The living heart of off-grid building

I am building a new van conversion and trying to decide between 12V and 48V. I have heard 48V has lower cable losses and is better for larger solar arrays. But everything is more expensive and harder to find components for. My planned system is 600W solar, 300Ah batteries, 3000W inverter. Does 48V make sense at this scale?

I park in cities a lot and I want to stay as stealthy as possible. Roof-mounted rigid panels are a dead giveaway. I have looked at low-profile panels, folding portable panels stored inside, and flexible panels that blend into the roof colour. What approach actually works for urban stealth?

Bifacial panels claim 10-25% more output from reflected light on the rear surface. On a van roof the panel is sitting on metal with no air gap. I doubt there is much reflection happening. Has anyone actually tested bifacial vs standard mono on a van roof? Is there any real-world benefit or is it just marketing for ground-mount installs?

Installing a pressure water pump in my off-grid cabin. I have seen 12V pumps rated 60W and 24V pumps rated similar. My system is 24V. Is it more efficient to run a native 24V pump vs stepping down to 12V? And how do I calculate the daily Ah draw — it only runs when water is used so the duty cycle is hard to estimate.

The spec sheets say 3000-4000 cycles to 80% remaining capacity. But that is tested at ideal lab conditions. In a real-world off-grid cabin in Montana that cycles daily through all seasons, what should I actually plan for? And does regularly discharging to 90% DoD vs 50% DoD make a significant difference to total lifespan?

I have a 100Ah Battle Born and want to add a 200Ah Epoch. Both are 12V LiFePO4. Is it safe to wire them in parallel or will the different capacities cause problems with the BMS?

Running 2x 200W Renogy panels in parallel on a 12V system. Currently have the 100/30 but wondering if I should have gone the 100/50. My panels can theoretically push 22A combined. Am I losing much?

Running 4x 100W panels in series-parallel giving me about 400W total. The 100/30 is cheaper but I'm wondering if I'll regret not getting the 100/50 for headroom. What do you recommend?

Upgrading from AGM to lithium. Budget is around $1800 AUD for the battery bank. Battle Born is well known but Enerdrive is Australian made. Anyone run both? Mainly use it for 3-4 week trips in the Kimberley.

Running a BCDC1225D in a 200 Series LandCruiser. On long highway runs in summer the unit cuts to float mode after about 2 hours. REDARC says it is thermal protection but the unit is mounted in the engine bay with decent airflow. Is this normal or do I have a mounting issue?

Building a tiny home on wheels. Want to run a microwave (1200W) and occasionally a hair dryer (1800W) but not at the same time. Battery is a single 100Ah 12V LiFePO4. Is this feasible or do I need a bigger bank?

I want to charge two separate lithium battery banks from my alternator — one house bank and one start/winch bank. Could I run two separate DC-DC chargers from the same alternator positive? Or would that overload the alternator? The alternator is 130A and each charger would be 40A.

Planning my narrowboat electrical upgrade. Choosing between a 150Ah LiFePO4 with 100A BMS or a 200Ah with 150A BMS. I want to run a 3000W pure sine inverter for induction cooking. At 24V that is 125A draw. The 100A BMS would not handle that sustained draw. Am I right to rule out the smaller BMS?

Running a Redarc BCDC1225D on a 2022 LandCruiser 300 Series. After about 45 mins of highway driving the alternator gets very hot and the DC-DC cuts out. Is this a smart alternator issue or am I drawing too much?

Compressor fridge rated at 45W average but my Victron BMV shows it pulling 80W consistently. Running a 200Ah LiFePO4 and 200W solar. Should I be worried?

Running a 6-vehicle convoy for guided tours in the Pilbara. Each vehicle has a Victron system. Is there a way to get a central overview of all battery states without checking each vehicle individually? Cerbo GX with VRM portal?

i am so sick and tired of Renogy poor service

Choosing a roof vent fan for my Sprinter conversion. The three most popular seem to be Maxxair, Fan-Tastic, and Dometic. The Dometic Ibis 4 is the most expensive but claims to be the most efficient. Does the power draw difference between these actually matter for a well-sized solar system?

Current setup: 1.2kW panels into a Victron 100/50 MPPT on a 24V system. Works well. I want to expand to 3kW by adding 6 more 300W panels. The 100/50 is already at its input power limit. Options: add a second MPPT in parallel, replace with a single larger MPPT, or upgrade the whole system to 48V. What do you recommend?

I have 4x 200W panels (Voc 24.3V, Isc 8.7A each). Running a 24V system with a Victron 150/70. Should I wire 2S2P or all 4 in series? Roof is unshaded.

