Battery drains fast!

[goral]

I have a question relating to the battery.
I am concerned about it draining quite quickly.
I have no e-bike experience and perhaps this is the correct symptom.
Well, new kit, it is about 2/3 weeks old, due to the poor weather I have not been able to test it properly yet.
Before I rode out I charged the battery to 100%, (the battery is a 52V 20Ah) rode about 6 miles the battery indicated 99%-100%, after a few days I rode for about 10 miles and the battery dropped to 50%.
While driving the battery was able to drop from 97% to 65% only to return to 90% after a while.
The effect is that I now have 50% after 17 miles.
I have only charged the battery once, is this a normal effect, and should it be like this, or start the warranty procedure?

Thanks.

 

[saneagle]

I have a question relating to the battery.
I am concerned about it draining quite quickly.
I have no e-bike experience and perhaps this is the correct symptom.
Well, new kit, it is about 2/3 weeks old, due to the poor weather I have not been able to test it properly yet.
Before I rode out I charged the battery to 100%, (the battery is a 52V 20Ah) rode about 6 miles the battery indicated 99%-100%, after a few days I rode for about 10 miles and the battery dropped to 50%.
While driving the battery was able to drop from 97% to 65% only to return to 90% after a while.
The effect is that I now have 50% after 17 miles.
I have only charged the battery once, is this a normal effect, and should it be like this, or start the warranty procedure?

Thanks.

It could be normal. How much current are you taking from it?

 

[thelarkbox]

Whats the bike, 52v? do you mean a fully charged 48v battery perhaps?
16 miles unassisted riding on a very heavy fat bike might drain that sort of power from a battery it depends on the terrain too?

if your bike display shows an indication of watts expended (a number with a 'w') take note of this when the bike is working hard.. as it will help with a back of an envelope calculation of expected range from your bike/battery under load.

 

[goral]

It could be normal. How much current are you taking from it?

I will check this later, I will change the display from watts to amps.

Whats the bike, 52v? do you mean a fully charged 48v battery perhaps?
16 miles unassisted riding on a very heavy fat bike might drain that sort of power from a battery it depends on the terrain too?

if your bike display shows an indication of watts expended (a number with a 'w') take note of this when the bike is working hard.. as it will help with a back of an envelope calculation of expected range from your bike/battery under load.

No fat bike, hybrid bike.
unassisted ~40%
mostly flat terrain with small rises. Nothing serious or very steep.
The maximum power that the display showed was 1200W, mostly without pedalling about 250W to 500W with pedalling less than 250W.

 

[saneagle]

I will check this later, I will change the display from watts to amps.

You shouldn't need to check anything. You must have either chosen a controller for your installation, or if it's a crank drive, you must know which version you bought. Which one did you get?

 

[goral]

You shouldn't need to check anything. You must have either chosen a controller for your installation, or if it's a crank drive, you must know which version you bought. Which one did you get?

Is Bafang BBSHD

 

[matthewslack]

The battery indicator is crude, just a voltmeter, so the only way to know range is to ride until it stops.

How fast are you going, how many stops and starts? What quality is the battery? Cheap generic, or a known, good specification?

 

[goral]

The battery indicator is crude, just a voltmeter, so the only way to know range is to ride until it stops.

How fast are you going, how many stops and starts? What quality is the battery? Cheap generic, or a known, good specification?

The fastest I've ridden is downhill pedalling at about 27 mph - I don't go faster than that because it's admittedly a new but cheapest bike, so I don't really want to risk it.
I stop rather little, in 8 miles, maybe 5 times, mostly as a street crossing.
The battery is new, I bought the whole set about a month ago. I don't know who the battery manufacturer is but the seller states on the website that it could be Samsung or LG.

 

[guerney]

I have a question relating to the battery.
I am concerned about it draining quite quickly.
I have no e-bike experience and perhaps this is the correct symptom.
Well, new kit, it is about 2/3 weeks old, due to the poor weather I have not been able to test it properly yet.
Before I rode out I charged the battery to 100%, (the battery is a 52V 20Ah) rode about 6 miles the battery indicated 99%-100%, after a few days I rode for about 10 miles and the battery dropped to 50%.
While driving the battery was able to drop from 97% to 65% only to return to 90% after a while.
The effect is that I now have 50% after 17 miles.
I have only charged the battery once, is this a normal effect, and should it be like this, or start the warranty procedure?

