Battery life

[Nealh]

Overvolting a 36v mid drive is a no go, the controller will smoke typically the capacitors.
It will depend on the amps setting which has been programmed, if it is set for 25a then as the battery pack voltage lowers then as said at the 25/30 mile stage the BMS lvc probably come in to play.

The cells can deliver both range and high drain but not both, with high drain cells you have to balance usage. Its one or the other, if you want to extract range from the 3000mah cells you have to be a bit more frugal with the amp delivery. The cells can deliver but at the expense of either or.

 

[Nealh]

Re programme the settings in the 'Basic' tab, have different assist/speed set ups and have two motors in one.
In the settings reduce the Limit C (A) to 18 or 20a.
Set parameters in assist levels 1 -5 for low torque high speed when riding flat terrain and use these mostly to eke out mileage, for assist 6 - 9 the parameters can be changed for high torque low speed for inclines/hills and use only when needed to gain the advantage that the cells can deliver.

In 1 - 5 set the A% limit to low draw range 20% - 60/70% & speed setting to high 80 - 100%. This will deliver lower draw/current but enable you to pedal with speed.

In 6 - 9 do the reverse set A% limit to 100% in all & speed setting to ramp up from 20/25% to 50/60%. This will sacrifice speed for high draw for torque and the drive unit.

As mentioned bike gearing needs to be appropriate for the terrain you mostly encounter or want to use it on.

In ' Pedal Assist ' change the keep current to 70 - 100%.
Also reduce ' Start C% to 20 or 30%.

Use the assist as two motor settings to get the best out of the battery.

 

[wheeliepete]

You will need one of these and a Windows PC/laptop, it's pretty straight forward and there is always help here if you need it.

https://www.ebay.co.uk/itm/Programming-Cable-for-Bafang-8Fun-BBS01-BBS02-or-BBSHD-Mid-Drive-Electric-Bikes/282891248569?hash=item41dda1e3b9:g:en0AAOSw9Rda~FwD:rk:2:pf:1
Also consider using this software, as it's a bit clearer and includes a useful help file.

https://penoff.me/2016/01/13/e-bike-conversion-software/#more-1538

 

[John Roach]

Thanks guys
Start of with the cheaper option by running another charge and trying to make better use of the power and gears and aiming to consider that 70% usage is about whats available. Also taken the rather fat 1.9 inch Maxis holy rollers the there max inflation to reduce drag. at 35psi they took some peddling compared to the tiny bald ones fitted to my road moulton.
will publish results

 

[John Roach]

You will need one of these and a Windows PC/laptop, it's pretty straight forward and there is always help here if you need it.

https://www.ebay.co.uk/itm/Programming-Cable-for-Bafang-8Fun-BBS01-BBS02-or-BBSHD-Mid-Drive-Electric-Bikes/282891248569?hash=item41dda1e3b9:g:en0AAOSw9Rda~FwD:rk:2:pf:1
Also consider using this software, as it's a bit clearer and includes a useful help file.

https://penoff.me/2016/01/13/e-bike-conversion-software/#more-1538

Ordered but will need to find a mate with a windows PS

 

[anotherkiwi]

Can we have a bigger picture of your bike, the profile shot is kind of tiny.

 

[Fat Rat]

Hi welcome to the forum

 

[Andy-Mat]

Hi having just built my first bike by fitting a Bafang 500w mid drive kit to a 1994 Moulton APB which turned out to be somewhat less than straight forward. The kit uses a 36v motor and a 36v battery of 14.5 amps.
Battery life is a little disappointing. After about 30 miles the battery is still showing around 30% but even the slightest gradient will force the motor to stall. Is this normal ?
I also note that some info on the web sees higher voltage batteries fitted, not being electrically minded it seem a bad idea to fit a 48v battery to a 36v bike.
Ant moments please
John

 

[Andy-Mat]

Hi having just built my first bike by fitting a Bafang 500w mid drive kit to a 1994 Moulton APB which turned out to be somewhat less than straight forward. The kit uses a 36v motor and a 36v battery of 14.5 amps.
Battery life is a little disappointing. After about 30 miles the battery is still showing around 30% but even the slightest gradient will force the motor to stall. Is this normal ?
I also note that some info on the web sees higher voltage batteries fitted, not being electrically minded it seem a bad idea to fit a 48v battery to a 36v bike.
Ant moments please
John

Although some here will tell you its OK to put a higher volatge battery in, its really not. Simple Ohm's Law.
The motor will have been made for a specific voltage, and often the electronics too. If you really feel you need higher voltage, then sell your old bike and buy a new one.....Remember if you are in the EU (still?) then the largest motor you can legally ride is only 250 watt no matter what voltage you chose.
A better "quality" of cell may bring you more.....but usually at far higher cost.
Some "re-cell" a battery, which might help, but can also bring problems.
The only other problem you may have is that one or more cells are low on capacity, and the capacity levelling electronics, is taking down the capacity of the good cells to match the bad ones....
Remember, though many do not believe this, leaving your battery on charge AFTER the LED has gone green is a bad idea for the life of the battery....
The capacity leveling does not need the charger connected....as some believe.
Remember, every battery has a specific number of recharges, I usually say about 2000, but even a short charge, not even fully charging, is still a charge cycle.....
I keep meaning to design a small unit to attach to a charger, to stop further charging once the LED is green....
But a cheap 24 hour time switch, the ones with a tiny synchronous motor, not LCD, if rewired so that the power for the motor is also shut off at a specific time, is really just as good!! And very cheap and easy to organise! Just time a full charge once and use that as your timer setting....
regards
Andy

 

[wheeliepete]

.Remember if you are in the EU

The 250w limit is part of the reason some of us like to "play" with our motors. We are aware of the risks and would not blame anyone else for our failings. It's not for everyone, but nor is skydiving!

