Solar Panel Charging Level

[Fozzi in Lancashire]

Hi Everyone, done well over the Winter months with our ongoing Springer renovations. Batteries & hot water unit fitted - all good!

Just finished the 100w solar panel which is now charging the starter & 2 domestic batteries, the CMTD Charge Controller Manual 

shows the Parameters Display for the Stop Charge Voltage at 14.7   This is a default setting from the manufacturers and I just 

wondered if this was slightly high? Should it be 14 to 14.2? All batteries seem to be ok so far but just want to check please!

Lets hope for some warmer weather soon - still need to finish the painting!! Thanks everyone, Fozzi

[WotEver]

What batteries do you have? (Type)

[Fozzi in Lancashire]

Batteries are 100ah lead acid batteries x 3

[Murflynn]

I believe my Victron 75/15 goes to 'battery life maintenance' at 14.4v  with lead acid batteries.  

[WotEver]

18 hours ago, Fozzi in Lancashire said:

Batteries are 100ah lead acid batteries x 3

If they’re ‘bog standard’ Batteries (whatever that means!) then 14.7V is probably a bit high in the summer but ok for now. Think about dropping it to 14.5V once the weather warms up. 

[Jim Batty]

Here's a good batteries link about the 3 stages of charging: Bulk, Absorbtion and Float. 

https://www.batterystuff.com/blog/3-stages-of-smart-chargers.html

To quote the Bulk Charge info:

Quote

The primary purpose of a battery charger is to recharge a battery. This first stage is typically where the highest voltage and amperage the charger is rated for will actually be used. The level of charge that can be applied without overheating the battery is known as the battery's natural absorption rate. For a typical 12 volt AGM battery, the charging voltage going into a battery will reach 14.6-14.8 volts, while flooded batteries can be even higher. For the gel battery, the voltage should be no more than 14.2-14.3 volts. If the charger is a 10 amp charger, and if the battery resistance allows for it, the charger will put out a full 10 amps. This stage will recharge batteries that are severely drained. There is no risk of overcharging in this stage because the battery hasn't even reached full yet.

Our MPPT controller off 2x100w solar panels delivers about 14.4v at peak charge to our ordinary sealed batteries, and it drops to about 13.5v at float.