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Connecting Lithium Batteries to increase capacity

We are seeing a few vans coming in to visit with us and noticing they have multiple lithium batteries joined in parallel. We have always avoided this and insist our customers buy the correct size system. But we often lose the sale to someone else due to them offering a “cheap” large capacity system by joining 2 cheap batteries in parallel.

This article explains very well why we dont offer a inferior way of setting up a lithium system. If you are going to spend good money on a very expensive battery system then it should be done properly.


Can I Connect the ePOWER B-TEC Lithium Battery in Series or Parallel

The two questions we have been constantly asked about the ePOWER B-TEC batteries is;

Q1: “Can I connect these in parallel to increase the overall capacity”

Q2: “Can I connect these in series to increase the overall voltage”

A1: When manufactures of lithium cells build batteries, careful consideration is taken to choose matching cells to build the battery pack. The batteries are assembled by the manufacture that is experienced and certified to test and assemble battery packs. The individual cells are tested and sorted by machine so that each ePOWER B-TEC battery pack has matching cells with the same capacity and internal resistance.

Paralleling individual lithium batteries like the ePOWER B-TEC unit is like taking out a lottery ticket. There is a million to one chance that you would end up with two lithium batteries off the shelf at your local retailer with exactly the same capacity & resistance.

When assembling lithium-ion cells into functional battery packs, it is common to connect multiple cells in parallel. When lithium ion battery packs are connected in parallel and cycled, matching of internal resistance is important in ensuring long cycle life of the battery pack. Specifically, a 20% difference in cell internal resistance between two battery packs cycled in parallel can lead to approximately 40% reduction in cycle life when compared to two batteries parallel-connected with the same internal resistance.


Internal resistance mismatch becomes an important problem for applications where the lithium battery packs are paralleled and subjected to high C rates, (i.e. large inverter loads and moderate to high charge rates) and are also required to have a long cycle life.

The detrimental effect of internal resistance mismatch between parallel-connected batteries arises because differences in internal resistance lead to uneven current distribution and capacity between the batteries, resulting in a decrease in battery pack life and performance.

The ePOWER B-TEC batteries internal management system (BMS) monitors and optimize each single prismatic cell within the battery during charge & discharge. However the BMS does not have the ability of making a physical connection to a second BMS system for balancing of the cells between each battery.

A2: In series connected batteries, charging and discharging is inherently limited to the condition of the ‘weakest’ cell. This is particularly so with lithium-iron (LiFePO4) batteries.

A weaker cell would cause an imbalance. A weak cell may not fail immediately but will get exhausted more quickly than the strong ones when under load. On charge, the low cell fills up before the strong ones because there is less to fill and it remains in “over-charge” longer than the others. On discharge, the weak cell empties first and gets hammered by the stronger cells. Cells in multi-packs must be matched, especially when used under heavy loads.

Again, the chances of finding two ePOWER B-TEC batteries off the shelf, with exactly the same individual cell capacity in each battery would be near impossible.

So bottom line;

Can I parallel connect the ePOWER B-TEC lithium batteries?

The short answer is yes. BUT as described above, overall performance of the battery pack and life expectancy will be reduced.

Can I series connect the ePOWER B-TEC lithium batteries?

The short answer is no. Early failure of the battery pack is virtually guaranteed due to the mismatch in cell capacities.

PLEASE NOTE: For absolute maximum performance and lifespan, Enerdrive do not warrant the ePOWER B-TEC product in a parallel or series connection configuration.

If you are requiring a larger battery system than the ePOWER B-TEC battery, please look at the Enerdrive Lithium Power Pack Systems which can offer the level of cell/battery balancing protection.

Waeco Reversing Camera

Can you please tell me if the Waeco cameras are PAL or NTSC video?

They are PAL/NTSC (automatic switching).

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Off-road Camper Trailer with Truma Gas Heater

Our customer desired heating in there offroad camper. They wished to only carry gas on board and so we fitted a Truma E2400 Gas Heater.





Due to the location of the exhuast and the possiblity of burnt gases coming into the camper – we fitted a safety switch, to keep it safe and complaint.








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Ultimate Campers Offroad camper – upgrade

Earlier Ultimate brand campers have a 3-way fridge fitted to them as standard.

Unfortunately it gives disappointing performance due to its location and not being a tropically rate fridge.

These are a clever little camper - with a few upgrades an older one is a great buy.

We recommend changing out the RM2350 3 way fridge with a CRX-110 12 volt compressor fridge.

This means an upgrade to the battery storage. We normally fit 2 x 110amp batteries, a decent size 240volt charger and DC/DC charging system to charge the AGM batteries whilst you are driving.

