[hyuni30]

Hi all, i'll keep it short .. my 2013 Hyundai i30 (2nd gen) battery voltage is resting at 12.1v. The car starts great (touch wood) - first time every time. I only tested the voltage out of curiosity after my girlfriend had an issue starting her Suzuki Swift one cold morning earlier this month. I have ordered a 'smart charger' in case of emergency but am planning to give the battery a good charge when it arrives. The owners manual states that I should disconnect the battery to charge it (it's an AGM battery if that makes any difference) but I have seen a lot of comments online/ on motoring forums that suggest it would be fine to leave the battery connected. I would prefer not to disconnect the battery given the complications that can arise by resetting the ECU. What do you guys do when charging your AGM batteries? The charger is a 3.8A 12v output Autoxel model. Also (again out of curiosity) my stop start has only every kicked in twice in my car in almost 18 months of ownership. Could this have anything to do with the battery voltage being so low? TIA. Appreciate any insight. Modern batteries can be very confusing!

I cant comment on the ISG problem as I've never had the feature to test, someone here will be sure to have some suggestions though.

Regarding the maintenance smart charger, it is fine to hook up while battery is connected, I do the same for mine if I ever leave the car for an extended period of time.

[StokeyBry]

12.1v is quite low at resting voltage, if it is the original battery it would be due be replaced now. I changed my battery from a 13 GD last year because the voltage was 12.1~12.3 at resting.
Charging the battery may give it a boost but it will gradually drop back down due to the battery only being at 50%~60% capacity.

Mine is not a stop start so cannot add to that but it would certainly make sense that it wouldn’t work often because of the battery voltage being below what is required

[hyuni30]

I cant comment on the ISG problem as I've never had the feature to test, someone here will be sure to have some suggestions though.

Regarding the maintenance smart charger, it is fine to hook up while battery is connected, I do the same for mine if I ever leave the car for an extended period of time.

I have seen a lot of posts on here/ other forums suggesting that the ISG requires lots of parameters be met in order to function. If not the battery voltage then i'm sure it could be one of the many other parameters!

Thank you for your response re the charger. Can I ask what charger you use? what kind of power does it charge with?

[hyuni30]

12.1v is quite low at resting voltage, if it is the original battery it would be due be replaced now. I changed my battery from a 13 GD last year because the voltage was 12.1~12.3 at resting.
Charging the battery may give it a boost but it will gradually drop back down due to the battery only being at 50%~60% capacity.

Mine is not a stop start so cannot add to that but it would certainly make sense that it wouldn’t work often because of the battery voltage being below what is required

Up to 12.22 this morning 

I don't think I do enough long journeys to get it up to 12.6 - 12.7 unfortunately which is why I thought i'd give the charger a try before giving up on it! Definitely think it will be a handy device to have any way!

I agree that a new battery may soon be required. This is my first AGM and I didn't realise what a faff they are! Can't even change the battery myself without it needing coding so that the car recognises it as new?? far too complicated! 

Thank you for your response re the charger. Can I ask what charger you use? what kind of power does it charge with?

Mine is a different type to what you'll require, I use the CTEK Lithium charger (pictured below)

They have chargers for all types of batteries and are mains power to 12v, I only have to plug into the supplied connector that is attached to the battery and let it do it's thing





They do a model specifically for Stop Start vehicles CTEK | Battery chargers for all types of vehicles

[hyuni30]

Thank you for your response re the charger. Can I ask what charger you use? what kind of power does it charge with?

Mine is a different type to what you'll require, I use the CTEK Lithium charger (pictured below)

They have chargers for all types of batteries and are mains power to 12v, I only have to plug into the supplied connector that is attached to the battery and let it do it's thing


They do a model specifically for Stop Start vehicles CTEK | Battery chargers for all types of vehicles

Very helpful - thank you! My girlfriends dad swears by CTEK so perhaps I will splash out!

 

This model is a also compatible for Stop Start AGM CTEK | Battery chargers for all types of vehicles has some extra features over the previous unit like recon function and likely a bit more expensive, both will work though