Poor Battery Range Bosch 750

[michael.kozera]

on screen battery % is usually directly going off of battery voltage, usually smoothed out with some kind of delayed averaging mechanism programmed into the software.

if you start at 100% (4.2v/cell) and start going up abunch of hills, ur battery voltage will drop to say 3.6v/cell and ur % will read 50% after only a few miles of riding. however if you stop and let the battery sit, it will go back to 4.0v/cell and read something more realistic like 90-95%. this is called voltage sag, and all batteries do this, some more then others depending on specs.

i have a 1200wh battery and my bbshd is pulling close to 1800w, so after riding only 10kms of HARD riding, my battery will read 50-60%, i then go on to ride an additional 150km's until batter dies.......

 

[Marcharry]

I’m picking up my new Cube 140SL this coming week so will be doing a couple of test rides and will report back

I’m sure you’ll be very happy with it! With cube you get a lot for your money

 

[Marcharry]

It may even be your display readout that's not accurate, after all, it is not a scientific instrument.
My neighbour has just taken delivery of a Cube and was alarmed at how quickly the first 20% of the battery disappeared.
Have you emptied the battery on a ride yet as that will obviously give you the better idea of range than a digital gadget will.

I must admit, I noticed the first 20% went down quickly. The last 10% went down slowly. Maybe it’s supposed to be this way so people don’t run out of battery unexpectedly?

 

[friendlywrench]

This is perhaps a dumb question, but have you checked your drive train to see if there is any unexpected resistance? Do both wheels spin freely? Is there any resistance when the system is off? If something was out of place you may not notice it because the drive unit is providing assist that makes you not notice it.

 

[Marcharry]

This is perhaps a dumb question, but have you checked your drive train to see if there is any unexpected resistance? Do both wheels spin freely? Is there any resistance when the system is off? If something was out of place you may not notice it because the drive unit is providing assist that makes you not notice it.

Hi, thanks for the suggestion, I have looked at everything like that when setting up the bike. I suspect maybe a faulty battery but I’ll see how it performs after a few charge cycles. I’d imagine Bosch will be bring out a software update soon to iron out any issues with new smart system.

 

[michael.kozera]

I would say it's highly unlikely that the battery is faulty.

i however would suggest u remove the battery and place it on a simple watt meter and test the wh that come out of the battery. if it reads 90% or higher then u can confirm the battery is A-ok

 

[friendlywrench]

I would say it's highly unlikely that the battery is faulty.

i however would suggest u remove the battery and place it on a simple watt meter and test the wh that come out of the battery. if it reads 90% or higher then u can confirm the battery is A-ok

Unfortunately the BMS has to be switched on by the computer in order for the battery to be active. This is where the battery would have to be tested either by an official Bosch capacity tester, or a hacked up equivalent.

 

[SurreySteve]

My mate has a new Decoy with a much bigger battery than my old 2017 500Wh Powerfly.
He doesn't weigh much more than me but he gets less range. In this case it seems he has a reserve battery for the non existent lights whereas my old Gen-2 with no lights doesn't.

 

[Hanzzzie]

Same here, 750w Cube 140 Action team, 60km 500hm is about the max i did and batt was only 10% left.
i would think it could reach a bit more, buddy that was riding along with older reaction 625wh bike (same weight) was at 35% left

 

[michael.kozera]

Same here, 750w Cube 140 Action team, 60km 500hm is about the max i did and batt was only 10% left.
i would think it could reach a bit more, buddy that was riding along with older reaction 625wh bike (same weight) was at 35% left

i mean , thats totally reasonable. my 1200wh battery i can get as low as 40km only, or as high as 250km.

thats the problem with attributing WH of a battery to a set distance, wayyyy too many factors.

however, i have found that its roughly 1km per 10wh. thats the average ive observed across many riders.

 

[Mabman]

Keep in mind that wh's are calculated as (system) volts x ah = wh's. However in reality due to the low voltage cutoff programmed into the battery management system module to keep the batteries from going below a certain voltage per cell that would degrade them a battery might provide up to 100wh's less than the "advertised" rating.

To me the whole "%" calculation is a misnomer because the voltage that as mentioned above is the base for the percentage rating from fully charged to the LVC varies under load and at rest. Certainly 10% of lower voltage has much less energy available than it does at the higher starting voltage or even the middle of the range.

