The Traxxas E-Revo is a pretty flexible truck when it comes to power sources. Out of the box, it can use 7.2v or 8.4v NiMh packs, but I’m fast becoming a LiPo convert, so I wanted to use LiPo with my E-Revo. Here’s how I did it.

First things first – out of the box, the normal E-Revo isn’t really suitable for LiPo batteries. The thing with LiPo batteries is that you musn’t let them discharge too much, unlike NiMh batteries which you can just keep using until they run down. If a LiPo battery drops below a certain voltage, it’s had it. Anyway, usually if you’re using LiPo you need an ESC which has “low voltage protection” built into it – this means the ESC will monitor the batteries, and when they start to get low it will shut down before they can be damaged. The E-Revo’s standard ESC, the Traxxas EVX-2, doesn’t have this feature, but fortunately, you can add it on yourself.

All you need is a “Novak Smart Stop LiPo Cut-off Module”, some Traxxas battery connectors and a bit of soldering, and you’re done. What you need to do is create a cable to connect the Smart Stop between one of the batteries and the ESC. I simply copied the photo that can be found in this thread over on the Traxxas forums. Then plug the ESC’s receiver cable into the Smart Stop, and the Smart Stop’s cable into the receiver instead, and you’re done.

You can now connect LiPo batteries quite happily, and when they start getting low, the car will “judder” as the Smart Stop interrupts the power. There’s also a bright blue LED that will start flashing.

Now all you need to do is pick up some cheap LiPos off the net and you’re away!

Spektrum DX3S transmitter

After unpacking, charging up the batteries and checking everything worked, the first thing I wanted to do with my new E-Revo was replace the radio gear. Don’t get me wrong – the transmitter and receiver that come with the model are fine, and I’ve not read any complaints about them, but since I bought a Spektrum DX3S for my touring car, I’d much rather use that.

The main benefit of using the DX3S is that it’s a 2.4GHz system – so it should have a greater range, and no risk of interference from other transmitters. There are other benefits too – it only needs 4 batteries, not 8, and since has a 10-model memory, I can set it up to work with the E-Revo and the T2R Pro straight away using the two receivers it came with, and by picking up another receiver I can  control the AX10 with it as well. I might even use it for the boat – one transmitter for all my non-flying models…

Anyway, the point of this post is to describe how I got everything set up to use the DX3S with the Traxxas E-Revo, so let’s crack on.

I’m choosing to use the SPM SR300 receiver in the E-Revo. You could use the SR3300T receiver which also comes with the DX3S, but as that is the one with the telemetry options I’ve put it in the Xray. The Spektrum receivers are nice and small, so should fit quite nicely.

1 - Open up the receiver box and note which wires are throttle and steering

The first thing we need to do is check everything works happily with the new receiver, so open up the receiver box and make a note of which wires go into which socket – two are for the steering servos (labelled CH1) and one is for the ESC (CH2). Fortunatly, the DX3S is a three-channel transmitter with matching receivers, so the presence of two steering servos isn’t a problem.

Next, you’ll need to trim off the tabs on the plugs so that they’ll fit into the Spektrum receiver. Use a sharp knife of a pair of snips, and be careful not to break the plugs. Once you’ve trimmed the plugs, fit one of the steering servo wires into the Aux port on the servo. On the DX3S transmitter, enable the Aux channel. Plug the batteries into the ESC and turn it on – now test that the steering works. If it does, you’ve successfully set up the second servo on the Aux channel.

2 - Check it all works

Next, unplug the batteries, plug the throttle plug and the other steering servo into the throttle and steering ports on the receiver, and unplug the Aux servo. Turn on the transmitter, plug the batteries in to the ESC and turn on the ESC – blip the throttle trigger on the DX3S and the wheels should spin, turn the wheel and the steering should work (this proves that both steering channels are working, and you’re not just using the one). Next, disconnect the batteries, plug the Aux servo back in and you’ve got everything working. If anything hasn’t worked, check it’s all plugged in the right way around and in the right ports. If at any point you can’t turn on the ESC, chances are you’ve got a steering servo plugged in to the throttle port.

3 - Remove Traxxas receiver and replace with Spektrum receiver

Next, you’ll need to remove the old receiver – first, loosen the screw you can get to on the cable-holding box alongside the receiver box. This is a neat little device that keeps the receiver box waterproof – the cable are fed through some foam inside it, which keeps moisture out. You’ll only need to undo the one screw, and then you can pull the aerial lead out from the receiver box. The 2.4GHz aerials are very short, so don’t bother trying to feed the new one through – it should be fine just tucked inside the receiver box. With the old aerial lead free, you can gently (but firmly) lever up the Traxxas receiver. Use a bit of servo tape on the new one to stick it in place, carefully replace the blue waterproofing ring around the edge of the box, and screw the top back into place.

