the Victron Q&A link above.

Cheers, RickG

Where did you find the 1.5A value? Also is that 1.5A per battery? If you have 2 batteries in parallel would the tail current be 3A?