Sargent AC-DC Battery Chargers
Official technical documentation and workshop diagnostics for AC-DC Battery Chargers.
Master Troubleshooting & Diagnostics Matrix
| Error Code / Indicator | Symptom / Meaning | Step-by-Step DIY Fix | Suggested Actions |
|---|---|---|---|
N/A | The electrical system shuts down by itself randomly. Possible Cause: Over voltage. The Sargent system detects a voltage higher than 15V and shuts down, commonly caused by a faulty solar regulator or a fault with the mains charger. | To check if your solar regulator is faulty, determine if the random shutting down only happens during the day when it is sunny and the solar regulator is active. You can disconnect the solar input from your system, or cover up the solar panel to see if the problem stops occurring. Alternatively, you could measure the voltage coming out of the solar regulator, though this can be hard to pick up because the output can fluctuate depending on shading from clouds. To check if your charger is faulty, note that if you have a fixed voltage charger the voltage should be no higher than 13.8V. If you have a PX300 installed, visit the PX300 product page to find a downloadable attachment to check the operation of the charger. | DIY Safe |
N/A | Battery is overheating and showing symptoms of being overcharged. Possible Cause: A failed cell within the lead-acid battery (turning it effectively into a 10V battery, causing it to draw more current and overheat under normal charge voltage). | Check the battery for a failed cell. If suspected that the charger rather than the battery is at fault, consult the article 'My PX300 charger isn't working correctly?' for further troubleshooting. | DIY Safe |
N/A | Lithium battery has entered Deep Sleep mode (DSLP) with State of Charge reduced to 0% and output switched off. Possible Cause: The battery State of Charge has reduced to 0%. | Re-charge the battery as soon as possible to avoid reducing lifespan and performance. If the battery is in Deep Sleep mode, the 'lithium wakeup' feature of the Sargent PX310 charger may be able to wake the battery and start charging as normal, or apply a fixed voltage of 12V to 15V briefly across the terminals. | DIY Safe |
N/A | Lithium battery has entered Under Voltage Protection mode (UVP) because internal cell voltage dropped below 2.5 volts per cell or terminal voltage fell below 10 volts, switching off power from the cells. Possible Cause: Critical low internal voltage of battery cells due to deep discharge. | Re-charge the battery immediately. Attach a fixed voltage charger to recover the battery cells to a point where they can switch back on (2.8 volts per cell, i.e., 11.2 volts in total for four cells). Depending on the state of discharge, this may take up to 30 minutes. | DIY Safe |
N/A | PX300 charger isn’t working correctly | Navigate to the PX300 product page via the link provided, locate and download the attachment, and follow the instructions within to test the output voltages of the PX300 and ensure the charger is working correctly. | DIY Safe |
Frequently Asked Questions
Q: What happens when the Sargent control system detects the battery State of Charge falls to 15%?
The control system will first issue an alert on the control panel screen to warn the user that the battery requires re-charging.
Q: What happens if the battery is not re-charged and the charge reduces further to 5%?
The control system will alert again, then power off all switched circuits to avoid further discharge. Note that any circuits powered directly from the battery will still be active and consuming current.
Q: How can I extend the lifespan of a Sargent lithium battery?
Avoid frequent deep discharges and maintain a partial state of charge, ideally between 40% and 80%. Do not rely on Under Voltage Protection (UVP) as a signal for when to charge the battery.
Q: I would like to fit a Lithium battery
Most Sargent systems have a Battery Charger like a PX300 or PF200 connected to the system. If your vehicle has another charger fitted, please consult the manufacturer's manual to check its compatibility with Lithium batteries. The PX300 charging profile is suitable for many Lithium batteries designed for the leisure industry that are fitted with an internal Battery Management System (BMS). You can find a downloadable attachment detailing the charging profile and voltages on the PX300 product page, and you will need to ask the battery manufacturer of your choice if the PX300 charger would be suitable for their battery. Sargent systems fitted with a PX300 are: EC328, EC400 Series, EC500, EC600, EC700, EC800, and EC400+. If your system is NOT fitted with a PX300 then your charger will have a fixed voltage of 13.8V and this is normally considered to be unsuitable to fully charge a Lithium battery. You will also need to consider if you need to install a DC-DC charger when changing your battery to Lithium to limit the charging current.
Q: I would like to fit a different AGM battery
Whilst we do not recommend any specific make or model of battery, the PX300 charger used in systems including the EC400/EC400+, EC500, EC600, EC700, EC800, and EC328 is compatible with the majority of good quality AGM batteries available in the UK. The charge profile of the PX300 is shown in the instruction manual attached below. If you are in any doubt as to the fitment of a battery you should confirm with the battery distributor or manufacturer that the PX300 charge profile is suitable.