The latest post on battery warranty touches on this, but I would like to talk specifically about battery chargers.
Driving any of our two cars will be limited to very short grocery trips due to this Coronavirus Emergency.
I am concerned about battery health in my two Mazda cars .
Have a 2016 1.5 SEL MX5 ND with the original OEM 45Ah battery (no start stop).
I also have a 2017 Mazda 3, 2.0litre Petrol 120ps Sportnav with a start stop battery. The OEM battery has no useful info on it. Looking online it seems I must use EFB battery for the Mazda3 (whatever that means). and I believe it may be a 65Ah battery. The Mazda 3 start stop is being defeated (āNOT READYā) due to the battery.
Thing is I am looking to buy a good smart battery charger to charge the batteries without disconnecting them from the car.
Not sure what I should be looking for. Can anyone who has used smart chargers help point me in the right direction?
I use a CTek on my MX-5 with the receiver permanently attached to the battery posts. Mineās a Mk3.5 so no works about BMS etc.
My Suzuki Vitara is a different problem in that it does have stop/start and BMS so Iām confused as to whether a maintenance charger can be used. Obviously it canāt be attached directly to the -ve post due to the risk of frying the electrics, but will the BMS keep up with the chat status of the battery. Suzuki recommend disconnecting the battery if the car is going to be unused for 4 weeks, so I tend to give it a good run before that happens.
A good smart charger is what you need. I have no knowledge about the ones sold by Aldi/Lidl so Iām not in a position to comment on them. I use an Optimate 4 on mine, not as cheap as the aforementioned, but then the cars cost many thousands of pounds so I was not going worry about spending more on a product that getās good reports from trade users as well as private ones. I have two, the oldest of which is ten years old, in continual use and no problems, firstly for the Jazz and then for the ND I bought in 2015, the second one I bought last year for the 30AE. Others will suggest a CTEK which is on the same cost/quality level as the Optimate, again I have no experience of those so I canāt comment on them either. So ultimately itās a matter of āYou pays your money and you makes your choiceā. Read some reviews. Good luck!
PS: I use the permanent leads on both mine, and the 30AE has the same āstart/stopā as the Mazda 3 and no problems with that.
If it is low on charge then the iStop is disabled, because the clever system is taking every opportunity to top the battery up again.
An EFB is not as tough as an AGM, but itās easily good enough for the āsmallā 2L engine and itās a lot cheaper, which is why Mazda used it.
Any Smart charger from 3A to 5A will be fine. Donāt go for one too much bigger, no real point when any of the smaller (3A to 5A) ones can refill it overnight, and being Smart will not cook it.
Your (presumed) Q85 battery is an EFB with 65Ah capacity, for Stop/Start In other words itās an ordinary lead-acid battery with mechanical improvements to cope with a higher duty cycle. There should be raised letters on the top near the negative terminal to identify it, a torch can be useful to see black on black.
Not driving it much so no opportunity for recharge. Would need good 40 mile to 60 mile round trips and that is not in keeping with the Coronavirus emergency.
Anyhow It would appear that either of the two CTEK chargers would be well able for both cars.
I did take a note of all markings on the batteries before starting this post and yes the Mazda 3 is a Q85. Thanks for confirming it is an EFB 65Ah. Good to know for when it is time to replace it.
Noted embossed ā46B24L(S) MFā in black beside the negative terminal of the MX5 45Ah battery. Does this mean anything ?
Itās a 45Ah 450CCA lead-acid sealed-for-life fit-and-forget battery, usually made by Panasonic. Pretty good, provided it gets enough charge.
See the excellent wiki article on Lead-Acid batteries which covers all the options on how they are made, how they work, what applications the different varieties are most suited to, etc. It also mentions something which suggests fast charging a deeply discharged battery is bad for it, better to use a lower rate for longer.
Hi all,
I bought a Maypole smart charger off Ebay last week. (around Ā£25).
It has selectable Normal mode & AGM mode. also cold weather & 6v.
I think the ins. implied it charges the AGM at a slightly lower rate.
Anyway the charger is rated at 4 amp max.
Tried it once so far seems OK.
Good morning.
I have been using a Streetwize SWTBC 1.5 Amp Trickle Battery charger on my Mx5 all winter. It keeps it topped up and costs Ā£18.99 from Screwfix Ā£18.22 Toolstation and many other outlets. It is āIntelligentā as it only charges when it needs to and does not over charge and damage the battery. I did research for a while before buying and yes you can buy more expensive ones if you want toā¦
You donāt have to go out and get it either! Be safe.
