A632

Can someone please clear up and ongoing discussion within our cycling group which is - What do owners of ebikes believe is the best charging regime for longevity of the battery.

• After every ride regardless of battery drain
• When I drops to 75% charge
• When it drops to 50% charge
• When it drops to 5/15% charge

Manster

...it is total time with the battery at 100% SOC that hurts longevity. I charge to 85% after every ride and only top off right before a longer than usual ride.

alloo

I charge from 15% to 100% or every night when commuting. When not commuting once a week. I store the battery inside of my home when not riding.

Doc_Wui

I recharge our batteries after every ride, and charge to 100% when we are using our bikes every day. When I know we're not going to use a battery for a week or more, I'll leave it half charged.

I've not seen the studies, but I suspect that running a battery down to 20% before recharging is more stressfull for life than recharging after every ride. It's also less stressful for my range anxiety to go out with a 100% charged battery vs one at 80%, even,for a shorter ride.

speedy25

The controversy remains. Yes, there are those who think some wild regimen will make their battery last for a hundred years but it just wont happen.

Treating your battery like a lead acid battery and having it continuously on the charger? BAD. No controversy over that.

How low can you take it? I have totally discharged batteries on rides and charged them right back up with no seemingly ill effects. I will typically plug a battery in when it is low, or top it off for a long ride when its below full. The only real caution is if you run a battery down and forget about charging it for a month or two it may not charge because of the BMS seeing a lower voltage than expected. Thats the only bad thing.

Get out and ride your bike. Charge it up as needed. Enjoy the ride, and forget bout silly controversies.

2old

Several years ago I read an article about Tesla (who were using 18650 batteries similar to the ones in our kits then) that stated they were able to give an eight-year (or whatever) warranty on their batteries by not allowing them to be charged past 80% nor be discharged below 20%. That's good enough for me. I only charge to 100% if it's going to be a long ride. Gave away my last battery (52V, 10 ah) after five perfect years and it was still as good as new (qualitatively).

klevin

To some degree, things depend on the charger. We don't usually know, for example, to what voltage our chargers take the battery, nor do we know how our battery charge indicators are calibrated. It's possible that a particular brand of battery, bike and charger says 100% when the battery is at 80% like a Tesla.

Lots of unknowns. Personally, I just plug in when I get back from a ride. Range anxiety is not something I want to deal with. I have a Trek/Bosch system, and have not read anywhere a single comment about battery failure. YMMV, especially with low cost generic stuff.

skookum

I think that is a common tactic among electric car manufacturers. Over build the batteries in terms of capacity then charge only to 80% and make sure they can't discharge more than 30%. That greatly increases the number of cycles you can get out of your battery. Some chargers can be programmed to do that.
Do commercial ebikes (as opposed to DIY bikes) have this kind of option for charging or do you just have to watch the time carefully?

klevin

Smart chargers, which we hope are all lithium battery chargers, use voltage sensing, and switch to low current trickle charging at a certain point. No charger could use time as a variable. Perhaps a consumer, based on experience, could do so? But why? Where's the evidence that charging to a certain level, as indicated by the charger or the battery, has any value. Too many unknowns.

Doc_Wui

An electric car can afford the weight penalty to overbuild the battery, since it's very hard to replace them. I suppose an electric bike could do the same, since so many folks are loving their 75 pound bikes, Cannot argue with the science. Running a pack between 80% and 30% will maximize battery life.

Still, unlike cars, bikes do not have battery heaters for cold weather running. Unlike smart phones, bikes don't usually carry temperature sensors to inhibit charging when the battery is below 40F. You could follow a strict charging regimen and still screw up your battery recharging it after a sunny winter ride,

klevin

For all we know, the BMS in branded battery systems could already be limiting useful capacity to extend battery life. Since I have a Bosch system, I'll ask on a different forum to see if anyone knows. There's a Bosch guy there regularly.

2old

I have a 52V Luna charger that has a switch for 80%, 90% and 100%. Checked the voltage after each cycle and the numbers agreed with expectations, about 55V for 80%, 57 for 90% and 58.8 for 100%. My Yamaha-Haibike has battery "voltage" indicated as % on the display and I charge for 10 minutes after the blinking charge light gets to 75% and am in the 80% range. Checked the voltage on it and it was reasonable for the % charge. I read (can't remember where) that charging and discharging to 90/10 will double the life of the battery and 80/20 quadruple it.

mclewis1

One of the better threads I've found that contains many external references to battery technology and charging information.
https://electricbikereview.com/forum...y-guide.24443/

chas58

Does it really make a difference?

Like stated above, OEM vehicle makers - especially with a range extender ICE, used to keep SOC between 30% and 80%. But as battery technology and experience has changed, that has kind of gone out the window. I've kinda scratched my head at this too - if you only use the middle 50% of the battery and the battery can take twice as many charges - well isn't that what you would expect? That would end up with the same amount of miles ridden/driven.

What really hurts is if you go too low on state of charge - something that in my experience can be exacerbated by leaving the battery in freezing temperatures. Leaving it at 100% isn't geat either, but its not the end of the world.

Realistically, I fill it up after every ride (and try not to run it dry).

