Help Designing 300 Watt System

[Browneye]

Howdy...new guy here, first post. Found the forum researching solar options. Good stuff here.
I've read through this thread which covers a lot of what I want to do so thought I would post here instead of starting a new thread.

Also looking at 200-300 watts for a class-A motorhome with 1 pair of GC's. Calc our usage to be 30-50AH give or take and can always run the gen for an hour if panels don't make enough to fully recharge the bank. Current prices are down to about a buck a watt so I figured to start with 2 or 3 and go to 4 if I needed a little more. I expect to get 12-18amps on average and that should be sufficient for what I need.

Here are my questions as I plan to buy components:
1.  2 or 3 100w panels - put one or two on the roof and keep one out for remote placement in the case of shade or low winter sun. Is this worth doing or just put everything on the roof? I have a perfect storage compartment to slide a 21x46 panel into. Would only use it when actually needed.

2. For a 400w or less system at 12v seems a PWM controller is sufficient. I really don't have a place to mount a wall unit but have room for a flush-mount controller. I have narrowed it down to a Blue Sky Sun Booster or Renogy Adventurer. The KID seems nice but don't think I need mppt and it's a lot more $$. Can anyone comment on Blue Sky vs Renogy for quality and reliability? The former is about $140 and the latter about $80. Seems like the Renogy is the way to go but not if there are too many failures or if it's too hard to program or read. Good reports on the Blue Sky of course. I think both will handle up to 400 watts of panels, right?

3. Eco-Worthy has 100w panels for $105 shipped - anyone had any issues with these folks or their products?

Thanks of course!

 

[SternWake]

 Calc our usage to be 30-50AH give or take and can always run the gen for an hour if panels don't make enough to fully recharge the bank. 

Here is the issue, it takes more than an hour to top charge a lead acid battery.

80% to 100% can really not be accomplished in less than 3.5 hours and that is when held at absorption voltage of 14.4v to 14.8v.  later in the day, Your plug in/ generator powered charging source/converter might also see 13.8volts because of the lower slower solar charging, and decide the batteries are full and then not seek to bring the batteries to 14.4-8v. So you could be running that generator for an hour and accomplish next to nothing.

Getting 'smart' charging sources to seek absorption voltage when other charging sources have gotten battery voltage above 12.8v, requires trickery, mainly loading battery with heavy loads until voltage drops below 12.8v, and then restarting charger. It should then seek 14.x volts at maximum output.  Once 14.x is reached, the batteries limit how much amperage they accept and the closer they get to full, the less they can accept.

Also the less healthy the battery the longer it takes for them to reach full when held at Absorption voltage.
Also the more cycles the battery has seen without a 100% recharge, the longer it takes to reach 100% when held at ABSV

Some converters like progressive dynamics are automatic, but have an override to force it to seek 14.4v.  A big +

So running that generator for an hour when the batteries are lower( before midday) , and when they can accept lots of amperage, makes much more sense than later when they can only accept very low currents on their way to full.  Solar is good for the low and slow last 20%, not so great on getting them to 80% charged from 50%.

As far as your other questions much is personal preference and you seem to have a fairly good grasp on it.

My bluesky MPPT sb2512i + IPN pro remote has been working well for 9 years now.

No personal experience with renogy

 

[Browneye]

I have the: IOTA DLS-45 12V 45AH converter charger with built in IQ4 smart charging.
Not sure if it would kick and charge if a solar controller was already charging it.

 

[Browneye]

A whole thread here on iota converter/charger living with a solar charger here: http://forum.solar-electric.com/discussion/9928/charge-batteries-from-charger-and-solar-at-once

Seems the iota has a higher absorption charge rate so would also charge even if the solar controller is charging. In my case, still under 20% total charge rate for the bank AH rating, so likely fine.

However they did recommend iota charging earlier in the day like StenWake has mentioned, and then let solar top up the bank. That would seem like a PITA to do every day though.

Seems like it would be better to run the gen late in the day after solar charging was done and only if the bank still needed a few more amps to top up. By then the solar controller would no longer be raising the standing voltage level of the bank.


I would still like some input on keeping a panel off the roof for portable use. Seems like if you camp under or near trees this would have value.

Any problems with shorter or longer leads from the panels to the controller? Just wire them up parallel?

 

[Browneye]

Excellent article here on using a bulk charger (like Iota) in conjunction with a solar controller: http://roadslesstraveled.us/charging-rv-marine-batteries-solar-power-shore-power/

Yes, it's complicated. But likely they will live together just fine. Just get your batteries all charged up by the end of the day so you can make it overnight.