DIY Protected Lithium Battery Holder




Introduction: DIY Protected Lithium Battery Holder

In this instructable I'll show you how to make a battery holder for Lithium 18650 batteries so you can use unprotected cells in your DIY projects without worrying about over discharge, overcharge, or short circuit.

What we need:

- 18650 Holder ( Edit: These are cheaper. Thanks Elac.

- 18650 Battery protection boards ( buy 5 sets and it's cheaper)

- Soldering equipment

- Hot glue

If you find cheaper alternatives for the Holder and protection boards please let me know in the comments. With these items every protected holder costs 0.97$. Edit: With the Battery holders suggested by Elac. it is only 0,83$.

Step 1: Preparing the Battery Holder.

Start off with the removal of the negative side of the battery holder. To do this bend the retention brackets to the center. From experience the easiest way to bend them is to use a small flat-blade screwdriver. Then you should be able to pull the spring and the wire out. The Wire is connected to the spring with the metal post you just pulled out of the battery holder. Separate the wire, the metal post and the spring. We won't need the post but keep the black wire and the spring.

Now push the red wire through the hole to the inside of the battery holder. The red wire will be the wire from the battery to the protection circuit. Measure the length of the battery holder and cut the red wire to a length that it reaches the negative end of the battery holder.

Step 2: Preparing the Protection Circuit

Strip the end of the positive wire inside of the battery holder. Make sure not to remove too much of the insulation. Just enough to later attach the wire to the B+ pad of the protection circuit.

Take a wire (preferably a black one as it will be the negative side). The one previously attached to the battery holder is perfect for this. Cut the wire into two pieces. One short one which reaches from the B- pad to the other side of the protection circuit. This wire will connect the spring to the B- pad. The rest of the wire will be used for the P- pad and act as your negative output. So don't make it too short.

We will need a red wire too. The leftover of the previously cut wire is probably not long enough but if you think it's long enough to fit your use go with it.

Step 3: Connecting Everything to the Protection Board

Now it's time to attach everything to the protection board.

Start with soldering the long black wire to the P- pad, the short one to the B- pad and a red wire to P+ pad.

After you've done this solder the red from the battery holder to the B+ pad.

We're almost finished. Just solder the spring to the short black wire. Make sure you solder it in oriented correctly as it'll make life easier later on.

Now glue the spring to the underside of the Protection circuit.

Step 4: Final Assembly

Before putting everything into the battery holder make sure everything is soldered in the correct way and please ensure that you haven't created any short circuits.

Finally put the red and black wire from the P+ and P- Terminal through the hole of the battery holder and put the protection circuit into the battery holder. You may wan't to glue the Protection circuit into the battery holder but from my experience I can tell you that it isn't necessary. Just insert a Battery once and it should stay in place.

Now you have a protected 18650 battery holder for your projects so you don't have to worry about your unprotected 18650 battery.

Disclaimer: I'm not responsible for any damage. Please be extremely careful when dealing with Lithium batteries. They can be dangerous if they are mistreated. If you have no experience with Lithium batteries whatsoever please inform yourself about the dangers of Lithium batteries and how to treat them correctly.

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11 Discussions

Could I make a 3s battery, 11.1V with these and then charge them with a balance charger? Just asking need some clarity.

1 reply

Yes you can.
1 protection circuit however can only handle 3.7 V. So you can't connect 1 circuit over the 11.1V and would need at least 3 circuits.

nicley detailed DIY. would i be able to make 4 of these then once all 4 are done can i wire them in parallel to maintain 3.7v and wire them into 1 mini usb 5v li-ion charging board? i am gonna make a bluetooth speaker and plan on a 4 of these batteries. will run 2 mini amps (2×3w) powering 4 (2" 3watt) speakers and will b adding a bluetooth module as well. any suggestions greatly appreciated, seein that im new to this and only k ow what ive learned through all the great diy's (incl. this one) on thanks

Can I charge the battery with this pcb also?

What kind of psu can I use for it, I have some 5v usb chargers from cell phones, will that work?

1 reply

It is possible to charge the Battery through this PCB. But you can't just put 5 V on the plus and minus terminal. This is too much for a Lithium battery. The circuit will kill the connection to the battery and nothing will happen. You need a lithium charger. I can recommend these: The work with 5 V USB. But if you only need 1 cell you might want to use a different version of this charger. It has a battery protection circuit into grated. This might bring the cost down.

And can I protect 2 batterys paralell with this? Cant find any info about it.

1 reply

Yes this is possible. The only downside is that you can only draw 2 A I think as the PCB will open the circuit.

Compact and neat, thanks for sharing.

Here is a link to 10x 18650 battery holders for $3.32 free shipping.

1 reply