Battery Charger seems stuck in absorption mode?

[dpb]

I have a 2007 Beneteau with a Dolphin 12v 40A charger (REYA code 299740).
I have:
2 Lead acid Starter batteries that I can check and top up if necessary. They are each connected separately to the charger. Batteries are 5 years old.
2 Sealed lead acid Domestic batteries. They are connected in Paralell to the charger. Batteries are 2 months old.
The dip switches are set for 'wet and flooded' batteries.
The problem is that the charger seems to stay in equalisation mode for a very long time instead of switching to float. Today they have been in equalisation for more than 24 hours.
I have been reading up to try to understand but there is confusing use of terminology so not much better off.
Is this a problem?

Thanks

 

[PaulRainbow]

What voltages are listed in the manual ?

 

[noelex]

Three of the most likely possibilities are:

1. One of the batteries is defective and therefore not rising to the absorption voltage despite the full output of the charger. The absorption time is not counted down until the absorption voltage is reached so the charger will stay in absorption mode indefinitely. This can happen even to a new battery that develops an internal short.
2. There is a poor connection causing the same problems as 1.
3. The battery charger is defective.

It should be easy to sort out which one of these issues applies by measuring the voltage at the battery. A defective battery or poor connection is also likely to be hot.

 

[dpb]

Voltages as per photo of manual. I am using the top setting.

 

[dpb]

I should add that we are 'living on board' long term at the moment so always some load on the circuits.
I have switched charger off for the night to check battery voltages in morning.
I could find no heat when checking today but did not check at isolators.

 

[Alicatt]

Reading with interest, we have a duff sealed lead acid battery that was self discharging to 8V when disconnected from the circuit.
Our system is 235Ah @ 24V and that the dud battery was being used to deliver 12V to some systems on the boat.

Last weekend it came to a head and I could not get the batteries to hold any charge, they started to over heat and gas off enough to trigger the gas detector which is right above the battery bank.

We have 2 new 240Ah batteries on order and should be delivered on Monday.

We have a Victron Multiplus Inverter/charger, the one annoying thing about it is that there is no bypass for the shore power, you have to switch the inverter on to switch on the 230V and that also switches on the charger. The starter batteries are 2 x 100Ah 12V giving 24V and they are fine being charged by the Multiplus.

 

[PaulRainbow]

I should add that we are 'living on board' long term at the moment so always some load on the circuits.
I have switched charger off for the night to check battery voltages in morning.
I could find no heat when checking today but did not check at isolators.

Those voltages are OK, but i wouldn't want 14.4v all of the time. Turn the charger off, as well as as many loads as you can. Leave for a short while and then disconnect the negative cable from one battery at a time and measure the voltage with a multimeter. If you find one that reads low, leave it disconnected and turn the loads and charger back on, keep an eye on the charger now.

 

[PaulRainbow]

Reading with interest, we have a duff sealed lead acid battery that was self discharging to 8V when disconnected from the circuit.
Our system is 235Ah @ 24V and that the dud battery was being used to deliver 12V to some systems on the boat.

Last weekend it came to a head and I could not get the batteries to hold any charge, they started to over heat and gas off enough to trigger the gas detector which is right above the battery bank.

We have 2 new 240Ah batteries on order and should be delivered on Monday.

We have a Victron Multiplus Inverter/charger, the one annoying thing about it is that there is no bypass for the shore power, you have to switch the inverter on to switch on the 230V and that also switches on the charger. The starter batteries are 2 x 100Ah 12V giving 24V and they are fine being charged by the Multiplus.

I would fit a bypass switch.

 

[dpb]

Charger switched off overnight.
This morning starter batteries 13.22 and 13.19 volts.
Domestic, which have been powering the boat ( fridge, lights, TV etc) 12.3 and 12.7 volts.
Loose connection found on the 12.7v battery.
So batteries OK.
Charger back on so will monitor.

 

[dpb]

Charger has entered float mode so all seems OK. The issue was most likely the loose connection that I found, as suggested by others.
I will keep an eye on the charger and meanwhile thanks for the help.