Cheap Lipo4 from China

[onmebike]

Once charged and left alone for at least 24hrs the battery seems to settle on 40.7V for those interested.

Mine was last charged a month ago and is currently 40.1volts. I dare say the BMS being permanently connected, consume's some miniscule amount

 

[JohnD]

Very low capacity?

I only use my bike back and forth to the railway station - 4 miles each way with a big hill in the way. I have a 10Ah battery - this seems to be overkill.

Is it possible,do you think, to ask for a 2/3 Ah battery?

 

[Synthman]

That would be a bad idea. You will be using the extreme ends of the charge/discharge cycle, and shorten its life. Always better to have a higher capacity and only use a bit of the charge.

 

[jerrysimon]

I use a DIY 36v, 2.3Ah, A123 battery which gets me to work and home about 8-10 miles.

I have been using it nearly a year with no problems. I am of the opinion too, that it is pointless carrying more battery weight than you actually need.

Regards

Jerry

 

[JohnD]

I use a DIY 36v, 2.3Ah, A123 battery which gets me to work and home about 8-10 miles.

That's the sort of thing I was thinking of - what does it weigh?

 

[Phil the drill]

Hi
I have made DIY battery packs with 26650 tagged cells, copper strip for bus bar and bms's supplied programmed to order by BMS battery in China. The last one was a LiFePO4 24v 12Ah one for my wifes Saracen e-bike conversion. It has worked fine for the last 6m. The cells were glued together, shrink wrapped, and put in a home made neoprene 'sock' (made from an old wet suit).
I'm currently about to start on re-celling my old Wisper 905 battery using 26650 tagged batteries and a BMS (same source), this time using Li-ion cells now rated as 800 cycles (individual cells) and 2C (continuous). I can't get enough cells in the original case to get the original 14Ah capacity, but I can get in enough cells to get a 12Ah rated battery plus the BMS in. The cost of the cells and BMS, including shipping to the UK works out at about £165.
It is lower capacity and heavier than the original plus it involves a fair bit of effort and time to make. It does save you £350.00, however... .
When I bought the bike, replacement batteries were quoted as £299-00. I could live with that (just). When it suddenly jumped to £500+, well that seemed like rampant inflation. I don't blame Wisper, I understand their reasoning, I just can't justify that on a three year old bike, which is now of intrinsically low value.
I should add, however, please don't do this yourself if you don't know what you're doing, you could have a BIG accident (you'd be surprised how big), so give it a go if your sure, or else find someone who does know what they are doing to do it for you and keep them in beers whilst they do it !
Phil

 

[jerrysimon]

That's the sort of thing I was thinking of - what does it weigh?

Details in this thread

Regards

Jerry

 

[jbond]

Small battery packs. One solution here.
http://www.pedelecs.co.uk/forum/electric-bicycles/6956-diy-stage-9-a123-nano-battery-pack-photos.html#post88165

 

[NRG]

That's the sort of thing I was thinking of - what does it weigh?

Be careful, Jerry is very economical over his 10mile ride, <8Wh / Mile from an 83Wh pack.

I think you'll have to try and workout how much Wh you use over your journey, I'm reasonably fit but I struggle to get under 8Wh when hills are involved and my 'consumption' is more like 12~14Wh which would mean a 6 miles range.

Going with A123 cells is a good idea as they recover from deep discharge well without the associated fireworks and keep balance exceptionally well.

 

[jerrysimon]

Be careful, Jerry is very economical over his 10mile ride, <8Wh / Mile from an 83Wh pack.

Yes valid point if you have steep hills then you may find that 8-10 mile range is halved. A simple watt meter (Turnigy) connected up will tell you how much charge you are using so test it out first.

A charger at work is also an option so you can charge both ways.

Regards

Jerry

 

[Cyclezee]

The battery has two pairs of leads (black and red =live and neg) the thinner wires are for charging and have a kettle plug fitted that plugs into the kettle plug socket on the charger output.

I received a 15Ah battery today, 10 days after ordering. It was delievered by FedEx so I will have to wait and see if I have to pay any taxes. The delivery sheet had a value of $60, so even if I have to pay it shouldn't be to bad.

Old Timer,

I have the battery charging right now and haven't taken the precaution of checking polarity of the battery output leads yet, you said (black and red =live and neg), don't you mean red = live and black = negative


J hn

 

[Old Timer]

I received a 15Ah battery today, 10 days after ordering. It was delievered by FedEx so I will have to wait and see if I have to pay any taxes. The delivery sheet had a value of $60, so even if I have to pay it shouldn't be to bad.

Old Timer,

I have the battery charging right now and haven't taken the precaution of checking polarity of the battery output leads yet, you said (black and red =live and neg), don't you mean red = live and black = negative


J hn

yeh! should have read red=live. Having said that I think if you check the kettle plug that is fitted you`ll see that on the plug where it has an L for live the actual black wire goes to that pin. Seems like most of my kettle plugs are wired that way.

 

[onmebike]

I received a 15Ah battery today, 10 days after ordering. It was delievered by FedEx so I will have to wait and see if I have to pay any taxes. The delivery sheet had a value of $60, so even if I have to pay it shouldn't be to bad.

Old Timer,

I have the battery charging right now and haven't taken the precaution of checking polarity of the battery output leads yet, you said (black and red =live and neg), don't you mean red = live and black = negative


J hn

I wonder if Old timer mean't, check the polarity because the actual live[red] and neg[black] don't correspond with the markings on the kettle socket? Red goes to the side marked N and Black to the side marked L.

 

[Cyclezee]

yeh! should have read red=live. Having said that I think if you check the kettle plug that is fitted you`ll see that on the plug where it has an L for live the actual black wire goes to that pin. Seems like most of my kettle plugs are wired that way.

Thanks Old Timer,
I was only concened about the output wiring and the fact that other readers might be confused
I will use Anderson connectors for the output and report back when the battery has been used for a while.

J hn

 

[Cyclezee]

I wonder if Old timer mean't, check the polarity because the actual live[red] and neg[black] don't correspond with the markings on the kettle socket? Red goes to the side marked N and Black to the side marked L.

I see what you mean Onmebike

J hn

 

[onmebike]

You may find at the end of the charging process the charger wiill alternate between red and green, leave connected until green light stays on.
You'll find the final voltage when charged a tad below 41volts, this will settle after standing a while to approx 40.5volts then remain stable.
In use the BMS low voltage cutoff will come in around 36volts because its set at 3volts per cell.

 

[Cyclezee]

You may find at the end of the charging process the charger wiill alternate between red and green, leave connected until green light stays on.

Thanks again for that tip. Do you mean it changes from green to red to green rapidly or is there gap of minutes between? Also, does the charger power down with the green remain lit and the fan stop when fully charged?

J hn

 

[onmebike]

Thanks again for that tip. Do you mean it changes from green to red to green rapidly or is there gap of minutes between? Also, does the charger power down with the green remain lit and the fan stop when fully charged?

J hn

When led changes to green the charger powers down and fan stops, but it may alternate between on and off[fan included] before finally settling on green.

 

[averhamdave]

Got mine earlier in the week. 14 days to deliver, which I think is excellent.

Cut the plug off the charger and fitted a 3 pin with a 3a fuse and charged it. Took about 3 hours (@ 0 deg C!) for the green light to come on and hold steady.

Its on the rack of my Torq at the mo, as a temp replacement battery.

 

[jbond]

Got mine earlier in the week. 14 days to deliver, which I think is excellent.

What are the dimensions of yours? Do they match the auction details?
36V-16AhR, 5.50 kg, 220x105x150 mm