CTEK 250S Dual or Redarc BCDC 1240?

G'day all,

Just after some advice on your preference between the above two systems. I will be setting up a power system in the Camper Trailer which will need to Power Fridge, Power Sockets for Phone charger, Water Pump and LED Lights.

They will initially be powered by one 120ah battery which will be charged by Solar Panel and the Car when connected.

Any advice in this area would be awesome. I am leaning towards the Redarc system as it has a MPPT built in which will replace the cheap MPPT that came with the solar panel.

I would love the BMS from Redarc but that price is just riediculous!

redarc make a smaller unit also, its around 25 amps, redarc unit is more compatible with solar from what ive read
I just fitted a redarc 40 to my ute simply because of what it needs to operate.
twin motor arb compressor
40l engel in the ute
charge 2 100ah AGM batterys in the camper
run a dometic 3 way fridge in the camper

Thanks Mate, I have seen the smaller one, what's the best way to work out how big you need? I'm leaning towards the redarc.

i just worked out what the most important things I needed to run were, then factored in the rest of what I will be running, when I tow the camper with fridge etc I am pulling about 20 amps, I then figure a spare 20 amps would be good to charge the camper batteries.

Just work out how man amps your accesories will be drawing and go from there, but the rearc 25 has the solar input but the 20 does not

I reckon i'll go the 40 with the Solar input, thanks for your help

Say you already have a gd battery & regulated solar panel setup; what advantage does a DC-DC charger have over a gd 240v 6-7 stage charger running off a small inverter from the vehicle when running?

I to thought of doing the Inverter to power a a 230VAC charger but ended up just going the DC-DC charger route. The reason, there is a loss of effecientcy with an inverter. Some may argue, well the engine ir running anyway so what's the problem with that. Well not a lot but my system works and battery charges to a high state of charge without one. An inverter is handy if you want to power any mains equipment from it at the same time but I thought I could always add an iverter latter if required. The other detractor from a having an inverter is- if you want to listen to AM radio, which I like to do on a trip. When it's running it's just about impossible unless the signal is really strong as an inverter has alsorts of harmonic emissions (RF interferance) coming out of it and needs to well shielded to reduce this. Good pure sine wave ones are better but still emit lots of interferance.

Fewer components. The C-Tek D250S and Redarc 1240 are pretty much the same beast - both choose the best (of two) inputs for charging the battery and both have built-in solar regulators. Both compensate for lower input voltages (drop over distance on long cables) too.

I use the same system you do (C-Tek 7A 8-stage charger driven by an inverter). The amount of power consumed to manage the voltage compensation would be slightly more than the power needed to create the 240V but it's still negligible when driving. The DC-DC solution is far safer in an accident - inverter output is just as lethal as a household power point.

boostin_7 said:

Say you already have a gd battery & regulated solar panel setup; what advantage does a DC-DC charger have over a gd 240v 6-7 stage charger running off a small inverter from the vehicle when running?

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More efficient. each conversion costs energy and it is a case oe one dc-dc conversion Vs dc-> mains and then Mains-> dc.

Thanks for the replies, the safety issue of having 240v in an accident is certainly food for thought.
I assumed there would be less efficiency with using an inverter powered battery charger, but was wondering if it's worth going to added expense of the DC-DC route if your solar setup was adequate & you already owned the charger inverter etc.
I prob will end up going the DC-DC charger way, but was just wondering ....

I'd actually like to put the two methods to the test. Inverters these days are 90% or more efficient, and the DC-DC converters have to boost the voltage up - which means they're doing a similar thing to the inverter anyway. There probably are more losses with the smart charger, because the circuitry will consume a bit of juice to run the internal computer too.

Without actually trying to convince you on the brand, you may like to take a look at the CTEK solution. Either a D250S dc-dc battery charger, or D250S as well as Smartpass would effectively charge both the distant power supply in camper, but the deep pattern power supply in your vehicle. 6 B&S wire would be right for camper.

So is it right to assume that the ctek unit will charge the battery @ 20amps from the starting battery once the car is running?
Also does the solar input power the dc-dc charger unit to restore charge, or does it just regulate it just like the regulator on most panels do?

boostin_7 said:

So is it right to assume that the ctek unit will charge the battery @ 20amps from the starting battery once the car is running?

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It will actually take it from the generator/alternator. Ideally you have a auto switch(jargon?) that doesn't start passing current to the dc-dc charger until the car starter battery has been recharged.

Also does the solar input power the dc-dc charger unit to restore charge, or does it just regulate it just like the regulator on most panels do?

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Former. it takes charge from the largest of alternator or panels and then pumps it into your battery(ies).

I have the C-tek D250S fitted and currently only running on solar panels.

Did you get the ctek unit because your panels had no regulator, or did you prefer to run them through it for a particular reason?
Sorry for all the questions, but im just trying to understand the technology.

I purchase unregulated roof panels and added the c-tek D250S for the installation.

The panel regulators are designed to output a set voltage, whereas the C-tek sometimes wants higher or lower, depending on attached battery and state of charge.

Normally you disconnect any attached regulator on stuff like folding panels, etc.