Have the older MPPT 450/200 that didn’t have the MC4 connectors and we’ve got the newer MPPT RS 450/200 with the MC4 inputs to replace it. It came with MC4 connectors for the PV. Due to requirements from the old MPPT, we ran finely stranded PV cable and we’ve used EVO2 MC4 connectors for that wire since regular MC4 connectors didn’t work for it. So my question is, do the MC4 connectors that come with the newer MPPT RS work for finely stranded PV cable or do we need to get more EVO2 connectors?
PV cable is normally H1Z2Z2-K and always works for MC4 or compatible connectors. Insulation is UV proof and good for up to 1800 Volt DC.We even crimp ordinary H07V-K. Assume you have the correct crimping tool it should also work with every AWG/AWM cable for string voltages upt to 800V although the PVC insulation is not sun proof and MC4 cable glands are to water tight what is a dont care for use with RS450 inside dry inverter room.
OGPS
(Ed @ Off-Grid Power Systems - offgridps.com)
3
The MPPT RS 450/200 MC4 version only comes with MC4 bulkhead connectors and they are already wired to the connectors on the circuit board. You will need your own MC4 connectors on the ends of your PV wires to connect to the ones that come with the MPPT. So your question is largely irrelevant. Just use quality MC4 connectors that mate properly with the ones on the MPPT.
Alternatively, remove the MC4 bulkheads that comes with the newer MPPT, crimp your own ring terminals to your existing wire, and hard wire the PV cables like you did with the older MPPT. In our shop, we’ve started removing the MC4 bulkheads from the newer MPPT RS 450 units and gone back to direct-wiring to the PCB. I don’t like that VIctron only offers the MC4 version, but it’s not too much additional labor to revert back to hardwired.
Mine came with a little plastic bag with some MC4 connectors (I thought that’s what they were), but maybe they’re replacement bulkhead connectors? I’ll check more closely.
OGPS
(Ed @ Off-Grid Power Systems - offgridps.com)
7
I stand corrected, then. I don’t do day-to-day installations these days so it appears I am wrong. Still, you can hardwire if you prefer or use whatever MC4 connector works with your wire. Test for a low resistance connection if you can, or keep an eye on things for a bit after you turn it up. Mating MC4 connectors from different manufacturers is not always kosher.
No, I think you’re right actually. The first MPPT RS we got from the regional Victron dealer. It came with MC4 connectors (I think, but need to confirm they’re not replacement bulkhead connectors), but it appears he just threw those in for us and they don’t come standard with the MPPT because we ordered a second MPPT RS recently from a different dealer and I just confirmed it did not come with MC4 connectors.
So I just need to find that little baggy of connectors and see exactly what they are, but whatever they are they must be an extra the dealer put in.
It may be that with the new MPPT RS with the MC4 connectors built in, that the “very fine stranded” requirement went away, and so these MC4 connectors might just be for regular PV wire now. I just need to look them up and see since we’ve already wired out system with the very fine stranded cable.
I should have looked and done more research before posting this question as it turns out.
OGPS
(Ed @ Off-Grid Power Systems - offgridps.com)
9
Got it. Makes sense. Even on the older units, we terminated standard PV wire (or THHN) to a ring terminal and to the stud on the input PCB of the MPPT RS. We install both exterior and interior disconnects so to keep the number of MC4 connections to a minimum, we try to only mate MC4 connectors to the panel strings. Everything else are terminals we can properly torque.