battery aand repairable parts

[Eddie F]

Hi I’m having to post here as i cant post in the tec area.

I am in the market for a ebike and the only weak point is the battery life. I will not be thrashing the bike I’m getting as only doing 10 miles a day and I will peddle just need the help up the hills. I am doing this to save £`s. if i get a 24v system with a battery fitted to the frame, carrier, and 10ah, say, and after 12 months fails for whatever reason. I could just get together any type of battery or batteries wired together as long as I could get connected to the wiring system. Would this power the bike.

If the controller failed, What does the controller do?(not the twist grip `throttle`) but the electrical controller. could the battery be wired direct to the motor via a on off switch.
These maybe naive questions but i need to know if any of the `repairs` can be done myself, as i am quite handy but not trained.
I look forward to you advice
eddie

 

[NRG]

Anything is possible with time, money and know how.

First you can't connect battery to motor directly, motors I believe are generally brushless 3 phase with the controller switching current to each phase in turn so a controller is essential.

Installing an alternative battery can be done but you will be looking at a new charger and BMS if its of different chemistry. Plus you may also need to look at a different mounting location...

Forgot to add that replacement controllers are cheap and available.

 

[eddieo]

Anything is possible with time, money and know how.

Indeed! and one member on here built his own bike and trounced all the manufacturers offerings at Prestiegne last year. but for us mere mortals a kit or ready built bike is a safer option. You need a reliable bike especially if commuting. if you have a nice bike already, a kit from the likes of Alien have good reviews or if money tight there are cheaper but probably more risky alternatives via ebay

 

[Alex728]

Don't Alien now make entire bikes as well which are also keenly priced? I think they've also expanded their customer service resources which is a good thing..

 

[flecc]

You are posting in the right area for queries Eddie F, the Tech area is for permanent items.

Most batteries in use now on e-bikes are lithium types, quite expensive and generally lasting around two years, though the dearest ones with your use could be ok for 3 years.

With few suitable NiMh cells available now, the only practical alterrnative is the SLA type (sealed lead acid). These are between a quarter and a half the lithium price for a set, but they only last around a year to 18 months generally. Also they are extremely heavy and don't give the range you might expect in comparison, since this type can only deliver about half their content at the high currents that e-bike motors need. However, using the popular 7 Ah types they'd be ok for your 10 miles daily.

Motors and controllers are generally very reliable but easily replaced by anyone practical. The most important thing is to buy an established make which will still be around when you need parts. Very few ebay sources qualify in this respect, though Alien and Synergie are probably honourable exceptions.
.

 

[daniel.weck]

First you can't connect battery to motor directly, motors I believe are generally brushless 3 phase with the controller switching current to each phase in turn so a controller is essential.

...and in addition to that, most electric motors have 5 extra wires for the hall sensors (so that the controller can be informed of the position of the windings relative to the permanent magnets). Some motors only have 3 phase wires and therefore only work with the corresponding type of controllers (which detect the motor rotation based on current variations induced by electromagnetic forces)...well, that's the idea, in a nutshell.

The point being: you'd need to do some research before going the full-DIY route...or you could "half-DIY" your e-bike by retrofitting off-the-shelf kits, like the Alien, etc. (which come with every needed part)

Sometimes it's best to purchase a fully-made e-bike with a warranty, as it saves a lot of time and hassle. It depends on your needs, really.

Cheers, Dan

 

[Eddie F]

I am going to get one of the cheaper ebay ones. I am just weighing up the lack of backup and spairs. v the cost. and what i can fix myself if i can get the bits but i should have 12 months Warrantee. hopefully

 

[flecc]

but i should have 12 months Warrantee. hopefully

Not necessarily on the battery. The laws on minimum warranties don't apply to consumables, and batteries are consumables. Some cheap makes give six months warranty on batteries, but not all state one.
.

 

[Lloyd]

Brushed motors can be connected direct to the battery, but I would never, never recommend this of course. Ahem.

In fact, Some say that without the controller and hall sensor of a sensored motor, if you increase the voltage it will just go faster and faster until it melts/blows up/hits 88mph and goes back to 1066.


Regards

Lloyd