Camper Trailers Tech Tips

LiFeTech lithium iron phosphate battery install




LiFeTech lithium iron phosphate battery
imberley kamper install

Ben Lace with the 12volt 180Ah lithium iron phosphate battery

The aim of this article is to explain the steps taken in installing a LiFeTech lithium battery in a Kimberley Kamper camper trailer to replace the original manufacturer supplied lead acid batteries. Ben Lace, the owner of a Kimberley Kamper decided after much research to contact Lithium Batteries Australia with a view to upgrade the battery system in his camper to lithium. I personally provided assistance with the installation of the battery at Ben’s home as well as the training of the battery diagnostics system.

So one warm summer Sunday recently I spent the day with Ben installing his battery, charger and battery monitor. We hope this step by step article will be helpful to those camper trailer owners who are contemplating upgrading their battery to lithium so as to have a much more efficient and lighter weight battery system and which provides far superior performance compared to any lead acid battery.

modifying the battery tray

The factory supplied batteries were six 35Ah Exide sealed lead acid batteries. These fit end to end in the metal carrier which is located under the bed. It was found that the most suitable lithium replacement battery was a single 12V 180Ah lithium iron phosphate (LiFePO4) battery from the LiFeTech Energy HPS series. This battery was found to be the perfect height and allowed approximately 20mm of air gap between the top of the battery and the bottom of the bed. Ben was able to make a slight modification to the tray to hold the lithium battery by welding a narrow frame to prevent the new lithium battery from sliding. It was found that the lithium battery length was only half of the length of the battery tray and a second battery could be fitted in the remaining tray length available. Ben remarked that in future he could further modify the battery tray so as to fit a second, identical lithium battery should he decide to add air conditioning to his camper at a later date.


installation of battery, charger, battery monitor and battery/computer data box

Due to inaccessibility of the batteries under the bed the LiFeTech batteries are the best “drop in replacement” for the old lead acid batteries since they feature inbuilt battery management system (BMS) and a low voltage cut off protection board. In addition to the power connections for 12V at the battery terminals, a data type connector plugs in to the DB9 data port fitted to the front of the battery between the positive and negative battery terminal posts. This data cable was run under the bed and down along the side of the camper to the entrance of the van. Close to the entrance door of the camper was decided by Ben to be a convenient location for plugging in his lap top computer via the supplied battery data converter box and software for detail checking of his battery without having to go to the trouble of removing his bed again to gain access to the battery in the far front corner.

With the bed entirely removed it was simply a matter of refitting the modified battery tray and fitting the new lithium battery and wiring. The original lead acid batteries are all connected to each other with six pairs of battery connection terminals this was no longer needed since connection was now only required to be made to a single battery. Therefore only one pair of lugs was crimped to the main power cable leading from the battery to the load/output supply power wiring providing power to the LED lights, fridge and other electrical appliances being supplied by battery power. An additional heavier gauge cable was also connected to the battery cables and run a few metres to the location near the door where the data connector was located. An Anderson connector was fitted to this cable to allow the high power lithium battery charger to be plugged into this point. All the cables were neatly cable tied in position.

The charger supplied was the most powerful charger which could be connected to Ben’s small Honda generator without overloading it and would allow the battery to be recharged in about two hours. This charger would not need to be used often since the battery would be mainly charged while driving from the car alternator and kept topped up from solar panels.


checking the finished installation

After the battery was installed and all of the wiring completed and tidied up it was time to perform a few checks. The charger was connected to top up the battery. This did not take long since when the lithium batteries are delivered they are almost fully charged. A factory quality control battery test report is supplied with every LiFeTech lithium battery so it is easy to see the actual capacity and performance of each individual battery.

After the battery was fully charged the battery/computer interface was tested. One end of the data box connects to the cable which was run under the bed to the data port on the battery. The other side of the battery data box has two cables with USB connectors. These two connectors are plugged in to spare USB data ports on the computer and provide power for the data box and battery data to the computer.

