question

gratzer avatar image
gratzer asked

Phoenix frying batteries!

Hi! I'm new to this so excuse my simplistic question! I bought an old boat that has a Victron Phoenix (multi) compact 12 1200 50 inverter/charger running on 220v. When I put it into charge mode the battery bank (3 x 110ah wet lead acid leisure and 1 × 110ah wet lead acid starter battery (split with a victron diode splitter) would start fizzing. I checked the voltage and it was about 14.5 (can't remember exactly but what I would have expected). I checked the batteries and the electrolyte was low so I topped them up and tried again. It fizzed! I assume the batteries were old and replaced them with new EFB batteries 3 x 110ah and 1 x 100ah. When I took the old ones out I realised they were only a couple of years old so I assumed the last owner had abused them. Installed the new batteries, turned on the cage charger any they all started fizzing within about 10 seconds! The voltage isn't too high so I'm assuming something crazy is going on with the amps? I played around with the jumpers to make sure it was set to flooded lead acid. My clamp meter won't read through the wires so I can't check what the amps are. There's no fizzing when I run the alternator plug in a 20 amp smart charger. Is this a common problem? Is there an easy fix?! Thanks!

Phoenix Inverter
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3 Answers
snoobler avatar image
snoobler answered ·

Phoenix is an inverter only, so I assume you mean a Multiplus Compact.

Depending on battery type, 50A charging is good for about 500Ah battery. If you have less battery, there is a risk of electrolyte loss and damage due to excessive current.

Exposed plates on flooded lead acid (FLA) is a formula for ruining them. Step 1 before charging is ensure the plates are fully submerged. Fluid level rises as charge level increases. Once the batteries are topped off, add distilled water to the proper full mark.

Checking cell specific gravity (SG) is also very important. Depending on brand of battery, SG 1.265 is full, and all cells within a 12V should be within 0.03 on SG.

Maintenance of FLA is ongoing and demanding. You need to check fluid levels VERY regularly and add distilled water as described above. SG should be checked at least monthly.

Lastly, properly charging of FLA requires temperature compensation. Charge voltages are only valid at 25°C. If temps are hotter, you need to charge to LOWER voltage. If temps are cooler, you need to charge to HIGHER voltage. Typically, it's -5mV/°C per cell, so a 12V FLA temp comp value would be -30mV/°C.

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kevgermany avatar image
kevgermany answered ·

Low flooded batteries will fizz when charged. So do AGMs, but it's less noticeable. Make sure the battery compartment is well ventilated and no chance of sparks/ignition. As @snoobler said, keep on top of the electrolyte level with distilled/deionised water.

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dwmarine avatar image
dwmarine answered ·

The Pheonix Multiplus is an earlier version of the Multiplus, It has the red pic of the bird on the front cover.

Possibly someone may have altered the charge settings with a dongle. This over-rides the dip-switches.

you may need to use a Victron Mk2 or Mk2.2 dongle to check the charge settings.

The later Mk3 dongle will not work.

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