Battery upgrade for Cycloctricty Stealth 1000w

I was hoping if someone could advise on this as a possible upgrade for the current 48v 12ah battery on my stealth?

 

http://www.eclipsebikes.com/whale-175ah-lithium-frame-battery-sanyo-cells-p-1129.html

 

I can just about get to work which is around 15 miles on the current battery using my preferred power and assistance settings.

 

I'm likely to be moving around 3 miles further from work, using pretty much the same route in. Unless I knock my power assistance levels down a fair bit, I don't think it will make that extra mileage.

 

So, I was wondering by how much I should expect this battery to take me....assuming it fits of course!

I'll think you'll find it a lot better. Your last battery was probably on the edge of its capability, while as that Eclipse one would be cruising.

 

It's very heavy for a bottle fixing. I'd add at least one more rivnut to your frame. Something like 4 in total would be good.

Thanks d8veh, Ill put it on my wish list, i'm doing 120 miles a week so another factor i need to take into account with the current one is battery degradation I guess.

Could a second battery simply be wired into the first one to give double the capacity?

Could a second battery simply be wired into the first one to give double the capacity?

Yes, but it's complicated. They have to be at the same voltage when you connect them and they have to be disconnected when you charge them.

 

If you could find or build a second battery that has a BMS where the charge and discharge wires go to the same pad, i.e. not separate charge and discharge mosfets, you can leave them permanently connected and charge both of them through the charge socket on your original battery.

OK thankyou. Just so I'm clear....if they were both fully charged when they were connected and they were re-charged separately then this should work.

Is that correct?

 

Has anyone tried this?

Yes, I do this with a pair of lawn mower batteries.d8veh gave me the same advise as above on the small battery bargain thread. My batteries where bought new and have always been used as a pair,except when I used them once each to see how they performed singly.If you do this with a used battery and a new one I think the used one will drag the new one down a bit capacity wise.ie amp hours.

 

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I suppose another way would be to have the two batteries separated by a switch and then when one was exhausted you could switch to the other.

I suppose another way would be to have the two batteries separated by a switch and then when one was exhausted you could switch to the other.

 

I thought about that for quite a while and came to the conclusion that it was just as easy to swap batteries. The advantage of having the batteries in parallel is less sag on the hills.

It doesn't matter if new or old or different types. The only thing that counts is voltage. I supposed if one was completely knackered, like self-discharging, you shouldn't do it.

All sounds very complicated,,,I think for me it would be easier to put the spare battery in my backpack and swap them over if needed, although its not the lightest battery in the world !

Has someone suggested getting a second charger? Think about topping up the battery at work?

I have to recharge my battery when i get to work ready for the return leg, so take the charger with me. Touch wood, Ive not managed to leave it at home yet

what kind of speed you ride at to flatten a 48V 12AH in 15 miles?

Variable speed really, along the off road paths probably around 19 to 20, on the road stretches, around 17. All depends on the wind and the weather. I have studded tyres on at the moment too, which dont help the cause either I guess.

I do put a fair amount of effort into it too, but not so much on the way to work that im dripping with sweat, I save that for the return leg.

 

Ive done 900 miles on it so far, dont know if the range is decreasing already

what kind of speed you ride at to flatten a 48V 12AH in 15 miles?

 

Power consumption seems very high to me.

 

I wonder if the battery is holding anything like 12ah.

 

It's unlikely to have lost capacity already, so the quoted figure may be ambitious, or the pack has been faulty from day one.

Is there a way I can check that with a standard multimeter? I have one, but dont really know how to use it, apart from to test for voltage

You might like to take a look at the Bosch range cockpit which will give you an idea of how speed kills range.

 

Pick the Performance Line Speed motor, turbo assist, and the 400 battery - nearest to yours - and have a tinker.

 

https://www.bosch-ebike.com/en/service/range-cockpit/

That gives some interesting results, thanks Rob. I would say im not getting quite what i should be from the battery after playing around with it a bit

Is there a way I can check that with a standard multimeter? I have one, but dont really know how to use it, apart from to test for voltage

Yes, simply measure the battery's voltage before you set off then again when you arrive at work. Post the readings here, we'll help you to make sense of these readings.

Yes, simply measure the battery's voltage before you set off then again when you arrive at work. Post the readings here, we'll help you to make sense of these readings.

 

Thats great, thanks. Might be a couple of days as manflu has started to kick in

Don't forget this is a 1kw hub @30a so can pull over 1400w.

There's nothing wrong with your battery. 15 miles would be about right.

Yes, simply measure the battery's voltage before you set off then again when you arrive at work. Post the readings here, we'll help you to make sense of these readings.

 

I know the overall feeling is that my battery is okay, but I thought I would post these results hopefully to confirm it...

 

Start voltage was 54.4

 

14.5 mile commute, took 56 minutes. Its a pretty flat journey along part dirt track, canal path and a couple of miles on average condition roads.

A lot less wind than there has been of late, but the cycle path was still quite wed and muddy in places. Ice spiker tyres on still, running at 60psi

My weight is around 80kg, bike around 25 and my bag probably 4 or 5 on my back.

Bike was set on high power, and I would say power assist level 1 for 25%, level 2 for 60% and level 3 for 15% of the journey. Don't recall using the throttle.

Felt like there was a bit of juice left when I got here, as it quite often does the almost empty fuel tank thing.....you know when you're car has enough fuel in the tank for another mile, if you are going down hill and the fuel is at the right end of the tank? Weird that, but it does seem to happen.

 

Voltage now when I am about to charge it is 49.1

 

Dont know if this is expected, but it shows 4 volts when not switched on, both before the ride and after.

When it has drained on the odd occasion when I get here, it takes 3 hours or so to charge....

 

 

Many thanks

Hi Andy,

 

Your battery is OK. The range of battery voltage is 10V (from full to empty), you use roughly 53% of your 12AH capacity for 15 miles, 19.3WH per mile. That's normal for a direct drive motor.

It is unpleasant to ride on a more than half empty battery when you may be pressed for time but I am pretty sure you can squeeze 3 more miles out of it without needing to buy a new battery.