 

[Hanzzzie]

i mean , thats totally reasonable. my 1200wh battery i can get as low as 40km only, or as high as 250km.

thats the problem with attributing WH of a battery to a set distance, wayyyy too many factors.

however, i have found that its roughly 1km per 10wh. thats the average ive observed across many riders.

Moght be but compared to my buddy's older system with 625wh, driving along the same trails its a bit weird imho...

 

[1oldfart]

I started riding Yamaha Ebikes 3 years ago.
My system has 5 lights so each morning i start at 5 lights, full charge.
From hundreds of days my observation is i receive about 22% of the potential on each of the firtst 4 lights.
My last is time to reach home, maybe 10-12% of the full potential.

 

[Hanzzzie]

so just go YOLO and dare to go the extra mile below the 10% ?

 

[Morton027]

Moght be but compared to my buddy's older system with 625wh, driving along the same trails its a bit weird imho...

I’m riding in the same scenario, my 140 SL 750 quotes a much lower range than my dad’s year old Reaction Pro 625.

I need to do more riding and charge cycles to see where that is in a month or 2, but there are a few differences from Full Suspension, tyre types, and even the smart system vs Purion to account for.

 

[tommygun]

Hello there,

just jumping in to say that I have the exact same bike as the thread opener (wonderful bike, BTW!), and I'm seeing the same pattern here: lower mileage despite better battery.
I also have an Haibike SDURO 7.5 trekking with the previous gen Bosch CX with 500Wh and despite having 25% more battery capacity now, the range is way less than the older bike. The onboard display gives me more than 100km on Eco on a full charge on the Haibike, a bit more than 60km on the Cube on the same setting.
The "real life" riding seems to confirm this: I didn't do a lot of trips on the new bike yet, but when I'm back home I'm usually with lot less battery left compared to the Haibike.

Now, I know these are only estimates and a lot depends on track type, rider's weight, outside temperature, etc etc, but seeing this difference in figures is very worrying, given we are talking about the same manufacturer.

Let's see if actually Bosch will release an update of some sort.

 

[Hanzzzie]

Changed the Addix Soft gravity tires for some slightly better rolling ones, can't wait to test em out but the next week and some it's gonna be shit weather here in Belgium
( The Big Betty / Magic Mary combo was overkill anyway for my type of riding and terrain )

 

[malc101]

Was there mud on your ride? I’ve found the texture of the mud to be the biggest factor. That just thawed glue mud costs me 20% over hard pack dirt on the same ride, while an inch of snow had no effect.

 

[malc101]

Hello there,

just jumping in to say that I have the exact same bike as the thread opener (wonderful bike, BTW!), and I'm seeing the same pattern here: lower mileage despite better battery.
I also have an Haibike SDURO 7.5 trekking with the previous gen Bosch CX with 500Wh and despite having 25% more battery capacity now, the range is way less than the older bike. The onboard display gives me more than 100km on Eco on a full charge on the Haibike, a bit more than 60km on the Cube on the same setting.
The "real life" riding seems to confirm this: I didn't do a lot of trips on the new bike yet, but when I'm back home I'm usually with lot less battery left compared to the Haibike.

Now, I know these are only estimates and a lot depends on track type, rider's weight, outside temperature, etc etc, but seeing this difference in figures is very worrying, given we are talking about the same manufacturer.

Let's see if actually Bosch will release an update of some sort.

.
I’ve also got a Haibike 500wh Yamaha and I bought a Giant trance with 625wh+250wh booster. I figured that would allow me to go from the Haibike’s 50m/4000ft rides up to maybe 80m/6000ft. Not the case. In fact, maybe I get an extra 5 miles. I think that this is all due to available watt hours from the different batteries according to what the firmware lets you use. The batteries are marketed according to cell capacity, which may or may not be fully available based on how high the cells are charged and how low you can deplete them.

 

[1oldfart]

.
I’ve also got a Haibike 500wh Yamaha and I bought a Giant trance with 625wh+250wh booster. I figured that would allow me to go from the Haibike’s 50m/4000ft rides up to maybe 80m/6000ft. Not the case. In fact, maybe I get an extra 5 miles. I think that this is all due to available watt hours from the different batteries according to what the firmware lets you use. The batteries are marketed according to cell capacity, which may or may not be fully available based on how high the cells are charged and how low you can deplete them.

