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rithym1964 avatar image
rithym1964 Suspended asked

WARNING - RS 450 Controllers DERATE CURRENT SEVERLEY OVER 57V !!!

I would like someone from Victron to answer my question on the above title. I Like Victron equipment in general as the feedback via remote console & VRM is far superior to any other product I have tried. Over the past several years I have spent considerable money switching to a complete Victron setup. My RS 450/100 is the latest addition.

But, why on earth would Victron release a controller RS 450 series that DERATES the charging current severely once the voltage rises above 57V ??? I have a 48V traction FLA deep cycle battery which requires a 60V absorption charge. Whilst the RS 450 is in Bulk mode with the voltage well below 57V I see around 3000W on each tracker (100A total) but the moment the voltage approaches & exceeds 57V the charging current is SEVERELY throttled down. By the time the battery voltage reaches the actual absorption point (this morning that is 61V as the battery is quite cold) the charge current produced by the RS 450 is only about 1200W on each tracker. THAT IS A LOSS OF 60% !!! This means the absorption set point takes much longer to reach due to the throttling down of the charge current whilst stll supposedly bulk charging.

I find this problem unacceptable. I have been trying to figure out why they would release such a product then I see that the charging routine on their Lithium 48V batteries is around 56 - 57V so, is this a ploy to coherse everyone to purchase VERY EXPENSIVE Lithium batteries ??? those of us who choose to remain with a much cheaper 'proven' technology like FLA get a controller that simply will not charge these batteries as it should. There is absolutely no mention of the 57V derate in any of the manuals for the RS 450 series (unless it has been added recently) or I would have seen it before my purchase. What Next?? will we see firmware updates on other controllers that will also derate them above 57V... it could be happening already I do not know. Personally, I only bought the HV controller because my latest arrays are 60 meters away from the control room so a higher voltage controller seemed the right choice... how wrong I was, the RS 450 sucks!!

I hope Victron is listening to these posts you should not be manipulating software in your products to coherse people in to buying only a certain type of very expensive battery. For example my FLA 48v 1000AH battery cost me 5K Euro brand new and will last 10+ years cycling 70 - 80% SOC daily. An equivalent Victron Lithium battery 600AH cost 30K Euro and will last ?? years cycling 20 - 80% SOC daily. I bet the unknown figure for the Lithium is not x6 longer as is the cost comparison - even if it were true, a battery that lasts 60+ years is a pontless investment for a retired electrical engineer at 60 years old, even if I had the money.

Please Victron fix this issue quickly it can be done with a simple firmware update. It doesn't matter which battery type I choose in the settings menu the same derate occurs, this is ludicrous and a huge waste of 10 KW PV potential.


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Matthias Lange - DE avatar image Matthias Lange - DE ♦ commented ·
Please add some more information about your system. What other components do you have? What solar panels and how are they wired? Some screenshots of VictronConnect.
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rithym1964 avatar image rithym1964 Matthias Lange - DE ♦ commented ·

Current Setup

venus-gx-own-config.jpg

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4 Answers
mvader (Victron Energy) avatar image
mvader (Victron Energy) answered ·

Dear @rithym1964 , you are right.

It derates indeed. And the information is, to my embarrasment, missing in the manual and datasheet. And to further the embarrasment, it also appears we might be able to reduce the derating; with a firmware upgrade.

The maximum output current is reduced on a linear basis from full current at 57V to 5A at 63V.

What we're doing now is investigating what the derating should be; and then I'll get back to you.


All the best, Matthijs

UPDATE 2022-03-25: firmware v1.09, planned for end of march (next week), will derate like this:

The Charger set-points (float and absorption) can be set to max 60V. The output voltage at the charger terminals can be higher, due to temperature compensation as well as compensation for voltage drop over the battery cables. The maximum output current is reduced on a linear basis from full current at 60V to 5A at 62V. The equalization voltage can be set to max 62V, the equalization current percentage can be set to max 6%.

Datasheets have been update to be more clear on max configurable charge voltages as well as to include above sentence. More details in a comment further in this thread.

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rithym1964 avatar image rithym1964 commented ·

@mvader (Victron Energy) Thank you for your honest reply it is refreshing to hear truth rather than denial of what I consider, is a severe derating problem. I sincerely hope the issue can be addressed in a firmware update and I look forward to keeping the RS 450/100 as part of my system. If you would like me to beta test a firmware update and give feedback I am happy to do this we get plenty of sunshine here in the Algarve, Portugal

PS Whilst you are investigating the derating issue can you please also look at EQ setting of the RS 450. For some reason it is limited to 62V but my flooded battery requires a voltage of 2.65 - 2.7V per cell which is 63.6 - 64.8V. The other two Victron controllers in my system allow a higher setting but the RS won't go higher than 62V. I would like all the controllers to match settings so they have the best chance of working in unison via the DVCC setting in the Venus GX setup menu.