I need my CPAP every night — it draws about 30W for 8 hours so roughly 240Wh. My current 100Ah AGM barely makes it through the night. Thinking of upgrading to LiFePO4 but want to know if there are other tricks too.

Converting a 40ft catamaran to solar. Planning 600W of panels and a 200Ah LiFePO4 bank. Do I need a marine-rated MPPT or will a standard Victron SmartSolar work? Concerned about corrosion in the marine environment.

Looking at fridges for my sailing boat. Boat fridges seem to be either 12V DC compressor types or household 240V fridges via an inverter. The 12V compressor fridge (like an ARB or Engel) is more expensive but runs direct from the battery. The 240V household fridge needs an inverter running all the time. Which approach is more efficient?

I have seen some wiring diagrams with fuses at both ends of the cable — one near the battery and one near the load. Other diagrams only show a fuse near the battery. When do you actually need fuses at both ends? What is the purpose of the secondary fuse? Is it about protecting the wire or the load?

I have two 100Ah 12V LiFePO4 batteries from different manufacturers — one Battle Born, one Epoch. I want to run them in parallel to get 200Ah. Is mixing brands a problem? Should I match capacity exactly? And does it matter which terminal I connect my positive and negative cables from for balanced current?

Just upgraded from AGM to 200Ah LiFePO4 (Epoch). My Multiplus is still set to AGM profile. What absorption voltage, float voltage and charge current should I use? BMS cutoff is 14.6V.

Installing on a 28ft sailing yacht. Both seem well regarded but the Victron has Bluetooth monitoring which appeals to me. Anyone run either of these in a marine environment long term?

Running a remote cattle station in the NT. Daily load is about 3kWh (fridge, lights, water pump, comms). Need 4 days of autonomy for the wet season. What battery bank and solar array size am I looking at? Currently on a diesel generator.

"Why does my 12V LED light strip appear dimmer at the end of a long 20-foot run compared to the beginning?

I have two Renogy 200W panels (Voc 24.3V each) that I want to run into my Victron SmartSolar 75/15. If I wire them in series the combined Voc would be 48.6V which is under the 75V limit. But the combined Isc would stay at ~9.8A which is under the 15A charge limit. Is there any reason NOT to do this? I'm charging a 12V 200Ah LiFePO4. Will the MPPT handle the voltage step-down okay?

My partner uses a CPAP machine every night — non-negotiable load. It draws about 30W on average (ResMed AirSense 11 without humidifier). I want to make sure this is always protected and never gets cut off by low voltage disconnect. Should I run it directly from 12V with a dedicated circuit and higher LVD threshold, or through a small UPS-style inverter for cleaner power?

I see pure sine inverters cost significantly more than modified sine. Most of what I want to power is a laptop, phone chargers, and a 12V fridge which has its own DC connection anyway. Does modified sine wave cause actual problems with modern laptop chargers and USB-C power bricks?

Off-grid cabin in the Otways. Daily load is about 2.8kWh. I have 400Ah LiFePO4 at 24V (usable ~80%). How many days can I run without sun? And what panel size do I need to recover in 2 days?

Heading to the Kimberley for 3 weeks. Some stretches will be 4-5 days between towns with no shore power. What autonomy target should I be designing for — 3 days, 5 days?

My current setup has everything bolted directly to the battery terminals. I have seen proper electrical builds use copper busbars. When is this actually necessary vs overkill? If I have 4 circuits coming off my battery (MPPT, inverter, DC fuse box, DC-DC charger) is a busbar required for safety and neatness?

I have 4 x 100Ah AGM batteries in my 28ft sailing boat on a 24V system so 200Ah usable. Been running them for 4 years. Starting to notice they do not hold charge as well. Replacement cost in AGM is about $800 AUD. LiFePO4 equivalent would be $1800-2000. Given I sail mostly weekends plus 2-3 longer trips per year, is the lithium upgrade worth it?

ARB 60L fridge rated 45W but my Victron BMV shows it pulling 80-100W. Running 12V 200Ah LiFePO4 with 300W solar. Is this normal? Will I run out overnight?

Planning a full-time Sprinter build for NZ. Running fridge, laptop, lights, phone charging. Winter in the South Island worries me — is 200W going to cut it or should I go 400W from the start?

Building a shed/workshop setup. I want to be able to run a 2400W kettle and occasionally a 1200W microwave. I know I can't run them at the same time. Do I need a 3000W inverter or can I get away with a 2500W? Also — pure sine wave vs modified sine wave for these appliances?

My narrowboat is continuously cruising, meaning I move to a new mooring every day or two. Panel orientation changes constantly. Some days I am moored under trees. How do I realistically calculate solar yield when I cannot rely on fixed-position data? I am planning 400W of panels on a 7-metre roof.

