Cordless tool battery

As a guess, the nominal voltage is fully charged - just marketing guff, as 'bigger is better' (same as using mAh, when 1000xmilli=1 - excessive precision over accuracy) - and it's actually 36V - 10x3.6V cells.

You'd have to take the battery apart (or find a video where someone does) to confirm. There should be overcurrent protection *somewhere*, but in some tools it's in the tool not in the battery. I think the cheaper tools have the BMS in the battery (and so a dumb wallwart/plastic box charger rather than a fancy Makita thing) so it might be OK.

Hard to say. I wouldn't be surprised if there's a motor temperature sensor that causes the BMS to shut off. But the battery might power up if it can't detect the temperature sensor, for testing etc.

Is this the Ferrex Activ Energy range, btw? There are plenty of videos of teardowns of those on YT. If it's a one-off special they often have a non-standard battery and those can be a bit pot luck.

(I've been spotting a load of cheap Chinese tools on Banggood this morning and wondering if there's any standardisation in the Chinese battery ecosystem. Not sure I'm willing to risk the £20 battery chainsaw though :-)

Theo

Yes it is a AEB 2040, I have two of them, £30 each.

By jumping B1 + to B2 - with a pair of male spade terminals I can series them up and then power the EV bike wheel motor at full voltage and it all seems to work. The T terminal not being used.

The bike came with 3 x 12V gel cells of 14Ah capacity but if I can get a cheap 36V 500W motor controller ( about 20 quid on ebay) I can do a test run with the two ferrex batteries giving me 5Ah if I can risk the current draw.

In fact I suspect 4 of these ferrex batteries in parallel would give me equivalent range at low power as the lead acid, for much less weight and cost. Full power use would favour the lead acid because of lower internal resistance.

I don't see how anyone might be able to answer this question without looking inside the grinder. Brian

As a guess, the nominal voltage is fully charged - just marketing guff, as 'bigger is better' (same as using mAh, when 1000xmilli=1 - excessive precision over accuracy) - and it's actually 36V - 10x3.6V cells.

Yes I think so too Peter, do you have a stutter?

What I need to find now is what a reasonable current draw would be on this battery.

What's the power rating of the Aldi grinder?

Whatever that figure is, divide it by 36, and knock off 20% to provide a margin.

You can look up the HE4 datasheet to see if there's a peak discharge or cell resistance listed - a motor load is going to have a substantial starting current.

Theo

Beware, that is probably not going to give you the peak current draw even for the AG.

Thanks Theo I'll have a watch of it.

Of course but you are supposed to start pedaling first.

In practice when I first got the e bike I only ever used the assistance up hills.