Should Battery Reach 100% Charge?

[mpc]

I have a 67 plate C250 S205 and I realised the battery needed charging as I was getting silly things happening with it standing still more recently.

I have a RING Smart Charge battery charger, I set it to AUTO and made sure it was on the stop/start setting.

RSC612

www.ringautomotive.com

Battery has been charging now for 24hrs, this morning it was on 90% charge, just been to check it and its now showing 80%!?

Why would this be and should I keep it charging until its showing 100% or is it doubtful that is achievable?

Any advice appreciated.

Michael

 

[Bobby Dazzler]

I don’t know that charger but could the percentage refer to charging rate rather than percentage charged?

The reason I ask is that the charging rate will slow down as the battery reaches full capacity, and might explain it.

 

[mpc]

I don’t know that charger but could the percentage refer to charging rate rather than percentage charged?

The reason I ask is that the charging rate will slow down as the battery reaches full capacity, and might explain it.

Looking at the manual it states the percentage showing is 'Performance / Completion'

 

[oldguy57]

A 12A charger should take a lot less than 24 hours to fully charge a 12v battery, unless one or the other are faulty. I'd be checking with a voltmeter.

 

[Petrol Pete]

Being a 2017 Mercedes Benz I would say its time for a new battery , or batteries. This forum is full of stories of 5 year old MB's breaking down due to their original batteries failing for no good reason

 

[190]

I wouldn't assume it's a faulty battery and I'd make 3 observations about modern auto chargers:

To get a battery from 80% to 100% can take disproportionally longer than to get it up to 80%

When I have used a modern charger they have never got to 100% although that might have been lack of patience on my part.

The whole point of these modern chargers is you can connect them up and forget about them as they will automatically default to float mode. If you can afford the time just leave it connected for a few days.

 

[Bobby Dazzler]

I wouldn't assume it's a faulty battery and I'd make 3 observations about modern auto chargers:

To get a battery from 80% to 100% can take disproportionally longer than to get it up to 80%

When I have used a modern charger they have never got to 100% although that might have been lack of patience on my part.

The whole point of these modern chargers is you can connect them up and forget about them as they will automatically default to float mode. If you can afford the time just leave it connected for a few days.

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