Help! New Swytch Max kit that loses most of its power after 15km on a normal ride

[xla99]

Hi there,

I've an issue with my kit and I gave up with the Swytch Support, which is amazingly inefficient. I can't believe it, they are close to psychological harassment with their techs almost as bad as their AI agents asking me over and over again the same things without answering my questions.

My wife bought a Max kit in September (no throttle installed). That was working fine the first weeks, and it suddenly started to lose power after 15km. I did all the tests asked by the support, rechecked the câbles, the wheels, reset the controller and everything is fine.

A typical ride now looks like that :

1. Full charge, 10km to work, arrive with 4 power bars remaining (60% power limit setting with a 3/5 PAS)
2. On the way back, after 5km, it suddenly drops to 1 power bar, the motor runs on & off and she may end the trip without assistance
3. The battery is fully recharged in the evening and it's the same the next day

That ride is not steep, no wind, good weather, 5 degrees. We have a friend with the same kit that does the same ride. He has no problems to come back, with 2 power bars remaining at the end of the day.

I couldn't even get an answer from Swytch about if that's a normal behavior for a new kit or if it's an issue. So I ask it here, do you think that's an issue and if you do, what could be the root-cause ? The controller and/or the battery ?

For now, we bought an expensive Swytch charger and she charges her battery at the office but I would like to understand that issue and maybe fix it.

Thanks.

 

[sjpt]

I gave up with the Swytch Support, which is amazingly inefficient. I can't believe it, they are close to psychological harassment with their techs almost as bad as their AI agents asking me over and over again the same things without answering my questions.

No, they are very efficient at their main objective: to avoid giving you any support.

 

[saneagle]

Hi there,

I've an issue with my kit and I gave up with the Swytch Support, which is amazingly inefficient. I can't believe it, they are close to psychological harassment with their techs almost as bad as their AI agents asking me over and over again the same things without answering my questions.

My wife bought a Max kit in September (no throttle installed). That was working fine the first weeks, and it suddenly started to lose power after 15km. I did all the tests asked by the support, rechecked the câbles, the wheels, reset the controller and everything is fine.

A typical ride now looks like that :

1. Full charge, 10km to work, arrive with 4 power bars remaining (60% power limit setting with a 3/5 PAS)
2. On the way back, after 5km, it suddenly drops to 1 power bar, the motor runs on & off and she may end the trip without assistance
3. The battery is fully recharged in the evening and it's the same the next day

That ride is not steep, no wind, good weather, 5 degrees. We have a friend with the same kit that does the same ride. He has no problems to come back, with 2 power bars remaining at the end of the day.

I couldn't even get an answer from Swytch about if that's a normal behavior for a new kit or if it's an issue. So I ask it here, do you think that's an issue and if you do, what could be the root-cause ? The controller and/or the battery ?

For now, we bought an expensive Swytch charger and she charges her battery at the office but I would like to understand that issue and maybe fix it.

Thanks.

I'm pretty sure that it's a battery issue. It's probably just out of balance, but it could be defective. How many miles has it done?

If you have any technical ability, you can open up the battery to check various things. If you haven't, then the only thing you can try is to leave it on charge for several hours after you get the green light to see if it improves.

If you can, measure the battery's voltage immediately after you take it off the charger. Any less than say 41.2v would mean that it needs some attention.

 

[xla99]

I'm pretty sure that it's a battery issue. It's probably just out of balance, but it could be defective. How many miles has it done?

If you have any technical ability, you can open up the battery to check various things. If you haven't, then the only thing you can try is to leave it on charge for several hours after you get the green light to see if it improves.

If you can, measure the battery's voltage immediately after you take it off the charger. Any less than say 41.2v would mean that it needs some attention.

Hi Saneagle,

It has almost no mileage. My wife started to use in December @+-50 miles a week. It worked well the two first weeks and started to bug last week.

I haven't any technical abilities in that field but I'll try to keep it charged the full night and check the volage with a friend's voltmeter.

Thanks for the tips.

 

[Bikes4two]

I haven't any technical abilities in that field ................................

Well, you've come to the right forum to get 'technical abilities' which given the lack of Swytch support is going to become a bit of a necessity if you're looking to keep the Swytch kit or even if subsequently going to some other conversion kit (others before you who have given up on Swytch have used the wheel and motor and then put a system together using easily and cheeply available parts).

..........and check the volage with a friend's voltmeter.

Pop down to Screwfix and the like and buy a perfectly adequate (for ebike fault finding) multimeter for £10.

As Saneagle says it sounds like a battery issue and to determine this is more easily identified with a volt meter than anything else.

