Mastervolt Charger voltages

[Slim]

First time of posting so here goes!

 

My Mastervolt MASS 12/60 has suddenly started charging at slighty higher voltages and I'm concerned about reason for this and the damage it may do to my batteries.

 

The system is a Mastervolt MASS 12/60 supplied by either a landline or on board generator, a Mastervolt MICC monitor/controller and a 550ah domestic battery bank (3 - 4 year old AGMs). I also have a Sterling 150 amp 3 step charger as a backup.(in reality this is 2 chargers separately switched in one case). I should stress that this unit is not part of my problem

 

Up to recently the charge voltages were exactly as stated by Mastervolt eg in bulk rising to 14.4 v, in absorption constant at 14.25 v, in float constant at 13.8 v (with dip switch set to Gel compensation). Now they rise to 14.62 v in bulk, remain at 14.62 v in absorption and fall to 14.3 v in float. Setting the Gel compensation to off reduces the float voltage 13.6 v.

 

The MICC has been checked against 4 digital meters, including one that had recently been calibrated, and is accurate to within .02 of a volt at around 14 v. It is wired to sense at the batteries. Voltages have been double checked back as far as the battery bank using several digital meters. All cables, connections have been checked and double checked. All cables and wires are significantly over spec ed.

 

I temporarily replaced the batteries with 2 almost new 110ah ones with the same results.

 

If I switch off the Mastervolt and switch on the Sterling charger (half of it) I can continue to monitor charge voltage via the MICC. Whilst I can't quote offhand the bulk and absorption voltages I do know that it settles down to a float voltage of 13.25 v.

 

I have spoken to someone at Aquafax who are now the UK agent for Mastervolt and he didn't seem to think I had a problem!! He suggested it could be the batteries (since proved not to be so). He also suggested it might be the heat (we were talking during our brief summer a couple of weeks ago). Not so as the problem pre-dates that time. His final and most forceful 'explanation' was that by disconnecting the boat from the mains when I left it for any any time I was using the charger incorrectly and that it should be left connected 24/7. He didn't want to hear my point that my concern was that the charging characteristics had changed.

 

Am I worrying over nothing or is there something wrong somewhere? Have I overlooked something obvious?

 

Any help or suggestions would be much appreciated

[Guest]

First time of posting so here goes!

 

My Mastervolt MASS 12/60 has suddenly started charging at slighty higher voltages and I'm concerned about reason for this and the damage it may do to my batteries.

 

The system is a Mastervolt MASS 12/60 supplied by either a landline or on board generator, a Mastervolt MICC monitor/controller and a 550ah domestic battery bank (3 - 4 year old AGMs). I also have a Sterling 150 amp 3 step charger as a backup.(in reality this is 2 chargers separately switched in one case). I should stress that this unit is not part of my problem

 

Up to recently the charge voltages were exactly as stated by Mastervolt eg in bulk rising to 14.4 v, in absorption constant at 14.25 v, in float constant at 13.8 v (with dip switch set to Gel compensation). Now they rise to 14.62 v in bulk, remain at 14.62 v in absorption and fall to 14.3 v in float. Setting the Gel compensation to off reduces the float voltage 13.6 v.

 

The MICC has been checked against 4 digital meters, including one that had recently been calibrated, and is accurate to within .02 of a volt at around 14 v. It is wired to sense at the batteries. Voltages have been double checked back as far as the battery bank using several digital meters. All cables, connections have been checked and double checked. All cables and wires are significantly over spec ed.

 

I temporarily replaced the batteries with 2 almost new 110ah ones with the same results.

 

If I switch off the Mastervolt and switch on the Sterling charger (half of it) I can continue to monitor charge voltage via the MICC. Whilst I can't quote offhand the bulk and absorption voltages I do know that it settles down to a float voltage of 13.25 v.

 

I have spoken to someone at Aquafax who are now the UK agent for Mastervolt and he didn't seem to think I had a problem!! He suggested it could be the batteries (since proved not to be so). He also suggested it might be the heat (we were talking during our brief summer a couple of weeks ago). Not so as the problem pre-dates that time. His final and most forceful 'explanation' was that by disconnecting the boat from the mains when I left it for any any time I was using the charger incorrectly and that it should be left connected 24/7. He didn't want to hear my point that my concern was that the charging characteristics had changed.

 

Am I worrying over nothing or is there something wrong somewhere? Have I overlooked something obvious?

 

Any help or suggestions would be much appreciated

The float sounds too high, but hopefully Gibbo will give a proper diagnosis.

 

I suppose a charger would ideally be left on permanently, although mine never has been. I can't see how this would increase the charge voltages.

[nb Innisfree]

Up to recently the charge voltages were exactly as stated by Mastervolt eg in bulk rising to 14.4 v, in absorption constant at 14.25 v, in float constant at 13.8 v (with dip switch set to Gel compensation). Now they rise to 14.62 v in bulk, remain at 14.62 v in absorption and fall to 14.3 v in float. Setting the Gel compensation to off reduces the float voltage 13.6 v.

 

Surely you mean 14.2v in bulk rising to 14.4v in absorption instead?

[dave moore]

Hi

Contact Keith Meadowcroft, AKA Volt Master and a trouble shooter for Mastervolt. He's an authority on their systems and will be happy to help. Mobile 07740 200 775

Cheers

Dave

[Keith M]

Hi

Contact Keith Meadowcroft, AKA Volt Master and a trouble shooter for Mastervolt. He's an authority on their systems and will be happy to help. Mobile 07740 200 775

Cheers

Dave

 

 

Try disconnecting the battery temperature sender from the battery charger.

[Arnot]

My Mastervolt MASS 12/60 has suddenly started charging at slighty higher voltages and I'm concerned about reason for this and the damage it may do to my batteries.

 

Up to recently the charge voltages were exactly as stated by Mastervolt eg in bulk rising to 14.4 v, in absorption constant at 14.25 v, in float constant at 13.8 v (with dip switch set to Gel compensation). Now they rise to 14.62 v in bulk, remain at 14.62 v in absorption and fall to 14.3 v in float. Setting the Gel compensation to off reduces the float voltage 13.6 v.

 

Any help or suggestions would be much appreciated

It sounds like the battery temperature sensor isn't working properly. You can check by removing it from the battery and dipping it in a mug of hot water then into a mug of cold (iced) water to see if it controls the voltage and that the results are in line with the graph shown in the instructions. If it isn't, try replacing it.

 

Regards

 

Arnot

[Slim]

Went down to the boat earlier today, disconnected the temp sensor and BINGO!. Float voltage fell back to 13.25 v within a few minutes. Left a few lights on (charger off) and will go back later to see what bulk voltage is once I reconnect charger.

 

In the meanwhile many thanks to everyone

 

 

Frank (slim)

[Slim]

Just to say that having spent the day checking out voltages at all stages of charging I'm now getting readings that mirror those quoted in the Mastervolt instructions.

 

Once again thanks to everyone especially Dave, Keith and Arnot.

 

 

Frank (Slim)