Solar panel, small battery charging Question

[Blackfriar]

Hi all.

I'm interested in putting together an emergency use solar panel setup for charging small batteries. This would be squirrelled away and brought out when necessary. I do not want a permanent system with 12v batteries to worry about.

I want to charge AA's, AAA's, 18650's and some 22400mah USB power banks. For charging the cylindrical batteries, I have a 4 bay "XTAR VC2" charger, as well as a 1 bay "XTAR MC1 PLUS" charger.

I've looked into the larger sizes of portable folding panels, and I don't like the durability vs. cost. I want to use an aluminium framed panel like this one: http://www.bimblesolar.com/210w-allblack-used

For charging the cylindrical batts, could I connect the panel to a cheap MPPT charge controller, and then connect one of my battery chargers to the charge controller? Will the charge controller work correctly WITHOUT also being connected to a 12v/24v battery bank?

Many thanks in advance if you can help me out with this one.

[Yorkshire Andy]

In a word no

Without a battery connected it won't have it plus a charger can put out about 18v during charging which the battery will absorb could fry some 12v kit

[Blackfriar]

Thanks for clearing that up. I've found this on Ebay: http://www.ebay.co.uk/itm/Solar-Panels- ... 1927211595


If used in this manner: https://www.youtube.com/watch?v=5fUkdJI ... L&index=14 could it replace the MPPT in my system, allowing me to charge small batteries without a 12v battery bank?

[Yorkshire Andy]

Why the aversion to a 12v battery?

Let's you charge at night etc?

[oldman]

Let's you charge at night etc?

Nights have got a lot brighter since I was last in Yorkshire.

Sorry Andy, I get what you mean but it just struck me as funny.

[Blackfriar]

I had planned to keep the entire solar kit stored away and only bring it out if the grid goes down, for charging mobile phones, batteries for my torches, etc. I don't really have the space (or need) to install it and use it daily.

From what I've read these deep cycle 12v solar batteries should be kept charged above a certain level, and also monitored and maintained pretty regularly, to prolong their life? My problem is that I don't have the space to set it all up and keep it running. If this is not the case and the battery can happily sit unused then I'll definitely go down that route.

Living in a tiny flat really sucks.

[oldman]

Have you considered a hand cranked charger? I know they do them for mobile phones.

[Deeps]

I had planned to keep the entire solar kit stored away and only bring it out if the grid goes down, for charging mobile phones, batteries for my torches, etc. I don't really have the space (or need) to install it and use it daily.

From what I've read these deep cycle 12v solar batteries should be kept charged above a certain level, and also monitored and maintained pretty regularly, to prolong their life? My problem is that I don't have the space to set it all up and keep it running. If this is not the case and the battery can happily sit unused then I'll definitely go down that route.

Living in a tiny flat really sucks.

I know you said in the OP that you weren't keen on the portable folding panels but they sound ideal for what you want to do. Its the system I have and use it once or twice a year to keep it 'ticking over', there's no reason I couldn't use it more often other than its easy to plug my phone into the wall. Are you thinking short term loss of power or long term ? If its hard to justify the cost, as folk for Amazon vouchers for xmas, I tend to buy my 'extravagances with birthday/xmas money. I'd planned on setting up a 12V system with a semi permanent panel this year but its still not happened, I can see me doing it with xmas money this year, good luck with your plans mate.

[Brambles]

You can charge direct from a solar panel but you need a battery to use a charge controller.

I found this on Youtube if it's any help.

https://www.youtube.com/watch?v=yqd1Qf08jMY


OR

You could do what Mortblanc does and cannibalise solar garden lights and use them as chargers.

https://www.youtube.com/watch?v=HWxdYndce9I

[Mortblanc]

Those cheap solar garden lights are great stuff!

Several years ago I did some simple testing and found them extremely durable and useful. Stick them out in the lawn and gather them back up and bring them inside at night for handy emergency lighting. They are not floodlights but they will keep you from stumbling around inside, are less dangerous than open flames and put out enough light to read labels and such

I have a window in my hallway that faces northwest and gets only partial sun. I placed one of the cheap lawn lights in the window for the purposes of having a "night light" for navigating the hallway at night and to see how well the $3 (US) lawn light worked and how long it lasted.

That cheap little solar light went through complete charge and discharge cycles for more then 18 months, more than 500 cycles, before the battery died. The charger and light portion were still good. I consider that money well spent to do a job many people spend a small fortune to accomplish. Batteries solar charged and ready on demand.

I rework these lights to use for recharging button batteries and keep several of them on my screened in back porch charging AA batteries just for use in emergencies.

As for life of the battery and system while in storage? I would say that if you bought a half dozen and packed them away without messing with the protective tags that keep the battery isolated while in the carton they would last indefinitely. I have never seen a "use by" date on any of them and I am pretty certain that the big box stores do not keep tabs on the life span of garden lights, putting them out and taking them back to storage as required by seasonal shifts in marketing.

In another instance I was living off grid and using a $20 (US) solar panel to charge a 12v deep cycle marine battery. During the summer months I was working outside most of the evening when home and only used lights in the house for a couple of hours each night. I was working off a 12v florescent system (this was before LED was common) and I did not run out of juice from April until October when the days grew short. I am pretty sure that with modern LED lights I could have done without the generator being turned on for longer.

You should investigate using a 12v battery to power an inverter for charging USB and other things in spite of your aversion. A small panel is cheap and a small battery such as is used for a lawn tractor or motorcycle is small and easy to tuck away in a cabinet.

If you have any kind of vehicle at all you will have 12v battery and power on hand and adding a simple dashboard charger to the preps is a one step fix to the problem.