Makita 40V Batteries - What's their life expectancy

[00:00:00]Hi, Lyn here. How long do you expect your Makita batteries to last? What's the life expectancy? I've got eight of these 4 amp 40 volt batteries. Four of them are pretty new. They've only been cycled a few times, and four of them are between 3 and 5 years old, and they have been cycled between 200 and 500 times each. So, what I want to find out is how much have those old batteries degraded.

[00:00:21]I've designed four tests, and I'll run a new battery and an old battery through each test. I've cleaned all the batteries. have all been fully charged yesterday and they're all sitting inside except this one. This will go back inside shortly. I'm going to allow each tool to cool down in between tests.

[00:00:37]Before I get started, chuck down in the comments how much you think the old batteries have degraded. I genuinely don't know how this is going to go.

[00:00:47]The first test is pretty simple. I'm going to rip as much timber as I can.

[00:00:51]So, this is 90x 45 or 4x two 2x4. I've set the saw to about 50 mil depth. So, should go through pretty cleanly. Let's go.

[00:01:29]No, it's done. I would say that's possibly overheated. For the second test, I've got this beam here, and I'm going to cut it up with my saber saw.

[00:02:02]getting down. Maybe I think now it's down.

[00:02:22]might get two more.

[00:02:26]Okay, maybe not. No.

[00:02:32]No, she's done.

[00:02:35]Next test, I'm going to see how much timber I can plane. So, I'm going to plane the 45 on edge. I'm going to set it to 3 mil deep.

[00:02:44]I think if I set it to four, it's going to max out too quickly. And that, for reference, is the max that the 18 volt one will do.

[00:03:33]Oh, that's a stall.

[00:03:36]Oh, we are on one.

[00:03:38]Oh, that's it. Oh, she's pretty toasty.

[00:03:42]Did a lot better than I thought, though.

[00:03:44]And now for the final test. I am going to see how many cuts I can get with grinder. I've soaked these in water, but I don't know if it's going to be enough to keep the dust down. All right, let's go.

[00:04:24]done.

[00:04:27]Oh, that was brutal.

[00:04:29]Maybe I should have come up with a different test.

[00:04:35]The tools have all had a chance to cool down. So now I need to run through all the tests again with old batteries. It's full.

[00:04:54]Hey, really the heck? It's not flashing.

[00:05:11]Three.

[00:05:23]No, it's done.

[00:05:30]Here we go.

[00:05:41]Feels like it's slowing down.

[00:05:58]That's one stall.

[00:06:02]Two stalls.

[00:06:04]Oh, and it's done.

[00:06:07]Light comes on but won't go flashing.

[00:06:10]It's pretty warm. On to the second planning test. And I've just checked on the batteries from the previous test.

[00:06:16]There's something interesting going on.

[00:06:17]I'll get back to that in the meantime.

[00:06:21]See if this battery does well.

[00:06:59]That's dead.

[00:07:31]What's the [ __ ] Okay.

[00:08:01]Okay.

[00:08:17]Hey, thank goodness for that.

[00:08:25]>> It's been a few weeks. I finally sat down and put the video together so that I could analyze the results. But before I get into it, as promised, I'll talk about the weird thing that was happening with the batteries. It's not really that weird. Basically, most of the batteries overheated. So, you get the flashing one bar, which indicates either it's overheated or it's completely depleted.

[00:08:46]Most of the batteries were still on two bars, which you could argue invalidates all the tests. I would argue no because as the capacity drops, the internal resistance increases, which means they basically heat up because for the given capacity, they're working harder. The only exception to them overheating was both grinder tests where I think because I was operating the grinder with one hand, I wasn't able to push on hard enough to really strain the grinder. So, the test took ages and the batteries didn't quite work hard enough to overheat. That's my thinking. Now, let's get into the results. For the saber saw test, I had one of my two oldest batteries. I bought them when I started my apprentichip five odd years ago, and the old battery only cut about half of what the new battery did. And since then, the batteries died. Uh-oh. I might try to jump start it later, but I think it might be uh kaput. My other oldest battery that I got at the same time did something a little bit weird, which I'll get back to. my third oldest battery which I got I think with my weed whacker. So that's about 4 years old. Um 31% loss. So it's lost essentially a third of its capacity. And my newest battery or fifth newest I guess has lost uh 20% capacity in just over 2 years. So it's not terrible. Definitely not enough that you'd notice it unless you're actually doing these sorts of tests. So I think it's pretty decent. I've heard uh not good things about other brands.

[00:10:12]Maybe you've got opinions on that.

[00:10:14]Comment below the test that went wrong before I forget. I noticed during the test on the run with the new battery that uh there might be an issue. I'd completely forgotten about it until I was looking through the footage and I double checked. I'd done everything right. I had the lineal meters measured out right. Definitely the right battery.

[00:10:34]The numbers just weren't stacking up.

[00:10:37]Apparently, it's only lost 8% in uh almost 5 years, which doesn't seem right. However, I noticed when I was recording it that there potentially was an issue. So, when I was pling 3 mil going pretty hard, the planer was getting clogged up quite a bit. Oh, that stalled.

[00:11:00]I wonder if blocking is going to complicate this. On the second run, I was making a habit of making sure it was unblocked at the end of each run. And I think that's where the results uh got a little bit messed up, but I think it's pretty obvious that yeah, over 5 years they've uh lost a bit of capacity. I think I've just got time. So, I'm going to try jump start this battery. I hope it doesn't blow up in my face. I really don't have high hopes for this. It's not getting warm at all.

[00:11:33]which means the circuit board in that has probably disconnected it, I'm guessing. All right, we will call that a fail. I might get a new circuit board for that battery or I might not. We'll catch you guys next time for uh hopefully replacing a shower that was installed completely wrong. I'm not even exaggerating. It was terrible.