 

[Sturmey]

What is the capacity of the battery?

 

[Ghost1951]

Is it possible that the problem is the colder weather?

There is a noticeable loss of range in colder weather if you have a low capacity battery.

The difficulty in comparing how much your friend has left in his battery on the same ride is that it is uncertain how much energy he is putting into the mix, in comparison to your wife's input. More pedalling from him would certainly mean he has more capacity left at the end of the ride.

Putting a multi meter on the output port after a good full charge will confirm whether the cells are out of balance. Although the battery is new, it is possible it could be out of balance since September. If the voltage is low after a full charge (saneagle gave you a figure to raise suspicion of that) a long, supervised charge with the charger on the green light should improve things.

Hope you get it sorted. You should really be seeing about 41.9v on a new 36 volt battery at full charge, 42v even. Don't forget to switch the battery on when measuring.

 

[thelarkbox]

This suggests a 250wh battery?? and the 30-40 mile range at speeds upto 20mph (restrictions allowing) is a claim! not a very credible one unless its all downhill, but thats more than the generous boast given for my twice the size powerpack (36v 13ah)?470wh? Even so i would expect to get 20km from it still.

Keeping the battery at room temps and lagging against the cold (old towel and a windproof carrier bag??) when on the bike may mitigate against the cold if it is a significant factor, monitoring start and end of trip battery voltages too could help.

 

[eas2lv]

MAX is only 180Wh. OP getting only 15 km from it at PAS 3 to 5 in cold weather is not surprising. Put on more manual effort to keep it at PAS1 and only occasional higher assistance to get more range.

 

[Sturmey]

The wind slows down a bike and it takes a lot of energy (i.e. battery power) to cycle against it. As a rule of thumb, I estimate my range to be only about 80% of normal on a circular/return journey on a windy day but this loss of range could be a lot more on a one way journey facing into the wind.

 

[Bikes4two]

@xla99 said:

My wife bought a Max kit in September (no throttle installed). That was working fine the first weeks, and it suddenly started to lose power after 15km. I did all the tests asked by the support, rechecked the câbles, the wheels, reset the controller and everything is fine.

So what was the range in the first few weeks? Was your wife riding the same route and using similar levels of assist as in the first few weeks?

And you also said

We have a friend with the same kit that does the same ride. He has no problems to come back, with 2 power bars remaining at the end of the day.

How good is this friend I'm wondering as you could ask him to ride with your wife's battery to see whet range he gets vs that on his own battery, or off course borrow his battery for your wife to try?

What I don't understand is that on arriving at work (a 10 Km ride) the power bars are at 4, but after only 5 Km into the return journey the battery is down to 1 bar. I know power bars are a very inaccurate way of determining battery levels but even so, that does seem a bit odd.

--------------------------------------​

Appaling as Swytch support seems to be (from the many posts you see around), one can understand how difficult it is for 'remote diagnosis' regarding battery and range - here's some ramblings from me on the subject:

• As said the MAX battery gives 180Wh from its 5Ah battery with a quoted range (unspecified cycling conditions) of 20-30Km
• Let's assume in PAS level 1 the battery consumption is around 7Wh/mile - this gives a theoretical range of 26 miles (42 Km) BUT that's riding quite energetically and in calm weather and easy terrain.
• Given the usage of higher PAS levels, windy conditions, cooler weather etc then battery consumtion is going to be at least double that, so a theoretical range of 13 miles/21 Km maybe?
• These (theoretical) figures need further modification in that the MAX battery is a 10s 1p configuration using 5Ah Samsung 50E cells (I took a MAX battery apart (Link)) and given that when determining cell capacity the manufacturer usually test to a low voltage cut-off lower than the LVC in the Swytch controller, then a more useable battery power capacity is likely to be around 150Wh
• So taking the use the cases above and on PAS level one this may give a range of say 21 miles/34 Km or on the higher PAS levels then maybe 11 miles / 17Km.

That's all assuming a lot but the exercise does give a bit more of an understanding of what to expect from the MAX battery and of course in all of these assumtions there's a great many variables such as rider weight, terrain, PAS level used vs rider effort to name the main contenders.

Have you bought that multimeter yet?

 

[sjpt]

Further to bikes4two's comments above, have a look at the Bosch range assistant.

eBike range calculator for Bosch drive systems

How many kilometres do the different Bosch eBike batteries last? The Bosch Range Assistant displays how many kilometres your pedelec can travel on a single battery charge.

www.bosch-ebike.com

Obviously designed for Bosch powered bikes, but with a little interpretation about battery capacity, motor type and power setting it can give a very good idea for other ebikes.

