Anyone use/recommend a timer for your charger?
03-11-24, 08:07 AM
#26
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When it is on but not in use, there is a small current draw from the battery management system (BMS) that may eventually drain the battery. Nowhere NEAR the amount of current needed to power the motor, but enough that it would eventually drain it. When it goes to sleep, this stops until you do whatever it is you do to wake it up.
03-12-24, 05:33 AM
#27
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But an ebike? The Bosch Powertube batteries have a warranty for 800 charge cycles (or two years, whatever is less), and this type of battery typically can last 1000 cycles or more before losing more than 30% of its capacity. 800 charge cycles is at least 70,000 km on my bike. I will not live long enough to put that kind of mileage on it, nor do I think the bike will live that long. So it seems to me that trying to extend the life of the battery is a waste of time.
That said, it's common sense that if you are not going to use the bike for a while, that you shouldn't charge it to 100%.
03-12-24, 08:24 AM
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To each his own, but the battery on my Haibike - Yamaha is seven years old and doesn't appear (qualitatively) to be less effective than when new. It's important (to me) to maintain it as long as possible since the bike is used sparingly; usually I ride MTB and for e-MTB my DIY system is preferable. The Haibike uses about 7 - 10 wh in pretty severe off road terrain, same as when new.
03-13-24, 09:13 AM
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I have thought about how useful it would be, to be able to set the charger to cut off at some charge level less than 100%. On a laptop where the computer often outlasts the battery, this could be really beneficial.
But an ebike? The Bosch Powertube batteries have a warranty for 800 charge cycles (or two years, whatever is less), and this type of battery typically can last 1000 cycles or more before losing more than 30% of its capacity. 800 charge cycles is at least 70,000 km on my bike. I will not live long enough to put that kind of mileage on it, nor do I think the bike will live that long. So it seems to me that trying to extend the life of the battery is a waste of time.
That said, it's common sense that if you are not going to use the bike for a while, that you shouldn't charge it to 100%.
But an ebike? The Bosch Powertube batteries have a warranty for 800 charge cycles (or two years, whatever is less), and this type of battery typically can last 1000 cycles or more before losing more than 30% of its capacity. 800 charge cycles is at least 70,000 km on my bike. I will not live long enough to put that kind of mileage on it, nor do I think the bike will live that long. So it seems to me that trying to extend the life of the battery is a waste of time.
That said, it's common sense that if you are not going to use the bike for a while, that you shouldn't charge it to 100%.
Charging to 100% then not using it for weeks/months/years will cut down the amount of charge cycles it can handle DRAMATICALLY.
03-13-24, 09:24 AM
#30
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I have always kept my laptops at 100% almost all the time and the battery life has been OK.
What concerns the bike, however -- I leave it partially discharged when I leave town and won't be using it for a while. So the only time I charge it to 100% is just before using it.
The 750 watt/hour battery is more capacity than I really need. I would only need the battery full if I were going on a full day trip somewhere. So I would really prefer to be able to charge it to 80%. Unfortunately there is no such option other than disconnecting the charger in time.
03-13-24, 09:42 AM
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Writing it off as "it lasts pretty well" is fine if you don't mind spending the $700 for a new battery sooner rather than later. Or if you don't mind losing more capacity after 2 years instead of 5.
I have always kept my laptops at 100% almost all the time and the battery life has been OK.
What concerns the bike, however -- I leave it partially discharged when I leave town and won't be using it for a while. So the only time I charge it to 100% is just before using it.
The 750 watt/hour battery is more capacity than I really need. I would only need the battery full if I were going on a full day trip somewhere. So I would really prefer to be able to charge it to 80%. Unfortunately there is no such option other than disconnecting the charger in time.
The 750 watt/hour battery is more capacity than I really need. I would only need the battery full if I were going on a full day trip somewhere. So I would really prefer to be able to charge it to 80%. Unfortunately there is no such option other than disconnecting the charger in time.
03-13-24, 10:13 AM
#32
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I've seen it from several reputable sources. One source said it can up to TRIPLE the battery's useful lifespan. Do some Googling and you'll find them too.
Writing it off as "it lasts pretty well" is fine if you don't mind spending the $700 for a new battery sooner rather than later. Or if you don't mind losing more capacity after 2 years instead of 5.
Writing it off as "it lasts pretty well" is fine if you don't mind spending the $700 for a new battery sooner rather than later. Or if you don't mind losing more capacity after 2 years instead of 5.