I agree that the **full potential** is different than the real life potential.
I think a problem is marketing. To sell they went from 50nm to 70, 75, 85nm.
I am no engeneer but if a system is more powerfull it burns more energy.
The small 1270cc motor from a 1980 Toyota Tercel needed very little fuel.
Now with new technologies fuel mileage should be better but it is worst.
They are selling 3000cc.
Just lower the assist and report if you get more distance.
My Yamaha/Giant has 5 levels of assistance. Guess what?
If i select lower assist tada i can rid more hours.
That is a real life test. Same tires, rider, trails.
Not some BS marketing, not some fake reviews.

 

[Planemo]

It would be really good to know what actual cells Bosch have used in their 500/625/750Wh packs. I haven't managed to find any concrete info. You could have 3 cells all with the same stated Wh but could give noticeably different capacities depending on the current drain. Most cell discharge charts show curves at different currents for exactly this reason. For example a 3450mA Sanyo 18650GA (a brilliant cell IMO) gives about 3200mah at 2A and 2700mah at 10A (tested down to 3v).

Something like the LG MJ1 (very similar advertised capacity) managed about the same mah at 2A but the test had to be terminated at 10A due to overheating, at which point it had recorded 2500mah.

I know we don't run each cell at 10A in our ebikes, but it's a possible reason for some discrepancy between packs, and I do know that Bosch haven't stuck to one particular cell throughout their product life.

 

[michael.kozera]

this is true.

depending on what BMS u use, my 1,600wh pack cuts out at 2.75v/cell and full charge at 4.18v/cell. using MJ1 3500mah, im only getting about 3100-3200mah out of each cell, so my 1,600wh (1,588wh to be exact), only gets about 1,400wh.

most power tool batteries only charge to 4v/cell and cut off at 2.9v/cell, thus only 70% of the rated capacity is actually usable for most power tools.

 

[malc101]

I ride on the lowest setting in my ebikes and go to the second setting on climbs usually only later in the ride. On giant I even have the lowest setting reduced to 75pct of its default. On Soecialized the lowest setting is set to 19%. I am 6’5 and 230 lbs, and caret 15 lbs of water/tools/spares/clothing into the back areas. I never use the high power settings. Still, the difference in the range of the larger packs is not proportional to the WH differences.

 

[Planemo]

depending on what BMS u use, my 1,600wh pack cuts out at 2.75v/cell and full charge at 4.18v/cell

I would assume that Bosch would have used the same BMS LV/HV cutoff limits for all their packs so this wouldn't be a factor. If they don't, then yes you might be right as it would have an effect.

 

[michael.kozera]

I would assume that Bosch would have used the same BMS LV/HV cutoff limits for all their packs so this wouldn't be a factor. If they don't, then yes you might be right as it would have an effect.

To be perfectly honest. it sounds like they didnt,

i would be more suspect of a different BMS, or perhaps firmware/software rather then a physical problem with the cells, any cells for that matter. even cheap china cells work great and last long, i would know, as i build batteries all the time.

someone should take a few apart and find out.

 

[Morton027]

A bit like this guy with a Powertube 500?

 

[Planemo]

i would be more suspect of a different BMS, or perhaps firmware/software rather then a physical problem with the cells

I wasn't suggesting that there was a physical problem with the cells, only that different cells with the 'same' advertised capacity can be different depending on the discharge rate. I know you will know this, but I just wanted to clear up any confusion.

 

[Planemo]

A bit like this guy with a Powertube 500?

The battery doctor has done loads of teardown vids, but I don't think he has clarified whether cells are different between the various powertubes, and certainly hasn't compared any differences between BMS' (specifically low/high voltage cutoffs). I don't think he has torn down anything over 625Wh either.

 

[antoinelc]

I’m riding in the same scenario, my 140 SL 750 quotes a much lower range than my dad’s year old Reaction Pro 625.

I need to do more riding and charge cycles to see where that is in a month or 2, but there are a few differences from Full Suspension, tyre types, and even the smart system vs Purion to account for.

How is it now?

 

[Morton027]

How is it now?

Circumstances and weather have stopped me getting out much yet unfortunately. Hoping to change that soon.