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Question

Question related to how battery charging systems work

by Aug 8, 2015 12:18PM PDT

I am salvaging some laptop batteries for use in a project. What I need to know is if the PCB built in to the battery handles the current regulation, or if the laptop motherboard has a part to play. So if I want to charge them without the laptop they wouldn't explode if left overnight.

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6 Posts
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Answer
Most laptop batteries are simple things.
by Forum moderator Aug 8, 2015 12:36PM PDT

About all the schematics I've seen simply have a temperature sensor. Later some battery packs incorporated more but in a consumer system it's all about cost. So the charger in most systems is on the motherboard, the temp sense being crucial to avoid pushing the battery pack too hard.

Since it's a PROJECT why not some ready to use battery pack like this one?
http://www.amazon.com/gp/product/B00BB5GR0A is 23 bucks today, has been on sale many times and can run many things like the Rasberries and more. Power to the pack is a simple 2 Amp USB charger.

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Not so simple for me
by nck2000 Aug 8, 2015 1:19PM PDT

That battery pack is awesome for the price and would be the perfect solution, but I live in Costa Rica and shipping things like that is extremely complicated, plus it would take too long

I am making a backup power solution for my rep rap, the power is extremely unreliable here. The machine is 12 volt, and uses a power supply to step it down from the main. I could hook it up and use it, only problem is the charging circuit, which of itself is a complex thing.

If I could get my hand on some sort of charger for an appliance that uses 12 volt lithium ion batteries then I would be set I think. It might need a relay, or it might just be hooked up directly.

I don't mind putting extra time in this to learn how to do it, it's kind of the nature of what I am doing down here. It's like recycling, so its extra full-filling this way.

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Now that I have done. But I never used laptop batteries.
by r. proffitt Forum moderator Aug 8, 2015 1:53PM PDT

I used the old car battery and a solar panel with a charge system. While you want to do what you asked, it may take a few courses in electronics to get to the point where you can make your own NiMHD or LiPO or LiON battery chargers.

As to the model I noted I saw those all over Asia and South America.

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(NT) Think I found a way
by nck2000 Aug 8, 2015 4:18PM PDT
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Think I found a way
by nck2000 Aug 8, 2015 4:25PM PDT

Making the circuit from scratch would be a very involving afair. I hope to find a way to hack parts from appliances that work for what I want them to do.

I think I've figured out a way to use the protector circuits in mobile phone batteries. I thought I needed one that can take 12 volts, but if you hook them up between each bank of batteries in series then it will work, with even better synchronizing between all the cells.

If it works, I'm gonna document it because it has so much application for DIYdiy battery set ups.

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Here's the generic charger I'm using.
by r. proffitt Forum moderator Aug 8, 2015 5:29PM PDT
http://www.amazon.com/gp/product/B003MXMJX8 came in real handy on a NiMH failed charging system. It had to earn my trust but would never put it in anything less than a fire proof enclosure.

I bet you can find such for LiON and LiPO too.
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