Touring teething problems, extraction or remidial work?

[pault]

Hi, just bought two new Decathlon Elops 900 bikes and cycled Madrid to Malaga.
OK it was a risk on new bikes but its also a risk on old bikes!
Came well prepared and fully charged (on the controller read out it showed max 6 bars)
At 3 bars battery power (out of 6 bars) both bikes cut out and refused to continue under power.
Hotel, charge and repeat, (they were first time charged at the store so I guess they are not fully bedded in)
One bike gets to 4 bars and cuts out second one gets to 3 and cuts out.
Rest of the 6 day total ride one bike very rarely gets past 4 bars, second one seems OK and goes to two (wanted to leave some in reserve).
Under power up hill seems to trip them out in particular.
So, is it likely a battery issue (but read out shows 4 bars) a controller issue, a BMS issue....
Decathlon have been great and offered money back, new bikes, new batteries.

Can any one shed any light on this?

Many thanks Paul

 

[danielrlee]

Welcome to the forum.

Have you tried leaving the batteries on charge overnight?

Sometimes the individual cells that make up a battery become unbalanced (unequal amounts of charge from cell to cell) and this causes some of them to become fully discharged before others inside the pack. The battery management system (BMS) contained within the battery can require quite a long time to balance the cells and bring them all to a full charge.

 

[Deleted member 4366]

It's normal for the voltage to go down when you go up a hill, which is what trips the battery. Your battery display is nothing more than a voltmeter, but some of them are very damped, which makes a lag between the actual battery voltage and the displayed one,

The question is, how far did you go before cut-out?

As Daniel says, batteries that have been standing for a while in a shop can go out of balance, so it takes several charges to sort themselves out. No need to worry just yet.

The balancing only happens when the battery is fully charged, so leave them on charge overnight for the next two or three charges to see if they sort themselves out.

 

[pault]

It's normal for the voltage to go down when you go up a hill, which is what trips the battery. Your battery display is nothing more than a voltmeter, but some of them are very damped, which makes a lag between the actual battery voltage and the displayed one,

The question is, how far did you go before cut-out?

As Daniel says, batteries that have been standing for a while in a shop can go out of balance, so it takes several charges to sort themselves out. No need to worry just yet.

The balancing only happens when the battery is fully charged, so leave them on charge overnight for the next two or three charges to see if they sort themselves out.

Thanks for your swift replies. Both batteries were charged each night (5 occasions) until they went to green, around 5hrs each. Bike ones battery which was used on the same occasions as bike twos failed daily whilst showing 4 bars and the meter never dropped below 4 even though the bike wouldn't power up. Does the 'tripping' of the system disable it until it's recharged? As mentioned it was showing 4 bars available.

 

[danielrlee]

Thanks for your swift replies. Both batteries were charged each night (5 occasions) until they went to green, around 5hrs each. Bike ones battery which was used on the same occasions as bike twos failed daily whilst showing 4 bars and the meter never dropped below 4 even though the bike wouldn't power up. Does the 'tripping' of the system disable it until it's recharged? As mentioned it was showing 4 bars available.

You need to leave the batteries charging after the indicator goes green for the BMS to do its job properly. Leave them both charging overnight and see if the situation improves at all.

 

[anotherkiwi]

La batterie (grande autonomie, puissance de 360 watts par heure) est une 36 volts / 10 A... Eléments Samsung très stables. Garantie 2 ans (de 350 à 500 cycles de charges à 100%).

OK so it has a 10 Ah Samsung celled battery. Some very serious hills over 540 km did you take the N-420? How much baggage? How much do you weigh? Was the battery on the bike with the heaviest load the one cutting out quickest?

Frankly I wouldn't have set out on that route with a battery of less than 15 Ah myself and loaded with my baggage expected about 60 km on a charge on the steeper sections.

 

[pault]

La batterie (grande autonomie, puissance de 360 watts par heure) est une 36 volts / 10 A... Eléments Samsung très stables. Garantie 2 ans (de 350 à 500 cycles de charges à 100%).

OK so it has a 10 Ah Samsung celled battery. Some very serious hills over 540 km did you take the N-420? How much baggage? How much do you weigh? Was the battery on the bike with the heaviest load the one cutting out quickest?

