Can I use solar controller without battery? I only need USB to charge my power banks.

[asukabat]

Hi Newbie here , I am wondering if I buy a solar panel kit without battery , can I use the USB in solar controller to charge my power bank? I learned that the proper setup is to insert first the battery wire to solar controller before inserting the solar panel wire. What will happen if I insert the panel without inserting battery? Thank you in advance !

I am planning to buy this 50w Noma solar panel kit. I will be using it for camping.

General PDP Template

www.canadiantire.ca

 

[Pappion]

Many solar controllers are dual 12v / 24v, determined when battery is connected. Still, I would not want to do a smoke test. Also leakage current's could cause the voltage to keep rising, in the absence of a load. Cheap stuff like this switch between the negative terminals, so it's a real mind bender to predict how that interacts with USB and power bank with other connections.

 

[HarryN]

If your goal is just to charge USB devices, and you are willing to take some risk, why not just buy a cheap solar panel and a 12 / 24 volt USB port and plug it in without a solar charge controller? It may or may not work without it.

They are pretty inexpensive, so you can try it at home and see if it works.

12/24V DC Dual USB Charger 4.8A with Intelligent Device Recognition - Blue Sea Systems

Engineering high quality marine electrical components for safety, reliability and performance

www.bluesea.com

The other approach is that you can just use a capacitor and no controller. The capacitor will charge up to the panel Voc.

Buy a panel that has a Voc of more like 15 volts.

 

[HarryN]

Rollable Solar Panels

Rollable Solar Panels are lightweight, flexible, IP67 rated, durable, and ideal for charging boat batteries and other 12V systems in marine environments.

www.powerfilmsolar.com

Take a look at these. I put some in my daughter's cars when covid hit to keep the starter batteries from going dead.

Might be closer to your needs.

You are right in general though - the intention of most systems is to charge a 12 volt battery and then USB from from there, so be sure to test first.

You can try purchasing a very low power USB port and see if that helps to deal with the low power available - now sure if that will work with your power bank though.

https://www.bluesea.com/products/1016/12_24V_Dual_USB_2.1A_Charger

 

[Craig]

I do not think you will smoke your charge controller but I think what @HarryN said is a great option.

 

[littleharbor2]

I managed to smoke a controller once, granted it was a tiny, cheapie, but it sizzled right away . You can get a small sealed battery like this and have the ability to connect small 12 volt loads as well.

 

[HarryN]

LightSaver Max Portable Solar Charger (LSM-1)

Lightweight 1.5-pound flexible thin-film solar charger with a built-in 18000mAh battery, USB-C input, 12V input, dual-USB outputs, and a 12V output.

www.powerfilmsolar.com

Kind of pricey, but it turns out they even make a version that is exactly what you are trying to do. Has a USB C outlet port and is built to charge USB devices.

 

[Craig]

So I made a quick test this afternoon and running the panel directly to a 12v usb socket works well

 

[HarryN]

So I made a quick test this afternoon and running the panel directly to a 12v usb socket works well

View attachment 157334

View attachment 157335

Thanks - does that tester indicate what the setup can deliver power wise or is that how much your USB load was pulling?

I am just wondering if that test can be used as an indication that it would actually charge a USB type power bank as those might charge at various rates?

Now I need to go take a spare panel and USB port from the garage and borrow my wife's power bank for a test.

 

[Craig]

That is what the phone was pulling. But I tested it with a few other devices and the best i could get is about 25 watts in total. This is similar to what I get from a USB wall plug.