Iāve had good experience with the Halfords smart charger, the optimate and ctech if it was my own money Iād buy the optimate as they cover all the bases with compatibility and theyāve revived a few batteries I thought would need replacement
Really bewildered. All these different letters and numbers. The wikipedia link is a bit too deep for me.
Did a search using āpanasonic 45Ah 450 CCAā and got a link to a website āBattery Cellā in New Zealand!. It came up with a 45Ah 450 CCA battery and gave a long list of battery id numbers that it suited. One of them was MF46B24L that almost corresponds with the 46B24L(S) MF number on my OEM Battery. So obviously Richard FX post has me on the right track.
However when I search for 45Ah 450 CCA batteries I come up with various makes for 47Ah, 50Ah, 55 Ah, 60Ah, but no 45Ah.
Donāt really understand the 450 CCA reference either?
45Ah is how much capacity the battery has - in theory, it can supply 45 Amps for 1 Hour, or 1 Amp for 45 Hours (or 2 Amps for 22.5 Hours, or 3 Amps for 15 Hours, etc). Thereās absolutely no problem (apart, perhaps, from a tiny weight penalty) in getting a higher Ah battery, as long as it will physically fit.
CCA - Cold Cranking Amps - is how much power can be provided short term to start the car. Simplistically, the bigger the engine the more it will require. So a 5 litre BMW M5 will require a higher CCA than a tiddly 1.8 MX-5.
The very first thing to do is give it an overnight boost with a proper Smart battery charger - as discussed.
If the battery is OK and just a bit empty then the problem will be solved by the next day.
If the battery is not OK, then it will soon be obvious because the Smart charger will show that immediately, without wasting your time waiting for it to be full the next day. Only then do you look for a new battery.
Why is this happening?
Car batteries lose charge if the car is not used or if it only has short journeys, this is inevitable.
There are a couple of reasons, 1. the so-called Dark Current, 2. adverse Re-Charge to Discharge ratio.
Dark Current.
This is made up of several factors, mostly self discharge within the battery for older cars, and then with most modern cars also the alarm and locking systems and maybe the radio memory.
For example: a modern car battery left unattended on a warehouse shelf somewhere will lose at least half its charge in about a year. This is why they used to be supplied dry with a bottle of acid you topped it up with - a fully charged battery instantly. Now they lose it more slowly so are supplied full, but you still need to boost the battery or go for a long drive because the odds are it was sitting on that shelf for a year!
For example: security systems on a modern car typically take 20mA to 30mA. It doesnāt sound much, but in a day that is between about 0.5Ah and 0.75Ah lost from the battery. Now spread that over a month.
Re-Charge to Discharge ratio.
Discharge.
Each time the car is started, the battery will supply a very high current for a short time, somewhere between 100Amps to 300Amps for anything between 1 second (my NC ) and say 12 seconds (my old Zodiac), depending on many factors including hot or cold, mechanical or electric fuel pump, type of ignition system etc, ie anything from 0.025Ah to 1Ah. Not too bad if the battery is good.
However, there are other things taking current when running the car; electric power steering, ignition system, assorted fans and aircon, DRLs and headlights,brake lights, heated rear window, loud radio, electric windows, all the computers and accessories, anything up to thirty or forty amps or more in winter.
Re-Charge
This is another matter, much less predictable.
The alternator can provide 50A to 100A depending on type, most cars tend to be around 80A these days. But when running all the ancillaries on a cold winterās morning the battery might be lucky to receive 10A charge. 1Ah refilled at only 10A will take a tenth of an hour, or six minutes. If it has been standing for a couple of weeks, and its cold and took a few turns to get going, the car might easily need an hour of driving to put some reasonable charge back into the battery, maybe even a couple of hours.
If the charge to discharge ratio is adverse, eventually even a top of the range ultimate good battery will run out of charge.
Conclusions.
A lightly used modern car needs regular topping up of the battery with a Smart charger.
Any daily driver should be OK if the journeys are longer than about ten minutes AND it doesnāt often use Stop/Start.
Definitely overthinking! Gone for a CTEK 5amp. Supposed to arrive Friday (Good Friday and no post!).
If onlyI could go for at least a 10 minute drive a day without a risking a Ā£60 fine (then Ā£120 then Ā£240 then Ā£480 then Ā£960 then whatā¦Jail!) rather than a 10 minute drive for Groceries every 9-10 days in just one of our cars.
Thanks to all who advised their choice of smart charge, most helpful.
I did deviate a bit from the original aim of seeking advice re what smart battery charger, but I appreciate the knowledge passed on about battery operation and suitable replacement. Especially since after 3 years & 4 years our Mazda3 and MX5 respectively will likely need replacement batteries in the no so distant future
