Help with small affordable system for a bike shed

Saburai · July 2016

Hello all!
I'm helping a friend put together a little system for led lighting for his bike shed. He already bought a Renolgy 100w panel. I'm asking for a bit of advice on what equipment to purchase to go along with it. The shed is about 6x10 or so with some over head trees that he's not willing to cut. It does have southern exposure and he's not asking the system to provide much energy. He needs light to leave for early morning rides, perhaps a USB charging port to recharge a small led bike light and do limited basic maintenance and repair. I'm thinking a small PWM controller 8 or 10 amps, but which one? He was asking me about the AGM batteries from Deka and asked about this group 27
http://www.tristatebattery.com/8a27m-deka-intimidator-high-performance-agm-marine-battery-p-1355.html
I'd need to source some led's as well...
I've had great success with my 480w 440ah PWM 12v system over the past couple of years, but other than what I've researched and use, I've really got no idea of what to recommend. Help, please...

mike95490 · July 2016

If the panel is not going to be in full bright sun (no shade) all day, it's all pointless.

Saburai · July 2016

mike95490 said:

If the panel is not going to be in full bright sun (no shade) all day, it's all pointless.

Thanks for your input.
However, it's not in the least bit helpful.
I do disagree with your statement. As an example, the panels on my RV system are now due to our location, pretty much in the shade after 2pm. The system reaches full soc by noon. Pointless? Hardly. I'm sitting here replying to your post after watching a movie and taking a long shower. When I'm finished here, I'll get in to my warm bed heated by a 12v bunk heater. You certainly are entitled to your opinion, but to me my system is anything but pointless. I'd add that I've got no truck with you and no interest in arguments. As before, I've come here seeking the advice of the collective. It's not let me down in the past.
Many thanks to all,
Rich

vtmaps · July 2016

Rich,

I don't know how much sun/shade your panels will get, so it's not easy to apply any engineering formulas to your proposed system. You should have an alternate charging source... even if you have to carry the battery somewhere to get it charged.

btw, I don't think that battery is a true deep cycle battery.

--vtMaps

Saburai · July 2016

Thanks.
I'll be going to the site today and I'll do my best to get as much information as to how much isolation is available. Can you recommend a good affordable small charge controller?

z0xal · July 2016

That battery is a bit pricey for the application. If it has such a high CCA rating then it's design is not that much different to a car battery.

You could use 2, 3 or 4 small used car batteries from a vehicle dismantler yard up to approx 120Ah total, Will provide similar performance. If you do it this way, Check the dates of manufacture and get similar batteries, these places end up with with dozens of batteries and often cars crash with one to three year old batteries and the insurance company writes them off. Put an inline fuse of 30A on each +ve and use two strand of 17amp wire. Super cheap.

Either charge initially from a domestic supply or give a very high equalising charge from a 1kw petrol generator and 12v charger before connecting to the controller( if it's too far to run across power from the ac supply, as it involves less moving batteries around). Will need an eye kept on voltages, disconnect the fuses and check each battery voltage after a few days to make sure one isn't ruined, if so swap it for another scrap battery.

Assuming scrap yard batteries are as cheap where you are this will be ultra low cost and fine for the loads your friend intends.

Even if it loses capacity over time will remain functional until lead acid has been superseded by cheaper lithium or other chemistry batts

100w panel might only give out 30w if there are shadows but that's still going to be enough if the lights are used only some of the time

BB. · July 2016

MonringStar makes some nice/small charge controllers.

http://www.solar-electric.com/residential/charge-controllers.html?manufacturer=Morningstar+Corporation

Which controller does depend on how many watts of solar array, type of battery bank, and if the panel is a longer distance from the battery bank (PWM vs MPPT type charge controller--PWM are much less expensive).

There are a lot of inexpensive solar charge controllers from Asia--Some seem to work OK, others not well.

-Bill

basewindow · July 2016

Any simple and cheap 10-15amp Charge Controler MPPT or PWM would probably do. There are mountains on E-Bay for $20 or so. I've used one of these things in a very small system for my generator shed for 3 years with no issues. Many have built in USB chargers. You can buy two or three at that price if one fails. Battery 2nd hand 50-100Ah AGM telcom would probably do. 2-4 12v 3-5w LED lights. Maybe look at a folding relocatable panel if the other doesnt get much sun. If there are no critical loads etc and it's just for shed lighting for a few minutes or and hour or two each day, I don't know if I'd be bothered buying brand components etc. and proper deep cycle batteries. Just my thoughts.

z0xal · July 2016

Incidentally I use two cheap led lights originally meant to take three 1.5v AA batteries, have them wired in parallel from a single USB which can be run from the port on the charge controller (though I have it run from a separate USB 12v adaptor so I can switch off without reaching over to the light) . I agree mppt is not necessary for a low budget set up as your friend intends. I'm using a cheap 30A pwm controller (eBay cheapo model LMS2430 described as VicTsing IIRC) as mentioned above you could buy 2 as they are so cheap. Don't need the 30A but the display of battery voltage, panel volts and charge is handy, at the time the 10A version had no display and the price difference was small.

Have attached pics of the cheap pwm controller and light. Also while trying to find the same led lights on eBay I just saw a similar product that has a wireless remote, all on AA if you really wanted to show off with the budget setup you could install this and use a USB AA battery charger (I use one to charge a navigation light and torch batteries) to keep the remote charged. This way you could have the lights on the ceiling

Johann · July 2016

I have mono renogy panels.
In cloudy conditions I get about 10 % power out of them compare to full sunlight, but it depends of the darkness of the clouds and the density.
A shaded or partly shaded panel puts out nearly nothing. The heck.....just 1 leaf on the panels will let you know that there is something wrong.
Relocate the panel. A panel does not have to be on the roof. Put it on the ground or put it on the side wall of the building with an bracket. those panels are not heavy nor are they big to mount them where you need them.
The battery looks more like a starter battery and not a deep cycle, even thou it is listed as 92 ah battery with all the other data like CA,CCA, RC etc etc. Most true deep cycle batteries do not list CA and CCA etc. That is a Lot of money for a sealed battery that you can not do any maintenance on. Also that is a lot of battery( a lot of ah) for just one 100 watt panel, that battery may not get charged properly with just that 1 panel, especially if shaded. If a starter battery is getting used in such a systems that would require a deep cycle battery like in your friends system, such starter batteries may have a very short life. I tried car batteries, but they never would last, even with daily light loads.
If I remember right, that panel puts out about 5.5 amps max, so a 10 amp or higher charge controller will do. Don't forget to use fuses to protect the system and the property. Use DC rated switches etc for the DC set-up, whenever you can.
They make 12 volt E27/E26 screw-in Led bulbs that screw in in regular sockets, . Also Led strips seams to have good results.

Did you ever calculate how much load will be on that system?

Help with small affordable system for a bike shed

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