Was just about to do my weekly shop at Aldi when this warning came up - “Battery Management System Malfunction” Is this just another way of saying battery charge is low? Car is only used a couple of times a week locally and battery drain would be higher at this time of the year, and more so now due to restricted travel rules due pandemic…! Have read a few good reviews here on CTEK battery chargers. Was looking to buy this… 
Can’t answer the warning message question but can highly recommend the CTEK battery conditioners. Have the pictured version attached to my Volvo diesel every 3-4 weeks and a smaller version permanently attached to my MX5 in the garage (the battery has lasted 13 years on this!) .There are other makes including Aldi or Lidl’s own, which others in the club have had success with.
They are a good investment!
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I have my ND1 connected to a CTEK MXS 3.8 which I believe is sufficient for the battery output.
MXS 5.0 is for bigger batteries diesels etc.
Shop around on eBay and Amazon, I got mine for around £50.
I have the rings bolted to the battery terminals, so I can just unplug it when I drive the car.
The CTEK extension lead could be worthwhile, but they are quite expensive. At the moment the standard lead is so short the charger has to be under the bonnet with extension lead socket and the cable comes out at the base of the windscreen.
I have the MXS 5.0 with an extension cable, mine has been on it permanently since July and starts every time without issue.
I read the C-tek and Optimate are the leaders out there in the MX-5 world, well on here anyway.
My trusty Aldi charger had been brought back into play yesterday.
I have the Lidl version too which has been in use, it’s around 2 years old. It started buzzing, slight but noticeable. Still doing the job though.
The Aldi charger is silent and now doing the battery maintenance again, that’s around 5 years old.
I might cave in and buy an Optimate at some point just to bring things up to date.
Two minor things I don’t like about the CTEK chargers:-
- The unit is at the car end of the lead - Optimate units wall mount and only the lead goes to the car.
- They have a manual “mode” choice button - why? - Optimate units are fully automatic.
Otherwise I guess they’re fine - but I prefer Optimate.
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…read some good reviews on both Otima and Ctek…note some comments on Amazon about the Ctek having a problem with the button malfunctioning after a while.
I manged to get an Aldi cheapie a few years ago and it seems to work fine and was only about £15. I would probably go Ctek if I needed another…
My car lives outside, so the unit would have to be sheltered under the bonnet along with the plug to an extension lead…
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There are lots of threads on this, a recent one is this one (link)
Saves repeating everything I and others wrote last time.
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Aldi version. 5 years old - still use it permanently through the winter on my garaged NA. It just works.
Passes the afternoon away responding though, it’s a bit dreary out there and we can’t have a drive out for leisure.
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Thanks guys, and all replies very welcome!
Too much salt out there on the roads at the moment - So the charger will be useful…
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They are excellent…
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Perfect charger and yes buy the extension lead/s 
Currently £69.49 on Amazon.
I have 2 CTEKs currently connected to an NA outside and an NB inside. One of those is well over 10, could be 15 now, years old and has been keeping my original battery on my NB in good order all that time, its connected whenever the car is not in use. I think they’re brilliant. Connect the thing they give you to the battery terminals and just plug it in and forget it.
My MXS 5.0 is due to arrive today, so am looking forward to seeing the product and trying it out. My ND2 lives outside and hasn’t displayed the “Battery Management System Malfunction” again… But this gadget should condition and trickle-charge the battery as needed - plug-in and leave it…
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Just bought a Halfords Smart Charger Plus.
I have two Aldi chargers which have been fine for my needs till now but they just don’t have enough oomph for the lockdown-depleted enormous AGM lump in my stop/start 320d.
The 3.8 amps from the Aldi chargers just isn’t enough.
I’m hoping the 6 amps from the Halfords one will be.
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Hmm, a 10 hour overnight charge at 3.8A will put about 38Ah into a discharged battery, if it is still healthy.
That is about half capacity on a big battery, and ample for normal motoring if the car is still charging it.
At 450Amps for 4 seconds it will only need about 0.5Ah to start that car, less if it is quicker.
If the battery is on its way out then not even a much bigger charger will do the business.
If the charger suggests a previously flat battery is full after a very short time, then the battery has no capacity remaining. Think of the analogy of a silted up pond, it might have the same area it always did (volts) but only be a centimetre deep instead of a metre (charge).
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I am using my CTEK 3.8 to try and keep my 2019 2.0 ND battery maintained while the car is garaged and not in use.
On this vehicle and in the current cold weather should the CTEK charge setting be on SNOWFLAKE please ?
Thanks Richard,
The Aldi charger will charge it eventually but it just takes too long
The battery is a 3 year old Yuasa AGM and has never been deeply discharged, so should be good for a while yet.
The problem is lots of dark current consumption combined with insufficient use during these lockdown periods. I’m sure the on board charging system is fine, it just doesn’t get much of a chance to do its job.
I’m not keen on leaving it connected on the driveway permanently or even overnight, so I’d like to get a decent amount of charge into it during daylight hours,
The 3.8 will charge it eventually and it will, as you say, give it enough to start the car long before the battery is full, with the on board system then able to take over at a much higher charge rate . We’re not supposed to drive outside our immediate area though, except to get a covid test 
Strangely Halfords recommendation for suitability is not by battery capacity but engine capacity.
This one is deemed suitable for a 3 litre engine.
Battery specs:
105 ah 950cca
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