Thank you



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mvader (Victron Energy) avatar image mvader (Victron Energy) ♦♦ rithym1964 commented ·

Hi @rithym1964 , we finished the analysis of what is possible; and there is some good news in there for you, but also bad news:


New derating function: the maximum output current is reduced on a linear basis from full current at 60V to 5A at 62V. Note that this relates to the output voltage at the MPPT RS battery terminals, and not the voltage the battery itself, measured with voltage sense.

The maximum configurable charge voltage will be reduced from now 62V to 60V. The actual charge voltage can be higher, due to temperature compensation as well as voltage drop over the cables in combination with Voltage sense.

The reason to reduce the maximum configurable charge voltage is that specifying it at 62V is misleading, in combination with the derating. It makes people think they can use the RS to charge a battery at 62V volt, which they really can not.


And the technical reason behind these limitations on the upper side of the output voltage range lies in the internal power electronics design in the RS. Its a totally different converter, compared to our other solar charge controllers. Which has many advantages, but also some disadvantages like a more narrow voltage range.


We will be working on implementing this in the firmware; which might take a while. Would be great if you could join the beta group for this - if you are still interested; I can see how going from 62V to 60V can be a problem on this. I'll send you an email to discuss.

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rithym1964 avatar image rithym1964 mvader (Victron Energy) ♦♦ commented ·
Hi


If I am reading your proposal correctly you are saying the RS firmware can be changed so the controller charges at full 100A current up to 60V when the current will then be derated on a linear basis to only 5A by the time the voltage has risen to 62V. This means all the derating occurs above 60V.

As a consequence of this you need to lower the max configurable absorption and equalising voltages from 62V down to 60V. Effectively, this means the RS controller will not charge much above 60V so I would need to use my 150/85 to run an equalising cycle. (This has never been necessary in 5 years I always make sure to see a full 4 - 5 hour absorption charge at least every week which keeps the sulfation away)

This does seem like a good solution for my flooded battery and I will be happy to beta test the new firmware and provide any feedback required.

best regards


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mvader (Victron Energy) avatar image mvader (Victron Energy) ♦♦ mvader (Victron Energy) ♦♦ commented ·
ps. I've accepted my own answer, to get it to the top of answers.
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nickdb avatar image
nickdb answered ·

There is an awful lot of assumption going on here. Like it was said above, there isn't enough information here to even try and help.

This is a community forum manned by volunteers, so coming here and ranting doesn't help anyone, nor does it motivate the community to help.

If you want official help you need to contact your supplier who owns the support and can escalate for you.


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JohnC avatar image
JohnC answered ·

Don't be too critical guys, there's history here.. https://community.victronenergy.com/questions/118140/rs-450100-throttling-down-current-on-both-arrays-w.html?childToView=118707#comment-118707

And after Thiemo pointed it out, I checked the datasheet and it indeed showed 57V. But it's not there now!

Maybe firmware has fixed it, but I can't find a changelog entry.

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rithym1964 avatar image rithym1964 commented ·
There was a firmware update last weekend which I upgraded the RS controller too but it did not fix this particular problem of severely derating the current over 57V
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rithym1964 avatar image
rithym1964 answered ·

Here is the data from this morning at 1.0V increment rising voltage


01-vrm-screenshot-56v.jpg

03-vrm-screenshot-57v.jpg

05-vrm-screenshot-58v.jpg

07-vrm-screenshot-59v.jpg

09-vrm-screenshot-60v.jpg

11-vrm-screenshot-61v.jpg








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jens-due avatar image jens-due commented ·

Hello

It is not because you are above 85% SOC that it reduces charging current?

What happens if you turn off your MPPT 150/85 it produces 2000W maybe your RS will produce a little more.

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rithym1964 avatar image rithym1964 jens-due commented ·
Thank you for your input.


The controller should NOT reduce the charge current until the absorption voltage is reached. My screenshots clearly show it is doing this from 57V upwards even though the RS is in Bulk charge mode and absorption point is 60.84V.


I have tried disabling the 150/85 this makes no difference to the RS 450 reducing the charge current. All the array parameters are well within the RS 450 spec infact I could add x2 more panels to each string to raise the Array Output to near the max of 432V (8x Float Voltage 54V)

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