Battery charger testing

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Oct 23, 2009
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Anglesey North Wales
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Adria Twin 640SLB
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Question - how can you tell if you have a faulty charger . Given the problems I'm having with my batteries I’m beginning to suspect my CBE charger is not doing what it’s supposed to do and may be either undercharging or overcharging my batteries and therefore destroying my GEL batteries .
Is there a test for checking the charger and it’s performance ?
 
Stick your multimeter on the terminals and measure the output volts
 
But how can you tell it’s doing the correct float voltage for the time it’s supposed to ?
You can either sit there and watch it, or install a device that will take readings and store the history for you to view. For example, a Victron SmartSense will stick on the battery and send the voltage via Bluetooth to a phone app. Other similar battery monitors are available from Ebay etc.

The simpler battery monitors just measure voltage, and maybe temperature, with just a positive and negative connection. The other type will also measure the amps into and out of the battery, but this has a 'shunt'. The negative wires are disconnected from the battery and connected to one side of the shunt. The other side of the shunt is connected to the negative battery terminal.

The shunt-type monitor will have an inbuilt clock and chip, and will calculate the amp-hours into and out of the battery, so you always know its percentage state pf charge (SOC). These are much better than a simple voltmeter, which can be very misleading, especially if the battery is constantly being charged with solar or mains power.

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But how can you tell it’s doing the correct float voltage for the time it’s supposed to ?
Simplest and easier way, is find a small alarm 12v battery that will fill up quick. Wach it with a multimeter on the terminals and see it it stops rising on bulk, and holds absorb. Then return a bit later to see if it drops in float.
 
Is the Charge profile set to the Gel setting? In the manual it says there's A, B and C, and Gel is B, I think. 14,4V Absorption, 13.8V Float.
 
Last edited:
You can either sit there and watch it, or install a device that will take readings and store the history for you to view. For example, a Victron SmartSense will stick on the battery and send the voltage via Bluetooth to a phone app. Other similar battery monitors are available from Ebay etc.

The simpler battery monitors just measure voltage, and maybe temperature, with just a positive and negative connection. The other type will also measure the amps into and out of the battery, but this has a 'shunt'. The negative wires are disconnected from the battery and connected to one side of the shunt. The other side of the shunt is connected to the negative battery terminal.

The shunt-type monitor will have an inbuilt clock and chip, and will calculate the amp-hours into and out of the battery, so you always know its percentage state pf charge (SOC). These are much better than a simple voltmeter, which can be very misleading, especially if the battery is constantly being charged with solar or mains power.
Thanks I
Is the Charge profile set to the Gel setting? In the manual it says there's A, B and C, and Gel is B, I think. 14,4V Absorption, 13.8V Float.
yes I checked it’s set to B
 

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