Power Management

House Battery

Aug2013: The A'van Applause 500 motorhome is currently fitted with a single 12 V 100 Ah LiYFePO4 battery (see 12V electrics for more detail). Battery voltage, current drain or charge, and state of charge are monitored by a multi-function panel meter.

Elektroblock EBL 269-2

The 12 volt power in the Applause is distributed and controlled by a Schaudt EBL 269-2 "Elektroblock" management system. The Elektroblock charges the battery and supplies 12 V appliances with power. It consists of:

• The 18 A LAS 1218 charger module
• The 12 V distribution
• Fuses for the 12 V circuits
• Other control and monitoring functions.

A full description of the EBL 269 is provided by Schaudt, and some detail, including circuit diagram, is repeated here for the Applause.

The Schaudt philosophy appears to be to separately fuse each major electrical item. However, as received, A'van had wired the side step into the water supply circuit, controlled from the Switch Panel, and the aftermarket solar cells and controller were wired independently of the Elektroblock.

Control Panel

The control and switch panel is a Schaudt LT400.

Characteristics:

• Eight-step voltage indication of house and starter batteries
• Optical battery alarm in case of a great drop in voltage of house battery
• Four-step indication of water tank fill levels for fresh and grey water tanks (red, yellow and green LEDs)
• 12 V main switch with indicator
• 230 V mains-on indicator

Solar Power

(For details see the Solar page.) The Applause came with two 80 Watt solar panels fitted to the roof (see photo of the roof) and are presently managed by a MorningStar ProStar PV Charge Controller model PS-15M.

A third, 85 Watt, foldout panel has been added to increase the solar charging for longer bush camping. See how here. According to MorningStar, the ProStar is able to handle this extra panel.

Mains Power

A permanently attached heavy duty 15 Amp mains cable 15 m long is accessed via a hatch near the rear on the driver's side. It connects through two Load Balance/Earth Leakage detectors to two power points under the bed (one for the Elektroblock and the other to other power points in the Applause.

Mains powered equipment include:

• Truma Hot Water Service, which can use LPG and/or 230 Volt
• Dometic Roof Air Conditioner
• Sharp Microwave Oven (850 W)

The original Digitor LCD TV and the Philips HTS3105 6 speaker DVD/CD/Radio home theatre system have been replaced with 12 V DC equipment.

Sizing the Electrical System for the Applause

Given some experience in bush camping with the Applause, and all the changes I have made, what can be concluded about the adequacy of the present electrical system?

1. Estimate the expected load/usage. The compressor fridge is the dominant load, and I have done all I can about that. Other uses such as TV and lights and such add up but are not large. To help me test my estimates and relate them to experience, I used Richard's Solar Spreadsheet. The State of Charge Meter shows a total night (ie, no sunlight) consumption of approximately 35 Ahr.

OVER A 24 hr DAY	Total Ah	Night Ah
Fridge	49	20
Lights	4	4
Radio,TV	8	7.7
Pumps, …	2	1.2
Microwave (4 min)	9	9
TOTAL	72	42

2. Sizing the Battery. I need a battery that can supply the whole load for at least 24 hours in case there is no useful sunshine for a day or so. I had a 120 Ah AGM battery and for this the maximum Depth of Discharge generally should be about 30% for long battery life, but a DoD of 50% may be acceptable. Since it is very unlikey to be able to fully charge the AGM each day except if on mains power, its maximum SOC is likely to be around 85% so usable Ah would have been around 35% of 120 Ah or 42 Ah. We were using around 63 Ah (pre microwave usage on battery), so the battery would be flat in less than a day with no charge.

With the present 100 Ah LiFeYPO4 battery it is common to work with a DoD of 80% and since the terminal voltage under charge rises little, its easier to achieve a near-fully charged state under solar. Say 95% SOC. That is an available 75 Ah — almost twice that available from the larger AGM battery. The Li battery is able to cope with the 72 Ah usage (or 63 Ah if no microwave usage) comfortably in the unusual circumstances of no solar charge for a day.

3. Sizing the Solar Panels. It would be best if the solar panels could replace the night discharge from the battery and supply all the daytime load. Solar supply would need to be > 72 Ah over 24 hours. Assume Peak Sun Hours available is 4 (kWh/m²) for our locality, on average. This is everywhere north of Perth or Sydney in the Winter, everywhere in Australia in Summer. Then 72/4 =18 A. From my experience, an 80 Wpeak panel can give out up to 4.5 A to the Battery, so three 80 W panels could produce 54 Ah, which is not enough. In winter in Melbourne, Peak Sun Hours is about 3. For solar panels to fully supply the load we would need six 80 W panels.

These sums assume we must replace each day all energy consumed. An alternative is to allow a draw down of the battery. After all, a Lithium battery is quite happy to be at partial charge for extended periods, unlike an AGM battery. We typically consume 72 Ah and can usually generate 54 Ah by solar input. So we need to draw 16 Ah from the battery – say 18 Ah. A 100 Ah Lithium battery gives an available 75 Ah, and this would be consumed in 4 days. So we could camp for 4 days before resorting to a generator or driving around.

4. Battery Charger. For an Li battery this should be sized to supply ~C5 of capacity. So, for 100 Ah Battery, it should be capable of supplying ~20 A maximum current.

The Elektroblock 18 Amp charger is a good size.

Generator

Winter camping can require an additional charge source. Sometimes we carry a small (750 W) 4-stroke 240V/50Hz inverter generator, an IN800i (download USA manual: 10.4 MB) imported directly from China, just in case the weather is poor.

When using the generator it is convenient to set the Inverter switch to centre-off position so only the rear power points (which includes the battery charger) are active. It is important to turn off the mains switch for the hot water service, otherwise the generator will be overloaded.

LINKS

• A'van http://www.avan.com.au
• Schaudt Systems http://www.schaudt-gmbh.de

Electrics

The Schaudt electrics manager. An 18 Amp battery charger is built in.

Control and Switch Panel for Applause 500

Prostar Solar Power Controller for Applause. Battery temperature sense wire, power point wired to Controller, insulated Water Heater.