Looking at Victron inverters. The MultiPlus does inverting AND charging. The Phoenix is inverter only. For a van where I already have a DC-DC charger from the alternator, do I actually need the MultiPlus charging function? Or is it only useful for when plugged into shore power at a campsite?

Building a 48V system for a large caravan. 4x 200W panels, Voc 24.3V each. Planning to wire 2S2P giving 48.6V Voc. Is the Victron 150/45 the right call or should I go 150/70?

Building a permanent off-grid cabin in the Adelaide Hills. Budget is around $8k AUD for the whole electrical system. Enerdrive is Australian-made which appeals but Victron seems to have better community support. Thoughts?

Just finished installing a 200Ah LiFePO4 + 400W solar on my 28ft sailboat. Worried about corrosion on terminals and connections. I've used marine-grade tinned cable but wondering about terminal protection. Should I use dielectric grease, Lanox, or something else? Also — do I need a galvanic isolator with shore power?

I have 4 x 200W panels (Voc 21.8V, Vmp 18.2V, Isc 11.2A). My MPPT is a Victron 100/50. I am trying to decide between 2S2P or 4P wiring. The roof is flat so shading from one panel will affect all in series. But series gives higher voltage and better low-light performance. Location is subtropical QLD.

I have a 100Ah 12V LiFePO4. I want to run a 2000W inverter for a coffee machine (1200W) occasionally. Will the battery handle the surge current? What cable size do I need?

Running a 200 Series with a REDARC BCDC. Want to add a second battery under the bonnet. I know LiFePO4 doesn't like heat — is AGM still the right call for engine bay installs?

About to pull the trigger on a DC-DC charger for my 200 Series LandCruiser. Running a 200Ah LiFePO4 aux battery. The Redarc is $420 and the Victron is $380. I've heard the Redarc handles smart alternators better but the Victron has better Bluetooth monitoring. Anyone run both? My alternator is a standard 130A unit.

Installing a Redarc BCDC1240D in my Jayco Expanda — the run from the Anderson plug at the drawbar to the charger is about 3 metres each way. I've seen people say 6mm² is fine but others say go 8mm² or even 10mm². The charger is rated 40A continuous. What's the right call and does the fuse size change anything? I'm in Australia so using Australian cable standards.

Marine electrical suppliers always push tinned copper cable. It is significantly more expensive than standard automotive cable. Is it actually necessary for a freshwater sailing boat in coastal waters? Or is it mainly for saltwater offshore boats? I want to do the job right but not spend money unnecessarily.

Building a 24V off-grid system for a cabin near Queenstown NZ. Gets down to -8 degrees C in winter. I know LiFePO4 does not like charging below 0 degrees but AGM is cheaper. My budget for batteries is around $2,500 NZD. The cabin is only used on weekends so the batteries sit idle a lot. What chemistry makes more sense here?

Victron SmartSolar 100/30 with 2x 200W panels. 200Ah LiFePO4. The MPPT hits absorption at about 14.2V then drops to float but battery never reads above 80% on the BMV. Checked connections, all tight.

Want to run a single-zone induction cooktop (1800W rated, 2200W peak) from my 48V LiFePO4 system. What size inverter and what cable gauge do I need for the DC side?

Taking the caravan through the Simpson Desert next month. I've got Starlink Standard and I'm trying to get accurate power draw figures for trip planning. The official spec says 25-75W but I've seen people report much higher in hot conditions with the dish working hard. Anyone run Starlink in remote outback Australia and tracked actual consumption?

My narrowboat engine charges through a 70A alternator on a Beta Marine 38hp. I want to add a DC-DC charger to charge the LiFePO4 house bank properly. What size B2B charger should I get — 30A, 50A, or bigger? The engine typically runs for 3-4 hours a day when cruising.

Installing 2x 175W panels on a sailing catamaran. What connector type should I use for the panel-to-MPPT run? MC4 seems to be the standard but I have heard they are not truly waterproof below deck.

I've seen the Webasto and Dometic 12V aircon units. They claim 300-400W draw but I've heard real-world is much higher. Has anyone actually run one of these off solar and battery without shore power?

I installed a Victron BMV-712 shunt and the state of charge is all over the place. It'll show 85%, then drop to 60%, then jump back to 80% within minutes without any load changes. I've got the shunt on the negative terminal of the battery. All negative cables go through the shunt. Is there something I'm missing? Running 12V 100Ah LiFePO4.

