Hill climbing Oxygen E Mate

[david1949]

Bought the above bike Nov 2011 and only use it for leisure cycling i don't do many miles
when out on the bike. So when i return home after being out on the bike i have only used 2 out of the 4 battery lights some times i only use one battery light and i never had any trouble climbing the hill up to my house. Today was a beautiful day lovely and sunny so i went out on the bike and i went further than i would travel at about 5 miles from home i had only 2 lights lit i was 500 yards from turning into my street and climbing the hill up home when i went down to one battery light. I turned into the street and thought that all would be OK but even with one light lit it would not make it up the hill the light did not go out or even flicker it just did not have the power to get up the hill and yes i was peddling so had to get off and walk it up the hill and the Throttle is rarely used on the bike. One thing i have notice is that when the bike has only 2 out of the 4 battery lights left you have a small drop in the power and where you ride the bike in low power you have to shift it up to med power the hill climbing up home was on high power but as i said had to get of and walk it up the hill. So is this normal because i thought that with one light lit i would have about 8 to 10 miles left in the battery and hill climbing in high would not be a problem . It looks like as soon as i am down to 2 battery light i have to head for home and hope that i am no more than 2 or 3 miles away.

 

[Scimitar]

Yep. Ideally, your battery indicator would be accurately tailored to your battery pack, but there's so little leeway that it's not surprising it's off on the bottom end.
Have a look at the discharge curves here...
Torchy the Battery Boy: 18650 Batteries / Chargers

You can see they tend to fall off a cliff as they near the end and it's difficult to accurately monitor this on a mass-produced item. Of course, it can be done with a bit of care and attention, but all the rider can do is be aware of the characteristics of his individual machine.
It's directly analogous to the fuel meter in your car - been a long time since any of them were dead accurate, but luckily there's usually a fair bit of leeway there.

 

[eddieo]

handlebar battery indicator not very accurate, do you have LED panel on battery itself, as its normally a better indicator of battery state.

Are you using your gears enough to compensate for tail of on power, as normally a shift or two down will compensate.

 

[flecc]

With only one light lit the remaining range only holds true for flat conditions since power can reduce substantially with a low battery. The best hill climbing will only be when fully charged.

It's best to charge frequently, even when you've only used half or less of the content, then you'll get the benefit of best performance each time you go out. Also, since you mention only using the bike a little, make sure you charge the battery at least every two months, even if out of use for longer in the winter, since batteries left unused and uncharged can deteriorate and even fail completely.

 

[david1949]

Thank,s all for your replies and i will take your points on board i do know the bit about keeping the battery fully charged i just wont go as far next time i would say when 2 light go out you need to head for home to get the battery fully charged again. Must say when i was looking for a e bike i did not think
about power loss as the battery went down i an glad i only spent £1,375 an not the £ 2.400 on the
Kalkhoff Pro Connect i was thinking about.

 

[GaRRy]

Try thinking a bit more positive.

How far had you cycled before you hit the hill ?
Could you of done the trip at all without electric assist ?
You would almost certainly of walked up the hill anyway if you had a normal bike.

I know I have done trips I would not of even considered without a e-bike to take some of the strain.
I have also in the past when I know I'm pushing the range of the battery got of and walked up some slopes to save the battery to make sure I have enough to get me home (on principal that if crawling up a steep hill walking isn't much slower and hills are battery eaters)

One day will get true 100 mile + range batteries but until then have to learn to work around the limitations.

 

[flecc]

i an glad i only spent £1,375 an not the £ 2.400 on the
Kalkhoff Pro Connect i was thinking about.

In fact that second choice would have been better from this point of view, the sophisticated software of the Panasonic power unit evens this effect out, the power delivery being fairly constant for most of the charge. However, it's a very different system to ride and you might not have liked that aspect.

They all have their plus and minus points.

 

[david1949]

No i could not do the trip without the assist i find the bike to heavy i have had my two knees replaced and if i put a lot of pressure on them i am in pain for 3 or 4 days. As for the throttle i have only used it twice from i got the bike because i know it is heavy on the battery i would start my journey on assets 1 then as the power falls away i move into assist 2. i took a different root this time i had a lot of head wind and a lot of hills. As for the miles i don't have monitor on my bike to tell me the miles i would think about 35 to 40 i am very pleased with that as i could not have done if on my normal bike. As i said in future when i get down to 2 lights i will head back home to charge the battery.

 

[Eaglerider]

I have the standard controller panel with 4 lights for remaining power. From a full charge, on a 17a/h battery, and measuring the number of lights in a static no-load state, The first light goes out around 30 to about 35 miles, dependent on hills and wind conditions. I'm usually down to 2 lights, (no load) at around 38 to 45 miles. Whilst the power is noticeably lower, it still has plenty of grunt with pedalling, although with 2 lights left I would certainly be turning for home.