Based on the warranty period for the battery in cycles -- which Bosch count as 0% to 100%, such that charging from 30% to 80% is half a cycle -- I think my battery should outlast the bike, which seems to indicate that I should bother with any of this. On the other, I like to take care of stuff, especially expensive stuff. With the range of this bike and my riding routine there is absolutely no need to let the charge drop below 20% or even 30%, and I don't need to charge the battery full unless I'm off on a long weekend ride. So it's not actually much trouble.
Recent laptops are not 100% transparent on this. For example, I've found that my work laptop says "100% smart charged", digging into that, it means it maintains the charge at 80% unless Smart Charging is turned off. Likewise, iPhone has a setting to do something similar, after it has learned from our charging habits. For example, it learns I routinely plug in my phone before bed. It immediately charges to 80%, then tops it off to 100% right before my usual wake-up time. eBike chargers aren't this smart yet. My phone is about 3 years old and the battery health is still at 86% because of this.
Yep. Use a timer.
Yep. Use a timer.
But it's not much trouble to use a timer to limit the charge up. I'll start doing this. I guess trial and error will tell how much time will be needed to get to 80% from various levels of discharge.
04-02-24, 08:24 PM
#33
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I just bought a slightly lower voltage charger, which charges the battery to about 80%. If I need to fill it up, the original charger still works for that.
I also use a timer (a Wemo timer switch that also monitors the current it draws as a function of time).
I also use a timer (a Wemo timer switch that also monitors the current it draws as a function of time).
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04-08-24, 12:59 AM
#34
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Two things: 1. Amazon is just a retailer. Nothing more, nothing less. They don't sell more junk than anyone else. Or less. If you can buy something at Ace or Home Depot or Lowes, by all means do. But chances are GOOD that anything you can buy at those box stores is the exact same stuff you are getting on Amazon. Last SEVERAL trips to Mall 205 to buy stuff I came home empty handed because everything I wanted was online. Why does that matter? Because if you are doing it right, a trip to the mall cost you something in time and energy, because you didn't just jump in the car to get there! Buying online from retailer sites like Target, H-D, etc. takes days to two weeks for delivery and delivery charges that are up to 50% the price of what you ordered. Amazon rarely charges delivery fees and Prime delivery is never more than 48 hours, and in many cases 24. They are getting it down to 8 in many cities. I'm practical about things like this. Life is too short to spend it tilting at windmills.
2. You don't put a timer on your battery because an overcharged battery will explode and kill everyone in your house. It is a good idea to have an idea when your battery is fully charged because even the smartest chargers do not completely stop charging a topped up battery, they just continue charging at a much lower rate. The last charger I bought was pretty expensive and had all kinds of fancy features and may, for all I know, stop charging a fully topped up battery, but MOST do not. If your charger cost less than ~$100 it is safe to assume that your battery will continue to charge until you take it off the charger. Why is that important? Because overcharging shortens a battery's life. Once won't kill it, nor even twice, or even ten times but if you are overcharging your battery by four hours every day, you WILL see 30% or more reduction in battery capacity by the end of the first year. It will be worthless in two years. For my small battery packs I use my cell phone timer to alert me when the battery should be fully charged.
2. You don't put a timer on your battery because an overcharged battery will explode and kill everyone in your house. It is a good idea to have an idea when your battery is fully charged because even the smartest chargers do not completely stop charging a topped up battery, they just continue charging at a much lower rate. The last charger I bought was pretty expensive and had all kinds of fancy features and may, for all I know, stop charging a fully topped up battery, but MOST do not. If your charger cost less than ~$100 it is safe to assume that your battery will continue to charge until you take it off the charger. Why is that important? Because overcharging shortens a battery's life. Once won't kill it, nor even twice, or even ten times but if you are overcharging your battery by four hours every day, you WILL see 30% or more reduction in battery capacity by the end of the first year. It will be worthless in two years. For my small battery packs I use my cell phone timer to alert me when the battery should be fully charged.
You are thinking about Western Auto type battery chargers and lead batteries from the last century. We don't charge batteries like that today.
Purpose of a timer is not indeed to stop the charger from charging beyond 100% -- it already does that. It's to stop it at 80% or whatever.
Last edited by Dockhead; 04-08-24 at 01:29 AM.
04-08-24, 03:36 AM
#35
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Sorry if this has been asked before, but a quick search for "timer" just comes up with "first timer" and "old timer" posts 
I just purchased my first e-bike. A cheap REI Gen 1.1 - but I am pretty happy with it so far.
I don't want to over-charge the battery. So I thought maybe a timer between the charger and the wall would be a good idea. Depending on how depleted the battery is, I could set it for anywhere from 1-6 hours after which it would auto-shut off. That way even if I forget to manually shut it off (something I am VERY likely to forget) then I know it will stop charging after a given time.