We also usually add in an Anderson connector so you can utilise your portable solar.

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Ford Transit Van conversion to motorhome

Self conversion for Van to motorhome

Customer is doing a self conversion for Van to motorhome.

We fitted 300watts of solar, Battery charger, DC/DC charging system, 2 x 110amp AGM batteries, LED interior lightCRX-110 Waeco fridge, Roof vent and 240 volt inlet and powerpoints.

Ready for the customer to finish off the build.



Risks of using a heater in a Caravan or Motorhome.

Diesel heating is considered a very safe method of heating a Caravan or Motorhome.

Below we explain why:

Carbon monoxide poisoning is your main risk of heating in a confined space. Carbon monoxide is a colorless and odorless gas. It forms when a carbon-based substance (coal, LP gas, petrol, diesel etc, hydrocarbon) burns without enough air. The(only minor)indications are: headache, nausea, fatigue, and then unconsciousness. If you sleep, you may never wake up again. Carbon monoxide is rightly called the ‘silent killer’. It also causes brain damage at minor concentrations.

When burning a combustible fuel you are starting primarily with a Hydrocarbon molecule. When you start to burn a Hydrocarbon, Carbon monoxide (CO) is formed, if it carries on burning the CO turns into Carbon Dioxide (CO2). The major way in which combustion can be stopped at that point is through a lack of available oxygen, this also causes unburnt diesel fumes and smoke. Diesels heaters are designed to over supply oxygen (lean burn) under almost all conditions. Thus the CO production is almost nil and any potential smoke is reduced. Having lots of extra air does provide lots of nitrogen and left-over oxygen.

The primary products of diesel fuel combustion are carbon dioxide, nitrogen, heat and water vapour (typically all in the normal air we breathe).

Your second risk is oxygen deprivation. We need about a half a cubic metre of air an hour, of which we convert about 4% into carbon dioxide. If you are in a confined space the exhaled carbon dioxide level rises. As a result, remaining oxygen level falls. It is normally 21%, but symptoms (such as fatigue) set in below 15%. Brain damage consequently occurs shortly after. Oxygen deprivation is serious (or lethal) in poorly ventilated areas.

We use diesel heating in caravans and motor homes specifically to avoid such issues. We draw air from underneath the RV into a tiny furnace, but sealed from the living area. Diesel oil is injected and ignited in this furnace. Air to be heated is blown across the outside of the furnace and ducted to wherever needed. The ‘burnt’ air expels to atmosphere. Burning gas is thus totally sealed from the air heated within the vehicle.

So Diesel heating is considered a very safe method of heating a Caravan or Motorhome. This also explains why there are no requirements for certification of your install. We do recommend you utilise a suitably competent person to carry out your install as we have seen some very poor installations, some even carried out by caravan and motor-home manufacturers.

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Which caravan heater is better, Diesel or Gas ?

Diesel Heater or Gas Heater for a Caravan.

Most caravan dealers will direct you to a Gas Heater as it is a slightly easier install (less time consuming) and the Truma E2400 Gas Heater is a pretty quiet heater, but this is a bit simplistic.

In Europe and the United States there are many, many models and brands of gas heater. But due to deaths in caravans from using gas heating, the regulations covering Caravan Gas Heating are very strict in Australia, so far the Truma E2400 is the only complaint model available here. To make this happen Truma removed one of the heat settings to accommodate the required Carbon MonOxide monitoring. This means the heater has only one heating output of 2400 watts, so this comes on and off (controlled by a rotary dial type thermostat), this makes for one of the 3 issues against the heater, not an issue that bothers everyone, but it needs to be noted. This issue is where the temperature difference, from when the heater shuts off thermostatically, to, when it comes back on is quite large. The specification is 4 degrees, so if you have the heater turn off at 24 degrees then it will drop to at least 20 degrees before it switches back on.

The E2400 is a good heater, but,  in other parts of the world it has either been deleted from the range or replaced with the Truma VarioHeat Eco.

The new heater from Truma (at this time we don’t know if it will be made available in Australia) overcomes the 3 issues using a E2400 Gas Heater. 2nd issue is the Thermostat control knob – this is a rotary type of control knob, numbered 0-5, all other types of heater use a Digital control knob and with all diesel heaters having at least 3 flame/fan speeds – you get much better room temperature control, set to an actual temperature. The 3rd issue will, again, not effect most people, we don’t recommend the heater for serious off-road usage, we have found the fan motor mounts to be weak and allow the fan to break from its mounts in hard off road usage, it appears this has been recognized by Truma and the fan motor on the new (but unavailable here) model has different fan mounting.

