Power advice please...

[Disco Nic]

I have the NL25 Battery Box in my bakkie, costs me about 9000 (Namibia Tax) and it works flawlessly.

In the back of my trailer I have the DC/DC AND 240V system from Echo and the cheapest Chinese PWM solar controller I could find. Again, works flawlessly.

[iandvl]

I decided not to fire up the laptop over the weekend, and I've got a new phone so I've not sorted out my 4x4ag credentials on it yet, so I gave Manny a call.

As per original listing of the madman...

WRND - I've heard some not so positive things about them.
CTek - presumably great kit (apparently), but I cannot justify the price.

I am a firm believer in Victron. I'm also a firm believer of fault tolerance. So in my mind, I'd prefer not to have a DC-DC charge controller with built in MPPT. If it decides to pull a "Monica Lewinsky" (ie: go down) on a trip, your options become rather limited. ie: If your charge controller and MPPT is the same unit, it may mean you have no further options whereas if you have separate DC-DC charger and MPPT, you've still got possible options for coping...

As such, I roll with a Victron Orion DC-DC charger and a Victron MPPT controller. Despite having to buy "two units" (ie: DC-DC charger and MPPT controller) it is still cheaper than a CTek unit. And they support most battery types.

The DC-DC controller is blue-tooth compatible and you use an app to configure the controller. The MPPT controller is not. Some newer ones may be - not really sure.

Edit1: Although I used one for many years, I'm really not a fan of the NL battery boxes anymore. The remote monitor never gives a proper reading unless you wiggle the cable. They take up too much space. I disposed of my NL box and build my own battery box using one of the "voetspore" battery boxes when I decided to go the DC-DC charger route.

Edit2: One of these. This is the only photo I have of it currently and here it was still work in progress.

[Bugjuic]

Oh I love this topic. Come have a beer and we can chat hours.

Ok my take on it.

Firstly if space is not an issue or weight, the there is technically nothing wrong with good old AGM/Lead-acid deep cycle batteries, what I like about them is obviously they are cheap, but most importantly they are not fussy items, you can crank your vehicle if your battery fails, you can weld(bush weld) with them, they don't need to think about anything, they just work! And with everyone going to Lithium now, I picked up a DC-DC charger C-tek D250s for, R1000 second-hand. No worries about BMS, overloading, cutout voltages, regulators, smart chargers etc... BUT then make due to the fact you can only use 50% of its capacity and is heavy as hell. BTW, the C-tek chargers are excellent, no hassle system. No bluetooth, checking your phone every 5min etc... just reliable and working.

On the other hand and secondly is the new trend of lithium batteries. Here I would go the route of 16mm^2 cables to the back with a Victron Smart 12v DC-DC 18A or 30A dual battery charger with a separate MPPT charge controller to suite your panels. Now what is nice, is less than half of the weight, and almost double the capacity of AGM batteries. bear in mind though, lithium is not always that stable and has a BMS and needs to be set correctly with setup time. So in my honest opinion, I would only put in a "small" 60Ah battery with a DC DC 18Ah charger and you have the same capacity as the "old" AGM batteries. Or go overkill and buy a 100Ah one.

Now thirdly, and probably my next route would be to go with an eco-flow as Andreas mentioned. It believe their built-in safety modules are reliable and tested, and then you add and alternator charger, (there are many options), but here is an example: https://za.ecoflow.com/products/800w-alternator-charger, thus you have AC/DC output and alternator charging or solar charging in a neat removable package, that you can use versatile wherever you want to.

So the long and short of it. You have the space in the trailer, "second-hand" Lead acid chargers are dirty and cheap, real bush batteries. But a decent lithium setup will take you much further on cloudy days etc...

[iandvl]

The joy about the Victron DC-DC chargers is they work on a variety of batteries - including Lithium.

I've never been a fan of deep-cycle batteries. My aux battery is a "crank battery" as all my other batteries have been for several reasons...

1: I'm a luddite.
2: Back when I flew RC planes, Lithium batteries were "the bomb". Literally...
3: I'm a cheap-skate. Cost. I can buy at least two crank batteries for the cost of one deep cycle.
4: Multiply that point 3 by even more when looking at schmancier batteries.

