thshh avatar image
thshh asked

Charger IP67 12/25's going nuts: voltage fluctuates in Bulk, Abs, Float, Storage


any help is appreciated. IP67 12/25 is connected to AGM battery with 92 Ah, temperature -2° C.

In all charging states the volate is fluctuating. Charge algorithm "AGM spiral cell" has been chosen (abs 14,70V, float 13,80V, storage 13,20V.)

On the left you can see the charger working in storage-mode. DC-load was 3W for Globallink 520 and some USB-sockets without any load. Look at the curve: Voltage is fluctuating every second (not seen here because Globallink gathers data only four times an hour.) But when i am checking the Voltage via Bluetooth right beside the installation i can see that voltage fluctates between min 13,30V and max 13,70V! That i am not reaching 13,20V is ok due the temperature of the battery while using temperature compensation as it is set by factory (-16,70V/°C) Is that normal behaviour?

On the right side of the chart you can see the same battery being charged without any load by a CTEK MX 5.0 Polar. This charger also compensates the batteries low temperature but look at the voltage of the charging states: bulk, abs and float are clearly visible and NO VOLTAGE HOPPING.


AGM Batteryovervoltage
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1 Answer
Alexandra avatar image
Alexandra answered ·

When is is in storage, the charger us foing nothing. You can see a small current draw shown on the shunt. The pulse up in amos is when the charger is checking the battery to see if it should start charging. So the victron is not contributing there at all and has. Out moved out of storage or has not had rebulk triggered.

I can see no current draw when the ctek is plugged in so it obviously it is letting some power through and it is running your loads and acting a a power supply (after it charged)

So the two just behave differently because the ctek expected to start a charge cycle when it was connected so it did so.

What happens when you reconnect the victron? Does it then go through the whole charge cycle again?

Further comments, did you mean you had the IP65 as the ip67 does not have bulk/abs/float lights?

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thshh avatar image thshh commented ·
On the diagram show above the charge was in Storage for 18 days.

CTEK was in Float.

Victron will alwyas start a new cycle when it is reconnected and or settings have been changed.

But that is not the for my question: is it normal thats the IP67 behaves like this? Fluctuating up to 0,5V above the selected voltage-level?

I got a ip67. charging state is visible in victron connect app. no need to have a look at the charger itself.

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Alexandra avatar image Alexandra ♦ thshh commented ·


You can disable storage on the Victron. Change the battery profile. Since your system is not idle it does not make sense to have that on anyway.

For the victron to come out of storage the charge cycle has to be triggered by a voltage. Not sure what yours would be at.

Maybe the Ctek does not move into storage different algorithm. The victron pulses the battery in storage mode. You can see the pulses on the orange plot on the graph.

The victron is not in power supply mode, neither is it charging so maybe the battery fluctuations are likely the battery. You wont see it with the Ctek since it is providing CV CC to the battery while it is floating, since float on an agm actually uses power (hence the tail current setting on a shunt).

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thshh avatar image thshh Alexandra ♦ commented ·
In Storage the IP67 pulsed some current into the battery without leaving Storage itself and without fluctuation in Voltage. 3w will not affected IP67 to leave Storage into Bulk.

That could be a point: cc cv on the CTEK.

But: Is this voltage hopping of the IP67 normal? Even without load.

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