Battery chargers/optimisers

Our old battery charger/optimiser has packed up.  I usually have it connected to my MX5 on trickle charge and maintenance to stop the battery going flat over the winter.

Looked on MX5 parts but the optimate 4 they do is out of stock.  Any advice on what I should get and where I might get one this side of Christmas?

I’ve got a Numax, i’ve had it about 4 years now and my car has not moved out of the garage for the last 10 weeks now, and i know it will start 1st time.

£40ish e-bay.

I have a CTEK MXS 5.0 charger for mine that I got off amazon. I’ve had it a few years now and I leave it connected to the car whenever I’m not driving it. My MX5 is not a daily driver and so it stands for long spells and always starts first time. It also has a plug in attachment that you fix to your battery so that connecting and disconnecting is quick and easy and you don’t need to lift up the battery cover. I also have one for my caravan battery over the winter. It works perfectly on that as well. Prices for the CTEK charger range from about £50 depending on the model you get. I think they are probably the best you can get.

I use an optimate on my bike and car.

Have a look at this thread,

I am using one of these and it seems to work well. You may find that your local Aldi still has some available.


I have an Aldi charger/optimiser which I have used for 4-5 years now. They were available recently - well worth a look as the price is very good. Stock up with wine whilst you are there!



Thank you all for your advice

Another vote here for the CTEK MXS 5.0 charger. I think this is probably the best you can buy at any price. I have the CTEK MXS 5.0 TEST & CHARGE, but if I were buying again, I’d chose without the test feature. If you’re working on a budget, the Aldi copy seems a good buy.

Used this one for the last few years Carol - Trickle Charger


I have a c-tek charger on my mx5 over winter and wouldn’t use any other it’s been brilliant for the money.


I bagged one of these Aldi chargers a few weeks ago. Not used it yet but intend to get it coupled up to my battery as I think it needs to be used really.

Question…can I just leave the battery connected to the car and let the charger do it’s stuff or should I disconnect.  I don’t intend to keep it on 24/7 though, just enough periodically to keep the battery topped up.

I have an Optimate 3 and would recommend it highly.  I’ve used it on all the bikes and cars and it’s never put a foot wrong - it even recovered a ride-on lawnmower battery that was totally dead and gave me another two years of use out of it.  You can leave the Optimate connected permanently over winter: it gives a full charge and then maintains it with a float charge, and occasionally allows the battery to discharge slightly to test how well it is holding the charge it is getting.

On the subject of disconnecting the battery from the car for charging - I know you are supposed to do this, but I never have, and I have never had any problems doing so.

+1 for Ctek [(y)]

Regarding using without  battery disconnection.

I changed the crocodile clips for a simple plug which prevents polarity errors and fitted the male end permanently to the battery, which gives easy fitting.  

Disconnecting the battery can give ECU errors when reconnecting so best avoided.




Thank you everyone - I have ordered c-tek one.

I have used the CTEK bought off Amazon, for the past couple of years. As already reported, you can bolt on a flying lead to the battery, for ease of plugging the charger in.

A word about those flying leads you can connect permanently to the battery.  Excellent idea, as long as you don’t let them get damp.  Probably not an issue inside a car boot, but I had one on a bike tucked behind a side panel in a position where it got some road spray.  Even with a rubber cover on the terminal (as provided by Optimate), some moisture got inside and one day when I went to put the charger on the copper terminals inside had crumbled to a blue mess.  A permanent 12V supply and a bit of moisture had created a nice little cell and the electrodes had dissolved.  Anything connected to a permanent 12V should be kept very dry, and also covered securely to prevent the risk of a short circuit if things move inside the boot and perhaps bring it into contact with bare metal.

Hi Carol, if you have ordered a C-tek I have a spare C-tek cigar lighter adaptor which can plug into your cigar lighter socket. this works well with the early UK Mk1’s as the socket is live all the time and no need to bolt anything to your battery connections.

My way of saying thank you for all the work with MM


Peter that would be great thank you so much.  Have enjoyed helping out with mm.