Frankly I wouldn't have set out on that route with a battery of less than 15 Ah myself and loaded with my baggage expected about 60 km on a charge on the steeper sections.

Yes for sure the 420 was part of the route and for sure there were many hills each day. We are mid-weights but did have 10kg of luggage each.
However we never ran the bikes past power assistance level 3 (out of 6 power assisted options) and only on the toughest climbs, we cycled hard at all times (because of the total stoppage on the first day).
My concern wasn't so much on how long or far they went but that they showed above 1/2 power left everyday but failed at this level.
I would have thought if they were on 20% left then we might end up stranded but not with over 50% power still on tap?
I cant think of how we can assess the power available per day other than with the battery power display read out...am I missing something here?

 

[Deleted member 4366]

The only thing you can do is what we say. No point in arguing or discussing. Just do it and report back.

 

[anotherkiwi]

The power display only shows an estimation and some of them need some time to calibrate themselves. I never trust mine even after over a year of battery use. I look at voltage and km travelled and rely on my experience to estimate how much juice is really left.

 

[pault]

The only thing you can do is what we say. No point in arguing or discussing. Just do it and report back.

'only thing you can do is do what we say'
'No point in arguing or discussing'
Are you having problems at home?
I thought the whole point of forums was discussion?
Thanks for the other constructive comments.

 

[Nealh]

'only thing you can do is do what we say'
'No point in arguing or discussing'
Are you having problems at home?
I thought the whole point of forums was discussion?
Thanks for the other constructive comments.

No point in taking offence this is sound advice, batteries left standing will lose capacity and not all cells will so it will become unbalanced until in regular use and charged often. No point in jumping on those giving advice esp d8veh, what he doesn't know about ebike's isn't worth knowing.
Your bikes batteries are new so you will not know the full range of the batteries until they are optimised and used, as has been said some cell groups may be out of balance and need balancing through charging. Some may call it conditioning the battery but balancing is what it is, cell balancing only occurs near the very end or at the end of the charge so when the green light appears it means they the battery has reached a full charge as far as the BMS can tell then after this it goes into balancing mode and this may take hours with a new/out of balanced battery. The cells groups should each charge to about 4.2v but if one group of cells reaches 4.2v before the others the BMS stops charging, however some of the other battery cell groups may only be at 41.5v +/- .25v so this is an unbalanced battery. Hence leaving the battery to stay on the charger for several more hours will eventually allow the BMS to trickle charge these cells though it may not happen in one charge and could take 2.3 or 4 to get this right. You can check the voltage after each charge very easily with a DVM and this will tell you the state of play with the battery and if it is balanced.

 

[pault]

Thanks for the advice. The bikes are now in Malaga & I'm in the UK so I have to confirm with Decathon what is the next stage. It's tricky as both identical bikes bought/charged at the same time have behaved very differently. Trying to explain to them about the power read outs not relating to the actual available power wasn't easy and they just said they would change the bikes. From the advice I've received its sounds like the next ones would do the same. Shame that nowhere in the manuals does it indicate this or refer to the read outs being a general guide rather than a true indication. As many other visitors will use the bikes I'll have to be sure to make them aware of this. Post closed.

 

[danielrlee]

Thanks for the advice. The bikes are now in Malaga & I'm in the UK so I have to confirm with Decathon what is the next stage. It's tricky as both identical bikes bought/charged at the same time have behaved very differently. Trying to explain to them about the power read outs not relating to the actual available power wasn't easy and they just said they would change the bikes. From the advice I've received its sounds like the next ones would do the same. Shame that nowhere in the manuals does it indicate this or refer to the read outs being a general guide rather than a true indication. As many other visitors will use the bikes I'll have to be sure to make them aware of this. Post closed.

Are you having a laugh?

Just try leaving them on charge for a decent amount of time and see if things improve. No point in considering doomsday scenarios until you've done the basics.

Also, take what Decathlon says with a pinch of salt. They won't have a clue about electric bikes and members in this forum are much more knowledgeable.

Finally, where have you received such advice about replacement bikes?