Full battery down hill??

[Nostris 46]

So, a question for the experts. I live at the top of a hill. The road from my house to the bottom of the hill is about 1 kilometre and drops about 100 meters in height. I have heard that you shouldn’t ride downhill with a fully charged battery as the wheel will try to over charge the batteries during the decent. Is this true?  What would happen.? Would it damage the wheel or cause a cutout?   The wheel is a V8f ......your thoughts would be appreciated. 

[meepmeepmayer 12,751]

The wheel would beep at you, tilt the pedals, and in the worst case (if you ignore the warnings and keep riding downhill) shut off before overcharging the battery.

Just charge to 90% or 95% or whatever instead of 100% if you start on the top of a hill.

And you can always ride back up to lose more energy than you'll get back coming down. So worst case, if it complains, you ride back up a few meters before continuing downhill.

[Bumblebees 35]

You might get away with riding down a hill depending on the wheel and manufacturer.   I occasionally ride my 16x full charge downhill slowly.  I would not do it on my MSX.

[Gasmantle 630]

Like you I live at the top of a hill (although not as long or as steep), when I got my first wheel a couple of years ago (a V5F) I wondered the same thing and would ride 200yds or so on level ground first thinking that ought to just take a bit of charge from the battery.

A few times I forgot to do it and noticed no side effects so I just stopped altogether, I'm on my 3rd wheel now and never experienced any problem.

[madbikes 13]

3 hours ago, Nostris said:

So, a question for the experts. I live at the top of a hill. The road from my house to the bottom of the hill is about 1 kilometre and drops about 100 meters in height. I have heard that you shouldn’t ride downhill with a fully charged battery as the wheel will try to over charge the batteries during the decent. Is this true?  What would happen.? Would it damage the wheel or cause a cutout? 

You will most likely not have an issue if you ride downhill very briefly. The wheel can cutoff if you do so for long enough distances to prevent overcharging and there is no way around it, even with a Onewheel.

You can charge to full so cell balancing can take place, then ride off some charge before your desend. Or you can charge to say 95 percent and just start your desend immediately. I'd still charge to 100 percent occasionally so you can balance the cells.

[Tawpie 358]

100 meters isn’t very far “down”, just go slowly and don’t brake hard. Or, after your wheel finishes the balance portion of its charge cycle, unplug the charger, turn it on, lights on, and let it sit there for a half hour or so to burn off a little bit of charge.

[Nostris 46]

12 hours ago, Tawpie said:

100 meters isn’t very far “down”, just go slowly and don’t brake hard. Or, after your wheel finishes the balance portion of its charge cycle, unplug the charger, turn it on, lights on, and let it sit there for a half hour or so to burn off a little bit of charge.

The road is 1000 Mts long and has a change in height of 100 meters from top to bottom….the steepest parts are probably a 20%/25% incline.

[Nostris 46]

Thanks for all your replies, I’ll probably go with the 95% charge idea and see what happens. if it was a short distance I’d just chance it, but IMO a continuous decent for 1km is quite a time to be using regenerative braking. ..Better safe than sorry!

[meepmeepmayer 12,751]

Just start with a full battery and try and see when the wheel complains. Then ride back up a bit, and continue downwards. Then you'll now more. From then on you'll have a better idea with what battery % to start so you end up with 100% at the bottom of the hill.

Nothing bad will happen if you don't ignore any warnings. No need to be afraid. You can just try things

[ShanesPlanet 3,566]

1 hour ago, Nostris said:

Thanks for all your replies, I’ll probably go with the 95% charge idea and see what happens. if it was a short distance I’d just chance it, but IMO a continuous decent for 1km is quite a time to be using regenerative braking. ..Better safe than sorry!

Whats at the bottom? You could always just go faster and faster and faster and faster and ... well, you  know!

[xiiijojjo 215]

I have a very similar situation to @Nostris in the sense that i too live on a mountain with approximately 700 meters of road and it drops down about 150m from my house to the bottom of the mountain. If i charge my wheel overnight and disconnect the charging cable as i exit the house my gotway rs will start beeping and tilting back for the last 100-200 meters so my solution is just to continue to charge to 100% and before i mount the euc i lift and free spin it until i hear the 80% alarm, decelerate and mount it. Doing that will remove enough charge that i can go down the mountain at any speed doing any amount of braking.

Edited yesterday at 03:47 PM by xiiijojjo

[RagingGrandpa 631]

Popular topic this month...

On 2/19/2021 at 10:06 AM, RagingGrandpa said:

Assuming rider+EUC = 100kg, consistent grade, 32km/h riding (20mph), and no prevailing wind: net energy becomes zero on a 15% grade.
It means: if you are dropping 1500m over a 10km ride distance, you use no energy from the battery pack.
Ride steeper than 15%, and you're charging the pack.

15% is really steep for a roadway.
Public roads in the US are generally limited to 12% grade.
There are some notable exceptions, such as 23% in the city of San Francisco, but they are not sustained for long distances.

So overall, I think it is a very tiny percentage of EUC riders that live on top of a ride route with a 15% grade. Most of us don't need to worry.
Respect the beeps!
Thankfully, there is an audible alert for pack overvoltage. If you hit the alarm, turn around and ride uphill for 1km, then continue back down.

 

19 hours ago, Nostris said:

1 kilometre and drops about 100 meters in height

10% grade. No concern, just ride. Respect the beeps!
 

2 hours ago, xiiijojjo said:

700 meters of road and it drops down about 150m

21% grade. Howbout fully charge, then do a little pendulum practice in the driveway before descending?

[alcatraz 544]

Charge with a timer (fully charge once every month). Walk the hill or play a bit before riding down on a full charge.

[ShanesPlanet 3,566]

12 hours ago, RagingGrandpa said:

Popular topic this month...

 

10% grade. No concern, just ride. Respect the beeps!
 

21% grade. Howbout fully charge, then do a little pendulum practice in the driveway before descending?

We need a 'mic drop' emoticon. THIS is about as perfect an answer as one would hope to find. Aint like 2-3 minutes of pendulum aint good warmup for the muscles/reflexes anyhow... take a bow sir, and thanks for the information. Learn something new everyday!

Edited 9 hours ago by ShanesPlanet