I need to drive a 90w 5v circuit with 18650 batteries

Chris's picture

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Joined: Jun 03, 2020

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I need to drive a 90w 5v circuit with 18650 batteries
June 3, 2020 - 6:36am

I was wondering if I can do this at all really and I know very little about supplying power with batteries. Would I just use a DC-DC converter like the LTC3780?

Sourav Gupta's picture

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Yes, it can be used, but there is a problem. The 18650 has a maximum current rating. You should be careful that the current maximum load current rating should not increase. What is your planing for the input battery spec? voltage? mAH?

Chris's picture

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The model of 18650 I plan to use is 9900mAh, and I should be ok with 3 connected in parallel if I'm not mistaken.

here's an idea of what I had planned. I apologize that it looks like garbage, but I have quite a bit of work to do right now.

https://bit.ly/3AwgAx5

Sourav Gupta's picture

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TP4056 has 1A of current rating. 3 parallel 18650 9900mAH will take approximately 10 hours to charge fully. Is this ok for you? That is a really long time for such applicaiton.

Chris's picture

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Thank you for your reply, I ended up going a different direction and not using 18650 batteries. I used a 7.2v Tenergy NiMh pack and probably wasn't hiting half the max rating of the LED strips as I ran them at 18 brighness instad of 256. I ended up using a 15A rated buck converter just to be on the safe side.

Sourav Gupta's picture

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Good to know this. Use proper protection for the battery charging for a longer battery life.