 

[anotherkiwi]

If the motor has 250 W printed on the label it is legal. Motors are under rated by the manufacturer, they can take much more - a common 250 W hub motor will handle up to 1 kW without problems.

Over about 1.2 kW you will start to have heat problems and the first things to go will be the nylon gears. If you want to go higher you need to add a cooling fluid (to protect the wire insulation) and to reach 2 kW the best idea is to swap out the nylon gears for steel ones. People will hear you coming! You are no longer in stealth mode...

 

[russ18uk]

But changing out the sacrificial part is asking for major issues later on. It's nylon to protect the rest of the mechanical part of the motor.

 

[trevor brooker]

"You need a Watt meter between the battery and the controller, it will give you all the information you need about your battery usage. That is how I know I average 5.8 Wh/km - return trip to my GF's house is exactly 9 km and the watt meter reading is 53 Wh used. You also get peak Amps and peak Watts as well as battery voltage (real) and mAh taken from the battery."

If you do not want to have the trouble or need for a Watt meter fitted to your bike.

http://www.pedelecs.co.uk/forum/threads/how-do-i-calculate-watts-used-per-mile.31067/#post-433910

If you have a BBS your display will show the voltage. Record this before & after ride with mileage covered to calculate Wh/M​

 

[sjpt]

Remember, though many do not believe this, leaving your battery on charge AFTER the LED has gone green is a bad idea for the life of the battery....
The capacity leveling does not need the charger connected....as some believe.

I do believe you, and feel guilty that I too often forget and leave the charger on green much too long. But why don't the chargers just turn themselves off when full charge is reached rather than just making the light go green? I should connect the charger to a time switch.

Remember, every battery has a specific number of recharges, I usually say about 2000, but even a short charge, not even fully charging, is still a charge cycle.....

I have seen it stated many times (in particular by Bosch) that it is the total amount of charging that matters, and not how many partial cycles that is spread over. Mostly they are quoting much lower cycle numbers (around 1000 or less) for 'equivalent full charge cycles'.

Maybe both are true? So if you do charges when it is just 1/4 down you'll hit the '2000 any charge limit' and get 2000 charges or 500 full charge equivalents; if you let it go down by 3/4 each time you'll hit the 1000 'full charge equivalent' limit and get 1333 charges.

Or maybe the whole battery technology is such a black art that nobody knows ....

 

[wheeliepete]

Or maybe the whole battery technology is such a black art that nobody knows

Your right sjpt, there are so many differing opinions on this subject that it's hard to work out the best way to treat your battery pack. If you also consider the diff. cells, BMS's, chargers and quality of construction which will all effect the life of the pack, it will blow your mind. All I will say is charge your pack and enjoy your bike.

 

[jarob10]

Hi having just built my first bike by fitting a Bafang 500w mid drive kit to a 1994 Moulton APB which turned out to be somewhat less than straight forward. The kit uses a 36v motor and a 36v battery of 14.5 amps.
Battery life is a little disappointing. After about 30 miles the battery is still showing around 30% but even the slightest gradient will force the motor to stall. Is this normal ?
I also note that some info on the web sees higher voltage batteries fitted, not being electrically minded it seem a bad idea to fit a 48v battery to a 36v bike.
Ant moments please
John

My bbs02 is limited to 20a but runs permanently at 100% speed 100% current. No display or buttons fitted to the bike.

25 miles and the eclipse 36v 17.4Ah 29E battery is spent - I’ve learned to live with the range.

 

[KirstinS]

My bbs02 is limited to 20a but runs permanently at 100% speed 100% current. No display or buttons fitted to the bike.

25 miles and the eclipse 36v 17.4Ah 29E battery is spent - I’ve learned to live with the range.

Goodness me! With greatest respect you could buy a programme cable and massively extend your range. You really don't have to live with that. 30 quid ish

I have a bbs02 and run it max speed /max current almost never, all that torque on the flat just isn't needed. Even on throttle only without pedalling at all

I tend to flick between various pas settings depending on terrain. But it allows choice so my best range across the south downs, all off road with 2000ft of totall climbing is 45 miles on a 11. 6ah battery. At no point was the electrics turned off, just reducing current when not needed


Sent from my iPhone using Tapatalk

 

[wheeliepete]

You really don't have to live with that.

I think he must have set it up like that Kirstin, I don't think anyone would supply a BBS like that.

 

[KirstinS]

I think he must have set it up like that Kirstin, I don't think anyone would supply a BBS like that.

On a re-read I guess you must be right !(missed the no LCD part)

But point still stands for a relative newbie. It's an example of battery consumption at the mega extreme (and arguably needless )


Sent from my iPhone using Tapatalk

 

[wheeliepete]

I agree, pointless and deff. not recommended for any new user, very good chance of controller damage without careful gear selection. Maybe jarob10 will give us his reasons for running this setup.