Does this make sense? Has anyone else here done anything like that? Any recommendations if so?
Thanks.
I just purchased my first e-bike. A cheap REI Gen 1.1 - but I am pretty happy with it so far.
I don't want to over-charge the battery. So I thought maybe a timer between the charger and the wall would be a good idea. Depending on how depleted the battery is, I could set it for anywhere from 1-6 hours after which it would auto-shut off. That way even if I forget to manually shut it off (something I am VERY likely to forget) then I know it will stop charging after a given time.
Does this make sense? Has anyone else here done anything like that? Any recommendations if so?
Thanks.
04-08-24, 08:08 AM
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I see the purpose of the timer as a safety cutoff, in the rare event that the charger fails to shutoff. With most batteries, the BMS is what stops charging by refusing to accept any more current. As a result the charger light turns green. It requires a BMS failure then for the charging to continue, If the BMS has failed in this respect, it may let you down on its other protective duties.
I used to use a timer, but with sevral batteries and several ebikes, it got unwieldy. Now I just try to remember to unplug everything before I retire for the night,
I used to use a timer, but with sevral batteries and several ebikes, it got unwieldy. Now I just try to remember to unplug everything before I retire for the night,
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04-08-24, 08:33 AM
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By the way, how does one (user, battery software, etc) calculate the full charge of a battery?
I have 5 bars that indicate charge on my display. I had been assuming that each bar is 20%, but now that I am paying more attention, it seems like they aren't linearly distributed. For those who would prefer a number, how is it calculated? If your battery is rated at 52.0 V, does that correspond to the potential difference at 50% charge?
I have 5 bars that indicate charge on my display. I had been assuming that each bar is 20%, but now that I am paying more attention, it seems like they aren't linearly distributed. For those who would prefer a number, how is it calculated? If your battery is rated at 52.0 V, does that correspond to the potential difference at 50% charge?
04-08-24, 11:56 AM
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A 52 volt Lithium battery (like being discussed here) has 14 batteries in series which are fully charged at 4.2 volts per cell, so full charge is 58.8 volts. You can locate a chart online that shows SOC (state of charge) as a function of voltage (test with a voltmeter). Similarly a 36 volt battery is charged fully at 42 volts. The number of cells in parallel defines the capacity. As above, a Lithium battery won't explode because you charged it too long unless it's defective; by the same token don't charge when you're asleep.
Last edited by 2old; 04-08-24 at 12:20 PM.
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04-08-24, 02:31 PM
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OK, so does that then mean an 80% charge would correspond to 56 V ? (In other words, does battery charge scale linearly?)
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04-08-24, 04:18 PM
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New to this thread. Timer is excellent idea. I used to volunteer at a place that had about 10 handheld 2-way radios for the staff, this was 15 years ago and I didn't know if the chargers were "smart" chargers. All the chargers together did not draw much power, so I plugged them into two power strips, then both of those into a simple $5 light timer, I experimented until I knew about how long on average they took to recharge each day, set the time for a bit longer, can't recall if charge time was 1 or 2 hours each night. Set the start time late enough that it was 2 hours after all staff left, so no radios got missed, but early enough in the evening that I was still there while charging, a good safety precaution. Worked great.
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04-08-24, 05:25 PM
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My second charger then is nominally rated for 75%. It goes a little bit over, so I am probably close to ideal. Thanks for posting the chart tds101
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04-08-24, 10:43 PM
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04-09-24, 08:44 AM
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Thanks tds; I checked my Luna charger, which has settings for 80%, 90% and 100% @ 52V and the values corresponded with this chart..
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04-09-24, 09:36 AM
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The chart comes in very handy. My RipRacer has a voltage meter, so I'm always aware of the battery voltage. I just wish my bike had the torque sensor as well as cadence sensor. It's a smooth ride all the same. (I'm still considering selling it...)
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04-09-24, 06:35 PM
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Everything made perfect sense on that chart when I charged it up. My 80% charger really does charge to approx 80% (55.6 V).
But what has me confused is what is happening as I approach 50V (50.4 V is supposed to be 50% charge):
I've only put 330.8 miles on since the conversion, so I have no idea if the battery is half full, or ~ 20% (one bar). The chart says 20% should be 45.4 V.
But what has me confused is what is happening as I approach 50V (50.4 V is supposed to be 50% charge):
I've only put 330.8 miles on since the conversion, so I have no idea if the battery is half full, or ~ 20% (one bar). The chart says 20% should be 45.4 V.
