#170281  by NormJ
 Thu Feb 11, 2021 12:58 am
Hi again Miriam

I spent a year researching before starting construction on our campervan. (Joined lots of forums, watched a massive number of videos of what others had done, and how they had done it.) We are semi-retired, with an on-line business operating from home, so maybe have a bit more time available than many people.

After deciding to go with an induction cooktop, and a domestic coffee machine, there was no option but to have a large battery to supply the power. Then I decided to think about having have an electric oven too, and no LPG requirement. Not wanting to be limited to running one appliance at a time necessitated having a large output inverter, which in turn meant the battery could not be 12V because of the high current requirement to the inverter, and the huge cable size that would be required.

Anyone considering going down this path must do an Energy Audit.
Think of all the electrical appliances/devices etc that you want/need to have (230V, 12V, 5V USB etc).
Calculate all their wattage requirements (use Watts = Volts x Amps).
And how long they will be on for each day in hours. This will give Watt hours (Wh).
An example: https://diysolarforum.com/resources/sys ... -sheet.12/

This looks daunting, and possibly more detail than many will think necessary...
But so many motorhomes and vans have too small a battery bank, too little solar capacity to charge the battery, too thin cabling so get large voltage drops, etc. From the Energy Audit, you will then be able to determine your required battery capacity and thus Ah needed, and solar requirements to charge it.

It became obvious early on that a lithium iron phosphate (LiFePO4) battery was really the only option. Any of the lead battery chemistries was going to be way too heavy. Purchasing LiFePO4 in NZ requires silly money. So I researched, and finally imported from China 16 x 200Ah cells at nominal 3.2V. These were connected in parallel pairs to give 400Ah 'double' cells, then 8 of these connected in series to give a 25.6V 400Ah battery. So about 10,000 Wh. All cells are connected with heavy duty copper bars. The battery has a mass ('weight') of 100kg. To get the same usable power capacity in lead would have been many hundreds of kg. As we were starting a system from scratch it was an easy choice to make. Long term, LiFePO4 will work out significantly cheaper than any lead system too. The Battery Management System (BMS) to keep the cell voltages equalised, to protect from overcharging and overdischarging, and low temperature charge disconnect is an Electrodacus SBMS0, imported from Canada. This is a vey smart piece of kit. It also keeps track of battery capacity via a shunt.

The inverter/charger we have is the Victron Multiplus 24V / output 5000VA / charging 120A. Effectively about 4000W output. Yes, big, expensive, but amply provides for all of our substantial power requirements.

To charge the battery, we have 720W of solar panels (4 x 180W Perc connected in series) through a Victron MPPT 150/35 charge controller. We also have (but still to connect) a Buck-Boost DC-DC converter, which will take up to 100A at nominal 12V from the alternator and output up to 50A at 24V to the battery (so up to 1000W per hour). We can also plug into shore mains power if necessary.

A bit lengthy, but hope it helps.
 #171797  by kevpluck
 Mon Apr 05, 2021 11:22 pm
Just want to add my 2 cents:

I used a plug in induction hob at a BnB once which was brilliant! However the area that created heat in the pan was limited to a well defined ring. I can't recall if the pan was particularly heavy bottomed so not sure if a decent pan may resolve this. I did notice later that the same model was sold at The Warehouse.

Was impressed enough to know that I will indeed kit my van out with one when the time comes but wary enough to make sure the model I get included a larger induction area.
 #171801  by Nut17
 Tue Apr 06, 2021 3:18 am
Our new Winnebago ILUKA was able to be fitted during the build with a Thetford Topline Hybrid Hob https://www.mygenerator.com.au/thetford ... d-hob.html allowing the use of gas when poor solar generation encourages budgeting of available electrical energy. As my battery / solar system is an upgrade to a factory installed set up, running with a 12 volt configuration was the only practical option. In my case, I opted for the largest solar array that would fit (6 x 200 watt Perc panels wired in two banks to two separate 40 Amp MPPT controllers.) My 400 AH LiFePO4 battery comprises 8 x 200 AH 3.2 volt cells with HA02 cell balancers and a Votronic shunt based monitor being the only basic BMS used. In addition to the solar, I have two alternator based charging systems producing a steady 76 Amp charge.
On our recent three month shake down excursion to the South Island I was pleasantly surprised that we were able use the induction hob and microwave without limits, run the large 3 way fridge during daylight hours on 230 v, make regular cups of coffee using our Delonghi Magnifica S coffee machine and heat the water in our 20 lt Swift gas / 230 volt hot water service using the 1000 watt 230 volt element most days. At no time did we need to hook up to 230 volts. The 400 AH battery was not taken below 50% (200 Ah remaining) at any stage.
The battery / solar did not break the bank with the battery cells sourced from a local importer at $300 each X 8 = $2400, and the solar panels were $195 each $1170. Switch gear, solar controllers, mounting brackets, DC DC charger, cabling and other consumables added up to just under $2000 - so about $5500 all up.
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