OldRailfan

So do I ....however I was also "brave enough" to run the battery down until the error code "low voltage" showed up. I really wanted to know how many kilometres would be the outer limit!
In the real world the battery will handle 70 km of mixed terrain including some 12+% grades. The seller states 55km in the features (https://www.rbsmsports.com/product/r...-adder-e-bike/)
More from the real world; today's ride was 61+ km on a flat course (Rail Trail), at the start of the ride the battery was fully charged i.e. showing 100% and the charger had switched to green. At the end of the ride it still showed 66%.

The odometer has only 670km to show, so it's early days! Over that distance I figured out that matching the PA level to the gear and cadence will most likely result in the greatest distances on one charge.

BTW officially the "Mud Adder" is a e-MTB , but I consider it a good all-round bike for anything from "mild" single track to pavement.

Moisture

Keep the battery charged roughly between 30-80%. The battery will wear out faster when frequently used outside that range.

Numerozero

Grin Technologies makes the Satiator, generally regarded as the best ebike battery charger in the world. It is programmable for charging up to whatever percentage you like. Their info sheet shows how charging up to only 80% triples battery life: https://ebikes.ca/product-info/grin-...-satiator.html

OldRailfan

Thank you, lots of info and an interesting product.

klevin

Totally unreferenced battery life graph. Could be true, could be urban legend.

Hard data on this topic seems to be remarkably difficult to find. Ditto for real life experience. I asked on a Bosch specific forum if anyone had a battery failure. No replies. Asked for details on their BMS. None available.

The weakness of Grin's charger is that it sees the voltage as reported by the BMS, not necessarily the true battery voltage.

mclewis1

Could also be from little green men from Mars ... but given Grin's strong engineering background (rather than a marketing entity) and long experience in the marketplace it's much more likely that the data is from real world experience. But yes, it would be better if the chart's data was referenced ... perhaps you could make that suggestion?

The Satiator was apparently designed as a charger for a wide variety of battery products, rather than as a Bosch specific charger. Unlike the majority of commercial ebike batteries Bosch produces batteries that require chargers with unique pinouts and awareness of the internal BMS, likely for a level of vendor lock in. I don't see that lack of Bosch specific characteristics as a specific weakness in the Satiator product but more of the reality of creating a popular product rather than a vendor focused small niche product.

klevin

Who said anything about a Bosch specific charger?
Yes, the Satiator is designed to work with a wide range of battery types, including lead acid. The only way it can do that is to just have a user adjustable voltage limit. That's an OK approach, but hardly the most sophisticated that could be done. I'm sure it's an OK product, but it's not a particularly sophisticated solution to the charging issue, especially at it's price.

Unfortunately, we ebike users live in an information vacuum, with a dearth of hard, factual information regarding best charging protocols for maximum life. Yes, there's a lot of "I think" and "I read somewhere" suggestions. No doubt some of them are accurate, but which?

mclewis1

Yup, agree 100% ... and the other related area that gets me is the lack of info on the BMS used. There are lots of features and capabilities built into most of the popular versions but just try to figure out what the one in your particular battery is configured for, or if any of the functionality can be accessed or safely changed.

I have a 52v 14.5 ahr/750w battery in a downtube case. To go along with it I purchased the Luna Advanced charger instead of the basic 2a brick or the expensive Satiator. A few folks question the Luna's build quality but from a feature/functionality point of view it does everything I need. After a long ride I set the charger's switches to 2a and 80% and leave it for a while (I'll turn it off when I notice it's at 80% voltage or hear it cycling). Just before it's next use I think about what I'll need. I might leave my battery at 80% (with my battery that's ~450 usable watts) or if I need more distance I'll turn the charger up to 5a and 100% which only takes a few minutes to get to 58.8v or so (~600w usable). Occasionally (every few months) I'll charge to 100% at 1 or 2a and just leave it for a little while, letting the BMS do it's balancing thing. All very simple and straight forward.

The alternative for me with the way most ebike charger setups work would have been two chargers (2a and more powerful one), an AC outlet timer, and an inline voltage/amp/wattage display. Then it would take a little experience with my battery (noting it's voltage sag and charging characteristics) and some time with those battery SOC charts (modified with a time variable) that I'd refer to each time I charged my battery.

I don't understand why we don't see commercial ebikes coming with either more intelligent chargers or more flexible manual chargers (like the Luna). Well actually I do understand it ... they get to sell more batteries this way.

JohnFord

Optimal battery operation assumes a discharge of up to 10%.

mpetry912 

I do agree that continously charging to 100% takes something out of the battery.

I follow the "30 to 80%" rule for the most part.

one of things I learned from tesla is that if you have a battery charged above 90% there's no capacity for the regen braking to dissipate energy.

So, ride it down to 30 and charge to 80. Agree that some more information and smarter chargers would be useful.

/markp

Calsun

Battery packs have an estimated number of charge cycles in determing their life expectancy. If I charge when the battery pack is at 75% SOC I will be doing so 3 times as many times per mile as if I would recharge at 25% SOC, and I will be shortening its expected life by roughly 66% in the process. This is why I like the approach Specialized took with their Creo bike and the optional Range Extender battery pack. The bike can be programmed with the smartphone app so that the motor first draws down the external battery before drawing power from the battery in the downtube or it can draw from both packs at the same time.