Batteries won't charge past reconditioning stage

[SeanC]

In my 2008 D3 TDV6 I have an 80Ah Ultimate Extreme AGM as my auxiliary battery connected to a Century DIN85LH MH starting battery by a Traxide SC80.

It's not my daily drive and I have it connected to a CTEK MXS 10 when not in use.
It’s connected to the auxiliary battery on the AGM setting.

Even after 2 weeks on the charger it does not pass the reconditioning stage.
Any ideas?

[trout1105]

How old is the battery?

[SeanC]

Two years old. Both purchased at the same time.

[trout1105]

Two years old. Both purchased at the same time.

How much warranty did you get with them?
If they are constantly on the "reconditioning stage" then maybe one or both of them has a dead cell.

[drivesafe]

In my 2008 D3 TDV6 I have an 80Ah Ultimate Extreme AGM as my auxiliary battery connected to a Century DIN85LH MH starting battery by a Traxide SC80.

It's not my daily drive and I have it connected to a CTEK MXS 10 when not in use.
It’s connected to the auxiliary battery on the AGM setting.

Even after 2 weeks on the charger it does not pass the reconditioning stage.
Any ideas?
Hi Sean and what you are going through could possibly be a problem with the charger, not the batteries.

I have heard of this happening with Ctek chargers.

Try disconnecting your auxiliary battery’s negative ( - ) terminal and just charge your cranking battery.

If this works then leave the negative ( - ) terminal off the auxiliary battery and try charging it.

let us know how you go.

Regards, Tim.

[SeanC]

Hi Tim,

Am driving it today. Will connect just to the starting battery tonight and see how it goes.

[SeanC]

So this what I have.

After driving to work and back. 100km round trip at 100km/h most of the way.

I disconnected the neg auxiliary lead. The starting battery took 3 hours to reach the float stage.

I then charged the auxiliary battery. After 4 hours it was at stage 4 (absorption) This morning it was on float.

Connected the batteries together and after 5.5 hours it went to float. Don't know why they didn't get to float after almost 2 weeks on charge.

At least it got to float but the times seem fairly long.

Should it take 5.5 hours to get 2 supposedly fully charged batteries to float?

Up to now I wasn't paying much attention to the charging stage when I went to drive the vehicle.

I read recently that after 10 days of float the stage will change to pulse and I waiting for that to happen but it didn't get past reconditioning.