bdosborn wrote:MPPT controllers are cool and to quote the guys on Big Bang theory "everything's better with bluetooth!". But I'd pass on an MPPT controller; they're generally so expensive that the $/watt for the extra power they deliver is way higher than what additional panel capacity would cost. For a small system like a teardrop, PWM controllers with larger PV panels is going to deliver the best bang for the buck.
Bruce
MPPT charge controllers have come down in price enough to be a worthy choice for many of us. They're worth buying when you're well informed about what works best for your wants, needs, budget, available space on the roof, or storage space for portable solar panels.
Roof space on most teardrops is very limited. Few have enough space for mounting more than one solar panel. Or for a large high power solar panel.
I think it's very worthwhile to pay the small difference to use a MPPT controller instead of a lower cost PWM controller. A MPPT controller will harvest ~10 to 30% more power from solar panels. It makes more efficient use of the limited roof space. Having more available power enables you to camp or travel more comfortably and enjoyably. You can save money by having less, or no, need for camp $ites with electric hookups, which often cost extra.
A few years ago a
Morningstar Sunsaver 15 AMP Solar Charge Controller was the most affordable good quality MPPT controller available. Today (12/05/2017) the Morningstar Sunsaver MPPT costs $243.00 from Northern Arizona Wind & Sun.
Much more affordable MPPT controllers are now available. For example:
Victron's Blue Solar controllers (without built-in Bluetooth) start at $80.90.
Victron's SmartSolar controllers (with built-in Bluetooth) start at $119.95.
genasun.com controllers start at $65.00.
AM Solar does high quality RV solar installations. Their
DIY Instructions diagrams and videos are helpful and very informative.
amsolar.com sells both the Victron and Genasun brands of MPPT solar controllers.
You might choose to buy a
Renogy 100 watt 12 volt starter kit with a PWM controller for a teardrop that currently costs $180.99 from Amazon.com.
Instead you could buy a
100 watt panel for $106.99, a
Victron BlueSolar MPPT 75/10 Charge Controller for $80.90,
mounting brackets for $9.59, and
a pair of 10 guage cables with MC4 connectors for $21.98. Total cost $219.46.
The $38.47 cost difference is minimal between the two example 100 watt kits. With careful shopping the cost difference might be lower.
I bought a 160 watt solar panel to mount on my teardrop's roof to have enough power to operate the lights, recharge a cell phone or other electronic devices, and use an AC/DC fridge/freezer. I'll most likely buy a
Victron SmartSolar 75/15A MPPT controller which works with up to 220 watts of 12 volt solar panels.