Thanks.

Does the HD have a 30A controller? Was it supplied with a 21Ah battery?

The effect is that I now have 50% after 17 miles.

If so, that sounds about right IMHO.

If range and legality was important, you should have bought a 250W BBS01B.

To get more range, you could reduce the controller's amp limit using a programming cable, and go slow. If you do, don't mention it to the seller, because reprogramming your controller will probably invalidate your warranty... but that 1000W rated motor still won't be legal, because it's rated 1000W.

 

[sjpt]

You didn't mention how much you are doing the work and how much you are relying on the motor. That makes a huge difference to the range. Lots of people get 50 miles on a battery less than 1/4 the capacity of yours, but that's on a light bike that they ride pretty much like a regular one and just use some assistance on the hills.

The Bosch range assistant gives a good idea even for non-Bosch systems; you need to interpret the motor type, and allow for capacity (eg, select a 500wh battery and then double the range to match yours which at 52*20 is just over 1000wh) . Not too bad for the absolute value of range, and gives a very good idea about how different riding styles and conditions change the range. Leave most settings to default it will suggest 42 miles on your level on a 500wh battery or even 61 miles on eco. Select the lazy options and ride faster with less effort and it drops below 20 miles.

 

[matthewslack]

The fastest I've ridden is downhill pedalling at about 27 mph - I don't go faster than that because it's admittedly a new but cheapest bike, so I don't really want to risk it.
I stop rather little, in 8 miles, maybe 5 times, mostly as a street crossing.
The battery is new, I bought the whole set about a month ago. I don't know who the battery manufacturer is but the seller states on the website that it could be Samsung or LG.

So what is your typical speed, not the maximum. Are you riding at 20mph all the time, or a bit more, or a bit less? This, plus hills, plus weight of you and the bike, allows a rough estimate of energy requirement.

 

[guerney]

Are you riding at 20mph all the time, or a bit more, or a bit less?

I doubt many buy a 1000W BBSHD to potter along at a mere 20mph, or thereabouts.

 

[saneagle]

Pedal speed has a lot to do with it. I'm pretty sure that a BBSHD is 160 rpm at 52v, so if you pedal at normal speed of about 60 rpm, it'll run very inefficiently. If you want to pedal, you bought the wrong version. A 48v one would be better, and the BBS02 would be better still.

To get reasonable efficiency, the motor needs to turn at minimum 60% of max rpm, which is 90 rpm. That's very fast for a casual rider. It would be better not to pedal and use lower gears with the throttle so that the motor can spin faster.

The three main factors for how quickly your battery runs out are your weight, the hills and your speed. That assumes you run the motor in its normal efficient range, which is >50% of maximum rpm. When you drop below that, the inefficiency becomes the biggest factor.

The power shown on the display is the power coming out of the battery. You have to multiply that by the efficiency to see how much appears at the back wheel, though let say you were doing a constant 10 mph with 250w showing on the meter while you pedalled. You have approximately 1000wh in the battery, so you could go 4 hours, which would be 40 miles. You have to watch the LCD during a ride to see what the average watts is and your average speed, then you can do the above calculation for your rides, i.e. 1000/(average watts) x (average speed) = (your range).

 

[goral]

So what is your typical speed, not the maximum. Are you riding at 20mph all the time, or a bit more, or a bit less? This, plus hills, plus weight of you and the bike, allows a rough estimate of energy requirement.

Average speed is betwin 21mph and 18 mph.
I have no need to go faster.
The weight of the bike together with me and a few things is around 120 kg.

As for reprogramming the controller, I don't mind, especially if it increases the range.
I'll probably look into it but I don't currently have the cable to do it.
For now, I have a million questions because, as I wrote, this is my first e-bike and I have no experience with the battery, range, handling maintenance etc. I don't know how to judge if the battery is faulty or if this behaviour is as normal as possible.
Just this.
I'll probably ask more questions about it

 

[matthewslack]

Just ride it a few hundred miles, play with settings and gears, learn what you can.

It is probably behaving as it should, a powerful motor not necessarily operating at most efficient speed, so consuming lots of Wh per mile.

