Originally Posted by cpaharley2008
Welcome PaulK to our little world. You lost me above in your description other than it is a better controller than the stock one. What are the prices and installation procedures?
They're fairly expensive, which is why they seem to still be fairly niche.
The Ctek D250S DUAL, which I do not recommend unless you don't care too much about your solar input, is $239.97 on amazon
The much better Redarc BCDC1225-LV seems to not be sold in the USA, but you can import it easily. Redarc themselves will ship it to the USA, and they sell it for $659.93 Australian Dollars. I've seen it new on ebay for $390 Australian Dollars. That would make it $300 USD at today's exchange rate.
Installation should be fairly easy. It needs to be close to the battery, just like other chargers, so I'm putting it under the dinette seat. It should be secured to the floor or something else solid.
For the alternator only installation, just disconnect the +12 volt wire coming from the vehicle and attach it instead to the input on the DC-DC charger. Attach the output of the DC-DC charger to whatever the +12 volt line was attached to originally. Attach the DC to DC unit's ground to ground. Done.
Installation for solar requires an additional SPDT relay to switch between the solar input and the alternator input. Attach the relay's switch controlling terminal to the +12 volt wire from the vehicle, so that it selects the vehicle's alternator input whenever the vehicle is providing power. Attach the +12 volt line to input #1 on the relay. Attach the solar cable to input #2 on the relay. Connect the common output of the relay to the DC-DC charger. Remove the GoSolar charge controller since the solar cells attach directly to the DC-DC charger. Done
The Redarc manual accessible from their website has some visual diagrams showing various installations. I omitted a few minor details above for clarity, but those details are in the manual.
Redarc also sells a Relay that you can use, but these are commodity items and Redarc charges $100 for that component. I'd just get one from a hardware store.
In addition to the above, I'd recommend getting a Trimetric as neither the Redarc nor the Ctek has a display to show solar amps. A trimetric can show that after deducting the trailer loads, which you could argue is a better metric anyways.
So yes, in summary these are expensive units. They're still less expensive than a $800 Honda 1000 watt generator though for someone who is planning on only occasionally using one, and the 20% or more improvement in solar should be valued at about $170 considering a 160 watt solar panel is $850 when installed by ETI. I should mention though that a generator will charge you batteries a lot faster, so this only applies to very occasional users.