Motors and batteries

[jal03]

At the minute, I'm trying to assemble the money and components for my first build, a FW axebot. I am planning on buying some 18v drills for the drive. I am also planning to run the whole robot off the same set of batteries. I had a few questions:

• I understand that FW electric axes normally use 24v scooter motors. Would I be able to run these off the same battery as my 18v drill drive motors, or would I need higher-voltage drive motors to avoid overvolting them too much?
• If so, what voltage and Ah rating would be recommended for this battery?

Thanks.

[typhoon_driver]

You should be able to run the 18v drills off a 24v battery pack fine. The golden rule is that you can get away with overvolting a motor by 1.5 times it's rated voltage and it should be able to handle it.

I'd recommend a battery pack in the 3Ah plus range if going for lipo.

[jal03]

Ah, ok. Thank you!

[willcaddy]

I am in the same situation xD

Hey there,

I am also working on my first build! I am using 18v drill motors too and was also wondering the same thing!

I'm looking at driving an axe too but at the moment I'm just looking to get the drive up and running!

What would you say is currently the best brand/model of batteries and chargers for lipo's at the moment?

Thanks a lot!

Will

[jal03]

On the subject of batteries, I'm considering LiPos, but I'm not sure because I've had no experience with them and realise that they are quite high-maintenance (and come with a risk of bursting into flames if done wrong.) I may use LiPos, but if not, would NiMh be viable, and if so what ah rating should they be?

[daveimi]

Nimh are getting expensive as they're old tech. Get lipo's and learn to use them properly, save you a ton of cash.

[emisnug]

If you want to alleviate the risk of LiPos bursting into flames, it's well worth a look at LiFePO4 batteries. A bit heavier than LiPos, but no flame out risk

[jal03]

OK, thank you for the advice.

[jal03]

Can anyone recommend any specific batteries that they have used please? I'm looking for a battery that would be suitable to run both a set of 18v drive motors and a 24v axe motor on. I've looked around, but not been able to find anything. Thanks

[jal03]

Would Li-Ion be viable? I ask as I've realised you can't get 24v lipos and LiFePO4s are, well, super expensive. I've found a 24V, 3000mah li-ion for a reasonable price, and was wondering if it would be viable to use.

[Theo]

No. If I'm right, Lithium ion can be a generic term for many lithium-based battery chemistries. The only lithium batteries allowed are LiPo and LiFePo4. You can get a 6 cell LiPo, that is almost 24v, the scooter motor won't suffer much. Also, though you can overvolt drill motors, they won't last nearly as long with a voltage that high, so 2ish volts less will make them last longer.

[Maxamuslead]

scooter motor will be fine at 24, as it meant to run at 24, I am toying if i can give it more volts (7s 8s) however finding a ESC which isn't too big easy.

[maddox10]

Super expensive LiPo? Depends on what you want. For 6S you could use 2 of these 3S packs in series. That's about £20 for a powerpack.

Brushed ESC's for more than 6S , you're thinking heavyweight material then. Vyper and Victors come to mind.

[jal03]

Ok, thanks to all for the advice. I will most likely use either a) a 22.2v lipo battery or b) two of the Turnigy packs in series.

[jal03]

Ok, I'm about to buy a couple of the Turnigy packs that Maddox suggested; before I do, though, does anyone have a charger that they can recommend? Preferably not too expensive. Thanks!