I live in Montana at about 46 degrees latitude. My off-grid cabin panels are fixed-mount at roof pitch which is about 15 degrees. The optimal tilt for my latitude is more like 35-40 degrees. How much generation am I losing by not building a tilted rack? Is it worth the extra cost and added wind loading?

Building a 200Ah 12V van system. Already have a SmartSolar MPPT and BMV-712. Is the Cerbo GX worth the $400 for a single-battery single-MPPT setup or is it overkill?

Have a north-facing roof at 25 degrees but also a clear paddock area. Ground mount would be easier to clean and adjust seasonally. Anyone done both and have a preference?

Currently running a 100Ah AGM with a Renogy Rover 40A MPPT. Thinking of upgrading to a 200Ah LiFePO4. Do I need to replace the MPPT or can I just change the battery profile settings? I've heard some older MPPTs don't have a proper LiFePO4 profile and can overcharge. The Rover is about 3 years old.

I want to add a 240V shore power connection to my sailing boat for when I am at a marina. I keep reading about galvanic corrosion from shore power connections and the need for an isolation transformer. Is this actually necessary for a fibreglass boat in freshwater marinas? Or is an RCD alone sufficient for safety?

I want to use a small front-loader washing machine rated 500W with motor startup surge. My inverter is a Victron MultiPlus 24/2000. Will it handle the surge? And how much does running one wash cycle actually drain a 200Ah 24V battery bank?

Storing batteries in a van in the NT. Summer temps inside the van can hit 55-60C when parked. Most LiFePO4 specs say max 60C storage. Is this safe? Should I insulate the battery box?

Running a 12V system in my Transit. My loads work out to about 80Ah per day in summer but I am seriously worried about winter in Victoria where we get cloudy weeks. Currently have 400W of panels on the roof. Will 200Ah get me through? Or should I be looking at 300Ah? I have a 40A DC-DC charger as backup from my alternator.

We use our caravan maybe 30 weekends a year. Currently have 2x 100Ah AGM. A mate says to upgrade to LiFePO4 but the cost is 3x. At our usage level will we ever see the payback?

Hey all, I've got a Victron SmartSolar 100/30 paired with a 200Ah LiFePO4 (Renogy). The MPPT is showing absorption but my battery never gets above 13.1V even on a sunny day with 300W of panels. I've set the charge profile to LiFePO4 in the VictronConnect app. Any ideas? The panels are wired in series giving ~40Voc.

Running an 800W microwave is fine. But my 1200W air fryer trips the inverter every time after about 30 seconds. The air fryer is rated less watts than the microwave but has a fan motor inside. My inverter is a 2000W pure sine. I thought it was a surge issue but the microwave pulls more steady-state watts. What is happening here?

Running a 6mm2 cable from battery to a 40A MPPT about 3 metres away. I know I need a fuse close to the battery but what rating? The MPPT max input is 30A.

I have 3kW of solar and 400Ah LiFePO4 at 24V (9.6kWh usable). In Montana winters we can go 4-5 days with poor solar. I want a generator as backup. I do not want to run it often — mainly to top up batteries when we hit 20% SoC. Does a 2kW generator work or do I need 3-4kW to charge properly via the inverter charger?

My narrowboat has a slightly curved steel roof. Traditional rigid panels would need a mounting frame that holds them flat. Flexible panels could stick directly to the curve. I have heard flexible panels degrade faster and run hotter with no air gap underneath. What is the actual trade-off for a boat that lives outdoors year round in the UK?

Off-grid home in Gauteng. Load shedding is brutal. I want to run my whole house (about 3kW average) from a 48V 200Ah LiFePO4 bank with 2kW of solar. Is this realistic for overnight?

Shopping for a hybrid inverter/charger for my new 48V shed system. I have 4kW of panels and plan 400Ah of LiFePO4. I see specs like peak power, continuous power, transfer time, and efficiency curves. Which numbers actually matter day to day? What should I prioritise when comparing Growatt vs Victron vs Sungrow at this scale?

Installing fixed panels on a bach roof in Queenstown. Latitude is about 45S. What tilt angle maximises winter output? I have read 45 degrees but some say steeper for winter.

Setting up a BMV-712 Smart on my cabin system. I know the shunt goes on the negative side of the battery, but I'm confused about where the DC-DC charger negative should connect. Should it go to the busbar on the battery side of the shunt, or the load side? I want the BMV to see all charge and discharge current accurately. Also does it matter for the solar MPPT negative — same question.

Planning a proper off-grid cabin system in the Blue Mountains. Expecting to run a washing machine, chest freezer, laptops, and occasional power tools. Sizing around 3kW inverter, 400Ah battery bank. I've always done 12V van builds but this feels like the right time to step up. Is 24V enough or should I go straight to 48V given the loads?

