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How low voltage sag to activate alarm?


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Hello guys.

Just wondering if you have experience with this:

I would like to know how low does the voltage must sag down in order to trigger the 80% alarm.

Today I started running at 50%, sagged it down (according to eucW) to 10% but the alarm didn't trigger. 

I didn't fall or anything.. But I was trying to understand a bit how its triggered... I was hoping to hear the alarm at 20%, but didn't.

Then I activated the alarm 1 and 2 to see if they were still working, and they do just fine.

Then, deactivated both again, did a lift test, and it works too...

Edited by Sebrios
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Not sure what wheel you have but below 10% level riding will trigger the 80% alarm on my 84v MCM5 800wh and also my 84v MSX 1600wh.  Less sag on the MSX and can ride it down to 28% ish where as the MCM5 will trigger with 50% battery remaining when pushing hard.

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The GW 80% alarm is only triggered by speed. For example, on the 84V MSX the threshold is 58km/h on a full battery, linearly down to 45km/h at 10% battery. The low battery alarm plays at 15% battery.

 Those are the only factors that cause the GW alarms to play. Power consumption for example in itself does not.

 The EUCw battery meter does not (necessarily?) show the same values than how the firmware calculates the percentage. 15% battery is about 68V on a 84V Gotway, but about 64V on an 18XL.

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Im running a msx100V

Im pushing it hard so that I sag the voltage as much as possible (just to understand.. Its not my regular riding habit)

but I've found that even when I force it to go below 10% it won't beep.

In the other hand, im sure the 80% alarm is NOT controlled by speed only...

Oh, I am super light too. 57kg with all my gear on (that's like 118lbs)

 

when battery is very low, and you push it, it does beep

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I'm sure of that too and will test both. I know msx beeps between 30 and 32 after charging depending on where I'm riding, wind, incline etc, 90kgs.  The MCM5 will give me the 2 and 3 beeps when getting really low and from memory (not used for work since lockdown) I can get the 5 beeps at maybe 10-12mph if I lean in to it too hard.

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6 hours ago, Sebrios said:

but I've found that even when I force it to go below 10% it won't beep.

Do you perhaps have the EUCw percentage compensation enabled?

There is an interesting Russian review video on the MSP,. Every single wheel (MSX and MSP) beeps as they accelerate against a shallow uphill in a race. They are not running on low batteries, but they accelerate hard enough for the battery to sag under 15%. Just like EUCO posted the EUCw logs from their MSP vs MSX acceleration comparison. All of them started at or near 100%, and one of them dropped down to 7% during the acceleration.

6 hours ago, Sebrios said:

In the other hand, im sure the 80% alarm is NOT controlled by speed only...

Sorry, no. GW themselves posted the chart a few years back. It didn't include any of the Nikolas, but I think all current GWs from that time were included. For some reason I never find the topic it was posted in, hopefully someone else can chime in with the link.

And to be precise, the speed threshold changes with the instant battery level. So it's not "only" triggered by speed. But whether your battery sags from 100% down to 20% during the harshest of accelerations, or if the battery is at 20% during a calm riding on a slight downhill, your Gotway will beep at the same speed. Which speed that is depends on the model of course.

What makes it seem like a power based alert is the instant reaction to sudden battery voltage changes. Other manufacturers smooth out the battery metering so it wouldn't sag on every acceleration. GW does not.

 

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Was the gotway chart hand written? If so I have that on my phone.  It shows MCM5 at 33kph at 10% battery.  That's 20mph, mine will trigger way lower than that but I can get about 18mph if I build the speed up really slowly so not to trigger the alarm, flat no wind.  I thought the chart was the max speed you could achieve at certain battery levels under perfect conditions at optimal rider weight.  It shows 100% max at 43kph, so 27mph, I'm 90kgs and at full battery mine will alarm at 24.5mph and no more.  Only slightly over their test weight.  MSX 84v max 58kph (36mph) and min 45kph (28mph).  Max so far on my MSX is 32mph and alarms sub 20mph when low.

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42 minutes ago, Delmeekc said:

 I thought the chart was the max speed you could achieve at certain battery levels under perfect conditions at optimal rider weight.  It shows 100% max at 43kph, so 27mph, I'm 90kgs and at full battery mine will alarm at 24.5mph and no more.  Only slightly over their test weight.  MSX 84v max 58kph (36mph) and min 45kph (28mph).  Max so far on my MSX is 32mph and alarms sub 20mph when low.

Correct. The charts I have seen (hand written by Gotway and another digital one by ewheels) showed free spin test data. For the MSX 84v I think max was about 36mph at 100%. In reality, I never saw more than 33mph under load (when riding) before the 80% beep even with a full battery (because of sag). The MSX 100v is similar - 57mph free spin but around 43mph when riding.

