Nowhere near 10%! Look at the discharge charts. Show me one with 10% between 4.2v and 4.1v. Test it on your own bikes, like I explained above. Charge one of your bikes up to 42v. Ride it 10m and check the battery voltage. Repeat until you measure 41v. I guarantee that you won't reach London Road or the High Street. Compare that distance with the 40 miles or whatever range you claim for that bike, then tell me it's 10%!
Batteries Charging Routine
- Thread starter Az.
- Start date
Nearly all that power is converted to heat by the bleed resistors doing the balancing. It's completely meaningless to measure what's going into the battery at that stage, other than to confirm that the balancing is working.
Did you measure the 1.12Ah with an energy meter? If you did, you will have to deduct the conversion loss in your charger, the final amount will be about 0.9Ah or 9% of the capacity of your 10Ah battery.
Sure, I realise that.
However, I recall seeing a comment that you were seeing a charger going very quickly from 41V to 42V, so whilst re-charging mine I checked how long it actually took to go from 41V to the start of balancing, quite a while in my case.
I was mistaken, I thought you went from 41.1V to 41.2V. When I realised my mistake, I deleted that post. 41V to 42V is about 10%. Your 34 minutes are ball park figure.
I've learnt more about lithium battery charging from my 5.5 years of my e-car than in all the experience of pedelecs,,mainly due to having three charging options as I posted before. As said then, the thing that really matters most is charging speed, though it having low density cells is a benefit for long life.
If you haven't already read it, read that post first on this link , then read the following:
Having slow charged to full on Monday the reported range available was 164 miles, that still there this morning when I went to use the car.
When I charge to full on the normal so called fast charger, the 164 miles or whatever quickly loses 3 or four miles during the early part of that first run, thereafter losing range and actual miles covered at the same rate.
But it's very different when slow charged, this morning on my identical usual run, it ended with 154 miles range indication and 13.1 miles covered. So rather than ending up with only 161/162 miles of actual range, I had 167 miles, a gain rather than a loss.
It appears that the BMS cuts off earlier when charging at faster rates, the battery filling the most with slow charging. Another indicator of this is that fresh off the slow charger, the car cruises at 20 mph on the flat without any use of the accelerator pedal for over half a mile!
But that doesn't harm the battery life or capacity loss rate.
When I first received the car 5.5 years ago with its promised WLTP range of 168 miles, it would also show about 164 miles fully charged, but with the two reserves totally another 13 miles, meeting the promise. By the summer of year two it would often charge to 172 miles indicated range with the battery fully run in, therefore more than meeting the WLTP figure.
So now after that 5.5 years it's lost virtually nothing, despite well over half of all my charging being slow charging (50% in warm weather, 100% when it's cold), that slow charging filling the cells to the brim every charge.
So from all the combined experience with various pedelecs and the e-car, the magic mix for me to give both long range and long battery life is low density cells combined with slow charging.
The remaining key factor is of course consumption rate, and there the car wins. Setting off in normal urban conditions means the other 40 million vehicles on our roads give me little chance of flooring the accelerator. A pedelec in contrast will be working betwen 80% and 100% nearly all the time when riding.
P.S. In the earlier post linked to above, in a senior moment after typing kW several times I typed this:
"Slow from a 13 amp socket at up to 9kW rate"
Of course that should have been at up to 9 Amp rate, but I can no longer edit that original post.
.
If you haven't already read it, read that post first on this link , then read the following:
Having slow charged to full on Monday the reported range available was 164 miles, that still there this morning when I went to use the car.
When I charge to full on the normal so called fast charger, the 164 miles or whatever quickly loses 3 or four miles during the early part of that first run, thereafter losing range and actual miles covered at the same rate.
But it's very different when slow charged, this morning on my identical usual run, it ended with 154 miles range indication and 13.1 miles covered. So rather than ending up with only 161/162 miles of actual range, I had 167 miles, a gain rather than a loss.
It appears that the BMS cuts off earlier when charging at faster rates, the battery filling the most with slow charging. Another indicator of this is that fresh off the slow charger, the car cruises at 20 mph on the flat without any use of the accelerator pedal for over half a mile!
But that doesn't harm the battery life or capacity loss rate.
When I first received the car 5.5 years ago with its promised WLTP range of 168 miles, it would also show about 164 miles fully charged, but with the two reserves totally another 13 miles, meeting the promise. By the summer of year two it would often charge to 172 miles indicated range with the battery fully run in, therefore more than meeting the WLTP figure.
So now after that 5.5 years it's lost virtually nothing, despite well over half of all my charging being slow charging (50% in warm weather, 100% when it's cold), that slow charging filling the cells to the brim every charge.
