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Two mppt trackers in parallel

PyroRider

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Does someone has experience what happens if I connect two MPPT Trackers in parallel on a single string of PV modules? I have a single 250V string of panels and use my inverter (with mppt tracker) so it doesnt put any power in the grid, I want to use parts of the especially in summer overproduced power to charge a 48V battery bank, so I would like to put a BlueSolar 250/70 MPPT charger in paralle on the string to my inverter. Would this be a problem? With both tracker looking for the MPP, they should still find it and settle at that current, shoudlnt they?

Edit: Wrong charger mentioned
 
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Does someone has experience what happens if I connect two MPPT Trackers in parallel on a single string of PV modules? I have a single 250V string of panels and use my inverter (with mppt tracker) so it doesnt put any power in the grid, I want to use parts of the especially in summer overproduced power to charge a 48V battery bank, so I would like to put a BlueSolar 100/20 MPPT charger in paralle on the string to my inverter. Would this be a problem? With both tracker looking for the MPP, they should still find it and settle at that current, shoudlnt they?
An MPPT charger adjusts the load to get the max power under any light conditions. Having two will cause some amount of confusion between the two unless you have more PV power available than they both need. For example, 2 chargers that can use 1000w PV on a 3000w PV array. Neither would ever need to load the panels much in order to be maxed out. However, on cloudy or other low light conditions, they can't get much power anyway, so it they continually "hunt" it is not a big deal. Many chargers go to PWM mode in those conditions anyway.
 
You said you have a single 250V string.. irregardless if it would work or not that would be the wrong BlueSolar charge controller. You'd want one of their 250V models. They also have an online calculator to make sure you get the right one here: https://mppt.victronenergy.com. To actually get it to work I'd think you'd want some kind of switch so the panels are only either going through your all in one or the charge controller..
 
An MPPT charger adjusts the load to get the max power under any light conditions. Having two will cause some amount of confusion between the two unless you have more PV power available than they both need. For example, 2 chargers that can use 1000w PV on a 3000w PV array. Neither would ever need to load the panels much in order to be maxed out. However, on cloudy or other low light conditions, they can't get much power anyway, so it they continually "hunt" it is not a big deal. Many chargers go to PWM mode in those conditions anywa
Nice thank you :D
I just have more pv power than needed so the panels could keep my continious load up for as long as possible
You said you have a single 250V string.. irregardless if it would work or not that would be the wrong BlueSolar charge controller. You'd want one of their 250V models. They also have an online calculator to make sure you get the right one here: https://mppt.victronenergy.com. To actually get it to work I'd think you'd want some kind of switch so the panels are only either going through your all in one or the charge controller..
sry, the 100/20 is for another project XD
 
An MPPT charger adjusts the load to get the max power under any light conditions. Having two will cause some amount of confusion between the two unless you have more PV power available than they both need. For example, 2 chargers that can use 1000w PV on a 3000w PV array. Neither would ever need to load the panels much in order to be maxed out. However, on cloudy or other low light conditions, they can't get much power anyway, so it they continually "hunt" it is not a big deal. Many chargers go to PWM mode in those conditions anyway.
Based on what I have read in this forum, you cannot do this. Regardless of the amount of power that is available, each controller's algorithm will interfere with the others'.

Disclaimer, I am not an expert on the matter but I have read conflicting information to what you stated, and I encourage OP to search this forum and maybe do some more research elsewhere.

That said, having that much potential (double the power either SCC is rated for on a string is pretty significantly over-panelled. I would be afraid of frying a controller like that.

If op already has the capacity to charge additional batteries, instead of another MPPT, either get a DC-DC charger, or add a disconnect and fuse to add another bank of batteries to the existing DC bus.
 
Based on what I have read in this forum, you cannot do this. Regardless of the amount of power that is available, each controller's algorithm will interfere with the others'.

Disclaimer, I am not an expert on the matter but I have read conflicting information to what you stated, and I encourage OP to search this forum and maybe do some more research elsewhere.

That said, having that much potential (double the power either SCC is rated for on a string is pretty significantly over-panelled. I would be afraid of frying a controller like that.

If op already has the capacity to charge additional batteries, instead of another MPPT, either get a DC-DC charger, or add a disconnect and fuse to add another bank of batteries to the existing DC bus.
atm I only have the batteries but no charger, but doesnt matter, I just decided on another way to do my project :D
 
MPPT Algorithms search for the max power point. There is no way to synchronize the algorithm across multiple controllers (that I know of).
Because of this the controllers will probably be interfering with one another while trying to settle on the power point.
 
putting multiple controllers on the same panels would require synchronization...to search they have to disconnect the load from the panels, to synchronize two controllers they would need to be interconnected so that they could tell the other about when searching is happening and they would need to be programmed to search at the same moments as both have load disconnected
 
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Right now I am using 5 MPPT charge controllers powering the same inverter and charging the same batteries. All have their own independent strings of panels and none communicate with each other, they only read battery voltage. If I turn one off then turn it on it won't produce any power unless I wait till the next day or shut all the breakers to all the strings off, wait a few minutes and then turn them all on. It has been working fine for over a year. When the batteries are at or near full charge some will charge less than others but go back to full output as the load increases or the charge decreases.
 
Right now I am using 5 MPPT charge controllers powering the same inverter and charging the same batteries. All have their own independent strings of panels and none communicate with each other, they only read battery voltage. If I turn one off then turn it on it won't produce any power unless I wait till the next day or shut all the breakers to all the strings off, wait a few minutes and then turn them all on. It has been working fine for over a year. When the batteries are at or near full charge some will charge less than others but go back to full output as the load increases or the charge decreases.
Right that works fine.

The op is asking about "two MPPT Trackers in parallel on a single string of PV modules"

MPPT on the same string of PV modules would not be fine.
 
If anyones interested, I "solved" the problem by going the way of connecting my charger to the output of the inverter, of course the efficiency sucks even more that way but as its a whole "proof-of-concept" installation that doesnt matter right now. I am building myself an intellegent charging system that only uses the power thats not being used in the house to charge the batteries. And one day when the current setup works and gives some comparable data, I will decide wether to upgrade it to a real hybrid inverter and much better modules or to let it run the rest of its (probably due to manufacturing problems with the moduls) shorter life.
 
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