In particular, you can change settings for lots of things like hills, speed, wind, etc. Even if you can't get sensible absolute range values for your bike it gives a very good idea of how much different factors effect range.

Start with low speed, good road, light rider, etc (*), and then change the various settings. You'll find that even without changing the assist level you can easily drop the range estimate by a factor of 3.

(*) this is the typical 'up to' value lots of sites very optimistically quote.

 

[Ghost1951]

I am more and more convinced as the information has come in and sunk into my skull, that the bike is performing as you might expect in colder weather and the reduction of range is down to the temperature change as the seasons have changed. I have just roughly worked out how much energy per mile I use on my cheapo Argos folder and bearing in mind that I am not young but moderately fit and riding in undulating and hilly terrain, I seem to use about 12.5 watt/hours per mile in the bike's middle pas setting (assist to 12 miles an hour) and about 17 watt/hours per mile in the higher 15 miles an hour assist setting.

Given that the switch battery in question seems to have about 150 watt/hours, if it was me on my bike I might expect about 10 miles of range in mild weather. The Op's good lady is finding that her battery is exhausted in 14km or about 8.7 miles - I don't think there is anything wrong with it. I'm betting its just the cold weather.

 

[Cisco-man]

Late to the thread - sorry. My wife and I have four Max switch batteries. during the summer we could do our 16 mile round trip to our favourite pub on one battery IF you barely called for more than nominal help. We currently use two Max batteries in parallel to get us there and back with a good demand for assistance, and have a fair amount left when we are home again. Getting 14 miles out of one pack would seem about right. Opening these packs to measure anything would be destructive. They are not designed to be opened in any way.

 

[Bikes4two]

Opening these packs to measure anything would be destructive. They are not designed to be opened in any way.

I have opened a MAX battery pack (see my post HERE) and you can get into it in a non-destructive manner - not easy but do-able and re-assembly is more than feasible.

 

[xla99]

Hi there,

Thanks a lot for all that information. I better understand now why it's possible to get 15km range for a battery claimed as a 20-30km one.

I finally bought a voltmeter and tested the battery output. The result is strange with voltage fluctuating from 33 to 39V. Isn't it supposed to be steady ? You can see a video here. I tested with other batteries and I even changed the cables to be sure that the voltmeter wasn't the issue.

For now, my wife is able to do her 20km run with a 1/5 PAS but I would be curious to know why I get fluctuating voltage from the MAX battery and if that could be an issue (or if I'm not the one doing something wrong when measuring it).

Thanks.

Alex.

 

[eas2lv]

I finally bought a voltmeter and tested the battery output. The result is strange with voltage fluctuating from 33 to 39V. Isn't it supposed to be steady ? You can see a video here. I tested with other batteries and I even changed the cables to be sure that the voltmeter wasn't the issue.

Looks like you are measuring the voltage on the charging port which wont work. It is isolated by the BMS and wont give you the battery voltage. You need to measure it across the discharge port, but, in case of MAX even that is activated only when the battery is mounted on the bracket. There is a way to work around it using a jumper wire, but I only vaguely recall the procedure.

 

[xla99]

Looks like you are measuring the voltage on the charging port which wont work. It is isolated by the BMS and wont give you the battery voltage. You need to measure it across the discharge port, but, in case of MAX even that is activated only when the battery is mounted on the bracket. There is a way to work around it using a jumper wire, but I only vaguely recall the procedure.

I don't think I measured it on the charging port. I read in another topic how was setup the Max ports and my understanding was that :

1. The charging one is the 3+4
2. The descharing one is the 2+5
3. I guess that the 1 & 6 are not used

Therefore, I measured it in the 2+5.

 

[eas2lv]

I don't think I measured it on the charging port. I read in another topic how was setup the Max ports and my understanding was that :

1. The charging one is the 3+4
2. The descharing one is the 2+5
3. I guess that the 1 & 6 are not used

Therefore, I measured it in the 2+5.

iirc all pins are used: discharge is across 1-6 in your picture (not 2-5), and its activated only when 2-5 is shorted. That said, do not short anything without verifying the above as I'm writing from memory.

 

[chris_n]

iirc all pins are used: discharge is across 1-6 in your picture (not 2-5), and its activated only when 2-5 is shorted. That said, do not short anything without verifying the above as I'm writing from memory.

Are they trying to make a bomb? It is obvious that somewhere along the line someone will want to measure output voltage. They will read on the Internet that you need to short 2 pins then short the wrong ones . It would be much more sensible to have the short internal to the battery and have to open it to activate.