Redarc BMS with temporary solar

I'd wire in a Anderson plug where the solar input connects to the BMS.

As long as you have the polarity correct the BMS should be able to cope with the extra Amps.

running a second panel in parallel is ok, so long as the watt input doesn't exceed the maximum input allowed by redarc specifications

which is fairly low 250w max from memory

Connection ideally would go into same solar input connectors on redarc unit.

meaning two positive wires attached to redarc unit and negative wherever it required to go.

remember this also means the additional solar panel must unregulated as having to regulators opposing each other will cancel each other out.

The alternative method run a secondary twin core and connector separate to redarc system and then connect directly to battery. This however doesn't allow each "system to see" what each other is doing and over change maybe possible, but cloudy days probably negates this somewhat.

On subject of redarc folks had a alarm going off on a BMS systems for whatever relay it was (solar input or similar), turns out it wasn't fixable according to redarc so at reduced online price had to replace whole unit.

Hopefully you won't be in same situation as they were in.

If in doubt suggest contacting redarc directly they have a tech section n forum and have answered exactly same think I asked them about doing same thing.

Stoooge,
The 75 watt panel can be linked to the regulator input using a parallel connection anderson as mentioned above.
If the 75 w and, presumably a 120watt additional panel, will see only around 11 to 12 amps of charge on a good day. Therefore all should be quite ok with a 15 amp regulator of Redarc quality.

The wattage rating of panels is factory ideal conditions and never achieved in normal useage. I have two folding, same same, 120watt panels, ie, 240watts in theory, and on a cooler sunny day with strong sun it will only produce about 13 amps max with a MPPT regulator. The theory says 20 amps but reality is different.

If, and only IF, your regulator can withstand a high input voltage, ie, double the panel open circuit rating, you could arrange a connection using anderson plugs and double the panel voltage by connecting them in series for shady. cloudy days and the panels will then each deliver some usable charge energy when the normal parallel connection isn't going to do much at all, if anything.
A few checks and precautions to be observed to do this though, but it gets charge into batteries where normal systems stall.

We have a BMS 1215 in our KK. I have dual cables from the BMS solar input terminals running to Anderson plugs at the front and rear of the trailer so we have a choice depending on orientation, shading etc. Mostly I run 2 separate sets of panels in parallel attached at both ends, sometimes 3 sets if very overcast (with an Anderson double adaptor). You can put as many watts as you like into the BMS, it is the output that's limited to 15 A.

Panels in series is not an option with the BMS1215. Think from memory the input limit is about 25v and most portable panels are putting out about 20v.

According to the destructions.

- In parallel.
- Cant exceed 30V
- BMS will not draw more than 260W

I will install several points in parallel where I can place an extra panel when needed.

Use one of these to connect both panels to the BMS:




Available here:

Redarc anderson parallel cable

Ken