In your case, does the bike actually cut out under low voltage protection, or is it just that it needs a bit more pedalling but maintains some assistance. The drop in power you describe seems more severe than I have experienced. I would estimate the max power drop at near the end of the charge is about 30% less than with a full charge. If I'm really low on fuel, and climbing hard with just one light on, it will start to cut out, and then re-start again after a few seconds, but that's only when I'm on the last dregs of charge.

In these warm climes, the battery seems excellent. Last weekend I rode from Battle to the top of "The Long Man of Wilmington" and back. 46 miles round trip, half of that off road and I had 2 lights left on arriving back home. Probably half way on low or medium assist, but max power all the way home. I guess on flattish roads that's good for another 10 miles or so. Remarkable, especially as climbing the Downs in first gear the old Bafang got quite a leathering!

I wonder if a full conditioning cycle on the battery may help a bit, Flecc will know.

 

[flecc]

I wonder if a full conditioning cycle on the battery may help a bit, Flecc will know.

I did think of this, but since David has obviously run the battery very low on at least the odd occasion and fully charged afterwards, he's effectively done this already.

 

[eddieo]

David, 35-40 miles is a VERY good range on any e bike....

 

[Davanti]

David, 35-40 miles is a VERY good range on any e bike....

Really, Eddie? I am sure that I have had 68 miles on my Wisper 905sel.

Don

 

[david1949]

Hi Eaglerider you talk about the bike cutting in and out when one are climbing a hill with one light on.
I did not have this problem the bike just would not assist me going up hill with one light on and with it being so heavy it was better to get of and walk it up the hill. This is the first time that the battery has been so low from i got the bike. After a run out on the bike and back home again there would be 2 lights left on the battery i have never run the battery flat and then recharged it. Do you think i should run the battery completely flat and them recharge is and how often should i do this

 

[david1949]

I see that Oxygen have changed the LCD display to this /The new Emate range comes with the modern OXY Drive LCD display showing variety of function such as speed, ODO, average speed, power output , battery level indicator and 5 levels of pedal assist./ . My bike was bought in NOV 2011 and if i could change to this new display it would give me a lot more information.

 

[Eaglerider]

Hi David1949,

The short answer is I don't really know. What size battery do you have, and what is your normal mileage when you arrive home with 2 lights left? Do you always set off with a recent full charge?

I don't think Lithium batteries suffer with any memory effect, but I have read on here that flattening the battery a couple of times followed by an immediate and full charge helps to condition the cells in some way.

The cutting out I referred to is what happens on mine when the battery is virtually empty. The cut out occurs on and off probably 3 or 4 times dependent on load, and then it cuts out altogether and won't re set as the battery is empty, (or at least any load applied drops the voltage below the threshold set by the battery management system). Up to that point, I still have a reasonable amount of power available for climbing moderate hills.

You might as well try a conditioning cycle, just make sure you put it on charge immediately and don't leave it flat. It may help!

 

[DJH]

I've just got the new eMate city and found when running the battery down to empty on the first two occasions I used it I had a similar problem after about 30 miles of hilly riding. On PAS setting 5 it suddenly cut out while climbing, selecting 4 it carried on for about another 2 miles before cutting out under load and so on until all power was gone giving me a total of about 42 miles on those two occasions. I stress I wasn't trying to be economical with power usage as I was wanting to get this conditioning stage over. Normally my max journey is 26 miles with 1800ft of climbing and a 15 percent gradient and so far after 300 miles I have had no problems. A great bike and very comfortable

 

[david1949]

OK i going out to- day on the bike and i will run the battery flat and then recharge it when i get back and see if that helps .

 

[david1949]

OK i run the battery flat and walked the bike home and the battery i on the charger so we will see how i goes to-marrow.
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Now some more advice needed please this is to do with the rear wheel hub i had to take the back wheel off after i got a flat and change the tube. I always found the bike heavy if i don't use assist and thought it was the weight of the bike 24kg and me at 12 stones . But today i noticed that the rear wheel when spun is not as free as the front and there is a slight wine from the motor with no power on
so this causes a slight drag as well when riding without assist. So when the power to the hub is off does
this motor not disengage and let the hub run fully free like the front wheel or is there a slight wine and slight drag all the time.

 

[flecc]

The motor has a freewheel which disengages it, but the epicyclic gears driving the hub are always engaged since the gear rack they drive is part of the hub shell and wheel of course.

You should find the resistance and noise very different depending on the direction you spin it. Spun forwards should be quite free, trying to spin it backwards will have a lot of resistance and lumpiness. If that's how you find it, it's basically ok and working correctly.

 

[david1949]

Thank,s flecc i thought it would be you that would come back with the answer if i spin the wheel in the right way it is not quiet there is a low wine. Could you answer one more question for me flecc would i have the same sort of low resistance from a Kalkhoff Pro Connect as i am still thinking about this bike.