Redarc BCDC1240 Install

[Cuppa]

Hi mate,

Yeah I agree with you and I guess Redarc could be concerned about bucking power supplies or frying the auto voltage sensing circuit or damaging the MPPT or somesuch.
My best guess is that it may simply be that if the voltage sensing sees a Solar panel it will think it is a 24 volt Alternator so for Solar it must be floating or grounded... who knows

What gets me is why the hell did Redarc design a +$400 bit of kit with an onboard MPPT Solar Reg and then have to rely on people wiring up external switching to select between Alternator and Solar.
1 extra connection and maybe $5 worth of solid state switching circuitry inside at point of manuf and it would have been fully automated in the device, heaps more reliable and easier to use.

It's like designing a car without any plumbing for the fuel tanks and saying "let the customer sort it out whether he wants Main, Sub or ability to switch between both".

Yep. Mind you the whole idea of a sub tank which needs to be pumped into a main tank seems like a pretty strange idea to me! I would much prefer separate pumps on each tank allowing fuel to be used directly from either tank & a dasboard switch to choose between them.

There has been debate recently on another forum about Redarc choosing to restrict the float voltage on the BCDC1240 to 13.3v instead of incorporating temperature compensation into the unit. (Redarc have confirmed that this is what they have done ... http://www.redarc.com.au/forum/discu...voltage#Item_2 you may need to sign in to read it) Most batteries have a specified float voltage of 13.6v to 13.8v & much as I like the BCDC1240 it does strike me as pretty ‘cheap’ to leave temperature compensation out of the package.
The other forum debate revolves around whether it is harmful to have the batteries floated at a lower voltage than the battery manufacturer specifies. One person in particular is adamant that it will reduce the battery’s lifespan whilst others suggest that as long as the float charge is above the nominally 100% SOC charged voltage all will be well. I’m hoping the latter are correct, but nevertheless feel a tad miffed that temp comp, something I consider quite important was left out of a ‘high end’ dc to dc charger. I find it a bit hard to believe that the decision to do so was simply a cost cutting measure, but cannot think of any other explanation.

[the evil twin]

Maybe they needed the money to be able to afford to buy Autron... :-)

[macca]

A bit of a review of our set up.

We have a 120 watt folding panel, an input meter, a BCDC1240 Redarc and 2 super start agm 105 amp hour batteries.

The Ute has been parked for 3 1/5 days.

The weather has been mainly overcast and cool. So the fridge has not been working hard, nor have the panels had a lot of good sun.

This morning the solar was connected in good sun, the BCDC charged on boost (4.6 amp) for about 5 minutes, next time I checked it was on float (0.2 amp).

This system is working as designed, even when overcast the system goes to float mode and keeps the batteries fully charged.

This means we can easily camp for more than a couple of days without worrying about camp power.

Very happy with this set up, and a special thanks to Cuppa for his advice.

I would go as far as saying this is a 5 star system, cost a bit to set up but I wasted a lot on the previous systems that we discarded. Would have been a whole lot smarter to do this the first time. We live and learn.

[Cuppa]

We are sitting at camp on the shore of Lake Burrumbeet. Fridge (60l) is running at -2 & freezer (35l) is running at -19. (Gotta keep the ice cream hard!). The laptop is charging & we are listening to music. We have no battery currently in the Tvan, so last night I utilised our solar cable to supply power to it from the Patrol. This meant that the solar didn't get plugged in until I got up at 8am. By 10am the batteries were fully charged & floating. 360ah battery capacity. 300w solar (the 125w rooftop pane is in shade). Most amperage I saw coming in was first thing at 8am - 13amps which dropped down to 5 amps after a short time, still in good sun with clear sky. Prior to connecting solar this morning, with freezer cycling on battery voltage was 12.6v. Rose to 14.5v before dropping back to float at 13.3v. This system is designed for indefinite self sufficiency & to accomodate a minimum of 1 week’s poor solar weather.
Photos would have been better with my camera but I left the transfer cable at home, so these were taken with the iPad.

[macca]

Knew yours would work faultlessly.