After loading the battery diagnostics software on to Ben’s computer from the supplied CD the battery information can then be read. The battery information available shows-
1) the voltage of each parallel cell group inside the battery (1/1000th of a volt per cell).
2) the minimum and maximum internal recorded battery cell temperatures
3) the ability to set upper and lower voltage alarm set points for OHV (over high volts) and OLV (over low volts). This function is for advanced users and allows the battery to provide output signals which are used in more specialised applications (for example using the low voltage alarm point signal being used to disconnect a main power relay or contactor automatically so as to prevent over discharge to the battery or using this signal to start a generator automatically for charging as is often used when these batteries are used in large boats).

The great advantage of this remote system of battery monitoring is that it shows you what is actually going on inside of the battery and that it avoids having to crawl under a bed or other difficult to access location to reach the battery terminals with a multimeter, therefore you can comfortably check your battery while being seated or even from outside of the van.


how the system works

The battery can be charged using the same methods as you would use to charge a traditional lead acid/AGM battery ie, alternator (while driving), mains 240V charger and solar panels. In each case a dedicated lithium charger should be used so as to charge the battery properly and so not void the manufacturer’s battery warranty which can result from using a non specific or lead acid charger which may feature modes of charging such as “desulphation”. These “pulsing” modes are not required for a lithium battery and must not be used. Some existing solar regulator chargers can be reprogrammed to suit the charging requirements of a lithium battery so often there is no need to purchase a new lithium solar battery charger/regulator since the existing charger may be able to be used with some slight programming changes.

Due to vastly superior discharge curve of the lithium battery compared with lead acid batteries it is almost essential to fit a suitable battery monitor. This allows the camper owner to always know the state of charge of his batteries. In addition the output relay alarm contact available at the battery monitor can be set to provide an alarm at any convenient level of discharge. In most battery installations this is usually set at between 60% and 90% depth of discharge. When the battery reaches this alarm point either a flashing warning light or audible buzzer can be triggered drawing attention of the van owner to recharge his battery.  At this low battery capacity level, a low voltage battery disconnect can also be incorporated to automatically turn the battery off so it can not be discharged any further until action is taken to recharge it.

The LiFeTech XPS and HPS series of factory lithium batteries are unique in that they are the only lithium battery available which can have a low voltage cut off disconnect board fitted inside the battery and which is used in conjunction with the BMS. The cut off board is an optional extra which is not fitted to the standard batteries and which must be specified when ordering these batteries. This cut off board automatically disconnects the 12V power from the positive battery terminal in the event of the battery being discharged 100%. In a battery where the disconnect has activated there will be no output voltage at the battery terminals and by checking the voltage with a multimeter would show a reading of close to zero volts being measured at the battery terminals. This low voltage cut off is self resetting.

So with most lithium battery installations in campervans, caravans, motor homes and other RV’s it is usually recommended to use both a battery monitor or external low voltage battery disconnect as well as the internal battery low voltage cut off board. This provides two levels of protection and we like to think of this a bit like having a “main parachute” and a “reserve chute”. The main parachute (or battery monitor) is used routinely everyday to display the battery state of charge, run time remaining, volts, amps, watts and other information. If this device should fail (highly unlikely) the secondary available level of battery protection (used preferably never or rarely as in the case with a reserve parachute) is the battery cut off board built into the battery. This acts as a last line of protection ensuring the battery does not become discharged below 100% state of charge and thus potentially causing serious damage to battery cells.

While there are several suitable battery monitors available that can be used, in Ben’s Kimberley Kamper installation we used a Victron BMV-600S battery monitor. There is a user review of this device here

why would you install a lithium battery?

Ben and many other owners of camper trailers and caravans take great pride in their units and want to have the best systems available and this includes batteries. Some of the reasons given by owners for upgrading to lithium batteries include the following-

Much lighter weight The six lead acid batteries originally fitted to Ben’s Kimberly weigh approx. 70kg in total. The replacement LiFeTech lithium battery weighs 30kg. Not only does the lithium battery weigh less than half the original battery weight it also takes up close to half of the space occupied by the old lead acid batteries. Lithium battery weight is typically half to one third of an equivalent run time/capacity lead acid battery bank. This is often of major importance to many owners and has been of particular concern expressed to me by several camper trailer owners where the batteries are installed in the front of a camper or caravan. These owners often provide a major reason for looking at using lithium batteries to “reduce the weight over the tow ball”. The reduction of weight can also have a long term saving in less wear and tear of mechanical components such as wheel bearings etc and there may also be long term cost savings in other areas such as with better driving manoeuvring and slight petrol savings from towing a lighter weight camper.

