E bike battery

[gregwilson]

Please can anyone help I have just acquired a city e ride bike without a battery it measures 43.5 cm from the base to the centre of the locking pin and the square it fits in is 85 x 85 cm the plug that fits into the opposite side of the key is a three pin plug cannot find one anywhere does anybody know where I can purchase a battery

[hemo]

Show some pics of wher the battery sits.

[gregwilson]

Here are the pictures

[stodd]

That looks fairly standard, but there are too many little gotchas that I could miss so I'm not going to risk your money by suggesting an answer. I suggest asking (with the pics) at
https://www.pedelecs.co.uk/forum/forums ... cussion.2/

[gregwilson]

Sorry but not as standard as you think this is why I am asking for help as for the other forum would not let me join keeps saying it uses cookies and will not let me go any further

[Jdsk]

That looks fairly standard, but there are too many little gotchas that I could miss so I'm not going to risk your money by suggesting an answer. I suggest asking (with the pics) at
https://www.pedelecs.co.uk/forum/forums ... cussion.2/

And is this the specialist supplier who has been recommended in this forum on several occasions:

eBike Batteries:
https://ebikebatteries.co.uk

?

Thanks

Jonathan

[gregwilson]

Thanks for the email address for the battery specialist have just sent email anymore suggestions please

[hemo]

The 3 pin is the dis charge connection and is a kettle plug type and pretty obsolete on bikes today.
The battery is simialr to a silver fish battery case type, on ebay one can buy one with a new mounting kit to ensure the batteyr locks correctly. On pedelec's i have helped 3 or 4 people with this type of battery to get their Freego eagles working again.
Silver fish footprint is approx. 110mm x 76mm.

One is best to but a new battery with the fitting kit and charger, the batteries use bottom plate discharge contacts and then chop that discharge lead off and rewire it to the bottom discharge plate of the new battery. The likely hood is only two wires will be utilised the V+ & V-.

[gregwilson]

Great advice a bit confused with the amps some are ten amps which do I use also not too sure with the wiring please could you draw a diagram of the wiring because as you said it’s a kettle plug with three wires ?

[hemo]

Battery wise as long ad the correct voltage battery is bought then Ah wise is doesn't matter if it is 10ah, 12ah, 16ah or even 20ah. The Ah rating is just the battery capacity, the larger the capacity the longer the range and charging time at 2 amps.

I suspect the kettle plug althlough 3 pins outs only uses two as most geneirc batteries would be. One ideally shoud trace the discharge wiring back to the controller and confirm if only two wires are connected.

With a new silverfish if it fits the behind the seat battery space, one would mount the discharge plate (some are marked + & -) so that this corresponds with the battery polarity. The wires from the kettle plug (Red v+ & the Black V-) would need soldering from the underside of the base plate pins and a bit of heat shrink to insulate/protect the solder joint.

[hemo]

If the battery discharge wiring uses more then two wires connected to the controller then it is using the third wire for some other communication, this may mean a bespoke propriatory battery is needed which likely as it stands would make your bike obsolete and unusable.
So one needs to trace the wiring to see if indeed the third wire is used,the kettle type plug was mainly used because it only connects one way so no chance of cross polarity when connecting. As i mentioned that type of connector is pretty much obsolete in to days market and is an old style connection, I woul dbe surprised if the middle pin is actaull used. connected at the controller.

Most China type hub bike use generic electronics only needing two battery charge and discharge wires, these types of bikes can use any generic battery of the correct voltage.

[gregwilson]

Please can you explain the output on the hub 250 w have seen a battery on eBay which has everything you have described fittings charger 36 v but the output is 350w would this be ok if not could you point out which battery is suitable on eBay please

[stodd]

Please can you explain the output on the hub 250 w have seen a battery on eBay which has everything you have described fittings charger 36 v but the output is 350w would this be ok if not could you point out which battery is suitable on eBay please

I'm a bit confused with that.
Charger is to do with battery input. A typical charger will charge a battery at 2amps, so 72w for 36v.
A fast charger may be around 4 amps,144w.That is already enough that consistent use will shorten the life of a typical battery.

This is separate from the output power needed from the battery. 250w needs around 7amps; the battery needs to be able to provide that pretty much continuously without problems. Even a 250w motor peaks at much more power, so the battery should be able deliver much more than the 7amps for short bursts; allowing for inefficiencies along the way around 15amps or probably more.

[hemo]

I wouldn't worry about the sales blurb saying battery is suitable for 350w hubs/motors, what counts is does the battery continuous amps output rating supply more then the controller max amps rating.

Typically most 250w/36v rated ebikes have controllers that are rated as 7a nominal which complies with the 250w output rating, however these 7a controllers can temporary out put 14/15a but not as a continuous rating so therorectically allowing for some efficancy loss an ebike with a 7a controller can output some 400w - 450w. Ideally the battery needs to be rated for 20a continuous and it will be fine for the 250w ebike.

[hemo]

Please can you explain the output on the hub 250 w have seen a battery on eBay which has everything you have described fittings charger 36 v but the output is 350w would this be ok if not could you point out which battery is suitable on eBay please

The battery will likely be more than ample for your bike, but to be sure post a link to the battery so we can check out the spec's.