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Battery Extra User Manual

Battery Reconditioner, Battery Desulfator, Battery Rejuvenator Restore or Maintain Your Lead Acid Batteries in Top Condition



User manual for Battery Extra EX02 12-48-400, for voltages from 12 to 48 volts

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Please read this manual before using your Battery Extra

The Battery Extra (BE) is an electronic accessory, it is designed to be attached to lead acid batteries or battery packs. It uses the power from the battery to extend the life of new batteries. It will also revive many weak or old batteries that are thought to be dead or need replacing.

The BE is not a battery charger, it works in conjunction with your existing charger. It is fully tested and complies with EU safety regulations for EMC emissions, so it cannot affect the operation of any other electronic device fitted to you battery system.

The Battery Extra EX02 12-48-400 is unique in the fact that it will work with battery voltages from 12 to 48 volts and capacities up to 1,500 Ah. It also incorporates a large heat sink and internal cooling fan designed to maintain a stable temperature during operation. The fan only works at 24, 36 and 48 volts.

The BE creates a wide range of frequency signals, that are designed to dissolve the sulphate crystals that builds up on both the negative and the positive plates of a lead acid battery, and reduce its capacity. Dissolving the sulphate crystals back into the electrolyte decreases the internal resistance of the battery, and raises the specific gravity. This ensures that you will keep or return your batteries to their maximum capacity. It works during both charge and discharge cycles.

The BE will work on all types and brands of lead acid battery, including GEL, AGM, Maintenance Free, Deep Cycle, Sealed and Leisure.

The BE will not recover bad batteries with shorted cells, open circuit cells or sealed batteries that have dried out. It can sometimes be possible to add water to sealed batteries and then recover them using the BE. Some examples of how to add water to dried out batteries can be found on youtube.com search "add water to SLA batteries".

We recommend that you test for a bad battery before using the BE to recover your batteries.

It is also worthwhile to consider why batteries sulphate and then see what you can do about stopping it in your batteries. The main causes of sulphate build up are; sitting too long between charges, long storage without some type of energy input, undercharging, low electrolyte level, incorrect charging levels and settings. Also, when connecting a number of batteries in parallel using simple daisy chain connections can often cause the end batteries in the chain to be undercharged, sulphate and fail. Email us for a better way of wiring your batteries.

Testing your Batteries

It is always best to test your batteries before using the Battery Extra. This will confirm if a battery can be saved or improved. Even new batteries can suffer from being sulphated if they were badly stored before you bought them.

Always be aware that when handling batteries you should wear goggles and gloves.

First do a visible inspection. Replace any battery that has a cracked or broken case. Clean or replace any dirty damaged or rusty connections. On wet batteries check the water level, make sure the water just covers the plates. Fill only with distilled water. Be aware that the battery solution is corrosive.

You will need a voltmeter to test your batteries.

First, switch off, or preferably, disconnect any accessories or items that your battery powers. Next charge the battery or battery pack until it is fully charged.

If your battery system is made up of more than one battery, you should disconnect them from each other. Now let the batteries rest for 4 to 8 hours to allow any surface charge to dissipate, this is most important to get an accurate voltage reading.

With a voltmeter check the voltage of each battery. If your batteries have been in recent use i.e. not been in storage for a long time period of time, then any 12 volt battery recording less than 10.5 volts, or if you are using 6 volt batteries less than 5.3 volts, it is most likely that the battery has a shorted or open cell and is not recoverable. Replace that battery with one of the same make and capacity.

If you do not have a voltmeter you can just fit your Battery Extra to each battery in turn and check the voltage reading shown on the LED display.

Installing the Battery Extra

If you are installing the Battery Extra (BE) to a used or older set of batteries, we would ask you to please read the section in this guide on testing your batteries.

The BE comes with ring connectors for permanent fitting. Please make sure when you are attaching your connectors to the battery, you fit the red wire to the + and the black to the -. Fitting the wrong way round will not damage the unit, but it will not work.

