Hello,

I would like to build a battery charging circuit (instead of buying one). I would like to use solar panels as the power in. I am sure I could buy one cheaper than build it but my desire is more for fun than anything else. The end result will be to power a small Arduino board.

I have googled some and found a few IC’s like the Linear Tech’s LT3652 – DigiKey’s search gave me a hit on a Maxim and / or Analog Devices part also.

So far I have struck out finding a thru-hole option.

Can you point me to some circuit options / links / articles/ so forth (preferably thru-hole components)? (Solar in, charge rechargeable batteries)

Thanks

Sparky

 

Can you point me to some circuit options / links / articles/ so forth (preferably thru-hole components)? (Solar in, charge rechargeable batteries)

You didn't provide sufficient information for anyone to help you.

1. What battery chemistry?
2. What capacity?
3. What voltage?
4. What solar panel voltage and amperage?

 

You didn't provide sufficient information for anyone to help you.

1. What battery chemistry?
2. What capacity?
3. What voltage?
4. What solar panel voltage and amperage?

oops

battery = Lithium Ion ( I assume from seeing other projects)

solar panels = I have no clue I assumed I would just solve that with money, meaning buy what I need for the input voltage

the output voltage = probably 3.3 v - 5v ... The end result is to power an Arduino board (where no power is available) This board has one function - to monitor one digital pin and then transmit using LoRa. So I am going to sort by price and size on the board I don't need a lot of current (but don't know the number)

After searching more last night, I may do what I say I didn't want to do and buy a "module" that does this charging and monitoring. I found a few that seemed reasonable. I am not sure yet, thought it would be fun to build something but the prices on the modules aren't bad.

 

battery = Lithium Ion

For Arduino Uno, you'd need a 2S configuration. Texas instruments sells 292 different ICs; and yes, you'll need a charging chip due to the charging requirements.

When you buy 1 of the ICs, you'll have already spent more than buying a charging module from AliExpress would cost.

 

Yes, if you are relatively unfamiliar with this kind of thing, especially charging LiPo batteries, I would definitely recommend going for a dedicated charging module. The consequences of getting it wrong can be pretty dire! The item below, for example, will charge two LiPo cells from a solar panel directly and, for the next two days, is available for under £1.00! Then just use a buck module to give you 5V for your MCU and you're away.
https://www.aliexpress.com/item/1005006026796945.html?src=google&pdp_npi=4@dis!GBP!8.46!3.89!!!!!@!12000035382718768!ppc!!!&snps=y&snpsid=1&src=google&albch=shopping&acnt=752-015-9270&isdl=y&slnk=&plac=&mtctp=&albbt=Google_7_shopping&aff_platform=google&aff_short_key=_oDeeeiG&gclsrc=aw.ds&&albagn=888888&&ds_e_adid=775528715982&ds_e_matchtype=search&ds_e_device=c&ds_e_network=g&ds_e_product_group_id=2443451624588&ds_e_product_id=en1005006026796945&ds_e_product_merchant_id=5551326180&ds_e_product_country=GB&ds_e_product_language=en&ds_e_product_channel=online&ds_e_product_store_id=&ds_url_v=2&albcp=23055122542&albag=188614691009&isSmbAutoCall=false&needSmbHouyi=false&gad_source=1&gad_campaignid=23055122542&gbraid=0AAAAA_eFwRClLl-eElTXicL4zhjR8pa_5&gclid=CjwKCAiAl-_JBhBjEiwAn3rN7fM5nyNyDPRduDqZ2aqtBB_PV5Y5xTMarlr4CpJdCTz2LSvJKmiMGhoC0LEQAvD_BwE

 

Hello,

I would like to build a battery charging circuit (instead of buying one). I would like to use solar panels as the power in. I am sure I could buy one cheaper than build it but my desire is more for fun than anything else. The end result will be to power a small Arduino board.

I have googled some and found a few IC’s like the Linear Tech’s LT3652 – DigiKey’s search gave me a hit on a Maxim and / or Analog Devices part also.

So far I have struck out finding a thru-hole option.

Can you point me to some circuit options / links / articles/ so forth (preferably thru-hole components)? (Solar in, charge rechargeable batteries)

Thanks

Sparky

Most ICs for that application are in smd package, how about using converter from smd to dip package?
If not, you can use ready module for dip package if that so necessary for you
Regards

 

Note that the module that PhilTilson suggested is a MPPT charger. That is important if you want to get the most out of your solar panels.

Even if you use a pre-made module, please watch some videos of lithium battery fires and use that to inform your choice of where to charge the battery (especially while testing or after it sits unused for a long time). My RC plane batteries get charged in the middle of a concrete or tile floor (often under a bag of sand) or outside where they can't hurt anything. I've never had a problem, but talking to a neighbor as his house burned down due to a lithium battery fire made an impression on me.

 

Hello,

I would like to build a battery charging circuit (instead of buying one). I would like to use solar panels as the power in. I am sure I could buy one cheaper than build it but my desire is more for fun than anything else. The end result will be to power a small Arduino board.

I have googled some and found a few IC’s like the Linear Tech’s LT3652 – DigiKey’s search gave me a hit on a Maxim and / or Analog Devices part also.

So far I have struck out finding a thru-hole option.

Can you point me to some circuit options / links / articles/ so forth (preferably thru-hole components)? (Solar in, charge rechargeable batteries)

Thanks

Sparky

Hi,

It's not too hard to build a charging circuit for a single Li-ion cell if that is what you are doing.
The basic requirements should be fully understood however:
1. Accurate max voltage output.
2. Current limited.
3. Charge cutoff control.

You have to have a regulator circuit that has a max current less than the rating of the cell to be charged.
As the cell charges, the voltage rises, and the max voltage should be 4.200 volts for most cells (some are al little higher now).
As the cell gets fully charged, the charging should shut off, or you have to watch it and shut off manually.

This can be done with an LM317 voltage regulator for example.
If you want higher efficiency then you might go with a buck converter.

The LM317 circuit would look almost like a charger for a 12v car battery, but not exactly the same.