Today I'm going to do a review of the Cen-Tech battery charger. That's the current brand sold by Harbor Freight. My last Harbor Freight Chicago electric charger, kind of self-destructed. And if you want to see why, you can watch that video. If you look at the ad, you'll see that they're comparing it to a certain Schumacher model the SE-1250. And it's actually a little bit better in that it has an AGM mode and a trickle charge.
The reviews are kind of hard to figure out. This guy says, "Good. Can't beat the price." . . and then he gives it one star. So we'll go ahead and do a little bit more thorough review here. And I'll also dispel a few myths or misunderstandings about this charger and for that matter other chargers. And the instructions are fairly thorough. They're in Spanish and English. But what the instructions don't tell you are what this AGM mode, which is absorbed glass mat, means versus regular lead-acid battery mode. Now, unlike its predecessor, while it does not have a 6-volt mode, it does have the battery-type mode which switches between AGM and regular. And I think one of the claims or myths is that there are no wires attached or that the AGM mode really doesn't do anything. And I'll show some testing to put that to rest. The 3 charge modes for this unit are the quick charge, which is 10-Amp, then you've got the starter mode, which is up to 50 amps.
And you have a trickle charge which is 2 amps. This is really useful for maintaining batteries in standby vehicles. Another myth is that if you plug the unit in and there's no voltage on the battery clamps then it must be broken. And it's pretty clearly stated that this unit will not put out power if there is no battery attached. So I think I saw 4 negative reviews in a row that were complaining about that. The clamps are well sprung. The power cord is – both the cords are actually 6 feet long. The power cord is 18 gauge. And the battery cord is 14 gauge, so it's a little bit heavier. And sure enough, I can verify that in all three charge modes there is, in fact, zero output on the battery leads. And, of course, the only way to really get to know a device is to open it up. So we're going to go ahead and look inside. What we're looking for is general build quality.
And we want to verify it just a couple of things. And the build quality is not too bad. The transformer windings are a little bit heavier duty than the Chicago electric was. And also the output breaker is higher duty, it's 35 amp. And that compares to the 50 amp instantaneous rating of this charger. So that's not too bad. And we can also verify that there are, in fact, wires attached to the mode type switch, they call it, that toggles between AGM and lead-acid.
Now the solder connection quality isn't the best I've seen. Some of the connections look okay. But the ones on the AC side look a little bit rushed. The DC side, where you've got the rectifier and the DC Circuits, looks okay. This is the predecessor. This is the Chicago electric. It's a little bit tidier construction, but it is lighter weight. So you can see the transformer windings are lighter weight. Of course the rectifier did fail and that's what melted all these wires. But then, if you look at the rating on the output breaker it's only 20 amp. And they were calling this a 55 amp starter mode. So I would say that the this new Cen-Tech is heavier duty construction. One of the qualities of a charger is from what voltage can it rescue a battery.
Now this is an old motorcycle battery that was sitting on the shelf. It's only putting out eight volts. And the charger had no trouble activating for this battery. And we can confirm that in trickle charge mode, it's going to attempt to keep the battery at about thirteen and a half volts or so, which is what you want. If you put it into 10 amp or Quick Charge mode, it ups that to between fourteen and a half and fifteen volts, which is just fine. And while it's in a static charge mode, you can toggle back and forth between AGM and regular and you shouldn't see any difference and in fact you don't. But we'll get into that a little bit later. The charge guage is kind of strange. There are really no units, just percent charge. Where the Chicago Electric was in amps. So now we're going to check it on a car battery. We've got it hooked up to the suburban. Right now it's in trickle mode. And you can see the charge level is fairly low because this battery is good.
And if we put it into quick charge, it puts a little bit more level on that charge meter. It wouldn't be bad if the charge meter was backlit. I never really understood why they don't do that. Another myth, or false claim, is that the high amperage starter mode does not work. But it's important to remember that that high output will not occur unless the unit detects a starter engaging. We're going to put it in start mode. And you'll see that the charge meter cycles back and forth. It's waiting for the starter to engage.
And while the starters engaged, it goes to full charge mode; which, in starter mode, is up to 50 amps for a very short burst. Once the vehicle is running, we can go ahead and pull it off of starter mode. So now what we want to do is a volt range test. And to do that, I'm going to use the key fob to activate the accessories and draw the battery voltage down and see how far down the voltage goes before the charger kicks in. And for regular mode it's 12.7 volts. That's the minimum voltage that it will allow the battery to go to before engaging the charge. So, now I'm going to fast forward quite a bit and we're going to see how high the charger takes the battery before disengaging the charge. And in regular mode, it takes it up to 14.25 volts. So now we're going to switch it to AGM and we're going to do the same test. We're going to turn on all the accessories and we're going to see how far down the charger allows the battery to go before beginning charge.
And it's about 12.6. So it's actually lower than the regular mode. And we'll do the same thing. We're going to allow the battery to fully charge and see how high the charger brings the voltage. And in AGM mode, 14.65. So again, the charging ranges for the two modes are different. And the starting mode engaged properly. So this appears to be a good functioning charger. If this helps you guys out, please do give a thumbs up and subscribe. And if you know anybody else looking at these, please do share this video. Thanks for watching..