 

[goral]

Still a question, when do you charge batweries?
Every time you get home, or when the battery goes below a certain level? What level?
Does this affect the life of the battery?

 

[thelarkbox]

Average speed is betwin 21mph and 18 mph.
I have no need to go faster.
The weight of the bike together with me and a few things is around 120 kg.

As for reprogramming the controller, I don't mind, especially if it increases the range.
I'll probably look into it but I don't currently have the cable to do it.
For now, I have a million questions because, as I wrote, this is my first e-bike and I have no experience with the battery, range, handling maintenance etc. I don't know how to judge if the battery is faulty or if this behaviour is as normal as possible.
Just this.
I'll probably ask more questions about it

the maths isnt that complicated on the face of it, of course the sort of maths im talking about takes no account of heat loss inefficiency etc google for better info than me ..

20ah, 52v battery...

volts x amps = watts, so if you know your average wattage and howl long it takes to travel X miles say 16 and an hour so if you use 750w on average, since watts = amps x volts amps (used in an hour) = 750w/52v = 14..
if on average it was 500w ... 500/52= 9.6...
thats 14, or 9.6 Amps drained in an Hour from a 20 AmpHour battery...

 

[egroover]

if you are displaying watts being used at any one time on the display, then depending on what assist level you are in and how much (or little) effort you are putting in, if the display is showing you are using, say about 300w when it's assisting you, and you travel 15 miles in one hour, you are using 300wh of battery per hour, so your 1000whr battery will assist you at that same level for 3 hours 20min ish, and therefore 50 miles (3.3 x 15miles per hour) - therefore about 50 miles is the total range at that assist level
If you are using 600w assist while you are riding, then you'll get about 25 miles range, and so on. You'll always get more range than that, as they'll be times when you are going downhill or not freewheeling so they motor is under less load.
The above is a pretty crude measurement, as the watts displayed may not be super accurate, but I have found it a reasonably good way of predicting range/versus assist level on my BBS01 250w mid-drive (but best way is to get out and ride and use Strava etc and add a note of how much battery used/versus elevation/distance etc)

Also a smart plug with energy monitoring (TP LInk P110 for example https://www.currys.co.uk/products/tpl-tplink-tapo-p110-mini-smart-wifi-socket-10230067.html?istCompanyId=bec25c7e-cbcd-460d-81d5-a25372d2e3d7&istFeedId=4d7eb93e-055f-499d-8ee5-1cdcc50d67d1&istItemId=ppqwaqrxt&istBid=t&srcid=198&cmpid=ppc~gg~1051+(Shopping+Ads)+Smart+Home+Control+-+PMAX~~Exact~71700000115486728~&mctag=gg_goog_7904&kwid=GOOGLE&device=c&ds_kids=&tgtid=1051+(Shopping+Ads)+Smart+Home+Control+-+PMAX&&gad_source=1&gclid=Cj0KCQiA5-uuBhDzARIsAAa21T_m119xC_nXU97Ohir-4YdZ2oEayZLFkq3RWhqXVdrPUqF-y-Jw_KYaApO0EALw_wcB&gclsrc=aw.ds) is a good way of seeing how much charge yo are putting back into the battery - deduct about 10% for charger inefficiency

 

[lenny]

Still a question, when do you charge batweries?
Every time you get home, or when the battery goes below a certain level? What level?
Does this affect the life of the battery?

https://www.pedelecs.co.uk/forum/threads/batteries-charging-routine.45703/

 

[guerney]

the battery is a 52V 20Ah

52 X 20 = 1040W

The effect is that I now have 50% after 17 miles.

50% of 1040W = 520W

520/17 = 30.6W per mile

Average speed is betwin 21mph and 18 mph.

I travel at 15.5mph max assisted.

The weight of the bike together with me and a few things is around 120 kg.

Total weight of my bike + me = 93kg. My controller limit was 15A, max range was 43 miles using a 691W battery = 16W per mile. Your overall weight with bike is heavier, your controller has a 30A limit, you're travelling at a higher speed on a bike with bigger wheels than my 20" wheeled folding bike, it's new to you therefore you may well be letting the motor do most of the work (I did, still do), like I said:

that sounds about right IMHO.