Mixed battery bank?

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GTom

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My battery bank is becoming a mess, older units are still going strong but I am adding another member. So far I have two 4 year old and a 2 year old FLA's which every know and then get individual charging (otherwise they're on the Victron mppt/solar all together). This year I am getting an electric outboard for the dinghy and a 110Ah AGM with it. AFAIK AGM doesn't like overcharging.
May I keep the outboard battery in the bank if I decrease the float voltage to 14V (2.35V/cell)? Or keep it completely isolated from the FLA's?
 
'Decrease' to 14V float voltage? And bear in mind that 2.35V per cell equates to 14.1V, a tad higher still. Even that reduced float is way too high for your current flooded lead acid batts!

As a matter of interest, what is the float and absorption voltage now?

To start, I'd pull down the float to 13.5-13.7V and then consult manufacturer docs
 
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No idea, I am a thousand miles from the boat ATM, I'll check what's the voltage at the batteries when charged. You must be right, I recall seeing 13.x numbers when the victron was charging.
 
GTom said:
No idea, I am a thousand miles from the boat ATM, I'll check what's the voltage at the batteries when charged. You must be right, I recall seeing 13.x numbers when the victron was charging.
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No need to check what they are when charged, just check the settings are from the solar controller.
 
GTom said:
No idea, I am a thousand miles from the boat ATM, I'll check what's the voltage at the batteries when charged. You must be right, I recall seeing 13.x numbers when the victron was charging.
Click to expand...

As a matter of interest, have you ever edited the factory default settings?

If not, I can put your mind at rest! Victron MPPT's have a factory float set to 13.8V and absorption at 14.4V. The float is at the upper end of the spectrum, but as the solar is only working during the day it will do absolutely no harm whatsoever to your newish batteries.
 
dom said:
As a matter of interest, have you ever edited the factory default settings?

If not, I can put your mind at rest! Victron MPPT's have a factory float set to 13.8V and absorption at 14.4V. The float is at the upper end of the spectrum, but as the solar is only working during the day it will do absolutely no harm whatsoever to your newish batteries.
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Nope, left everything default should be all right then:)
 
Graham376 said:
If the charging regime for the different battery types is very different, just add another regulator for the outboard battery.
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FLA and AGM will happily co-exist on the same charging regime. It wouldn't be a good idea to fit a second MPPT controller to the say solar array in any case.
 
Graham376 said:
I ran two MPPTs from the same panels, each feeding a different bank until I paralleled them and fitted one larger MPPT. Worked fine.
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I see all sorts of wrongly installed electrics, the owner generally thinks they are all working OK. Just because nothing explodes or starts to smoke doesn't mean they actually are working OK.

It's bad practice to connect two MPPT controllers to the same array.
 
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