More battery charging...

[prState]

I have fully discharged 3 times the new Torq battery. I really only count 2 times, as the first try I decided could have gone deeper.

Now these partial charges.

1) Does "partial" include anything from 5 minutes to bringing it up to full charge?

2) Is there any advantage to varying the partial charges -- say after 5 miles, then 10, then 5, rather than all at 9 or 10 miles all the time?

And just out of curiousity, how does one make sure all the possible variables were eliminated when trying to optimize the usage of these batteries. For instance, how do you know a deep discharge every 20 charges is not the best thing for it, unless you've tested it that way? Or perhaps, some other routine?


thanks

 

[flecc]

It's always best to avoid deep discharge of these lithium batteries after the initial conditioning as it shortens their life.

There's no advantage in any particular rhythm or variation with partial charges since the cells have no memory effect and could not respond differently.

Where partial charges are concerned, its best for them to be worthwhile, five minutes definitely not worth it. I'd suggest using at least a quarter of the charge content before a part charge normally, though you might want to top up on the odd occasion when the range needs to be maximised for a long journey.

In general terms, these batteries last longest when they operate in their central charge region, never discharged below 20% and never charged above 80%, it's the extremes that are damaging, but of course that's not practical on an e-bike since it would be too restrictive. The best we can do is operate them in the upper charge region, 20% to 100% charge.
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[tillson]

In general terms, these batteries last longest when they operate in their central charge region, never discharged below 20% and never charged above 80%, it's the extremes that are damaging, but of course that's not practical on an e-bike since it would be too restrictive. The best we can do is operate them in the upper charge region, 20% to 100% charge.

Did I read somewhere on here that the Panasonic system has an upper and lower voltage cut off which keeps the charge content always in-between the 20 and 80 percent level? I have tried searching for it but can’t find it. I’m sure I have heard this said somewhere though.

 

[flecc]

Did I read somewhere on here that the Panasonic system has an upper and lower voltage cut off which keeps the charge content always in-between the 20 and 80 percent level? I have tried searching for it but can’t find it. I’m sure I have heard this said somewhere though.

Not the Panasonic battery. Though it's software is protective it couldn't operate to that and still give the range it's got.

You've probably seen mentions by both Jeremy and myself on how the Toyota Prius operates it's NiMh batteries within those two limits, 20% and 80%, and they have an 8 year warranty in consequence.

Of course that's charge cycling, constantly charging a bit, discharging a bit, so it's easy for it to be operated within those limits. Even if we operated our batteries within those limits they'd be used continuously between those points, so would be unlikely to last as well, even if they were NiMh types.
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[prState]

It's
In general terms, these batteries last longest when they operate in their central charge region, never discharged below 20% and never charged above 80%, it's the extremes that are damaging

Do you think there'd be any problem putting the charger on a timer (between the plug and wall) to shut it off after certain periods?

I was thinking of trying a system, whereby, charge it fully, then charge 1 hour at the end of every day until it gets too low a charge, then do a full charge again. (of course, I'd likely extend the 1 hour to more, but it's just to see how it works with my daily usage over time, and how fast the battery is depleted.)

A timer would give me the benefit of not forgetting to shut it off and getting an exact time in.

 

[Straylight]

The only problem with this as far as I can see is possible leakage of charge from the battery through the charger, though presumably they (chargers) have diodes to prevent this.

 

[flecc]

Do you think there'd be any problem putting the charger on a timer (between the plug and wall) to shut it off after certain periods?

I was thinking of trying a system, whereby, charge it fully, then charge 1 hour at the end of every day until it gets too low a charge, then do a full charge again. (of course, I'd likely extend the 1 hour to more, but it's just to see how it works with my daily usage over time, and how fast the battery is depleted.)

A timer would give me the benefit of not forgetting to shut it off and getting an exact time in.

There wouldn't be a problem with this, but I doubt you'd get much benefit. The state of charge would drift over time, either insufficient so you'd be running low over time, or more than needed so reaching full charge over time.

If your journeys are fairly consistent, a better method is to time how long your recharge takes a couple of times, then reduce that by a proportion. If the typical charge takes 3.5 hours for example, cut that to 2.5 hours which would take off the peak damaging part of the charge and help with the battery life. The last stages of charge are slow, so it's necessary to reduce the time by a minimum of an hour to have much effect on that.
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[flecc]

The only problem with this as far as I can see is possible leakage of charge from the battery through the charger, though presumably they (chargers) have diodes to prevent this.

The battery management system (BMS) on lithium batteries which sits between the cells and the charge current prevents this Straylight, so not a problem. The BMS evens the charge on the cells during the charge process and then cut's off the connection to the charger when the cells are at full charge.
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