I’m a bit of a beginner with Victron equipment, I bought and am installing all this…
I have a rather unusual question regarding the MPPT RS 450/100-MC4. Is it possible to parallel the [+]PV1 and [+]PV2 /// [-]PV1 and [-]PV2 terminals MC4 at the MPPT itself ?
I know this may not be optimal, and I’m not sure if it’s even possible (or if I’ll damage something in the MPPT itself)?
My point is that I currently have 14 450Wp PV panels (6300Wp total). They’re divided into two strings of seven identical PV modules (3150Wp) in one row. These two strings are connected in parallel at the PV panels themselves.
My PV strings are installed near the fence, all facing almost perfectly south. It’s located about 30 meters from the house where I have the MPPT and inverters.
However, I currently only have two PV cables (16mm² each) buried in the ground, each about 38 meters long. At the moment, I don’t have any way to replace it with four 6mm² wires, but I plan to do so in the spring, and then run four wires from each string to the MPP 450/100 to PV1 and PV2.
Can I use this temporary solution (paralleling the MPPT terminals as above)?
I realize it might not operate at full MPPT power and efficiency, but won’t I damage something by temporarily connecting it this way?
Hi Piotr,An MPPT charger adjusts the loads to get the max power under any light conditions.Having two will cause some ammount of confusion between the two,unless you have more PV power available than they both need….My suggestion: get another pair of cables and connecters,so you can fuse them(dc breaker) seperately.Also watch the max voltage which is allowed per(each) tracker.If you want to oversize(more power than needed) go for slightly higher Amps but never the Voltage.Best regards Frank
Hi,
Thank you for your reply.
Of course, ultimately I’ll definitely run four wires, two to each string. I’m clear on the PV voltage being too high; mine will be around 280-300V DC max. I have fuses and DC lightning arresters.
Currently, I have it working on a Chinese inverter (5.5KW - single-phase) connected as described (two wires). However, temporarily, until I change the cables in a few months (winter weather), I wanted to switch it from a Chinese inverter that has been working for me for 3 years and run it on an MPPT 450/100 and 3 MultiPlus-II 5000VA inverters (I want to make a 3-phase system with an energy storage of about 20KWh) - I have a full battery from a PeugeotPartner EV from 2019 - 22KW nominally - it consists of very good LI-ION Yuasa cells, each 75Ah, I want to make a storage of 5x15 pcs connected in parallel with LynxDystrubutors and LynxShunt with 5 pcs JK V19 BMS connected to CERBO…) Regards
I’m upgrading for several reasons: buying an electric car (the 2020 VW E-Golf has a 2-phase inverter, capable of charging 1, 2, 3, 4, 5, 6, and 7 kW), the need to increase the efficiency of, for example, the induction cooktop in the kitchen (on the current 1-phase inverter, only two cooking zones work, instead of four - four can operate on two phases). I’m upgrading all of this. Not to mention that the Victron has much greater capabilities…
The current inverter is fine; there are no problems with it, but it has a few drawbacks, including a low DC voltage range of 40-52V, which means higher currents flow at higher power. It can’t be temporarily overloaded (a few seconds) like you can with the Victron MultiPlus-II, or configured to draw excess power from the grid…
The Peugeot LEV75 cells are decent products from the Japanese YUASA. I’ve read that they’re quite safe for a battery. I’ve had these LI-ION cells for a while now, purchased at a good price. You can create any configuration with them, even high-voltage ones. I’m planning to build a 15S cell (connecting five 15S cells in parallel). The cell has a nominal 3.75V, and 15 cells should provide a safe voltage range of around 48-60V. We’ll see.
I’d appreciate it if someone could comment on the MPPT RS-450/100 and the possibility of paralleling PV1 with PV2 (temporarily, until I can convert the ground cable connection to four wires instead of two).
The trackers are independent and cannot be paralleled.
However, assuming you don’t connect them in reverse polarity, you can parallel the two 7s strings prior to the scc, i.e run 7s2p on the one tracker.
You will be limited by the 4kW per tracker limit, and 18A tracker soft limit, but should still see an improvement in overall output over single 7s string.
Personally I have run 10s2p on each of the trackers on my 450/100 in gloomy winter conditions (15kW of panels), it is designed for massive overpanelling.
Hi Brucey,
Thank you for the information. I’m about to connect (temporarily) my two strings to one PV1 MPPT port.
I’ll probably consider overpaneling this in the winter.
Yes, when it comes to MC4, I have some that were added to LG PV modules some time ago, Trinasolar connectors, they look quite solid.
Regarding DC connectors for battery storage, good, reliable, copper connectors are essential, I plan to use the ones from REMA / Anderson, the ones used in 80-160A forklifts, nice “with a handle”