On a single battery just connect the red to positive and the black to negative. If you are fitting to a battery set you will need to identify the first and last battery in the pack. In most cases this is a simple matter of identifying the terminals that the battery charger is connected to, then attaching the BE red to positive, black to negative.

The BE can be permanently mounted using screws and nuts, self tapping screws or tie wraps. We recommend that you mount the BE to a metal surface to help dissipate heat from the unit.

Now all you have to do is set up your BE parameters and leave it connected at all times, during charging and discharging, just use your battery pack as normal.

Setting Battery Extra Parameters

When connected to a battery bank the LED will display HI for a few seconds.

The display will then show a number followed by H, example 24H, this is the internal resistance (IR) of the battery shown in mΩ. Note: we recommend that when checking the IR of your pack, you always do this when the pack is full charged, and that the Battery extra has been connected for at least 4 hours.

The next display shows ON or OFF, this indicates if the low voltage cut off switch is in the ON or OFF position, by pressing the FUNCTION button you can toggle between the 2 settings.

The next display shows 200, this is the current draw the BE is taking from the battery pack in mAh, in effect it is the power setting. By pressing the function button you can set this to 200 or 400 mAh.

Finally the display will show the battery bank voltage. At this point the small red LED at the side of the unit will come on to show the BE is working. If the LED is not illuminated, it will normally indicate that the low voltage switch is ON and the voltage has dropped below the cut off voltage for your battery bank. Note: The Battery Extra may show a slight discrepancy in indicated voltage than from a stand alone voltmeter.

If you wish to reset any of the parameters or check the IR, without removing the Battery Extra from your battery bank, just press the function button and the display cycle will restart.

Display Features

Internal Resistance (IR). This displays the internal resistance of the battery pack. The reading is very sensitive and can be affected by various factors, so make sure you have a good clean connection between the BE and the battery bank, also that the BE temperature is the same when comparing readings.

Low Voltage ON / OFF. In the OFF position the BE extra will work at all times. In the ON position the BE will only work when the voltage of the pack is above 12 volts per 12 volt of battery voltage, for example above 24 volts on a 24 volt battery and 48 volts on a 48 volt battery and so on.

Power Setting. Put simply, the larger the battery bank the more power required to clean and maintain the battery bank. The Battery Extra EX02 12-48-400 has 2 settings 200 and 400 mAh. We recommend; 200 mAh for batteries up to 500Ah, 400 mAh for packs over 500Ah up to 1,500Ah.

Red LED. Located on the side of the BE, when lit this indicates the BE is working.

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Recovering Sulphated Batteries

Recovering sulphated batteries is a gradual process. You have to cycle (charge, discharge) the batteries, with the BE connected, and make sure you never leave the batteries in a discharged or part discharge state. Depending on how badly sulphated the batteries are, and the size of the battery pack, this could take anything from a few cycles to more than 20.

If your batteries have not been used for some time, or are very heavily sulphated the battery voltage may have dropped so low that your modern smart battery charger just thinks the battery is no good, and will not charge them. These batteries can often still be recovered one at a time.

One method, for 12 volt batteries, is to use an old type manual charger or regulated low voltage (14 or 15 volts) power supply that can trickle charge the battery with the BE connected, and with the low voltage cut off set to the off position, this will enable you to monitor the battery voltage until it reaches at least 12 volts, you can then switch to a normal rate of charge. Depending on the size of the battery this could take from one day to several days. Repeat this process if you have more than one battery in the pack. Once you have recovered all of the batteries in the pack, connect the pack to your regular charger, switch the BE to the low voltage on position, and cycle the pack. If any batteries fail to reach 12 volts it indicates internal damage and they should be discarded.

Another method is to connect the sulphated battery in parallel with a known good battery, this will often be enough to kick start the bad battery.

