I have a choice of no name solar panels at $189 for 140 watts at solar blvd.com or 140 kyocera 140 panels for $315 apeace which am I better off with? Also a sky Blue mppt charger or a rouge charger controller which is best and why?
Thanks guys I'm narrowing it all down now thanks to YOU!
Go with the cheaper panels. I know a lot people like Kyocera but it's not worth the extra loot IMO.
the Rogue controller is very nice
but with 17.6 working voltage if you parallel the panels you may not need to use an MPPT controller
in other words
MPPT gains are best utilized / gained by using higher voltage input into an MPPT controller
with only one or two panels wired in parallel you may get almost the same total amp hrs into your batteries
MPPT gains are best realized when the batteries are at low SOC and charge voltage can be less and there IS ExcEss voltage above the required charge level that the controller can convert to amps using a lower charging voltage
example if your nightly use is high and your batteries have a low soc in morning MPPT is an advantage
if your nightly use is small and your morning soc is 80% or greater MPPT may not give you any higher charge rate over a pwm controller using those particular panels
whatever type pwm or MPPT make sure you get one that "you" can adjust the charge voltage,
factory settings are often too conservative and not optimized for rv use
even MPPT controllers charge using PWM charging,
they just adjust the charging voltage and do their best to produce more amps, but can only do this IF there is excess voltage to work with
I would buy a monster size panel that will put out 290watts minimum but the voltage is wrong I need a 12 volt system!
What Mr Wizard said. Voltage of 290W panel is not "wrong" - MPPT controller is exactly what allows making a 12V system out of 30V panels. It steps the charging voltage down to 12V. PWM controllers can't do that, but MPPT can. Though, this is a "side" benefit of MPPT. Main reason to use MPPT is to maximize the output, especially in hot weather.
Now, voltage stepping-down is desirable because it allows getting more Amps out of panel with excessive volts (read - rated 27V or more). In your case panels under 180W will be (usually are) 12V nominal (if it says 17V in specs, this is 12V panel). Panels over 200W have voltage 27V or more, and 290W 30V panel will cost less than 2*140W 17V from the same maker, but it is more difficult to install. So, if you have to have 2 smaller panels, they will be 12V nominal. Don't know whether you will still benefit from MPPT with 2 12V panels. May be you will.
Rogue or Bluesky - don't know. Rogue is locally manufactured, BS is not. I think Rogue will cost more than BS if you need to have a remote interface plate that allows placing a controller anywhere. Without a remote interface, Rogue's distance from battery is limited to 15 ft length of voltage sensor cable. IIRC, Rogue includes a temperature sensor that can be placed on the battery, and in BS it is optional.
What panel brand - doesn't matter much, though I'd go for big brands like Sharp, Solar World, Kyocera, if this won't result in more than 30% price difference. SW has the lowest power deterioration rate, AFAIK, @0.7% a year. Which means 93% of the initial power after 10 years. Most other brands guarantee 90% after 10 years, and God knows how well less known Chinese knockoffs are made - could be a factory next door to the one that makes Sharp, and same equipment, but different QC.
Flat mounted 280W total panels should be enough in summer, though not enough for air conditioner and barely enough for microwave. Other gadgets draw very little.
* This post was
edited 04/15/12 03:50am by Almot *
Don, you right that Blue Sky doesn't include remote temp sensor. It only has a built-in sensor as a standard, and this is not the same as placing it on the battery. Optional remote display for Blue Skye isn't too expensive - if this is the one here. Remote interface for Rouge costs $105. But, the OP might not need a remote interface, and then Rouge with remote temp sensor is cheaper than Blue Skye with the same sensor.
PS - correction: Rogue with remote interface AND with its remote temp sensor included as standard is still cheaper at $430 total than Blue Skye at $552 with remote display and without remote temp sensor.
* This post was
edited 04/15/12 04:29pm by Almot *
Right. I looked at the display for a different model of Blue Sky. Those IPN displays for Blue Sky do range from $80 to $260. Controller itself (model 302 4il sans remote display) costs $350, so even with the cheapest possible IPN display it will still cost same $430 as Rogue or more - and will not include a remote temp sensor.
I would try to go without the remote. Once the program is set you can just let it do the program and you can get on with other things. If you have an issue you will be on the actual box anyway. Nothing wrong with having it but for those trying to save a bit on the install it is not a necessity.