Much higher electrical efficiency LiFePO4 lithium batteries have a much higher electrical efficiency compared with lead acid batteries. While lead acid batteries are typically 70% - 85% charge efficient LiFeTech lithium batteries are approx 98% charge efficient.

So what does this higher efficiency mean in real terms? It means that the lithium battery will charge better/faster than a lead acid battery and this can be particularly important where only limited charging methods are available such as from solar panels. We often receive feedback and comments from camper owners who have upgraded to more efficient lithium batteries and one recent comment received (which is quite typical of feedback received) is- “previously my old lead acid batteries would be fully charged from my solar panels by 4pm-5pm in the afternoon but now with the new more efficient electrical set up using the same solar panels, our lithium batteries are now fully charged by 10am-11am”.

Since the efficiency of the lithium batteries is close to 100%, virtually all of the power generated by the solar panels is stored in the lithium batteries for later use. The same cannot be said for lead acid batteries due to gassing/recombination, side reactions and other factors due to the very old technology of lead acid batteries and which don’t affect lithium batteries.

Much longer working/cycle life While the initial cost of good quality lithium batteries such as LiFeTech batteries is far more expensive to purchase and set up initially, the actual cost of ownership is considerably cheaper than lead acid batteries (calculated in terms of dollars per charge cycle).

In addition is the flat lithium battery discharge curve (the lithium battery voltage essentially does not drop under load until the battery is almost depleted) which allows for electrical equipment such as inverters to run more efficiently since they are seeing a constant voltage delivered to them (unlike with a lead acid battery where the voltage will drop and continue to drop from the moment it is connected to the output load devices so the connected electrical device must always try to compensate for this continually dropping voltage until it shuts down at its minimum operating voltage).

This means that electronic equipment being powered by lithium batteries will usually have a longer working life before failure than the same device connected to lead acid batteries (known as MTBF- mean time between failure).

One other important factor is that LiFePO4 batteries are not affected by Peukert’s Law (so in the case of Ben’s new lithium battery having a capacity of 180Ah while the total of the old lead acid batteries being 6x35Ah = 210Ah the slightly smaller capacity of the new lithium battery in actual use provides at least equal or better run time compared with the old lead batteries).

Faster recharge Lithium batteries can be recharged much faster than lead acid batteries. In fact the X2EF cell used in the battery pack fitted to Ben’s Kimberley Kamper van has the ability to be fast charged to greater than 90% capacity in 15 minutes. In reality a fast charger is chosen to provide charging times of 1-2 hours or the charger is selected so as to not overload a typical Honda or similar small camping generator

Other considerations Due to the higher electrical efficiency of lithium batteries they should never gas in normal use. They can be mounted in any orientation and can be fitted in a totally water proof battery box since no venting of batteries is needed. This makes it possible to drive through deep river crossings where the batteries can be totally submerged due to the cable entries from the battery box being made through waterproof cable glands.

LiFePO4 batteries are also the safest battery to use and the most eco-friendly battery since even if a battery should be damaged there is no corrosive sulphuric acid contained in the battery which can leak out nor does the lithium battery contain any toxic heavy metals such as lead or cadmium.

So as Ben and many others have found, the best batteries money can buy are available for private use by owners of camper trailers, caravans and other RV’s and are not only available for use by government.

For more information regarding any aspects of a lithium battery set up in a camper trailer please do not hesitate in either emailing or giving Armin a call at any time for personal advice

Armin Pauza
General Manager & Principal Electrical Engineer
Lithium Batteries Australia & Aide Solar Australia
phone 0420 948 757



march 2012