So beside it being a very old design, it is a great heater for those using there van onroad. Extremely quiet, reliable and maintenance free.

Diesel heaters are generally much more robust and slightly cheaper to run (this is debatable, but in theory is correct). They do make slightly more noise, from the air intake and exhaust (outside, underneath the van) when initially heating the van. When the van has warmed up the noise abates and the sound inside the van is no louder than a Gas Heater. The noise inside the van is quieter than a 240volt electric fan heater and is certainly quieter than a reverse cycle air-conditioner. The in van temperature is much more stable, with diesel air heaters having much finer temperature control than the Truma Gas heater.

I believe the way to make your decision on which type of heater is for you is quite simple. If you have a on road van, buy a Gas Heater. If you have an off-road van and carry spare diesel already, then purchase a Diesel Heater. For a motorhome use a diesel heater for 2 reasons, 1) you can tap into your existing fuel tank and 2) a gas heater is very difficult to find a legal location to mount.

The Truma is a well supported brand for Gas Heating and our recommendation for Diesel Heating is either the Eberspacher or Warmda brand heaters.

For a comparison of different diesel air heaters, click here,






Heron 2.2 Aircon not working properly

We purchased our 2007 Windsor Rapid Caravan 12 months ago and have never been able to get good performance from our airconditioner.
It’s a Heron 2.2. It seems to blow cold air but it doesn’t cool the van down at all. The previous owner said he never used to use it as it was poor.
We are going around Australia Jan 2018 and would like to have it sorted by then. What options do you have for me?


Personally we are not fans of the heron range of air-cons (mainly due to the direction they blow the air) – but they are generally pretty reliable/robust – as it is a split system it can lose gas over time (non split systems have to have a proper breakage to lose gas and they lose all the gas).

We expect about a 15degree variation in air temp entering the unit and the air coming out (all inside the van, at the air handler).

So it is most likely possible to improve the performance of your air-con. But we would need to do some testing to figure out if this is a repairable unit or not.
It is not just a simple top up the gas and hope for the best. We need to pressure test the system and determine the point of leakage, repair/tighten that, vacuum out system and then regas with a full charge of refrigerant.This is by far the best value option.

We can of course throw a rooftop aircon into the van – but we need to check your gas struts etc and you will need to be ready to spend a few thousand dollars for the best unit.

I suggest you give us a call and book the van in for us to check the aircon and advise you further.


Old 3-way fridge not working properly


I am planning a trip to QLD this summer in our old caravan. So starting preparation now.
We have an Electrolux rm36e fridge. I think it is the original that came with the 1976 model Millard van.
Freezer works well but Honestly fridge part does not cool the best on 240v which is probably not helped by what seems a poor installation effort. I understand that they run better on gas but I’m not game to run such an old appliance on gas without it being checked as safe.
Do you do safety checks on this model fridge?
What sort of cost for doing so?
How many fridges of this age do you see that are actually safe to operate on gas?
As another dumb question, is it possible to modify this fridge to work on 12v? I’ve read a lot of these old 2 way fridges can have a 12v element installed and set up to operate only when being towed with vehicle ignition on.
I’d just replace it but new fridges are really not cheap and I’d rather make do with what I have if I can.
Thanks for your help.
the fridge will work equally well on 240 or gas (we do our testing on 240volts as the gas side may need servicing).

The fact you are getting cold in the freezer and not in the fridge is caused by not enough liquid ammonia being produced for the refrigeration effect. The freezer gets the refrigerant first and then what is left over goes to the fridge section.

The common causes of this type of failure are:

1) fridge is not level

2) not sufficient ventilation (we are in winter at the moment so this wont be a cause of your problem)

3) the cooling unit is failing

So the fridge must be tested on 240volt, firstly you need to level the fridge – this means placing a spirit level in the on the freezer floor and leveling it perfectly in both directions – you need to do this very accurately – run the fridge overnight – turn the thermostat to maximum and we are expecting a minus temperature in the fridge.

We can check the fridge and carry out a safety check/service the gas side.
Fridges of this age generally are perfectly safe to run on gas.

Yes it is possible to add a 12volt element to the fridge. The fridge will also need a 12 volt feed from your vehicle (these fridges are not designed to run off a battery but to run off the vehicle engine).

You can drop the fridge only to us anytime or if you wish to bring the van in you will need to make an appointment. It would be good if you can do some testing first to see if the actual cooling unit is working well or not.
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200w Solar Panel Install on Motorhome

looking to maximise the amount of solar fitted to a relatively small motorhome – we opted to place the largest panel we could fit – a 200w solarking monocrystalline panel to this motorhome