Crazy idea, or not? Volts, batteries.

[Harry Bloomfield]

The mobility scooter, runs on 60v dc, 5x 20ah 12v sealed lead acid batteries. It is driven by a 60v 1000w, 3ph brushless motor. I'm wondering if, when these batteries need replacement, it might be worth considering fitting 2x larger 12v batteries, much larger ah, using a 24 to 60v dc to dc inverter. The two, fitted into the space of 5, would allow for much more capacity.

 

[big-all]

sometimes good ideas in our heads dont work in practice

you have a given volume with 60x12=720wh regardless off how you get it
reduce the volts increase the cable size and transmission losses

 

[ericmark]

My scooter uses two x 35 Ah, daft they will lift out of the scooter, but can only charge them in the scooter. Range 25 miles, although at 4 MPH no way would I do 25 miles, charge time around 10 hours.

My e-bike has a 48 volt battery, 12 Ah, lithium. OK also peddling a little, and it is really very little, range about the same, did Shrewsbury to Welshpool just using the cycle route, which is far more up/down than main road. The battery around ½ weight of scooter battery, and can charge off the bike, charge time around 3 hours. Motor smaller than scooter, but not by much, and 16 MPH instead of 4 MPH, and can be carried either inside behind front seats in an old Honda Jazz, or outside on a bike rack.

The scooter will come apart, so will fit in Jazz, but takes up the whole of the rear seat and boot, e-bike fits behind front seats with seat fobs folded up. So boot unused. It is a folding e-bike.

I can get e-bike on the train, no change with the scooter. Neither will go on the bus. I have recharged my e-bike battery in the train station, I am sure I could take the battery into a supermarket or pub and charge it, but since can't charge off the scooter, no change of charging with scooter.

I know the electric quad comes with an adaptor so it can be charged from EV charging point, good photo opportunity there, e-bike or mobility scooter plugged into an EV charging point?

 

[Harry Bloomfield]

My scooter uses two x 35 Ah, daft they will lift out of the scooter, but can only charge them in the scooter. Range 25 miles, although at 4 MPH no way would I do 25 miles, charge time around 10 hours.

This one has a speed limiter switch - 6kph (4mph), 12kph, and a naughty 25kph setting.

 

[endecotp]

The mobility scooter, runs on 60v dc, 5x 20ah 12v sealed lead acid batteries. It is driven by a 60v 1000w, 3ph brushless motor. I'm wondering if, when these batteries need replacement, it might be worth considering fitting 2x larger 12v batteries, much larger ah, using a 24 to 60v dc to dc inverter. The two, fitted into the space of 5, would allow for much more capacity.

If that would work better, wouldn’t they have designed it like that in the first place?

 

[Harry Bloomfield]

you have a given volume with 60x12=720wh regardless off how you get it
reduce the volts increase the cable size and transmission losses

60 x 20 = 1200wH. I had in mind, maybe 2x 12v 100ah, in series = 24 x 100 = 2400wh, less inverter losses. 2 batteries, instead of 5, cheaper, and more range.

 

[big-all]

60 x 20 = 1200wH. I had in mind, maybe 2x 12v 100ah, in series = 24 x 100 = 2400wh, less inverter losses. 2 batteries, instead of 5, cheaper, and more range.

they are 12v not 20
to get the the watt hour you multiply volts times amps

connecting them in series or series parallel will still give you the same answer/value
only the transmission losses will change

 

[Harry Bloomfield]

they are 12v not 20

OK different way...

12v x 20ah x 5batteries = 1200wh. My 60 was 60v, x 20ah = 1200

 

[flameport]

If you want more range, then forget about lead-acid and use LFP or similar,
example of capacity with physical dimensions: https://vi.aliexpress.com/item/1005008704595225.html

 

[JohnW2]

The mobility scooter, runs on 60v dc, 5x 20ah 12v sealed lead acid batteries. It is driven by a 60v 1000w, 3ph brushless motor. I'm wondering if, when these batteries need replacement, it might be worth considering fitting 2x larger 12v batteries, much larger ah, using a 24 to 60v dc to dc inverter. The two, fitted into the space of 5, would allow for much more capacity.

As has been said, it's Wh, not Ah, that matters.

If you replaced the existing 6 5 x 20 Ah batters with 2 x 50 Ah ones (plus an inverter), that would be electrically the same (give or take the 'inverter losses') - 1,200 Wh in both cases. If, as you suggest, there was space for 2 x 100 Ah ones (plus an inverter), then you would double the capacity - equivalent to having 6 x 40 Ah ones (2,400 Wh in both cases).

But, if you wanted to go down that road, why change to 2 x 100 Ah batteries (plus a 24 to 60 V intverter), rather than changing to just one 12V 200 Ah battery (plus a 12 to 60 V inverter)?

 

[ericmark]

My e-bike is lithium, there is a dial to show how much left, but when it goes, it goes, no limping home. The mobility scooter claimed a 25-mile range, at 4 MPH legal limit, that's around 6 hours constant running. Why would anyone what more?

It is reasonably easy to push an e-bike, in fact you can use it as a push-bike. I remember the mobility scooter conking out, and trying to push it home, turned out bad battery connection, but to push and steer is not easy.

 

[EFLImpudence]

As has been said, it's Wh, not Ah, that matters.

Does it not work out the same?

If you replaced the existing 6 x 20 Ah batters

Typo just to confuse everyone.

 

[Harry Bloomfield]

If you want more range, then forget about lead-acid and use LFP or similar,
example of capacity with physical dimensions: https://vi.aliexpress.com/item/1005008704595225.html

Thanks, that is an even better, cheaper option. The manufacturer offers a similar option, but at three times the cost. I was even considering building my own LFP battery up from cells, and adding a BMS, but that would be a more or less drop in option. The scooter is new, the batteries new LA's, so at the moment, just looking at options for the future.

 

[Harry Bloomfield]

It is reasonably easy to push an e-bike, in fact you can use it as a push-bike. I remember the mobility scooter conking out, and trying to push it home, turned out bad battery connection, but to push and steer is not easy.

Throw a tow rope in, attach each end, to each end of the handlebar, and tow it up the hills. Mine has proper brake levers, but I don't know what you might do, to tow one with an automatic, mag brake.

 

[JohnW2]

Does it not work out the same?

It does if the voltage is the same in the things one is comparing.

Typo just to confuse everyone.

Just to keep you on your toes (although the '5' and '6' keys are adjacent!) My apologies - now corrected.