Free batteries in exchange for genious

Low

Pedelecer
Dec 5, 2016
142
42
45
England norfolk
Mostly after tech advice..

Work for the NHS, we have a number of portable bits of emergecy kit that use 12v 2.3 batteries... These have to be in peak condition and are replaced every 2 years, instead of being destroyed i have aquired about 20 of them, they are mostly from electrical devices such as the manga-elk, an air cushion for helping people up from the floor.. I estimate the batteries have had very little use, what id like to know is if they can be used at all.

Image you are explaining this to a 37 year old toddler.. Literally saw the ridiculous zombie ebike thing and just started hunting from then so really know very little.

Really wanted a mega power non road legal 1500wat machine but the cost is too much for me.

So if you guys wanted 30+mph and 15 mile range and if these batteries could be strung together to do that, what woukd be the absolute cheapest way?

If anyone would be kind enough to be a go-to during my build il happily post you a half dozen 12 volt lead batteries

Kindest regards

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cyclebuddy

Esteemed Pedelecer
Nov 2, 2016
1,553
736
Beds & Norfolk
To get that kind of speed and range (30mph and 15 miles), I’d guess you’d likely need something like a 48-volt 1000-watt motor and a 15-amp battery (720 watts). If my maths is right, using these 12 volt batteries at 2.3 amps, you’d need to run 4 in series to give 48 volts, and 6 banks of 4 like this in parallel to give you 13.8Ah to get something near that 15 mile range. That’s 24 of these batteries wired together (662 watts)... the size and weight alone will make the bike frame buckle before you even get on the bike!

Lead acid chemistry isn’t the best for an e-bike application given their size and weight, which is why current bikes use lighter higher energy density Lithium batteries.

I’d think your Lead batteries probably have some life and value in them after just 2 years use (sulphate on the lead plates would be the killer if left undercharged and idle for any length of time), but these are intended for “standby and cyclic use” suggesting they are more akin to “leisure” batteries rather than “starter” batteries designed to give higher burst energy. Maybe you could sell these on the bay, and start saving for the "ridiculous zombie e-bike" you crave?
 

Low

Pedelecer
Dec 5, 2016
142
42
45
England norfolk
Perfect reply... Just looking at the math you have provided too very helpfull... These batterys arnt huge ones by any means, i think 12 wouldnt affect structure of the bike too badly... Quite a lightweight my self :)

If i were to have 12 of these, aim for 36 volts, could i make a usable bike from that, maybe lots of range loss and power loss but useable none the less, zombies cant run anyway right?

Again genuine thanks really well wriite help
 

Low

Pedelecer
Dec 5, 2016
142
42
45
England norfolk
With 12 of these and a 500 watt motor in 3 banks of 4 at 36 volts would that give me a chance?
Fyi these batteries are about an inch wide and 7 inchs long, 12 is defo ok weight wise.

Really trying to stick to lead acid because of the continued availability of them, i know im prob wrong but i trust them more too.

Thanks again
 

cyclebuddy

Esteemed Pedelecer
Nov 2, 2016
1,553
736
Beds & Norfolk
I really would steer clear of using your Lead acid batteries. The excess battery weight reduces power and range from the motor and will significantly compromise the bikes handling. There’re difficulties mounting all this weight/bulk safely on the frame too. And if you had an off-road tumble (bearing in mind that a bike of this power can only be ridden off-road on private land), I certainly wouldn’t want a cracked Lead Acid battery case leaking sulphuric acid all over me either – the skin burns would be horrific.

There are a few 48-volt bikes with powerful 1000-watt motors and proper lightweight Lithium batteries for around the £1000 mark (Pedalease offer a couple for well under that – around £700): As a valued NHS worker, you could probably wangle a purchase under the Cycle-2-Work scheme... get the bike now, and have the cost deducted from salary over time at a much reduced overall price because you don’t pay the tax. It might be worth asking about?

Or you could always buy such a bike and then, when the Lithium battery eventually dies, consider the practicalities of after-market mounting and using your Lead Acid batteries on it - electrically, the motor doesn't care whether it's powered from Lead Acid or Lithium, just that the voltage is right and there's enough current available to feed it.
 
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cyclebuddy

Esteemed Pedelecer
Nov 2, 2016
1,553
736
Beds & Norfolk
Sorry I killed your dream :(
 
D

Deleted member 4366

Guest
Another thing: They're standby batteries, which are not suitable for the high currents that electric vehicles need. You need cranking batteries or special electric vehicle ones if you want to use SLAs
 
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Low

Pedelecer
Dec 5, 2016
142
42
45
England norfolk
Thank you all for putting me on the right track, pedalease do a nice white number 1000w 48v with battery for 730 quid all in!

Have sent message on their website re cycle to work scheme, just waiting on a reply
 
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Alan Quay

Esteemed Pedelecer
Dec 4, 2012
2,351
1,076
Devon
To get that kind of speed and range (30mph and 15 miles), I’d guess you’d likely need something like a 48-volt 1000-watt motor and a 15-amp battery (720 watts). If my maths is right, using these 12 volt batteries at 2.3 amps, you’d need to run 4 in series to give 48 volts, and 6 banks of 4 like this in parallel to give you 13.8Ah to get something near that 15 mile range. That’s 24 of these batteries wired together (662 watts)... the size and weight alone will make the bike frame buckle before you even get on the bike!

Lead acid chemistry isn’t the best for an e-bike application given their size and weight, which is why current bikes use lighter higher energy density Lithium batteries.

I’d think your Lead batteries probably have some life and value in them after just 2 years use (sulphate on the lead plates would be the killer if left undercharged and idle for any length of time), but these are intended for “standby and cyclic use” suggesting they are more akin to “leisure” batteries rather than “starter” batteries designed to give higher burst energy. Maybe you could sell these on the bay, and start saving for the "ridiculous zombie e-bike" you crave?
To make things worse, typically you can only use 50% of an SLA, less from a low discharge rate one. So, the OP would need 48 of them. Even then, voltage sag would be an issue.

Sorry, there's no such things as a free lunch. Or battery.


Sent from my HTC 10 using Tapatalk
 

cyclebuddy

Esteemed Pedelecer
Nov 2, 2016
1,553
736
Beds & Norfolk
If we’re really going to cover all the bases, we’d also need to consider these are used/discarded part-worn batteries... stringing together a batch of unbalanced, inconsistently worn cells isn’t likely to deliver reliable performance either.

What these particular ex-NHS "cyclic"/leisure batteries would be BRILLIANT for however is an off-grid, solar powered battery bank for recharging the OP’s new e-bike Lithium battery. A couple of low-cost solar panels at the front end, and a low cost DP/regulator circuit at the tail (or a cheap DC-AC mains inverter feeding the standard e-bike charger), and hey-presto... Your own very "green", personal e-bike recharging station giving free energy. I’d stick one in my garden shed for sure!
 
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Low

Pedelecer
Dec 5, 2016
142
42
45
England norfolk
Now that i like! Thanks fir the tip!


You guys dont happen to have a phone number for pedalease do you, they arnt replying and i cant find a number anywhere!
 

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