Reliability of Mahle batteries

Electrically assisted bikes, trikes, etc. that are legal in the UK
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Joined: 24 Feb 2024, 6:37pm

Re: Reliability of Mahle batteries

Post by GC-uk1 »

PeterMar wrote: 21 Jan 2024, 1:03pm
Birdskowal wrote: 7 Jul 2023, 3:58pmHas anyone else experienced battery failure problems with the Mahle batteries or other Ebike systems?
Would you mind sharing how the batteries died of what were the symptoms of the fault. I have seen three batteries completely dead, no power output on battery, but system powers up when charger is connected. Not sure if this is relevant to your case, but I have found exactly the same problem in all three batteries. Component which costs less than a pound failure on the BMS, which is easy repairable if done immediately after the failure. If the battery is left like this for more than a week, the cells also fail due to deep discharge.
Hi Peter and all other members

Could you share how to replace( diagnose the BMS issues or who can mend. My battery isn’t working temp is reported as minus so hope with info I can repair or get someone to fix?

Appreciate you sharing the knowledge.

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Re: Reliability of Mahle batteries

Post by bikes4two »

stodd wrote: 24 Feb 2024, 8:01pm Worth asking at ... cussion.2/

I'm afraid you may just get lots of posts saying that's the problem with buying bikes with proprietary electrical systems but you may get one or two that really help.
All true enough about what responses to expect from that forum as there is a strong contingent of those who install kits with generic batteries or even build their own, thus avoiding the 'locked in' factor of proprietary system which is a real pain (financially and practically)
I suspect they aren't any less reliable than many other batteries
I am a regular reader of the pedelec and endless sphere forums and I'd say that the Mahle battery problems seem to arise more than other proprietary batteries - that is of course a subjective assessment but I've seen Mahle battery problems raised enough times that I'd not want to chance buying one although as has been said already, there are many happy Mahle owners.

That of course is no comfort to those who already have Mahle problems.
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Paul A
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Location: Chester UK

Re: Reliability of Mahle batteries

Post by Paul A »

I've got a Bianchi e-impulso with Mahle X35 system.
The bike is kept in an internal garage so never freezes.
It's done about 800 miles, though only switched on and working for less than half of that.
It over-wintered with a charge of about 60%
I usually fully charge it immediately before going for a ride.

I control the motor and monitor the battery state with an Orbea Coachsmart bar mounted remote.
My last couple of rides have seen the battery charge drop from 94% to 78% pretty much in the space of a couple of minutes.
After this initial rapid drop it seems to behave normally.

I've had the bike just over a year and I'm not sure how long the Bianchi or Mahle guarantee lasts.
Is this possibly the beginnings of trouble ? Should I take it back to the dealer to investigate?
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Joined: 10 Jun 2024, 4:45pm

Re: Reliability of Mahle batteries

Post by RichardBu »

Hi. I have a Ribble which is exhibiting these symptoms and suspect the Battery Monitoring System (BMS). I also know two Ribble owners with similar issues. Does anybody have any information on how to access the BMS and what sort of fixes are possible? Presumably you have to remove the battery and part dismantle it or find somebody who can? Any info much appreciated. Thanks
Bonzo Banana
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Re: Reliability of Mahle batteries

Post by Bonzo Banana »

I don't know much about the Mahle setup but maybe parallels with the Gtech ebikes where you have proprietary battery packs with low capacity so each cell is more aggressively discharged and the Gtech battery packs had more early failures and a shorter life because the cells were discharged at such a high discharge rate because there were so few cells. For Gtech it meant excellent profits because there were so few cells in the battery pack it meant a real saving in manufactoring costs and better margin but then the high failure rate probably destroyed their profits and created customer bad will. Cells discharged at such high discharge rates are also more prone to breaking down and leading to fires. However it all depends on how much the battery packs are discharged, some cheap 20" wheel ebikes only have 24V battery packs of around 150-200Wh but the motor only takes sub 200W and perhaps only generate torque of 15Nm or less and the small wheels compensate for lower motor power.

As a rough calculation it probably takes about 10 watts to generate each 1 newton of torque. A typical hub motor ebike of 40Nm probably sustains about 400 watts to generate that and a mid-drive motor around 800 watts to generate 80Nm of torque. Sharing that by 36V gives about 10-11A output for the hub motor and around 20-22A for mid-drive motor. Then you have to work out how many cells are in parallel and for small battery packs that is often only 2 cells at 36V so you are requiring about 5A of output per cell for a hub motor for a small battery pack where as 4 cells in parallel would only be 2.5A and 3 cells somewhere in the middle. You can understand big battery packs last much longer, run cooler and are less likely to lead to fires because the cells get a much easier life.
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