Nasty, Lazy and Cheap (12v 5A Charger Power Supply)
I don’t know about you, but I think the cost of RC power supplies is simply ridiculous. I have a hefty 30A bench supply that I was fed up of lugging around. I wasn’t about spend £50, £100 or even more on a ‘proper’ RC supply.
I wanted a small and light, and above all, cheap power supply to run my HOT POWER (AMAZING name!) charger off. So I made one…
In my Graupner Ultramat 14 charger I knew there was what looked like a laptop power supply to provide mains input capability. I know other chargers use something similar.
My charger only needed 5A input, so I trawled ebay for a laptop supply with 12v 5A output. £8.99 including delivery! Bargain.
Chopped the cable off short, soldered on some 4mm sockets. Then I ruined it by Shoe Gooing the cable to the side of the supply.
I could have gone to the trouble of putting it in a nice box etc, but that would have made it bigger. I could have left the leads dangling, but I wanted it neat and tidy.
The end result is brilliant, perfect for running a regular charger, or a soldering iron.
The boys laughed at my nasty construction skills, but funnily enough they agreed it was a perfect solution for less than a tenner.
Make one today. Hell, if you really want one I’ll make you one, for about £50.
Written by simon.
rcLazy LiPo Weight ™
rcLazy LiPo Weight (tm)
Using LiPos in a touring car has one big downside: they’re too light.
So you have to add masses of weight to them. Usually the shortcut is to stick weights all over the cells.
But, if you then want to use the cells in a different car, that needs different, or no weights at all, then you’re stuck.
Until I came up with my amazingly simple rcLazy LiPo Weight ™!
Underneath, simples.
How to make one:
- Get a lump of thin lead sheet, cut it a bit shorter than your lipo, then cut it to width by weight, I needed about 150g.
- Then, just fold it over the top of your lipo, perhaps with an extra fold on the outside edge to make it fit.
- Cover it with your favourite Fablon. (I do have a roll of very choice Smarties fablon, but I decided carbon look would be more acceptable by the Touring Car fraternity.)
Negatives
It’s not perfect, the weight it pretty high up in the car, and a bit towards the centre perhaps, but, it’s easy, you just clip it on, tape it down and race.
And, if you’re running a fat lipo, it might be a tight squeeze under your top deck.
Oh, and remember, it’s very bendy, so don’t squash it.
Written by simon.
Rating Springs for Radio Controlled Cars
Radio Controlled Car springs come in a variety of ratings, some hard, some soft, in a mixture of colours, from many different manufacturers, in different lengths etc.
It can be a bit of a minefield, especially if you’ve gathered springs from various sources over the years.
A really simple way of figuring out what you’ve got is to get all your springs for a particular car, make sure they are similar lengths, and then just get any two, put them on top of each other and press them together, the one that squashes up the most is softer.
Take the next and compare it with one of those, soon enough you’ll have all your springs in order of hard to soft.
Now, here’s the secret, MAKE A LIST! A really simple list of colours from hard to soft.
BUT, if you have several springs that appear to be the same colour, but of different hardness, get a permanent market, and on top and bottom, just put a dash, or two dashes, or three dashes. Then in your list, call it colour 1, colour 2, colour 3.
It’s so much easier then to think “right, I need a softer spring on the rear”, just look at your list and choose the softer one.
You then don’t have to have all the springs from the same manufacturer and you can mix and match to suit.
You can even go so far as put on your list some ‘known’ springs from a manufacturer, so you know roughly whereabouts in the list you are if you are comparing setups with other people etc.
Written by simon.
Weighting Tamiya M03 Mini for LiPo Cells
There are now several LiPo packs available that are shaped like a stick pack, so they will fit the Mini M-Chassis.
But! They are a LOT lighter than a pack of NiMhs. So much so, that most clubs that race minis now specify a minimum weight for all minis. It’s usually around 1350g.
This isn’t such a bad thing, as a LiPo mini without extra weight doesn’t handle very well anyway!
So, you need to add extra weight, usually in the order of around 200g. There are a few of ways of doing this.
1. Stick weights all over the place – ugly, but you can put them where you want to get the best handling. It’s up to you where you stick em.
2. Carefully put lead around the battery, and in front and rear bumpers – tidy, more concentrated weight where you want it. If you open up the chassis you’ll see a gap above the battery, you can put a strip of lead in there. It you take the bumpers off you’ll see they are hollow, you can fold some lead into those too. It’s very tempting to put lead in the large void at the back of the chassis, but that’s not really where you want to put it, the handling will be effected a lot.
3. Create lead packing strips to fit above and below LiPo – accurately imitates a NiMh pack, so handling isn’t changed whatever battery you use – and you can use either a NiMh or LiPo pack. Above the LiPo is usually a hollow, create a lead strip to fit into that hollow. Underneath the battery you can use a double thickness strip, it should hold in by friction. If you wrap the lead in tape it looks nicer, and can help you get the right thickness so the strip holds itself in. You can stick it to the LiPo if you wish, but then that LiPo can only be used in that car. The main advantage of this is the main extra weight is below the Lipo, and it actually ends up with a lower centre of gravity than with a NiMh.
The performance difference between NiMh and LiPo in an M03 is minimal, the voltage curve of a LiPo is a little better, so may be a bit stronger in the latter part of a race in comparison with NiMh.
Written by simon.
How To Add a 40mm Cooling Fan to Tamiya M03 Mini
Small fans are often used on Radio Controlled Cars, for cooling speed controls, or motors.
I was running a 30mm 3 Racing fan on my Tamiya M03 Mini, and I recently ’stuck my finger through it’. This is common occurence, where a misplaced finger causes the fan to break.
I had repaired it with superglue and it had been okay for a meeting or two.
In one run though, I felt I was down on power, and I reckon it’s cos the fan broke again, and end up looking like this…
Broken 3-Racing 30mm Fan
I think that was enough to jam it, and cause an increased power drain on the batteries, and hence a reduction in power to the motor, slowing the car.
Time to replace it, I wondered if there was a way of fitting a larger, 40mm fan in a similar place.
After some measuring, a failed attempt at a mounting bracket, I came up with a small bracket that mounts a 40mm fan above the motor.
40mm Fan and Bracket
The bracket is a simple piece of aluminium angle, with two M3 bolts securing it to the fan, and one M3 bolt securing it to the chassis.
Simple and neat. A 40mm fan is more effective and stronger than a 30mm fan.
