Display predictive battery range

[Atlav4]

Hi does the display use predictive battery range which is proportional to present load exerted on the motor ? Whilst on a ride after about 2 miles in I tackled a steep incline approximately 1 1/2 miles in length with 7.8% sections and in level 5 assist and second gear pushing hard crested the incline. Reaching the top of the moors the weather began closing in, fog and drizzling rain and to my dismay the display showed 2 bars remained on the battery. Faced with a long descent I switched the display off worried about remaining range (middle of nowhere) Rode about another 1 1/2 miles then switched display back on to find 4 bars left? Cut my ride down to a total of 14 miles slightly undulating terrain and still had 3 bars left on display. Hence my original post is the range load proportional.

 

[Brittas]

On my woosh Rio, The green LEDs on top of the battery is the only accurate guide to the remaining battery power ( or voltmeter ofc). The LCD display seems like total guesswork. I had 2 Bars remaining ...next day I had gained x2 lol

 

[sjpt]

Two things. Simple displays show battery level based on voltage, which drops as the battery is used up. However, it also drops under heavy load (voltage sag). The fairly simple one on our tandem (KM529, Woosh XF07 kit) often drops two bars going up a hill under load, sometimes even three bars. As the ground levels out the voltage and display restore themselves within 30 seconds or so.

The more sophisticated Intuvia display on our solo shows the predicted range (in miles), but it is unhelpfully based on the last mile or so of travel, which gives silly results anywhere there are significant hills. It would be much more helpful if it gave a more precise battery percentage rather than just the 5 bar battery display. Its battery display does not show sag, I think (??? not sure) it is using the more reliable technique of measuring and integrating current from the battery, rather than instantaneous voltage.

 

[sjpt]

On my woosh Rio, The green LEDs on top of the battery is the only accurate guide to the remaining battery power ( or voltmeter ofc). The LCD display seems like total guesswork. I had 2 Bars remaining ...next day I had gained x2 lol

Possibly the green leds are no more accurate than the display; it's just that you only have a chance to see them when the battery isn't powering the bike so no voltage sag.

 

[Nealh]

The predictive battery display as mentioned shows real time battery level, under load/current draw it includes the voltage sag as the cells deliver the extra power asked of them. Once the power demand ceases the voltage rebounds as the sag is only temporary, the display may not instantly record the voltage rebound so will have a time lag though you should see the battery display/bars recover to show the approx. voltage level left. With the bars you can only estimate the voltage but typically for 4 bars allow 25% for every segment or 20% if it has 5 segments.
The battery bars aren't very accurate but give you a rough idea of voltage remaining, only a true voltage readout can tell you the actual battery state.
On my town/commute bike once the last bar shows on the basic KT LCD, I know the voltage is about 36 -37v so know how much range is left. With out a voltage read out you need to manually check the battery with a voltage meter to get an idea of the approx. voltage left with each bar at home with the battery in various states of discharge.

 

[Atlav4]

Thanks for replies first time I’ve had the bike in weardale will have to watch some of the larger ascents carefully, many of which are great/terrible depending on your point of view. Watching the tour of Britain come through Stanhope last year inspired me but may need a reality check for some of the more demanding climbs.

 

[sjpt]

You'll get used to what is reasonably OK and how to interpret the battery bars. It helps a lot if the route is up and down rather than down and up (you don't live at St John's chapel or above?) I usually try not to let the charge go below 2 or 3 bars when cruising, which drops to no bars when we hit a hill. If it dropped much further the BMS would probably cut the battery completely to protect it; not what you want on a steep climb near the end of a longer ride.

 

[Atlav4]

Not as far in-bye as st John’s chapel. Great ride from Stanhope up to Rookhope drop down into Westgate , along to st John’s chapel quick gill in the Golden Fleece then Daddry Shields back road and return to Stanhope.