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Full battery down hill??


Nostris

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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. 

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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.

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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.

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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.

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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.

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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.

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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!

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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:)

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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!:popcorn:

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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 by xiiijojjo
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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!:thumbup:

Edited by ShanesPlanet
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  • 1 year later...

I basically live on a giant hill, and to get into town is about 500' of elevation downhill. Usually, I leave my house on full-charge and have had 0 issues on any of my other wheels (V10F, S18, 18XL, V8F). Every time I try it on the V11 I get tilt-back and a "please repair" voice which I assume is an overheat protection; it cools down in about 30 seconds and I can keep riding.

But it's super annoying, does this happen to anyone else? Just wondering if I have a bad voltage calibration or something...

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Hi @LandoCycle!

What is happening is over-voltage / over-charging protection, and it is a common occurrence for riders going downhill.
When you're braking downhill, some amount of energy is recovered via regen braking, charging your battery in the process, despite its cells are already at their maximum voltage. This is why it's making you stop.

It is possible that the V11 is a bit more strict and careful than the others wheels, or more effective at regen in this case. It is not a defect however.
To circumvent the issue, you can burn some energy before going down like by making a little detour, or not always charge to full.

What would be the most convenient for you?

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Yeah, if I ride hard for 5 minutes or so before going downhill I don't have the issue. I'm aware the board needs to dissipate the power into heat if the batteries are fully-charged. The odd thing is that NONE of my other wheels are bothered, just the V11. Glad it's not specifically my V11 though, and it's something I can work around.

Edited by LandoCycle
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3 minutes ago, techyiam said:

Just wondering, would the V11 still complain on a full charge, if you were to ride down slowly? 

Yeah, I tried it and same issue. I'm 180lbs with gear. My Gf on the other hand can go downhill on it just fine at 130lbs.

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@techyiam might be into something with the speed :D

Have you tried faster?
Higher speed means more energy will be dissipated in aero drag (mostly) and rolling resistance, so there won't be as much - if any to regen into the packs.

The catch is that if you have to brake hard in emergency from this higher speed, the wheel might not like that at all and throw you off or even cut-out to protect the cells by disconnecting the packs.

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This symptom is quite intriguing, at least for me. If the cause is due to overheating, how does riding for 5 minutes prior to going down make a difference? If it is overcharging or over-voltage, why it is OK for the lighter rider? Also, the "please repair " warning message is worrisome. 

1 hour ago, LandoCycle said:

 Every time I try it on the V11 I get tilt-back and a "please repair" voice which I assume is an overheat protection; it cools down in about 30 seconds and I can keep riding.

 

1 hour ago, LandoCycle said:

Yeah, if I ride hard for 5 minutes or so before going downhill I don't have the issue.

 

49 minutes ago, LandoCycle said:

Yeah, I tried it and same issue. I'm 180lbs with gear. My Gf on the other hand can go downhill on it just fine at 130lbs.

 

 

Edited by techyiam
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3 minutes ago, techyiam said:

This symptom is quite intriguing, at least for me. If the cause is due to overheating, how does riding for 5 minutes prior to going down make a difference? If it is overcharging or over-voltage, why it is OK for the lighter rider? Also, the "please repair " warning message is worrisome. 

 

I think because riding hard for 5 minutes drains the battery low enough that it can put some juice back into the battery during regen instead of dissipating as heat when going down-hill.

Edited by LandoCycle
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6 minutes ago, techyiam said:

why it is OK for the lighter rider?

It must be on the edge of over voltage... the higher mass of the heavier rider has more potential energy at the top of the hill than does the lighter rider. A (small) amount of that energy is converted to regen power but I suspect that because the lighter rider has less potential energy, they're actually power neutral or slightly using power on the way down.

I may be wrong, but I don't think there's a shunt to a resistor that'll convert regenerated power to heat—it's either sent to the battery or there isn't 'braking' power. Seems silly not to have a resistor though, maybe it just wouldn't be used enough to justify the cost.

An EUCWorld tour recording should be quite helpful...

Edited by Tawpie
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