Re: Batteries drained

by glyne lock Mon Feb 28, 2022 7:26 am

Roopert wrote:
glyne lock wrote:I tested the controllers and they all worked.
Of course they all worked. I didn't say that they would not work. The problem is that they will almost certainly not all be providing equal input to the battery. But externally they will appear to be working just fine.

If you want all of the panels to be providing equal input to the battery, they need to be on the input side to the controller, before voltage regulation.

The core of the problem is this: in order to "understand" the state of charge of a battery, the controller has to be the only device which is raising the battery voltage above its rest state. If multiple controllers are all trying to do it at the same time, they will not measure the state of charge correctly.

To any person reading this ask the manufacturer as I did and was clearly told that more than 1 controller can be used to the same battery so what Roopert might think is not correct

by Caraman Mon Feb 28, 2022 7:41 am

I remember marconi saying that having two MPPT regulators connected to the same battery works - in his case it was a Votronic DuoDig connected to both batteries and a Victron to just the leisure battery. Like Roopert though I don't understand how it can work efficiently. However, in my case I was planning for both panels to be connected through one regulator. I suppose I would have to be careful when connecting the second free standing panel that it is face down so that it doesn't spark and shock the regulator and then face it upwards to the sun.

by Roopert Mon Feb 28, 2022 11:44 am

glyne lock wrote:To any person reading this ask the manufacturer as I did and was clearly told that more than 1 controller can be used to the same battery so what Roopert might think is not correct

As I said, it will cause no harm at all.

The manufacturer would be quite happy if you were to buy 20 controllers and connect them all to the same battery - everything will appear to work just fine. And the manufacturer will be delighted that you are willing to waste that much money on their products.

But the resulting system will not work efficiently.