Time to decide upon which among the battery-packs amongst the inventory is usable for testing the prototype. The motor is rated at 24V but LiPo batteries (like the ones in your phone) for these purposes at least are produced like individual sheets of lasagne packed together: in each of these battery packs there are six (hence the 6S moniker).
Each of the cells in these packs is rated at 3.7 volts, so six together produce 22.2V as it says on the tin. The problem with powering a 24V motor is therefore that it falls between 6S (22.2V) and 7S (25.9V) battery-packs, although the latter would be usable albeit 'over-boosting' the motor at the higher throttle settings.
Note the different connectors: AS150 on the larger pack and XT60 on the smaller, and there are two key differences viz. (a) you can connect the former in series to double up on packs and extend your endurance at the risk of (b) joining the wrong connectors together to short-circuit the pack. I've done this with those larger packs ~ twice ~ and the effect is something like holding a small stick of gelignite whilst it goes off.
Perhaps the key difference between the packs though is the 'C' rating and in these terms at least the smaller pack wins hands down, which is why perhaps it is called a 'Supersport Pro' instead of a 'Supersport XL'. I guess the XL stands for XL, which it certainly is at 2.70 kilos in weight... which is why a 2.50 kilo bar-bell weight appears above, because during static testing in water it is a better means of ballasting the prototype altogether than using the real thing.
The 'C' rating represents the rate at which a pack can dump available energy if called upon to do so, and the smaller pack can do this at sixty-five times its regular rate in small bursts, and thirty-five times in short bursts i.e. 65C/35C as against 35C/20C in the case of the larger pack. This incidentally is why LiPos are used wherever higher instantaneous power is required ~ as with drones ~ while for endurance applications like motor vehicles Li-ion is the chemistry of choice.
At first glance then I am reassured that we can run with the smaller packs, not least because (a) they can deliver the extra amperage which we may need whilst (b) they are nearly eight times lighter at 366 grams instead of 2695.
Of course we could switch to higher voltage 7S packs to wring maximum power out of the motors, but as these retail at the best part of £200 per pack they can stay there.
Nor will the larger packs that we already have become redundant, as they'll be hooked up for the static test-runs that will call upon their greater endurance.
Next we'll get into performance data, which as ever we'll take with a pinch of salt.
