For those interested in a DIY lithium setup, here are some of the bits I used in my van:

Winston Thundersky 200AH cells x4. Total weight is around 32kg. Sourced from Drive by Nature on Nth Qld. About $1500 freighted to Bris. (12 months ago).  Trevor is very helpful but stock was erratic.

Battery management system is from EV Power in WA.  4 cell balance modules plus the BMS unit - about $300.

That made my 'battery' with the basic safeguards against under/over voltage and cell imbalance. Plus a big battery fuse.

On top of that I added a Victron BMV700 monitor ($200-odd) which has a programmable relay.  I set this to open at 10% SoC and this controls a 100A solid state relay ($50 from Jaycar) which feeds the whole van. So if the battery falls below 10% charge all power is cut.  

Charging from mains is via a Victron Multiplus 1600/12/70 inverter charger.  It is programmable via dipswitches to suit LFP batteries. It is rated at 70A but I left it at the default setting of 50A.  It cost about $1450 but is also a 1600W inverter.

Solar charging is via a Victron MPPT75/50 regulator. ($350-odd) Rated at 50A because I have 630W of panels on the roof (but I've never seen more than 350-odd watts - that's another story!). No danger of overload. Again there's a switch to set the correct charging voltages for LFP.

i also have a Ctek D250S Dual DC-DC charger ($250-odd) for charging from the tug, and for a portable solar panel. I use a couple of red Anderson sockets mounted front and rear for convenience.  The Ctek charging voltages are perfect for LFP.  

Finally, Victron make a neat Bluetooth dongle so you can check things from an iPhone App. I put one on the BMV700 to monitor the battery charge state and one on the solar regulator to monitor solar panel output.  A bit of overkill but I check the state of the power system from anywhere within 20 metres of the van - eg from under a shady tree.  Or from the car while driving.  

It all added up to a scary figure, but it has worked well so far.  (BTW the driving factor was our compressor fridge.  With no gas backup, a good DC power system is important to us for free camping. If we run out of power the fridge stops).  Using AGMs would have been a bit cheaper, but added more than 70kg.  

Phil

Thanks Phil on your DIY lithium setup, very informative.

Re your 630 watts of sola, the problem that I have is real estate on the roof of a 21'6" van what with 2x 80w sola panels, roof a/c, Wingard TV aerial and various roof vents along with sloping roof at the front to reduce wind resistance( around 1m), and I would like to fit a Sat dish and keep the wingard for local TV.

In Hindsight would you still go with the 4th Lithium battery.

Peter

Hi Peter

Yes roof real estate is a challenge.  Getting the right physical size of panel took a bit of searching.  I have 5 100W flexible panels that occupy all the bigger spaces between vents & A/C and two 65W flexible panels on the sloping front part.  One of them is curved over the transition between the sloping and flat roof.  I'd like to put another one on a spare bit of sloping roof - but am unable to find another similar one.  

I learned a lot along the way - the 5 100W panels are plastic backed and suffer badly from heat.  The 65W ones are aluminium backed and suffer much less.  I bonded the panels directly to the rook with Sikaflex - not a great idea when it comes to replacing them.  I had two panels fail (cheap Chinese Evilbay stuff) and ended up pulling 4 of them off and reinstalling two working ones with a 20mm air gap and bought 2 news ones (different type) and installed them with an air gap too.  I really wanted aluminium backed panels but they were physically larger and wouldn't fit the roof space I had.  I found some that looked promising but the working voltage was higher 23V instead of the 17V of the rest of mine.  So no go.

They seem to perform better now - often saw 320W last weekend.  Previously I was only seeing 180W. Even with overcast skies  last weekend I was getting 100W or more.  The MPPT regulator told me I collected 1420 watt-hours on a less cloudy day.  Pretty happy with that.

Another downside of direct bonding is the van ceiling gets quite warm under the panels. The air gap should reduce than.

Why flexible panels? Weight!  The original 500W system weighed about 11kg including Sikaflex.  500W of conventional panels would have weighed four times that.  

Cheers

Phil

some more info for those looking at Lithium.

from before you can see I now have 1.6kw of solar via 8x200watt panels.  Bought. Them for $400 second hand from someone I know. Had them professionally fitted and wired, they seem to be working fine.  Next step in the chain, the solar regulators.  Well I stuffed up here.  I have a PL20 which I reused for two of the 2x200 watt panels.  Saw 17amps a couple of days ago so they seem to be working.  Bought a GSL MPPT 60-2 second hand off eBay $350 and hooked up the other 6 panels via that.  The gsl is a very basic unit, got two charge settings, switchable by internal jumper so not really simple to change.  This second hand model is very very noisy.  but the big issue is that the two solar regs are not playing nice together.  I was warned by someone on the forum about this so completely my fault. 

Anyway next is the lithium Battery.  Currently have 3x105ah la bank and am swapping them for a 300 or 400ah LiFePo battery. I'm buying this for time reasons. I can get more charge in for a given time and I can get more power at 12v out in a given time. So not expecting more that 12 volts, not expecting more anything except time.

As proven above with the regulators I know enough to be dangerous so with the batteries I am going to get some help in choosing the correct setup. I'm going to get the battery in the next couple of months when we return from this trip.  I'm expecting around $2000 for the batteries, bms, etc.

I'll keep you updated with price and cost so people can see a real life example for reference.

mick

Hi Mick, I think Margaret has been in touch with you or replied to a contact you made.... never quite sure which way the office bit goes these days so I just get asked the questions and Margaret forms it into words that others might understand

All is not lost, with a bit of luck you can resell the GSL door stop and we can use the PL20 to control all the solar.... but that's secret squirrel stuff as one member of the private forum put it :lol: Let's just say the system is open ended as far as solar input, not limited to the 20 amps the PL20 can handle and we can combine the other gear you have into the lithium charge control system so you don't need to buy more gear, just the interface and control system that is all part of the battery protection system.

looking forward to a close up look regarding the wiring of that newly fitted solar, hopefully professionally installed means done in the correct manner with the correct sized cabling and not just professional as in charged money for the job which is the real meaning between amateur and professional

T1 Terry 

Thanks Terry. Yes I'm the annoying bugger on the emails. Looking forward to meeting you and Margaret for a nice glass of something or other.  We are doing a 10 month trip starting with April and May in SA so we will be seeing you  then hopefully.  

We work part time on our business from the RV and I'm in full agreement, our fairer halfs are much better with those word things!!

I was surprised at how heavy the cable was that he used.  Multi strand with a diameter of say 7mm.

and finally anyone want to buy a doorstop...I mean Solar controller!!! ;)

mick