When my narrowboat is plugged into shore power at a marina, I have a 240V battery charger (30A) constantly connected to my 200Ah LiFePO4 bank. Is it safe to leave a charger constantly connected once batteries reach 100%? My charger has a float mode — is that sufficient for LiFePO4 or does lithium need something specific?

I have a 200Ah LiFePO4 battery with built-in BMS rated 100A continuous discharge and a 2000W pure sine inverter. When I run my 800W microwave the BMS trips after about 45 seconds. The inverter is pulling about 70A from the battery which should be under the BMS limit. Could it be a microwave surge on startup causing an overcurrent spike?

On a long outback trip I drive 6-8 hours a day. I have 300W roof solar and a 25A DC-DC charger. Which one puts more into the battery on a typical driving day?

I've got 2x 200W panels flat-mounted on my camper trailer roof. In summer they get really hot and I've noticed output drops significantly in the afternoon. I'm in QLD so it gets to 40°C+. Is it worth adding a tilt kit? I've read panels lose about 0.4% per degree above 25°C. Would tilting help with cooling or just the angle?

My panels are 10 metres from my MPPT. The array is 800W at 24V so about 33A max current. I want to keep voltage drop under 3%. I know I need bigger cable for longer runs but I am not sure how to calculate it. The run will be outdoors under a roof overhang so it needs UV resistance.

I have a cheap 1000W grid-tie inverter from a previous project. Can I use it with a battery bank off-grid or does it need a grid reference signal to work?

Setting up a Victron system with SmartSolar and BMV-712. Should I use Bluetooth app monitoring or wire up VE.Direct to a Cerbo? Planning to be off-grid for weeks at a time.

I have 4 x 100W panels in 2S2P configuration (Voc 21.4V each, so 42.8V in series pairs). Running into a Renogy 40A MPPT charging a 12V LiFePO4. Max I ever see on a perfectly clear day is about 280W. The panels are rated 400W total. I have ruled out shading and dirty panels. Is this a wiring issue or just normal STC vs real-world difference?

Running a 40A circuit from my battery to a distribution board 5 metres away in a caravan. I know I need to account for voltage drop. What is the formula and what cable size do I need?

I'm building a cabin system and want to run 4x 200W panels. I'm planning to wire them 2S2P (two strings of 2 in series, then parallel). The Voc per string would be about 48V which is within the 150V limit. Is this safe? Do I need a combiner box or can I just use a Y-connector?

Installed a Redarc BCDC1225D. Works fine around town but cuts out after 20-30 minutes on the highway. Alternator is a 120A standard unit (not smart alternator). Wiring is 6mm2 with 40A fuse inline. No errors on the unit. Resets when I stop and restart. Any ideas what is causing this intermittent fault?

I have a basic setup — 100Ah AGM, 200W panel, cheap PWM controller. No shunt. The voltage reading on the controller seems unreliable. What is the cheapest reliable way to know my actual SOC?

My VW Crafter has a smart alternator (variable voltage, drops to 12.5V at cruise). I have been told an old-school VSR/isolator will not work with smart alternators. Is this true? If I get a Victron Orion-Tr Smart, does it handle variable alternator voltage properly?

Installing a 12V system in my van. I have seen some builds earth directly to the van chassis and others run a dedicated negative cable back to the battery. What is the correct approach? Does it matter for LiFePO4? And does polarity on the battery terminals actually matter as long as I am consistent with negative earth?

I'm going full-time in a Sprinter van. Planning to run an Engel MT45 (rated 45W average, but I've heard real-world is more like 30-35Ah/day). I'm in southern Australia so winter sun hours will be low. I've got 200Ah LiFePO4 and 300W solar. Is this enough for year-round use or do I need more panels?

Trying to decide between a Ford Transit (high roof) and Mercedes Sprinter for my first full conversion. I keep reading that the Sprinter has a better roof shape for solar and more headroom. Is there actually a meaningful difference in usable roof space for solar panels? I am planning 600W of panels.

Just upgraded from AGM to 200Ah LiFePO4 in my van. My old setup had a VSR (voltage sensitive relay) which worked fine with AGM. I've read conflicting things about whether a DC-DC charger is mandatory for lithium or if a quality VSR with a lithium profile is acceptable. Budget is tight — trying to understand if this is a must-have or a nice-to-have.

Building a solar system for our holiday cabin in the Snowy Mountains that we use maybe 40 days a year. We are quoted $18,000 for grid connection or we can do a full off-grid system for about $12,000. The off-grid system should work well in summer but I am worried about multi-day winter cloudy stretches. Is a small generator enough backup?