Battery power

Psycosis

Pedelecer
Oct 28, 2009
135
0
Walton On Thames
I need to figure out for once and for all what kind of battery i need.

I looked on many websites and some people don't rate the ping batteries to deliver the power for the bigger motors.
I have a 900w cyclone motor on my bike and i know it does 2800rpm maximum.

At half throttle for 10 miles, i need to work out what the usage will be on flat ground with no pedaling by me.

As per my other post, 3 SLA's got me 5 miles, and the top speed notched 20mph with no pedaling. I won't have enough space to stick loads of SLA's on the bike, so i was also wondering can you use a 24v LiFePo4 battery pack with this motor?

What difference will it make?
 

Fecn

Esteemed Pedelecer
Sep 28, 2008
491
2
Warlingham, Surrey
I believe the 36v cyclone controller has it's cutoff voltage set at 24v, so you might have issues using a lower voltage pack. I'd also expect you to get around a 50% drop in power (e.g. 450W instead of 900W). That would be around 20A current @ 24V.

Your range on flat ground will depend very much on your speed. Above 15mph and wind resistance becomes very significant. Below 10mph and you can roll along pretty much indefinitely. 10Wh/mile is an often quoted figure for e-bike power consumption, but I believe that includes a bit of pedalling... so I guess 15-20Wh/mile if you're not assisting on the pedals.

If you were looking for a 36V ping pack, I reckon you'd need at least the 15Ah version (7.5kg) to get the kind of current delivery you need. (30A @ 36V = 1080W).

It is also worth considering the voltages in-between 24 and 36V - I personally have a 9-series 29.7V, 20Ah ping pack which I specced up as a closer match to 29.4V 7-cell Li-Ion packs. Mr. Ping will build you any voltage/amphours you require if you ask. Ping will also customise BMSes and chargers to suit.
 
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NRG

Esteemed Pedelecer
Oct 6, 2009
2,592
10
Good advise from Fecn.

I'd stick with 36v 15Ah minimum or the 20Ah verion (prefered). The 15Ah is actually 5.6Kg so not too bad the 20Ah is 7.5Kg

What I have learnt is you are constrained by practical size vs Ah more than anything else regarding batterys, the 20Ah Ping mentioned above is a rather large 300x105x150 IMHO....although no where near as large as using SLA's!

They do a 30Ah version as well if you have the space and are feeling rich!

Results for V2.5 LiFePO4 Battery Packs:36V V2.5 LiFePO4 Battery Packs

Your only alternative is to go DIY and look at the RC Lipo packs to build up the capacity and voltage you need but this is not for the faint hearted...
 

daniel.weck

Esteemed Pedelecer
Aug 8, 2009
1,224
1
They do a 30Ah version as well if you have the space and are feeling rich!
11.5 kg ... my Brompton weights less :p (without accessories)
 

Psycosis

Pedelecer
Oct 28, 2009
135
0
Walton On Thames
what i need now is for someone to lend me a 20ah battery so i can see with a little pedaling if it will do the distance?
Any offers? :D

I have emailed Mr Ping and asked him if he can make me a 36v 20ah battery thats triangular shaped. It looks like this will be the only option really and i think with a bit of leg power as well i might actually make it to work with 20amps. i did look at the 30amp batteries but they are a bit too expensive i think.
i could always rig something with my existing SLA's if i needed to add 12v and 28amps, is that actually going to do anything?

There is one killer hill on the way to work, its a monster, and i doubt i could cycle up it at any speed, bizzarely there are i think 5 speed cameras on it, catch people on the way down.

Thanks for your help all
 
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