how to connect solar to a bcdc1220 redarc

HI Allan
No problem
That is the way it works
When no altrnator outpu,t the solar tkes over
No other switching needed

PeterQ

HI Allan
Cannot edit , But should have added when wired as per the diagram

PeterQ

HI
ooops ,one other point, if the solar has it's own regulator that should be removed
Cannot have two regulator in series!!

PeterQ

There is virtually no difference between a Redarc BCDC and a MPPT solar regulator. They both operate in the same way, taking a variable input voltage and converting it to a nominal 12v with a lead-acid charging algorithm.

The Redarc BCDC-120 (and all the BCDC series) accept 9 to 32vdc as input, not "just a straight 12 or 24v DC input", although they would be mostly employed accepting a nominal 12 or 24v input.

Hi Mark,
Yes, some of the responses above may confuse you. Trust me, or better still give Redarc a call on (08) 8322 4848 to benefit from their free Technical Assistance.

The BCDC-1220 inherently acts as an MPPT solar regulator and accepts input from 9 to 32vdc either from a solar panel or from an alternator. But if you wish to connect both inputs to the BCDC they must not be connected together at the same time as interaction conflicts arise. It is necessary to isolate the solar and alternator inputs by using a relay as in the Redarc wiring diagram above.

When arranged in this fashion the solar panel should be connected directly to the relay and BCDC without using a solar panel regulator, the BCDC does that job. Some may suggest leaving the BCDC connected as you have it now and simply connect the solar panel via a MPPT regulator directly to the battery. That does work without harm but the Redarc method with relay has advantages.

If I may be so bold as to offer some clarification on earlier posts.
1. The Redarc BCDC1220 does not incorporate a solar controller of any type.
2. The circuit diagram shown above is not applicable to the 1220.
3. It is incorrect to say the any of the Redarc units will automatically change to solar if they detect no alternator output. The blue wire which detects voltage is normally connected to the vehicle ignition, so as long as a voltage is detected there, it is irrelevant whether the motor is running or not.

Additionally, Mark,

If your solar panels have a solar regulator (controller) on the back of them they can be connected directly to the battery.

If your panels do not have a regulator then you need to get one and connect it as close to the battery as possible, leaving the long wires to run between the panel(s) and the regulator.

Either way, if your engine is not running the 1220 and the solar regulator will not interfere with each other.

When your engine is running it would be better if the solar was disconnected. You can do that by switching off the solar input from the panels to the regulator. You can do that manually if you have the panels connected with a plug and socket arrangement, or with a relay.

Depending on your installation, if its manual you might forget and then the 1220 and the solar might interfere with each other, as others have said. If you have to pack your solar up to travel, then that's not an issue, but if you have a permanent installation then you need to consider automating it with a relay.

Cheers

Thanks for the replies it will be on a anderson plug set up and portable so i will be packing it up before moving the car.

Thanks Mark

Ah then Mark, that is different, and simple.
Just connect your solar panel (via a MPPT regulator) directly to your battery whilst the engine is off using the anderson plug pair. Be sure that there is a 30A fuse close to the battery +ve terminal and keep the regulator as close to the battery as possible.

Folks - may I butt in?

There are quite some differences in the opinions expressed above, BUT in fact I think most people are largely correct in what they say!

From my reading of the BCDC specs, the BCDC 1225 and 1240 chargers offer both dc-dc charger AND MPPT solar controller. (Probably not simultaneously. ) The BCDC 1220 does not have MPPT solar characteristcs, but since it has a wide input voltage range (9-32V), it can safely accept the output of a solar panel and provide the required charging regime for the battery. By using the relay as suggested, the current input to the charger can be automatically switched between the cranking battery and solar.

It seems quite ok to use the BCDC 1220 this way as Redarc's diagram suggests. Since it lacks the true MPPT capability though, solar efficiency is unlikely to be at its optimum.

Mark asks if he can leave the BCDC1220 alone and run the solar independently through a solar controller direct to the battery. Yes! In fact that's exactly what I do. Both my MPPT solar controller and the dc-dc charger are wired to the battery. The roof mounted panel adds to the current coming from the dc-dc charger, or simply continues to contribute when the dc-dc isn't providing.

Cheers

John

Thanks for clarifying it Frank, there are so many experts on here it's getting beyond a joke, when I did training with Redarc they stipulated the same thing and the question was asked to one of the engineers.

Hence why they have the BCDC1220 and the BCDC1225 on the market.