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shivadas avatar image

Phoenix Multiplus 12/2500/120 good for LifePo4?

Hi,

I found a Phoenix Multiplus second hand for a decent price. Will I be able to properly charge my LiFePo4 batteries with it? I just realized that it is an older inverter/charger — can I manually set my charging profile?

Thanks!

MultiPlus Quattro Inverter ChargerLithium BatteryPhoenix Invertercharger
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wkirby avatar image
wkirby answered ·

If the battery type is set to "User Defined" then the absorption and float Voltages are programmable between 12V and 16V in 0.1V steps.
The settings are programmed in with DIP switches and push buttons. In these modern times, it's a bit clumsy but that is the way things were done back in those days.

Study the manual to familiarise yourself with the setup procedures:
https://www.victronenergy.com/Manuals/PhoenixMulti/UKISM010054000-rev00.pdf

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Thanks again @WKirby
I will then get it (half price of a new one) and figure it out :)

@shivadas Do remember as this is an old unit, it does not have VE.Bus. It will not work with a CCGX or anything like that.
Just adding this for information if you have future plans.

@WKirby Ok thank you for that info. Does that change my capability to charge the battery via alternator? Do you know how to set that up (I just posted a separate question about charging LiFePo4 with alternator)

Hi @WKirby, sorry to dig this back up. Question: I can trigger relays with my 123smartBMS and will use this to turn on charging from my starter battery. I'm wondering though — I know this is a bit of a noob question — Do I need to somehow attach a "stop charging" relay on the Multiplus (12/2500/120), or does it stop charging if set up correctly?

From what I understand I set an absorption at eg. 14.4V and a float voltage at eg. 13.5V — does that mean that it will essentially "switch to 13.5V" at that point, thus stop actively charging, thus overriding the need for a relay?

A stop charging relay is a very good idea.
Remember, the BMS monitors each cell of the battery. If one cell goes over Voltage, the pack Voltage may still be withing the charging parameters set up in the MultiPlus. You'd want the MultiPlus to stop charging if a single cell goes over Voltage.

Hi @WKirby, thanks for your response. Since I have an older Multiplus (12/2500/120), how to I stop charging while keeping the inverter working? I see a "charger only" mode in the manual, but not really the other way around?
And if not, would you suggest to put a relay on it that opens the moment it gives a "stop charging" signal (consequently disconnecting power every time my charging is finished)? I can see if I can somehow trigger the relay only for emergency over-voltage etc in stead of finishing charging.