BlueSolar Charge Controller MPPT 150/35

DIY
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1

Hi, Guys,

Offgrid system with 3x250W Solar pannels (~8A/32V) + BlueSolar Charge Controller MPPT 150/35 + Batter balancer + 2x90Ah DeepCycle Gel Victron+ 24VDC–>220V AC inverter.

Data sheet for Charge Controler says: Nominal PV power 1a, —> 24V:1000W —> If more PV power is connected, the controller will limit input power.

Planing to upgrade the system. For sure it will be 2x450W (10.09A/44,6V) —>900W.

Question: if i add in parallel another string 2x450W (10.09A/44,6V) —>900W. that turns total Power of 1800W, but it will not exceed Cotroller’s Maximum PV open circuit voltage (150V) and Rated charge current (30V) and it will not burn.

1st array 10,09A/89,2VDC + 2nd array 10,09A/89,2VDC = total 20.18A/89.2VDC

On the best sunny days it will deliver for me 1000W, and 800 will be cut/lost, but on less sunny days i will have chance to get close to the maximum what controler can “deliver” to batteries.

Am I right?

2

This is where the MPPT calculator is helpful.

You also want to check that you don’t exceed the charger’s Isc rating.

3

How do you get to these numbers?

The existing string has 32V x3 = 96V at 8A
The new string will have 44.6 x 2 = 89.2V at 10.1A

If you put them in parallel, then it will settle inbetween those voltages, currents add up but you wont see 18A since it wont be maximum power point anymore

It s a 150/35, this means the charge current can be max. 35A. At 24VDC output this means 840W. If the battery voltage goes higher once its getting charged, that will go to 980W at 28V

You can overpanel an MPPT, but in this case, with mixed strings, i suggest using a second unit for the second string

4

Hi,

The existing string 32V x3 = 96V at 8A will be completely removed, then the new string 44.6 x 2 = 89.2V at 10.1A will be installed.

And the question if i can add 2nd string (that is similar to new one 44.6 x 2 = 89.2V at 10.1A ) in parallel, then mathematicaly it would be 89,2V@2x10.1A.

Another possible option one string with 3 pannels —> 44.6x3=133,8V@10,1A —>1351Watts@ maximum sunshine, but limited to 1kWatts by charge controller.

Any comments welcom :slight_smile:

DJ

5

Oh, now i understand

If that works or not with the 150V max input is a question for the MPPT calculator, since panels produce higher voltage when cold

6

Oops seems 3 pannels —> 44.6x3=133,8V this is wrong as Open Circuit Voltage-VOC (V) per pannel is 52.9V then 3x52.9V—> 158,7V and it would burn the controller most probably.