Mixing AGM and Delphi Freedom Batteries

[pmyatt]

We have a domestic bank of 4 X 105 Ah Delphi Freedom batteries - about 2 years old. Have been offered a 4 year old 120 Ah AGM battery for peanuts - has been load tested and seems to be "as new" (yes, I know that this will not be the case!) (rich American MoBo owner who changes his batteries every 4 years). Was thinking of just adding it to the domestic bank but seem to have read somewhere that it is unwise to mix battery types because the charging regime (from Victron 12/2500/120 Phoenix Inverter/Charger) for the Delphis will trash the AGM. Have done a search on Forums but do not seem to be able to find a definitive answer - help please.

 

[ccscott49]

We have a domestic bank of 4 X 105 Ah Delphi Freedom batteries - about 2 years old. Have been offered a 4 year old 120 Ah AGM battery for peanuts - has been load tested and seems to be "as new" (yes, I know that this will not be the case!) (rich American MoBo owner who changes his batteries every 4 years). Was thinking of just adding it to the domestic bank but seem to have read somewhere that it is unwise to mix battery types because the charging regime (from Victron 12/2500/120 Phoenix Inverter/Charger) for the Delphis will trash the AGM. Have done a search on Forums but do not seem to be able to find a definitive answer - help please.

AGM's do have a different charging regime/voltage to your delphi's. I wouldnt do it. Also it's best not to add batteries of different ages/types to a bank, best to replace all at the same time, thats best practice, however I've also seen it done other ways. But I wouldnt do it.

 

[mlthomas]

We have battery charging problems too, which seems to have come from having wet LA domestic, sealed LA for the starter and AGM's for the bow thruster all from the same charger. The charger was set up for sealed LA, not sure if this is the cause but the AGM's have lost their performance to the point they need replaced after just over two years.
We have no split the charging so the domestic are separate from the rest and once we have replaced the AGM's (Maxxima 900dc's) we will have a separate charging regime.
Facing a hefty bill for a pair of AGM's I would not mix n match.

 

[exfinnsailor]

Different way of charging them. I have a Sterling Battery to Battery charger on board and this has to be set to AGM for the bow thruster battery. It is something like a four stage charging cycle with the last part at a higher voltage than normal wet batteries. So not a good idea to mix them up as your battery charger will probably only suport one type.

 

[sarabande]

how many peanuts for the battery please if you can't use it ?

 

[nigelmercier]

have read somewhere that it is unwise to mix battery types because the charging regime (from Victron 12/2500/120 Phoenix Inverter/Charger) for the Delphis will trash the AGM...

Do you have a spare output from the Victron? If so you could keep it charged, and use it as a switched reserve.