I've got a battery question EM NEO.

[Phildirt]

So I went for a ride today back in Glacier Park and tried to better my self from last weekend. 2450ft. gain
in 13.4 mi 90% in eco mode. I watched the battery level closely and thought I would turn around at one bar,
well I didn't and it just shut off. My question is I hope I didn't hurt the battery taking down to nothing (the bike is only 2 wks old). I usually recharge @ 50 to 60%.

 

[Phildirt]

Sorry I meant EM EVO.

 

[stevenast]

It is harmful, slightly. Certainly not the best thing you can do, and will shorten the lifespan of your battery a little bit. In my limited research, I would recommend you don't make a practice of it, never run your battery all the way down. But don't worry too much - just charge it back up again now, as soon as you can.

It also probably has some protection built in and actually shut down before fully draining the battery. Just charge it up as soon as you can, so it doesn't stay in that drained state.

 

[Marko]

My question is I hope I didn't hurt the battery taking down to nothing (the bike is only 2 wks old). I usually recharge @ 50 to 60%.

In the Turbo at least the battery management software functions so that it turns off support at 3% (lights still work) so that people dont drain them all the way. But I doubt that yours suffered any from that single incident and most likely it was not all the way drained even if it turned off.
According to my bike's manual it is harmful to store the battery for long times without recharging. Heat (around 100F already) is another enemy of lithium batteries, whereas cold is not unless you recharge in cold.

 

[George S.]

I think they all have something called an LVC, or low voltage cutoff, in the controller. The idea is that when the battery is getting completely depleted, the system will not allow it to continue to discharge. A lot of people, tinkerers, run batteries down to find the LVC, which is more meaningful if you have a voltage readout.

Anyway, I wouldn't worry. It's set up to not ruin the battery, and you never hear of anyone ruining a new bike this way. Glacier sounds pretty nice.

 

[Phildirt]

I plugged the battery in as soon as I got home, I will not do that again if I can help it. Glacier is fantastic, the best part is the road is only open to bikers and walking for some 28 miles until june when they finish removing all the snow.

 

[opimax]

I try not but don't loose sleep when I do , the battery in my Stromer has a BMS , I believe yours does also. I charge mine up after use but cooled down first if warm to my touch

 

[Ravi Kempaiah]

I plugged the battery in as soon as I got home, I will not do that again if I can help it. Glacier is fantastic, the best part is the road is only open to bikers and walking for some 28 miles until june when they finish removing all the snow.

It's perfectly alright to run it down a few times in the first week or so. It re-balances the cells.
After the first week, it's advisable not to do it; diminishes the capacity. National parks are the best places to have fun on an ebike.
Enjoy.

 

[stevenast]

It's perfectly alright to run it down a few times in the first week or so.

Uh, not so much. expert opinion says otherwise. Read the second paragraph under the graphic:

http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

"if at all possible, avoid full discharges..."

 

[Ravi Kempaiah]

Uh, not so much. expert opinion says otherwise. Read the second paragraph under the graphic:

http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

"if at all possible, avoid full discharges..."

No one has died of cardiac arrest during a mild hunger but many have died of cardiac arrest due to overeating and obesity
Anyway, nothing will happen for the first few cycles. Also, there is BMS to protect and maintain the voltage of cells. People who designed these battery packs know that it happens routinely.

PS: I'm not a noob to battery tech.

 

[stevenast]

Not a noob because you know someone who does it ... Okayyyy.

Your analogy of cardiac arrest is comparing a human to a battery?

No one has died of cardiac arrest during a mild hunger

Anyway, I am certainly not calling anyone a noob. Just pointing out that the complete discharge of these battery packs is a mild problem. Nothing to lose any sleep over.

 

[stevenast]

Edit: the following is for clarification only, not stirring anything up:

____________

You edited your previous post while I was replying to it, so people might not know that you stated that you know something about batteries because you know people who work with them.

 

[opimax]

I guess I wonder what full discharge means. I know what the obvious response but these bikes have BMS that are set most likely conservative by the manufacture. They must be able to take the max discharge and be able to handle (in my case) the 3 year warranty (w/the manufacturer's caveats). On a DIY battery I bet the voltage is allowed to drop more. My batteries so far have lasted about as the manufacture has stated I do run them down to 10 percent frequently as i need all the juice as I can get. When I don't have to I don't and swap out early but 65-80 miles is not real far but on full speed w/3 batteries I will run the 1st 2 down and need to make sure i can get home, last battery doesn't get beat as hard. i have 4 and rotate them.

My main point is the question of how the manufacture decides"empty". I have only had Stromers and don't know their info , it would be interesting to find out

 

[stevenast]

The attached is direct from Stromer. 80%???

Edit: maybe what they mean is that it has 20% charge left...???

 

[opimax]

It charges to 80% in 4 hours and finishes the in the last hour the last 20% in slower different charge mode is the way I read it, cell balancing???

I am questioning the voltage cut off of Stromer vs DIY from ES board on same battery chemistry

 

[deckofficer]

All my experience is with LiFePO4 large prismatic cells but applies to the small Li Ion cells used on the e-bikes. When I receive cells to build my pack the first thing I have to do is balance them. I have to decide by my intended usage if I should top balance or bottom balance the cells for the pack. Our lithium cells will give the most cycles if we operate them between the two voltage knees, the charge knee and discharge knee. A major advantage of lithium over lead is a rather steady voltage over this range and less voltage sag during high C discharge, hence a much lower Peukert effect that determines usable ahr for our pack.

Since the 18650 cell is the same used in the Tesla, going by Tesla's recommendations mirrors the above. The Tesla owner is able to choose charge termination %, and if their daily commute doesn't require the entire bank capacity, they will charge to say 90%. If a long trip is planned, the night before they will set up for 100%.

Here is a photo of my LiFePO4 prismatic cells that even at over 500 cycles still deliver more whr than spec during a capacity test.

Lead is Dead. Long live lithium.