How to make a battery connector



Some of you know me, most do not. For those of you that haven’t met me, let explain something – I’m cheap. I’m cheap in that if there’s a product on the market, but I can make something similar that’ll work, I’m all about making my own product. In this case, we’re going to talk about battery connectors. I was recently looking at an airplane that requires a 6S 3000-3200mAh Lipo battery. BUMMER! All I have on hand are some 6S 5000 mAh packs. So, I look into purchasing a couple of the required batteries, only to find out that they’re expensive (Remember the ‘I’m cheap’ part?)

So, I start looking at my battery shelf, and I realize that I have a handful of 3S 3000mAh LiPos that are sitting there looking for a new airplane. Then it hit me… “I can use two 3S batteries in series to get a 6S pack?” Great idea, right? Sure, if I had a way to connect them. So I start looking for a ready-made connector. About two minutes into my web search for the connector, it hits me – ‘Why don’t I just MAKE a connector?” Even better! So, without any more chatter, let’s get into assembling a battery connector.

What Will You Need?  

So you’ve decided to follow along and assemble your own connector? Great!

Here’s what you’ll need to get started:

1) A heat source: Depending on the task, I’ll use a propane torch or a trigger-type soldering gun. For this job, I prefer the propane torch. 

2) A pliers with insulated grips: Trust me on the insulated grip part – the torch can heat the handles of the pliers up quickly! The pliers I use have a bent nose, but straight pliers will work nicely as well.

3) Solder and Flux: Some solders have a flux compound in the solder, but I still prefer a separate flux for cleaning all electrical parts.

4) Flexible wire: I like to use a minimum of 16 gauge wire. The more flexible the wire, the easier it will be to assemble the connector.

5) Connectors: Since my batteries already have EC3 connectors attached, I am assembling the new connector to match. You can use Deans connectors or whichever connector is on the batteries.

One More Thing

Yes, I’m showing you a nasty looking piece of wood. This is my ‘soldering board’. I do all of my soldering on this piece of wood, so it keeps melted solder and excess flux off my building table.

Let’s Get to Assembly

The first task was to strip the ends of the three wires. The exposed wire ends were then coated with flux, and set aside. When I get ready to solder the bullet connectors, I use my bent-nosed pliers and ‘scoop’ a small amount of flux into the end of the connector.

The connector is then heated in the torch’s flame – just as the flux starts spattering, I tap the connector on the soldering board. This tap removes the excess flux from the connector prior to filling the ‘cup’ end of the connector with solder. With the cup nearly filled with melted solder, the stripped end of the wire is quickly inserted into the melted solder.

I repeated this step with the three remaining male bullet connectors, followed by the two female connectors. With all of the parts now laid out next to the two battery connectors (on the left), you can see where each part goes.

Using a special tool (OK, it’s really just a small pick with a broken tip), the bullet connectors are pressed into the plastic EC3 holders.

Now we get to the only trick part – making sure that all the wires and connectors line up correctly. For this task, I attached the battery to the new connector to verify which wires go where. After completing the verification, I used my ‘special tool’ to press the remaining connectors into the EC3 holders. With that, the basic connector was complete!

As you can see, the two 3S batteries are now connected in series to make one 6S LiPo battery. a Velcro tie strap holds the two batteries together, making it easier to install in an airplane.

So What Did We Learn?

Aside from learning that I’m cheap, I hope some you will realize that just because a product is available doesn’t mean you need to buy it – take a few minutes and make it yourself! All in all, this connector took me about 20 minutes from start to finish. Could I have purchased this connector from a hobby shop or internet distributor? Sure – but where’s the fun in that? 😉 





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