That’s it – job done!

Traxxas E-Revo

Over the last year or so I’ve been getting back into radio controlled stuff , and have been building up a collection of helicopters and cars that I never could have managed when I was a kid.

As you might be able to tell from other posts on this blog, I already have an Axial AX10 Scorpion rock crawler, and an Xray T2R Pro 1/10 touring car. But… I wanted another one. Why? Put simply, I want one for bashing. The T2R is only usable on a racetrack, and although the AX10 is great fun on rocks, it’s a bit too slow for any other scenario. For general messing around in the garden or elsewhere, I wanted something with a bit more grunt, so I started looking around.

What to choose?

There were a number of factors I took into consideration when deciding what to buy. Bashing will likely result in damage, so I wanted something with good spares availability and optional parts – so something from a big manufacturer like Traxxas, Losi or HPI was an obvious choice. So was four-wheel drive and decent ground clearance – meaning some sort of monster truck chassis instead of a buggy or truggy. In the end, I narrowed it down to things like the Traxxas E-Maxx, Traxxas E-Revo and HPI E-Savage. The E-Maxx is currently £269 from Modelsport (not including batteries).

HPI E-Savage

However, a bit of research suggested that owners considered the E-Maxx to be weaker and more prone to breakages than the E-Revo, and currently the E-Revo is only £299. So, the E-Maxx is out – no point saving £30 if I’m just going to end up spending it on replacement parts, I figure. The E-Savage is a tempting choice, at the same price as the E-Revo, and this is even including two battery packs and a charger that can charge them both at once. However, more forum surfing suggested that the E-Savage wasn’t quite as good as the E-Revo – here’s an example. So the E-Savage offers better value-for-money with it’s included charger and batteries – it really is a proper “ready to run” package – but again, the E-Revo seems to come out on top in forum discussions for general strength, reliability and, well, fun. Plus, I dunno, I think the E-Revo looks better…

There was one last option I considered – a Traxxas Summit. The Summit is basically a cross between the E-Revo and a rock crawler, with some pretty cool capabilities- it’s got remote locking/unlocking differentials, and a remote selectable high/low ratio gearbox. This means that it’ll run around at speed just fine (not as fast as a proper E-Revo but not exactly slow), but then when you fancy tackling some obstacles, you can lock the diffs, select the low ratio and off you go. A normal monster truck without locked diffs wouldn’t be very good at climbing – the diffs would just send all the power to whichever wheel(s) didn’t have any grip and you’d go nowhere. So, all the fun of a crawler and most of the speed of an E-Revo. Where’s the catch? Well, two things put me off. First, all that remote-locking and remote selecting of ratios. I can’t help but feel it’s going to be a bit fragile in that respect, and I don’t want to be replacing servo linkages and whatnot when a crawling expedition results in a roll down a hillside. Secondly, the price – currently it’s coming in at £449 – that’s 50% more than the E-Revo. Sure, it’s effectively 50% more capable, but still…

So, E-Revo it is, then!

Now it’s arrived, the first thing I’ll be doing is swapping out the receiver for the spare one from my Spektrum DX3S – the Traxxas radio gear is 27MHz, not 2.4GHz, and it’s easier to have the one transmitter and not have to worry about loads of batteries. I’ll be putting up some info on the swap out when I’ve done it.

Some photos of the E-Revo:

…and some video:

Click here to view the embedded video.

Click here to view the embedded video.

Traxxas E-Revo in red

Here’s my next big r/c purchase – a Traxxas E-Revo!

As much as I love my rock crawler, there are times when I’d like to go a little bit faster. The E-Revo should fill that gap nicely. Originally I was looking at the E-Maxx, which looks like it has much more ground clearance, but looking the specs it seems there’s on a small difference between the two, and the E-Revo is apparently a much more robust machine.

So far, though, it’s just in the “I want to buy one” stage – until there is more Traxxas stock in the UK (I’ll be getting it from Modelsport, I’ve used them before), all I can do is look…

I’m also thinking of getting the Spektrum DX3S controller. The E-Revo comes with everything, including radio gear, but it would mean carrying an extra transmitter if I took this and the crawler to the beach at the same time. With the DX3S, though, I could set it up for both cars and just use the one controller, since it comes with two receivers. I already have the DX6i controller for my helicopters, and that works nicely. Which is more than can be said for my flying skills at the moment…! Also, the DX3S can use sensors on the car to send data such as temperature and RPM back to the handset. Ok, that’s not really much use if I’m just pratting about on the beach, but it’s interesting…