Charging car battery

wijcc

wijcc

wijcc

Soldato
Joined
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London
I have a 2010 petrol Ford Focus, which I don't drive my car very often these days. As the weather is starting to be colder again the battery might struggle to start the car, can I charge my car battery using a mains battery charger while it is still connected in the car or is it better to take the battery out the car and then charge the battery?
Thanks in advance
 
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I always do it while still in the car.

Get a spanner, its usually a size 10mm

Loosen and take off both the terminals and move them to the sides of the battery out of the way a bit.

Use an extension lead and hook up the charger to the correct terminals and switch it on.

Keep an eye on it ( rain etc ) and depending on the charger it tells you when its charged.

Refit the terminals and tighten up again.

Keep charging regularly because they are a pain to bring back to life if left too long and can even die.
 
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You can charge the battery whilst still in the car and whilst still connected, no need to disconnect the terminals unless you have some old POS charger.

Connect charger positive directly to the battery and negative to a body ground.
 
Thanks, how do I tell if my charger is a POS charger.. my charger is a challenge mbc6617 charger?
I meant not disconnecting the battery from the car, as I am not sure if I know the stereo code.
Also is it better to trickle or fast charge?
 
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wijcc said:
Thanks, how do I tell if my charger is a POS charger.. my charger is a challenge mbc6617 charger?
I meant not disconnecting the battery from the car, as I am not sure if I know the stereo code.
Also is it better to trickle or fast charge?
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Upgrade your charger to something like this:

You permanently attach a quick release to the battery and then hang the connector somewhere convenient. It means you can connect it with zero faff. It also has all of the goodness that protects the battery from overcharging etc
 
Thanks, no point spending money on a new charger given that I have a working one already. So given my current charger is it best to disconnect the battery or remove it from the car before charging it?
 
I personally wouldn't be connecting a "no brand" charger to my car for any extended periods of time. YMMV.
 
Always removed battery from car boot (5mins with right socket size ready to go)
.. so invariably leave it unlocked overnight, and loose the radio settings, if I had a newer trickle charger that wasn't going to potentially put a big wedge of current into the battery I'd probably charge with it in situ.

Albeit, If car was new still under warranty, I might also have reservations that in situ charge could nack the regulator, leaving a forensic/error-code footprint for dealer to exploit.
 
Clarkey said:
Just connect the charger and be done with, no need for any of this messing around.
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Aye, and the charger I use it at least 30 years old and works fine, probably older, I'll take a picture later if I get a chance.

Edit: there, there is no date on that if anyone can guess how old, I have no idea but I'm guessing at least 30 years old.

IMG-20221108-081213.jpg
 
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Older car, newer car, older charger, newer charger - some combinations might cause problems, others will be fine charging the battery in place connected.

If you aren't worried about charge time look for Black Friday deals on a NOCO GENIUS1 which should eliminate any potential issues with charging in situ and can even be left plugged in through the winter for maintaining the battery (I got one for £24.99 last time they were on offer).
 
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wijcc said:
Thanks, how do I tell if my charger is a POS charger.. my charger is a challenge mbc6617 charger?
I meant not disconnecting the battery from the car, as I am not sure if I know the stereo code.
Also is it better to trickle or fast charge?
Click to expand...

That’s a very old school/low tech charger - you would need to disconnect your battery from the vehicle to use that charger.

Trickle charge is best to keep an old lead battery topped up over the winter. Once a month should be fine.

Either find out your radio code or buy a modern charger such as the one linked earlier.
 
Firestar_3x said:
Connect charger positive directly to the battery and negative to a body ground.
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One thing I'm not sure on - I've seen it said a lot that on a modern car, especially with AGM type, you should connect the charger to battery positive and body ground so that the built in BMS can detect the battery is being charged?!? but not sure if there is anything to that - while on older cars without fancy electronics it is better to charge directly to the battery.
 
Rroff said:
One thing I'm not sure on - I've seen it said a lot that on a modern car, especially with AGM type, you should connect the charger to battery positive and body ground so that the built in BMS can detect the battery is being charged?!? but not sure if there is anything to that - while on older cars without fancy electronics it is better to charge directly to the battery.
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I use my very old (as pictured) charger on an AGM battery direct to terminals works fine.
 
Rroff said:
One thing I'm not sure on - I've seen it said a lot that on a modern car, especially with AGM type, you should connect the charger to battery positive and body ground so that the built in BMS can detect the battery is being charged?!? but not sure if there is anything to that - while on older cars without fancy electronics it is better to charge directly to the battery.
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This is correct, the BMS could get all messed up if you charge directly to the battery, no idea what year BMS became wildly use though.
 
BUDFORCE said:
I use my very old (as pictured) charger on an AGM battery direct to terminals works fine.
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4 amp charger which likely struggles towards the end of the charge probably isn't the end of the world but some older higher amperage chargers will definitely affect the health of some AGM type batteries.
 
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