Welcome to the Solar Collector
Brainstorming and Development Page!


 

Home

Hot Air Collector

Hot Water Project 1

Hot Water & Space Heating

Solar Electric

Solar Construction 101

FAQs

Best Collectors

Simply Solar
Sign up Calendar Latest Topics
 
 
 


Reply
  Author   Comment   Page 2 of 2      Prev   1   2
Rick H Parker

Avatar / Picture

Registered:
Posts: 790
Reply with quote  #11 
"There should be a device that will sense when one battery is fully charged (or disconnected) and will switch that PV panel to the other charger.

The charge controller decides when the battery is fully charged, at least one of the charge controllers, lets call it the master, would need a port that could be used as a communication port to the external switch.

__________________
Rick H Parker
Kansas, USA
Electronics Engineering Technologist

stmbtwle

Avatar / Picture

Registered:
Posts: 2,857
Reply with quote  #12 
It appears the controller doesn't have that port, so it would have to be an independent device.
__________________
Solar is like the wind. It may be free, but putting it to work isn't!
Willie, Tampa Bay
Rick H Parker

Avatar / Picture

Registered:
Posts: 790
Reply with quote  #13 
If the decision to switch is made independent of the charge controller, it will interfere with the Absorption Cycle and Equalization Cycle.  One would be paying a premium in terms of battery life span.
__________________
Rick H Parker
Kansas, USA
Electronics Engineering Technologist
stmbtwle

Avatar / Picture

Registered:
Posts: 2,857
Reply with quote  #14 
True. But if it could sense when the controller went into float mode...

A lot simpler would be a pair of spdt switches. When a battery was disconnected, simply switch its panel to the other battery.

Though considering the "loads" are batteries, I think I could automate it with a pair of relays.

__________________
Solar is like the wind. It may be free, but putting it to work isn't!
Willie, Tampa Bay
JPWright

Registered:
Posts: 19
Reply with quote  #15 
I do not think that automation is necessary since I will using the bike or the E15 (up graded to a Curtis controller, mower, snow blade, and snow blower) every few days (or weeks in the winter). The panels are 350w, so they are big enough to do the jobs between mowing and biking.

However, as an engineering problem it would be useful to solve for others. Folks are always adding on to their small systems. If I add anything more, either panels or loads, I will invest in a 3000w inverter so the E15 and panels could power my small house in the winter.

E15 Winter.JPG 

stmbtwle

Avatar / Picture

Registered:
Posts: 2,857
Reply with quote  #16 
Hi JP,

After much thought and scribbling I concluded that "automation" of a system like yours would not be as easy as it looks and probably more trouble than it's worth. The manual SPDT switches would be easy, one on the lead from each PV panel, with outputs going to each controller, so you could select one or the other controller but not both, for each panel.  You could connect your battery then throw the switch to that controller. If no battery is present then throw the switch to the other controller.  Switches are cheap.

A relay could do the same thing "automatically" but it would have to be powered by the battery being charged.  No battery connected, relay is open. However the "odd" voltages involved could make just finding the appropriate relays difficult and/or expensive, and then what do you do at night/bad weather?  As the relay is being powered by the battery it would NOT shut off when there was no sun, and could eventually discharge the battery you're trying to charge.  This could be prevented by another relay (or solid-state device) on each circuit powered by the PV panel,  but now you have two devices on each circuit, one powered by the battery and one powered by the PV.  It would get complicated, and it STILL wouldn't switch automatically when a battery reached full charge. A current-sensing device could do it, but are they available in the voltages/configurations you would need? It COULD be done, as battery chargers and charge controllers do almost the same thing, but not by me.  That's a job for an electronics tinkerer or an EE.

As each battery system normally comes with it's own line-voltage charger, a much easier (and more flexible) setup would be to connect them to line voltage (inverter or grid), and connect the PV panels to the "house" battery as you mention or the grid. It may seem a roundabout way of doing it but at least the components are available and by using the common line voltage you could could connect virtually any other load as well. This is what I ended up doing.

That's my conclusion, anyway.


__________________
Solar is like the wind. It may be free, but putting it to work isn't!
Willie, Tampa Bay
Gordy

Registered:
Posts: 137
Reply with quote  #17 
Jp, 

Nice tractor ;-)  I always wanted one but around here most are over priced rust buckets from acid spillage. Though I missed a very nice Wheel Horse branded one at a mid day auction (while at work) it had all of the attachments and sold for $350 :-(

__________________
Gordy,
Minnesota
Rick H Parker

Avatar / Picture

Registered:
Posts: 790
Reply with quote  #18 
Custom electronics is like doing custom automotive modifications, everything depends on Make Model and Configuration.

There is a very good chance we could eliminate a lot of guesswork, if you would list the Make Model and Configuration of all your equipment.

__________________
Rick H Parker
Kansas, USA
Electronics Engineering Technologist
Previous Topic | Next Topic
Print
Reply

Quick Navigation:

Easily create a Forum Website with Website Toolbox.

 

web statistics