I kinda see where Mrelwood is coming from in that alarms are 'only' speed triggered, but the fact that they are also battery level dependant does play a big part. It's a great alarm system because of this - you always know where the limit is, whatever your current riding parameters or battery level.

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1 hour ago, Delmeekc said:

I thought the chart was the max speed you could achieve at certain battery levels under perfect conditions at optimal rider weight.

Iirc, the GW representative said that the curves were just for triggering the alarm. “Max speed you can achieve” would imply a faceplant if exceeded. I weigh 100kg, and have no problem reaching the 80% under much less than optimal conditions. No faceplant, just an alarm.

 The 80% alarm should be a different beep pattern from the 15% alarm, but I sometimes have trouble determining which is which. But my 84V MSX perfectly follows the alert system I (probably far from perfectly) explained.

1 hour ago, Delmeekc said:

It shows 100% max at 43kph, so 27mph, I'm 90kgs and at full battery mine will alarm at 24.5mph and no more.

I suggest you make a lift test at 100% battery. And if you have the guts, try to find a shallow downhill to test the beep. When a 90kg rider is riding at 24.5mph on flat ground, the battery is sagging much lower than 100%.

 But again, if you are monitoring speed or battery % with EUCw, make sure you don’t have any compensations enabled. Though I’m not sure if all of them even can be disabled. I use DarknessBot.

1 hour ago, Delmeekc said:

Max so far on my MSX is 32mph and alarms sub 20mph when low.

Sounds plausible. 32mph while sagging from 100% battery, and hitting the 15% alarm with low battery.

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7 minutes ago, mrelwood said:

 The 80% alarm should be a different beep pattern from the 15% alarm, but I sometimes have trouble determining which is which.

Very true, I had a beep the other day at around 35mph. I knew my battery was getting low, but given I always back off as soon as I hear a beep I didn't know whether it was a low battery alarm or a speed/battery one. Without staying on the beeps long enough to hear the full sequence (5 beeps or 3 beeps etc) its impossible to tell. When I got home I checked the battery % via EUCW and saw it triggered at around 27% (only an estimate because the % can vary wildly whilst riding). So the reality is it could either have beeped because:

A: It was the 80% alarm that triggered due to hitting 35mph at 27% batt or
B: It was the low voltage alarm that may have triggered if the batt went below 20%.

In reality it doesn't really matter to me, a beep is a beep and I know that if one goes off I back off. I rarely, if ever hear the full sequence. The only one I would risk riding on for the full sequence is the 20% or 15% battery alarms because by that time your speed has come right down, but even then I have never been there (yet) as I haven't taken my wheel that low.

7 minutes ago, mrelwood said:

When a 90kg rider is riding at 24.5mph on flat ground, the battery is sagging much lower than 100%.

I think many riders don't really appreciate just how much sag is encountered. The recent Veteran video highlighted it very well, and concurs with my own findings that sag of up to 30% is relatively easily achievable, even on high voltage 6P setups. So blasting away on a 100% battery can easily see it drop to 70% rapidly, hence why people get confused that their free spin beep speed is never achievable, even on a 'fresh' battery.

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I'll pass on the downhill test, I know the MCM5 will sag around 40% and the MSX around 20% under load.

The low battery alarms are much slower per second than the 5 beeps a second and I can tell which is which easily with the beeper mounted externally.  Totally understand sag too, MCM5 has lots and when I'm riding it I only take it to 50% at rest or I'll be 5 beeping everywhere.  The MSX is good for about 30% before that happens but not really run it down much. MCM5 has been much lower as I used it for daily commute and had to limp home on a few occasions when tube stations were closed in London and had to ride to other lines which then left me with the 2 miles home afterwards with what was left.

Also my boy has been riding the MCM5 for some 360 miles since lockdown and he pretty much gets the same as me albeit 1mph more.  Same experience too on the alarms, 80% and low battery 2 and 3 beeps. I can hear him behind me beeping.

If it beeps, 5 rapid I'll back off by the 3rd and keep doing that as all has been good so far.

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3 hours ago, Planemo said:

The only one I would risk riding on for the full sequence is the 20% or 15% battery alarms because by that time your speed has come right down, but even then I have never been there (yet) as I haven't taken my wheel that low.

My attitude towards the low battery warnings changed quite a bit when I realized that 0% on a GW (66V) is 25% on the 18XL. The original 18XL version has just started to throttle the top speed of 50km/h at that voltage.

14 hours ago, Planemo said:

I think many riders don't really appreciate just how much sag is encountered.

I’m sure. Other manufacturers have a very slowly reacting battery metering, exactly to hide the instant sag.

 

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I remember last month or 2 I sagged the battery down to 5% @38mph... that scared the s t out of me after I checked my phone.

By the time, I didnt have the beeper mod, so I didnt hear anything, and eucW didnt alarm me anything.. thats why Im still looking for good warning solution...

Edited by Sebrios
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