Energy Matters Forums

[Tracker]

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OK - I have come to realise that I have been fooling myself about my preferred Solar Charge Controller.

I have eluded to the problem in threads and having written to the manufacturers and got no response, I thought that I should be honest and "Come Out"..

Don't get me wrong - the device is simply great with it's value-for-money features, but if it does not do the most basic function "Correctly" , then you need to make a value judgement on it's worth.

Like most Solar (MPPT) Charge Controllers, the PCM5048 does not really like Sealed Batteries. AGM, Gell, VRLA etc. etc.
I can understand WHY, because there are so many technology differences with AGM, Gell, VRLA etc., and to have a One-For-All Algorithm, is just not practical..

We "Understand" that the BIG issue with sealed batteries, is that if it GASSES, then you are seriously damaging the technology..

FLOAT - What you would expect as the HIGHest voltage to be EVER seen.. !

PCM5048 - FLOAT.jpg (12.32 KiB) Viewed 7690 times

You don't have to be Einstein to believe that IF you set a MAXimum Float voltage and no Absorb, then, the MAXimum voltage that you would EVER see, is that FLOAT voltage.

At lease that is how it works with other CC's that I have seen... Like the FM60..

AND - still rising.. What damage would this be doing..?

PCM5048-OverCharge.jpg (18.42 KiB) Viewed 7690 times

Now if you encounter this display, showing that you are now 1V over the Float Limit, and the current is still flowing, you can understand how concerned one would become..

I noticed this issue early in my relationship with the MPPSolar PCM5048, but accommodated the problem, by incrementally decreasing the FLOAT voltage, until the FINAL voltage was where I wanted it to be ie.. 54.6V

For a long time, I lived with thinking all was fine, but that stopped, when I noticed the voltage at 54.2V and charge current at something like 2A.. at.. Midday - Full Sun - Expecting 20A (plus) and only getting 2A.

Clearly, the CC was responding to the float voltage ( Set at 53.3 --- ie. 1.3V lower than the needed float ) and reducing the current according to some kind of algorithm..

This means that I had been wasting many kWH of power, that I could have been put to practical use..

So - my question is -
"Does anyone else own a PCM5048 and can you confirm that YOUR device stops charging at FLOAT, or does it also keep charging to an uncertain and injurious voltage for sealed batteries..

( I repeat- NO Absorb, NO Equalise - Just set Maximum Voltage )

I have cheated and have solved the problem for my application..
I am using the HOUSE, as a "Dump-Load".

When Vfloat is set to the correct 54.6V and when Vbat reaches 54.8V, I use one of the two inbuilt Voltage Relays, to connect the Inverter to the house circuit.. Thus using any Solar-Power available in the home.
When the Vbat drops to 53V, the inverter drops out again..
All VERY practical..

BUT - I would love to be able to honestly recommend the device, and know that others are not looking for methods of overcoming it's shortcomings..

Do you own another model.. Like the PCM8048 (80A version) ... OR the High Voltage version (CX)..
Do you see the same problem with them..?

Our PCM series MPPT controllers come with large LCD display .....Parallel connections are also possible on our large size MPPT controllers (PCM-5048, PCM-8048) to handle very large array. Intelligent and highly efficient, these controllers are the best choice in any off-grid application.

Note: 240VDC high input voltage MPPT models are also available on PCM-CX series in 40A (PCM-40CX) and 80A ratings (PCM-80CX),

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[Privatteer]

Tracker, I seriously hope you have not connected an standard offgrid inverter to a mains supply without the necessary supply failure detection to prevent backfeed into the grid or your house on mains failure.
What happens if an electrical worker isolates your supply to work on it then your dump relay kicks in powering it up?

[Tracker]

Tracker, I seriously hope you have not connected an standard offgrid inverter to a mains supply without the necessary supply failure detection to prevent backfeed into the grid or your house on mains failure....?

Eh..! What are you on about..
What has that got to do with the PCM5048..
..
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[offgridQLD]

Just assumptions I think.

When people read I use one of the two inbuilt Voltage Relays, to connect the Inverter to the house circuit.. they assume it hasn't been done correctly.

Being able to predict peoples assumptions in advance can be a handy skill. Like negotiating with your wife. Don't ask me how I know

Kurt.

[Tracker]

Being able to predict peoples assumptions in advance can be a handy skill.

Possibly so, but I have told the full story SOoo many times, I did not want to confuse the subject..
Ie. Hybrid power, Dedicated circuits and ATS devices.
I think that Tracker has too much time on his hands.. just ask his bride..

Anyway, this is about the PCM5048, as I suggested.
..
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[AWDFun]

YES - I have had this as well, but WORSE!! Mines fizzled my batteries for about 1.5Hrs @ 60V ( Float was set at 55.2V ) before I checked setup. I had assumed it was just the fridge or freezer motors running that was making that sound but it was my 500AH battery bank at 48V.

I wrote and wrote and MPPSolar could not find the fault - "according to them"
They wanted me to post it back, but it cost too much, and I too found a way to get the thing to do most of the great things it does.

I'll give details laters with example of videos I had sent to MPPSolar to try and prove the fault.

This unit I have will seriously kill my battery bank if I had not caught it in time.

I am now using a Outback FM80 and can leave the house without worrying if the batteries will explode or catch on fire whilst Im away.

As I mentioned Ill post examples of whats happening previously before I ditched it.

[davidg]

Anyway, this is about the PCM5048, as I suggested..

When your ready for a real MPPT charge controller .......... say hi

[Quokka2]

I'll give details laters with example of videos I had sent to MPPSolar to try and prove the fault.

Will look forward to that - it would be nice not to have to spend twice as much on something that might not be twice as good.

[offgridQLD]

I can see both points but the charge controller is so critical . It has the steering wheel for $10,000 or more worth of battery's and potentially your house if it went silly and burnt it down.

The other big name charge controllers might be x2 the price but your not comparing apples for apples when you put the ebay unit againsed it.

The big names like midnite have more features. Along with much much better backup. (If you have a issue with your classic you get a answer from the makers of the product not just some 1/2 ars tech support and you get that answer within 24hr's on there forum even on weekends. Im sure the spec of the product isnt the same and the feature list wouldnt be .

On top if this your comparing a ebay price to a local sellers price. Comparing ebay price of both puts them closer.

Kurt

[Gordon-Loomberah]

Batteries that last a long time due to correct charging voltage, or cooked batteries...I'd say the one that does the job properly is more than twice as good