Bosch out of steam with range left

[sjpt]

Slight surprise the other day. We've had our 2016 Motus (Bosch) for well over 5 years, it was about 2 when we got it so 7 now. Very happy apart from a few niggles.
In all that time we hadn't let it run down to where the remaining range was being reported below about 5 miles.
I'd guessed that when it got to 0 is would really have a little reserve, so was surprised that when it got to showing around 4 miles left it effectively stopped giving any assist.
Luckily I only had a few hundred yards to go to home; but it was uphill which isn't the easiest unassisted pedalling on that bike.

I know the remaining range is always very erratic as it is based on much too short a riding history; but I did expect it to know the difference between 3 and 0. Probably down to voltage sag on an aging battery.

 

[saneagle]

I know the remaining range is always very erratic as it is based on much too short a riding history; but I did expect it to know the difference between 3 and 0. Probably down to voltage sag on an aging battery.

Yes, Old batteries become saggy; however the Bosch motor runs effectively at 24v, so there could be some sort buck converter keeping the voltage and power more constant. I've never studied the Bosch electronics to see how that works. Whatever it is, it might make the effect less than with worn batteries from other systems, but is still inevitable.

Why not treat yourself to a new battery now for longer journeys, and use the old one for local stuff?

 

[sjpt]

Yes, thanks. Certainly the battery meter on the display doesn't show any sign of 'sag' under load, so there may well be some converter keeping it more level, but unable to work complete magic.

I've been considering a newer battery before they start becoming an even more expensive 'vintage' item. We don't do many longer rides on the Motus, just lots around town. For now we'll probably just recharge that much more often which won't be that much of a burden. In fact, my wife had brought the battery inside to charge just before my ride above, but I decided the 10 miles showing would be safe for a quick 5 mile ride.

My wife and I share the Motus and use the tandem (Woosh XF07) when going out together. We treated ourselves to a larger new battery for that last year. I promptly detached my patella tendon so we haven't
really benefitted from that yet; short rides good, long rides bad.

 

[guerney]

Knees are weird (not yours specifically) - too much exercise post accident/surgery they don't heal, too little the immune system gives up trying and it becomes chronic. Or so my physio told me. Mine became chronic, despite bombardment with ultrasonic waves. Hope yours fares better.