Last edited by Polaris OBark; 04-09-24 at 07:33 PM.
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04-10-24, 10:37 AM
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Everything made perfect sense on that chart when I charged it up. My 80% charger really does charge to approx 80% (55.6 V).
But what has me confused is what is happening as I approach 50V (50.4 V is supposed to be 50% charge):
I've only put 330.8 miles on since the conversion, so I have no idea if the battery is half full, or ~ 20% (one bar). The chart says 20% should be 45.4 V.
But what has me confused is what is happening as I approach 50V (50.4 V is supposed to be 50% charge):
I've only put 330.8 miles on since the conversion, so I have no idea if the battery is half full, or ~ 20% (one bar). The chart says 20% should be 45.4 V.
04-10-24, 01:05 PM
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I'm not a trusting person, so I am going to test it (ride it uphill until it dies or I convince myself it really is just below 50%).
Edit: I ran it to the point of shut-off, which, fortunately for me, was on a hill half way between my house and my mail box. The voltage at that point was 44.5 V under load, and about 45 V idle. That was running with zero bars for awhile, and the outline of the battery with zero bars was flashing, which I interpret to be the equivalent of the fuel light turning on. I think "empty" is probably programmed to be about 20% charge in the battery, to keep the user from ruining it, but that is speculative.
Edit: I ran it to the point of shut-off, which, fortunately for me, was on a hill half way between my house and my mail box. The voltage at that point was 44.5 V under load, and about 45 V idle. That was running with zero bars for awhile, and the outline of the battery with zero bars was flashing, which I interpret to be the equivalent of the fuel light turning on. I think "empty" is probably programmed to be about 20% charge in the battery, to keep the user from ruining it, but that is speculative.
Last edited by Polaris OBark; 04-10-24 at 03:24 PM.
04-10-24, 06:46 PM
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I'm not a trusting person, so I am going to test it (ride it uphill until it dies or I convince myself it really is just below 50%).
Edit: I ran it to the point of shut-off, which, fortunately for me, was on a hill half way between my house and my mail box. The voltage at that point was 44.5 V under load, and about 45 V idle. That was running with zero bars for awhile, and the outline of the battery with zero bars was flashing, which I interpret to be the equivalent of the fuel light turning on. I think "empty" is probably programmed to be about 20% charge in the battery, to keep the user from ruining it, but that is speculative.
Edit: I ran it to the point of shut-off, which, fortunately for me, was on a hill half way between my house and my mail box. The voltage at that point was 44.5 V under load, and about 45 V idle. That was running with zero bars for awhile, and the outline of the battery with zero bars was flashing, which I interpret to be the equivalent of the fuel light turning on. I think "empty" is probably programmed to be about 20% charge in the battery, to keep the user from ruining it, but that is speculative.
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04-15-24, 12:40 AM
#50
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I've seen it from several reputable sources. One source said it can up to TRIPLE the battery's useful lifespan. Do some Googling and you'll find them too.
Writing it off as "it lasts pretty well" is fine if you don't mind spending the $700 for a new battery sooner rather than later. Or if you don't mind losing more capacity after 2 years instead of 5.
Recent laptops are not 100% transparent on this. For example, I've found that my work laptop says "100% smart charged", digging into that, it means it maintains the charge at 80% unless Smart Charging is turned off. Likewise, iPhone has a setting to do something similar, after it has learned from our charging habits. For example, it learns I routinely plug in my phone before bed. It immediately charges to 80%, then tops it off to 100% right before my usual wake-up time. eBike chargers aren't this smart yet. My phone is about 3 years old and the battery health is still at 86% because of this.
Yep. Use a timer.
Writing it off as "it lasts pretty well" is fine if you don't mind spending the $700 for a new battery sooner rather than later. Or if you don't mind losing more capacity after 2 years instead of 5.
Recent laptops are not 100% transparent on this. For example, I've found that my work laptop says "100% smart charged", digging into that, it means it maintains the charge at 80% unless Smart Charging is turned off. Likewise, iPhone has a setting to do something similar, after it has learned from our charging habits. For example, it learns I routinely plug in my phone before bed. It immediately charges to 80%, then tops it off to 100% right before my usual wake-up time. eBike chargers aren't this smart yet. My phone is about 3 years old and the battery health is still at 86% because of this.
Yep. Use a timer.
So I've concluded that it's not worth going to any material trouble to extend its life.
I will continue to charge it before it gets below 20% and never store it at 100% but I'm not going to bother with a timer.
If Bosch made a charger which could be set to charge to 80%, I would use that, but in the absence of that, I'm happy charging it to 100% then immediately using the bike.