[Nut17]

However, at 50% or less your average AGM would be lucky to provide 12 volts with even a modest load resulting in voltage sensitive devices such as TVs being unable to operate. Up until yesterday when I did the lithium battery swap we have been using our new rig with two 100 AH AGM batteries, 150 w solar and 20 amp DC DC charging. With our 11 days on the road, including two nights hooked up to 230v the only time the batteries reached 100 % was when we were hooked up to shore power. This is using very little electrical energy. Netspeed Router, laptop and iPad charging, two iPhone chargers, 24" Avtex TV and decoder, water pump, diesel heater (hardly used) and minimal "brain" requirement for three way fridge and Camec hot water. After living with lithium batteries for the last 8 years it was like going back to the dark ages with battery "anxiety" looming on a daily basis. The state of art BM Pro Battery management system in our rig incorporates MPPT solar regulator, DC DC charger, and mains charger along with battery monitoring , 12 v power distribution (no blade fuses - all internal auto reset fuses) and tank monitoring.
These are the batteries that were factory fitted (not el cheapo bottom end) https://www.electronicworld.co.nz/shop/ ... 100SD.html at a total cost of close to $900. A 100 AH lithium battery would provide the same daily usable capacity (above 12 volts) for around $600 http://sunnytech.co.nz/product/12v-100a ... 4-battery/ And only 12 kg compared to the two 29 kg units.!!
These are real world facts from eight years experience with LiFePO4.

[toyotahiacefan]

Hey Nut17, I had trouble following you. You said that you have been living for 8 years with Lithiums but you only changed your AGMs in your rig to Lithium yesterday?

So do you mean to say the AGMs were really hard to charge to 100% and the usable AmpH with the AGM costed you more that in Lithium?

[Neddy]

Chris, THF is aiming to create a small, cheap, simple RV. His electrical needs are quite modest, so he only needs a commensurately small, cheap, simple electrical system. Your many years of experience at the other end of the market are interesting and informative... but in this case, largely irrelevant.

This is what I would see as a really good setup for him :-
Dual Sensing VSR $138
120/150Ah AGM Battery $320
As little or as much solar power as he likes, up to 640 Watts.
(With appropriate MPPT controller, this would cost about $3/watt.)
Above 300W would be good. If he wanted to retain some roof-space for a bit of luggage, 480W would be the maximum.
Me? I'd go for the 640W. This would give a system with truly superb "low-light" performance. I bet his battery would never get anywhere near as low as 50%. Mine doesn't - ever.

[scubadoo]

I tend to agree with Neddy and say again how I see it.

For a Hiace van with presumably very little daily energy requirements KISS come to mind.
Solar whatever you choose or can fit combined with a quality MPPT solar controller. The more the better.
Battery. AGM or lithium drop in. 100-150Ah.
Assuming a standard alternator or ECU bypass. VSR between alternator, start and house batteries.
Enjoy your travels for years to come.

All modern vehicle alternators self regulate well before overload or destruction.

Option 2. Spend lots more money and complicate it all with the probable consequence of much lower charging rates.

[Nut17]

Hey Nut17, I had trouble following you. You said that you have been living for 8 years with Lithiums but you only changed your AGMs in your rig to Lithium yesterday?

So do you mean to say the AGMs were really hard to charge to 100% and the usable AmpH with the AGM costed you more that in Lithium?

The new motorhome just purchased was fitted with AGM batteries in the factory. We have had lithium in three new caravans since March 2012. We have had the new motorhome for just three weeks and needed to bring it back from Christchurch to get the lithium fitted.
Yes, on todays prices - per usable AH (over 12 volt under load) based on a minimum 5 year life span LiFePO4 is currently a cheaper option.

[toyotahiacefan]

The new motorhome just purchased was fitted with AGM batteries in the factory. We have had lithium in three new caravans since March 2012. We have had the new motorhome for just three weeks and needed to bring it back from Christchurch to get the lithium fitted.
Yes, on todays prices - per usable AH (over 12 volt under load) based on a minimum 5 year life span LiFePO4 is currently a cheaper option.

Cheers, that clarifies it!

[Paul-Carter]

There are two equal parts to this.
1/ the acquisition and storage of energy
2/ the efficient and economic use of that energy. (LED lights etc)
The first one gets most of the attention and can become a bit of a rabbit hole!
The second is just as important if not more so and should be done first as it will give you a much better handle on how far you need to go with number one and therefore the cost and it is very cheap to do.