1. Disconnect the dead or low voltage battery from the battery pack.
2. Connect the Battery Extra to the positive and negative terminals of the dead battery. Make sure the Battery Extra low voltage switch is in the off position.
3. Using jumper cables connect the positive terminal of a healthy battery to the positive terminal of the dead battery; then connect the negative terminal of the healthy battery to the negative terminal of the dead battery.
4. Connect your charger to the batteries and switch on.
5. Monitor the voltage of the dead battery with the Battery Extra voltmeter until it reads more than 12 volts.
6. Disconnect the jumper cables from the good battery.
7. Continue charging until the charger switches off, make sure the charge voltage reading does not exceed 15 volts or that the battery does not get hot to the touch (over 50c).If the charge voltage goes over 15 volts or the battery gets hot discontinue the charge.
8. Disconnect the charger and allow the battery to sit for 4 hours, check the voltage. A fully charged good battery will read 12.8 volts or more. If the bad battery reads more than 10.5 volts it should be recoverable. If any of the batteries fail to respond and still show low voltage discard those batteries and replace with batteries of the same make and size.
9. Leave the Battery Extra connected and cycle (charge/discharge) the battery in the normal way.

Sulphated batteries may take anything from 3 to 20+ cycles to recover to their full available capacity. On old batteries this may not be 100% of the original rated capacity. 

The main reasons for cell failure are:

Lead acid batteries are made up of 2 volt cells, so a 6 volt battery has 3 cells and a 12 volt battery has 6 cells, in most cases of battery failure only one cell needs to go dead for a battery to fail.

The main reasons for cell failure are:

A sulphated cell, a build up of lead sulphate on the plates which weakens the acid and increases the internal resistance of the cell until it can no longer produce energy. The Battery Extra dissolves the lead sulphate back into the acid solution and stops further sulphate build up. This significantly extends the life of the battery.

A shorted cell, generally due to shedding of lead particles from the plates building up at the bottom of the cell, which makes a circuit between the positive and negative plates causing a short circuit. The Battery Extra slows down the shedding by eliminating the sulphate build up. It cannot repair a shorted cell.

An open circuit, caused by a connection point in the cell burning out, this is normally the result of overcharging the battery. The Battery Extra can do nothing to stop this. If you batteries are getting very hot when charging, this can be an indication of overcharging. Modern battery chargers will normally revert to a trickle charge when the battery is fully charged. If you have a Battery Extra fitted this will be indicated by a drop in the voltage shown on the unit. If you do not see this voltage drop, check you charger. .

Tips for using your Battery Extra

When reviving old batteries it is often an advantage to allow the voltage to drop below the cut off value when cycling the battery, to do this just put the cut off switch into the off position, and monitor the voltage, never discharge the battery below the value of 10.5 volts per 12 volt battery in the pack.

It can be difficult to see the improvement in batteries when using the BE. A good way to check for improvements when reviving batteries is to check the run time. Example charge a 12 volt battery with the BE connected until fully charged, then attach a load to the battery, say a bulb or other item that will drain the battery, measure how long the battery takes to reach a fixed voltage, say 10.5 volts. Repeat the process and note any improvement in run time, continue until you get no more improvement. If you have a new battery you can run a side by side comparison, to get an indication capacity against the revived battery.

We often get call from people who have fitted the BE to a new set of batteries and they tell us that they cannot see any improvement in their battery capacity. Sorry but the BE will not make batteries better than new.

Should you see ERR on the voltage display, this means you have exceeded the maximum voltage for the model you are using, this will not damage the unit but it will not work.

Due to the wide range of voltages that the unit works with there is often a small voltage variation in the display, however this is a constant figure and does not alter the working or efficiency of the unit.

If you require any technical help, or have any questions regarding the use or operation of your batteries or the Battery Extra EX02 12-48-400 please contact us on 020 8743 2267 or by email at batteryextra@btconnect.com


The Battery Extra battery recondtioner really does work and we have 5 different models available, ranging from our basic unit for 12 volt batteries up to 250 Ah, to the top of the range model for batteries from 12 to 120 volt up to a massive 3,000 Ah. Check out which model is ideal for your requirements and how it can recover your batteries.



Unit M
Lammas Court
Lammas Road
NN17 5EZ
United Kingdom.

+44 20 8743 2267