That said, my setup works for me. When not driving far on a day, my panel is out or I am plugged in - in cases where I may have power.

My last aux battery lasted 6 years before I had to replace it. Which is super good considering the fact that aux batteries tend to get abused a little.

[BushWacker]

… make sure you buy appropriate spec’d (cross-section diameter etc) dimensioned wire cables and good connections for your set-up to minimise voltage drop and avoid cable heating .

Proper cabling is pricey esp if you opt to camp far from your array of Solar Panels !

[iandvl]

Oh Chasey come lately. Manny has already mentioned he has decent wiring (for DC-DC) running to the back... Also, if you have read previous posts, my hydraulic crimper is available to him. He has borrowed it before and did actually return it as well...

Stay of the drugs...

...Chas!!..<<~!WSDZXC

[BushWacker]

... car to trailer is a few meters
but Solar Panel/s to trailer may need 5 time that.
... is pricey since Covid etc

eg 36m cable @ R30/m and thats just 8mm2 cable.

Pay attention son.

[iandvl]

If you're buying your cable at ODW / 4x4MegaStealers etc.

You can actually get it substantially cheaper.

Pay attention, oubal.

[BushWacker]

... sure one can find different prices here and there ;
but my 20-30m panel wiring is all 16mm2.
A min 20A MPPT suggests (?), something like, 4*100W
panels of say 20v*5A each...
I have 3 fairly tired ~ 68aH AGMs that I use for back up around the house, cars and camping but they're generally
past being reliable crankers.
Something not mentioned is that they seem to charge faster and one is only ever topping-up the 45% drawdown.
Ive got a 200ah Li battery as back up for the house
but Im not entirely happy about its stability under excessive vibrations, temp extremes etc if offroad.
Still not 100% trusting!
Heard its not easy to extinguish them if they burn.

[Paul#25]

Chas, you don't need 16mm■ cables from your solar panel to the controller. The correct low impedance cables that are specified for solar installation is only 6mm■ and the strands of the wire are silver coated. It also helps to use proper solar cables connector plugs that are also low impedance.

[BushWacker]

My Victron MPPT is a 150/35 and is to be part of a standby
setup incase my main installed house system fails due to Eskom surges etc. so now I use 16mm2 cables.
Originally while camping I used 8mm Red-Black duel-cord
and at times it got warmed up by only 2*100w panels so I increased wire size.
But I certainly dont think it was a ‘silver coated wire’ or any specialised extra low impedence stuff … just what was available at ACDC at the time during COViD.

[Paul#25]

My Victron MPPT is a 150/35 and is to be part of a standby
setup incase my main installed house system fails due to Eskom surges etc. so now I use 16mm2 cables.
Originally while camping I used 8mm Red-Black duel-cord
and at times it got warmed up by only 2*100w panels so I increased wire size.
But I certainly dont think it was a ‘silver coated wire’ or any specialised extra low impedence stuff … just what was available at ACDC at the time during COViD.

Chas I buy all my solar cables and plugs from AC-DC where I'm registered as a contractor. The solar cables aren't with all the the other cables, they and the plugs are where the solar accessories are. This is the cabling that solar installers are supposed to use but often don't due to the cost. They are also double insulated and the outer layer is UV resistant for exposure to the sun in a permanent installation. I bought rolls of cable and MC4 connectors for different jobs during COViD from AC-DC. With the MC4 connectors you get pre-made 4 into 1 connectors to link the panels to a single feeder cable.

[BushWacker]

… OK , that makes sense to me.

Silver is probly best conductor
only then Cu , Au , Al etc
… and current mainly flows along
the outer surface of a wire strand …
and Victron say platted multistrand
is the way to go
so Ag coating of copper strands would
intuitively confer more far efficient
though expensive flow … esp now wrt Ag price.

[Mad Manny]

The Great, Ant Forgey, Driver of Patrols, 4x4er Extrodinair and the man behind Ants Customer Workshop, gifted me a C-Tek 250S.
So my problem has been solved.
Thank you all for your input...

[Anthony Forgey]

Manny had previously given me a broken 25amp ctek charger which I had repaired and has been I service in the workshop for years now.