I have a battery operated project I’m working on that I’d like to be able to charge with an inductive charger or USB power. I’ve been trying to find a power control board that can look after a lipo and deliver a regulated 5V output. It’s only driving a ESP32 and a couple of indicator LEDs so 1A will be plenty.
I was considering using the DF Robot “Sunflower solar power manager” with a induction coil in place of the solar panel. From the data sheet I see that the solar input accepts 4.5-6V so I can’t think of any reason it wouldn’t work reliabley.
The question is does anyone for see any issue with combining the below parts? Is the MPP tracking on the power manager going to be an issue with the induction coil?
I might get shot down in flames here but I think your main issue is the induction charger.
This has got to be a coil of some description and has got to be AC to transfer the charging energy. The receiving device has got to have a coil of some description in it to pick up and process this energy. I don’t see how you can just put anything on one of these devices and expect it to work. I think the receiving device (in your case the Sunflower thing) has got to be capable of charging in this manner.
I did think that but the wireless charging module already has built in circuitry for regulating the output of the coil to 5v DC. That’s within the accepted input range of the sunflower. I’m not sure if there is any weird interaction between the regulated output of the coil and the MPP tracking input on the sunflower though which is my main concern.
Any ideas on what would be a good alternative?
Sorry I wasn’t aware that the Sunflower had this capability. The last one of these I saw only had USB or Solar charging.
Hi Simon, Welcome to the forum,
There are a few sunflower boards and there is a bit more documentation available for them here:
The MPPT on this particular sunflower board can’t be disabled but is fixed to track towards a 5V maximum power point, which is fortunate as that is the output level of the wireless charging module.
I can’t say for sure but I’d suspect the MPPT shouldn’t be a problem as it’s just trying to impedance match towards what it expects to be a 5V input, you may need to verify through an experimental test.
One concern I do have is with stray RF noise from the wireless charging modules and how to isolate that from the rest of your project.
I guess I’ll give it a a go and see how well it works then
Please do report back with results so that your experiments can benefit other members of the community with similar projects.
And of course we can always try and find another way to get your outcome.
I connected all these on my test bench and it seems to work well. Charges the battery and the esp32 board I’m powering is happy. Can’t see anything obviously going wrong. I’ll try and follow up again once I run the project for a while and see if it’s reliable.
I would have thought the easiest way to do this would be to use the USB charging input. You say you have 5V coming out of your induction charger then forget about the solar input and perceived MPPT problems, just ignore that. You can use the same input for induction or USB charging.
I considered that but wanted to have the option for induction charging or USB depending on whats available. But I can’t trust the user not to try and use both. Hence using the solar input for the induction coil. I’ve been testing it over the weekend and it’s done 2 full battery charge cycles, one on coil and one on USB without any issues.
Fair enough, it can’t do any harm I don’t think as if the induction charger is at 5V the MPPT system won’t do anything. I think with these Sunflower units the USB charge takes priority. When USB is powered the solar charging is disabled. I think, check. The description should tell you.