So from all the combined experience with various pedelecs and the e-car, the magic mix for me to give both long range and long battery life is low density cells combined with slow charging.
The remaining key factor is of course consumption rate, and there the car wins. Setting off in normal urban conditions means the other 40 million vehicles on our roads give me little chance of flooring the accelerator. A pedelec in contrast will be working betwen 80% and 100% nearly all the time when riding.
P.S. In the earlier post linked to above, in a senior moment after typing kW several times I typed this:
"Slow from a 13 amp socket at up to 9kW rate"
Of course that should have been at up to 9 Amp rate, but I can no longer edit that original post.
.
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Discharge curve: SAMSUNG INR271700-50E, stuartsproject's battery.
Note:
As you can see, if you pull hard on a full battery, the voltage will sag, you can't measure anything meaningful right away. However the top plot (@ 0.2A discharge current) is pretty good as representative.
On the vertical axis, the plot starts at approximately 4.15V, so you have to extrapolate a bit to go back up to 4.2V. On the horizontal axis, 0.5Ah = 10%.
My estimate:
You lose up to 9% capacity if you stop charging at 4.1V. The benefits are better safety margin and longer battery life. I stick with 4.15V.
source: Test of Samsung INR21700-50E 5000mAh (Cyan) (lygte-info.dk)
/Samsung%20INR21700-50E%205000mAh%20(Cyan)-Capacity.png)
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just a brain fade moment. I see the numbers but somehow the brain registers something slightly different. In this case, I saw 4.1V and my brain does not go 10S=41V but 41.1V. Usually, a colleague will touch my shoulder and point at my mistake. The alarming thing is brain fade happens to me more and more often, most days now. I blame the diabetes. Still, I well passed my sell-by date.
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That's the mistake you're making. You can't extrapolate. The voltage goes vertical between 4.2v and 4.15v . That's why you can't see it on the chart. Have you never actually tested a battery?Discharge curve: SAMSUNG INR271700-50E, stuartsproject's battery.
Note:
As you can see, if you pull hard on a full battery, the voltage will sag, you can't measure anything meaningful right away. However the top plot (@ 0.2A discharge current) is pretty good as representative.
On the vertical axis, the plot starts at approximately 4.15V, so you have to extrapolate a bit to go back up to 4.2V. On the horizontal axis, 0.5Ah = 10%.
My estimate:
You lose up to 9% capacity if you stop charging at 4.1V. The benefits are better safety margin and longer battery life. I stick with 4.15V.
source: Test of Samsung INR21700-50E 5000mAh (Cyan) (lygte-info.dk)
The SANS charger we use gives only up to 41.5V at the output port. If you ask have I seen 42V at the output on a 36V battery then the answer is no.
I have of course tested batteries many times in the past.
Stuart's battery is practically brand new. I doubt that the bleed accounts for much in his experiment. Next time you charge your battery, check the power consumption when output voltage is between 41V and 42V and let us know what you see.
You would hope not, especially on a 'quality' battery that should be pretty well balanced in the first place.
At what exact voltage point would the BMS start the balance ?
usually 41V but you'll know if you watch the energy meter, balancing consumes about 3W-5W on the meter. Now and then, it may spike to 10W-25W for a few seconds, the LED on the charger will flash red. If your battery is already balanced, the LED on the charger will simply goes from red to green and the power consumption goes from around 30W smoothly down to zero in about 5-10 minutes.
Dont see any of that.
Charge current is flat dead on 2.0A till CC charge ends at 41.8V. Power rises slowly of course, but no jumps.
When CC charge stops the current tails off to around 55mA over 15 minutes when charge LED goes green. Current then drops to circa 20mA over another 10 minutes.
Yes - I noticed that when I tested the voltage when full on my 36V 20Ah battery - I was thinking that may end up with a longer life battery
I have a proper battery tester and cell testers. I'll use them both tomorrow to provide the definitive results. In case I forget, give me a reminder if you don't see them.
I will remind you, but remember, I am interested to know what the charger consumes when the voltage at the output is above 41V. My SANS charger does not let me do that above 41.3V
41v to me seems awefully low for balancing Tony , do your BMS have a lower set balance in them or are they generic ?
My Swizzbee has a LG BMS and it is programmed to balance at under 4.15v as that is the max the cells are charged to, even though the charger outputs 29.4v.
My Swizzbee has a LG BMS and it is programmed to balance at under 4.15v as that is the max the cells are charged to, even though the charger outputs 29.4v.
They are just generic. I have not seen a single battery needing rebalancing for a few years now so my experience with this issue may well be not up to date.