Upgrading to lipo, other electronics needed.

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coolspeedbot
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Upgrading to lipo, other electronics needed.

Post by coolspeedbot »

Hay guys thought my should ask about electronics needed to run the robot on a lipo.

Is it a case of using ESCs with a BEC in them? Also will I still need to include a fuse?
James Booth
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BeligerAnt
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Re: Upgrading to lipo, other electronics needed.

Post by BeligerAnt »

As with most things, the short answer is "it depends".

Some receivers will run happily off a 2S LiPo, but the majority are rated at about 6V maximum. So you generally need a voltage regulator to generate (typically) 5V to power the receiver. This is known in RC circles as a BEC (battery elimination circuit, from the time when aircraft would have separate power and receiver batteries) and may be built into an ESC.

If you run two separate ESCs, one for each wheel, you have to disconnect the power wire (usually red) from one of them to avoid the 2 BECs fighting over who gets to power the receiver, leading to the rapid demise of the loser!

So you probably need a BEC, which may already be built into your ESC.

If you run a weapon servo you may need to check that it can handle a 2S LiPo (8.4V when fully charged), otherwise you will need a voltage regulator for it too. In theory you can use the same BEC for the receiver and servo, but servos take quite a lot of current and most BECs are only designed to power a receiver. If the BEC isn't up to it you get lots of weird effects when you try to operate the servo and the voltage to the receiver drops, often causing it to reset.

If you're using one of Rory's boards I *think* it takes care of all this for you, but best to ask the man himself...
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Rapidrory
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Re: Upgrading to lipo, other electronics needed.

Post by Rapidrory »

BeligerAnt wrote:If you're using one of Rory's boards I *think* it takes care of all this for you, but best to ask the man himself...
Yes, it does. Just plug in a 2S lipo and you're good to go.
Rory Mangles - Team Nuts

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NanoTwo Motor Controllers: https://nutsandbots.co.uk/product/nanotwodualesc
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coolspeedbot
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Re: Upgrading to lipo, other electronics needed.

Post by coolspeedbot »

Oh I see, well currently both of my bots use servo boards as ESCs so most likely will need to replace them anyway.
James Booth
Team Coolspeedbot

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Killer-Wolf (2.0), Bunny-Ears (1.5), Blue-Terror (CAD).
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CSB 1 (retired) CSB 2 (under construction).
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coolspeedbot
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Re: Upgrading to lipo, other electronics needed.

Post by coolspeedbot »

Ok now that I have recovered from my uni graduation and trip home, I can try to respond better.

I did a quick online search and from what I can tell the 2 lemon RXs I bought months ago, 'should' handle the two cell lipo.

Now in regards to ESCs, I had taken an interest in Rory's Nano-twos, but the dsmx, dsm2 thing is a pain as my transmitter is dsmx and I wasn't really looking to invest in a new transmitter just yet.
James Booth
Team Coolspeedbot

Antweights:
Killer-Wolf (2.0), Bunny-Ears (1.5), Blue-Terror (CAD).
Featherweights:
CSB 1 (retired) CSB 2 (under construction).
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BeligerAnt
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Re: Upgrading to lipo, other electronics needed.

Post by BeligerAnt »

If you are using servo boards from standard size servos they should run OK on a 2S LiPo (mine do!), but if you use boards from micro servos they might struggle (or they might be OK...)
Since the Lemon Rx is OK you might be good to go.
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coolspeedbot
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Re: Upgrading to lipo, other electronics needed.

Post by coolspeedbot »

Oh thats handy, but don't I still need a BEC?
James Booth
Team Coolspeedbot

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Killer-Wolf (2.0), Bunny-Ears (1.5), Blue-Terror (CAD).
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CSB 1 (retired) CSB 2 (under construction).
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BeligerAnt
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Re: Upgrading to lipo, other electronics needed.

Post by BeligerAnt »

Not if everything is OK on the battery voltage. The Rx has its own internal voltage regulator (basically a built-in BEC) and the servo boards will work on the battery voltage.
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coolspeedbot
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Re: Upgrading to lipo, other electronics needed.

Post by coolspeedbot »

Oh cool, so all I need to do now is get new weapon servos to handle the voltage and Bunny-Ears and Killer-Wolf will be up and running.

Thanks
James Booth
Team Coolspeedbot

Antweights:
Killer-Wolf (2.0), Bunny-Ears (1.5), Blue-Terror (CAD).
Featherweights:
CSB 1 (retired) CSB 2 (under construction).
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Re: Upgrading to lipo, other electronics needed.

Post by Rapidrory »

The SG90s servo boards don't handle anything above 6v.
Rory Mangles - Team Nuts

Robots: Nuts 2 and many more...

NanoTwo Motor Controllers: https://nutsandbots.co.uk/product/nanotwodualesc
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