Van solar upgrade. suggestions and validations? 12v/24v/48v?

[ampsoma]

Hello all. I have some questions or rather looking for direction/opinions on how to update and expand the electrical system of my camper van. Ive spent a lot of time on this forum and other places while planning my moves and figured I would lay out my ideas here to get ripped apart or validated, and maybe hear some other options I had no idea about.

Current system:
• (2) 100w Renogy 12v panels in series for a max output of 200ish watts, at 35-36v and 5.75a
• Victron 100/20 mppt charge controller.
• Alternator charging via Victron Cyrix-ct 120 connected to the starter battery (charges bank at 30-40A when driving until its happy.)
• Victron smart shunt for battery monitoring
• 5amp battery charger for shore power connection
• Battery bank is the weakest link for the system right now and prompting the upgrade: (4) sla 12v universal 35ah batteries in parallel. So 140ah.

• Loads:
◦ 600w 12v Giandel pure sine inverter, for laptop charging, boot drying. and recently the addition of a 2.2cuft dorm fridge
◦ 12v Water pump
◦ 12v Lights all led
◦ 12v max air fan
◦ (2)12v interior fans
◦ 12v power socket for general cigarette plug shenanigans.
◦ 2kw diesel heater

Use case:
Vehicle is a 84 dodge 1 ton van, interior was totally stripped and rebuilt, class B with fiberglass high top. Use case is not for continuous living but, I am using it for a week at a time for mobile work housing sometimes (once a month or less) and for weekend adventures. Mostly off grid with little to no driving during the week. Some locations I can plug in 15a.

Battery age, health, and Cycles are unknown. They were cast offs from a friend and used when I was building the interior and did great while the van was really primitive and only had lights, maybe charge a phone and pump water for the cold sink. Food kept in a cooler and heat provided by a wood stove/Mr buddy. Never intended to use them long term but they kept working, and kept the system really simple.

Alternator wiring has been upgraded to 8ga and a 2ga wire from front to rear (about 20’-25’) has been run between starter battery and the Cyrix-ct. Chassis ground has been upgraded on starter battery and house bank is grounded to the chassis in the rear. House loads are grounded to fuse block. Not sure what size alternator is in it, probably stock 60a but could be a 120a as it was a fully built out RV at one point in its life. All of the loads except for the inverter are being run thru the Victron charge controller load terminal to a fuse block which maxes out at 20a, and I have had no issues with that limit (even with the diesel heater starting and water pump working)

This winter/spring I added the Diesel heater, a dorm fridge, and the smart shunt to monitor the battery better with the extra load on the system. I have been beating up these batteries ever since. Located in northern New England, so lots of cloudy weather, cold weather in the winter, and hot humid summers. Previously I was located out west which doesn’t have the cloudy issue, or the humidity problem, but still gets really cold and hot. Van is not driven in the winter, but sometimes used as a spare bedroom. It is very well insulated and the wood stove will keep it above 65 in -20f, the 2kw heater worked fine in -8f this winter and has a similar heat output as the wood stove.

Goals with this upgrade:
• Upgrade to modern LiFePo4 chemistry.
• Run a fridge, lights, and water pump 7+ days while using the van without resorting to a generator or alternator charging.
• Increase shore power charging to limit potential generator time, and maxing out my 15a input socket
• Max out solar potential of the roof both to shade more of the roof in the summer and produce more power in this cloudy environment, utilizing the 100/20 as much as possible.
• Get van ready powerwise for the install of a air conditioning situation that can be run while van is moving and with 4-6hrs of reserve, enough to dehumidify and knock off the edge in the sleeping section of the van. ie those 12v/24v/48 minsplit parking coolers.

Considerations
I am invested in the Victron system, but don’t want to totally drink the kool-ade, and blow my budget. Obviously I want to complete my objectives for a cheap as possible, and still be reliable, because why not.
I would like to keep some bidirectional charging of the starter and house batteries, like the Cyril-ct does now, so I can keep it on acc mode and listen to old country on the AM radio all night long, and still charge it with the house battery.
I really want to install one of those Semi parking air conditioners that I was seeing on a bunch of vans out west last year.
There is still a 50” W x 60” L space on the roof for more panels.
Current battery location size 32” long x 12” wide x 24” tall. I kinda set it up for a single 8d battery with some room, back when I thought I would just continue down the 12v AGM path. But the whole under bed/garage area is open for more batteries on the power wall side of the van (the other side has the diesel heater and all the plumbing) So I can fit whatever as long as its less that 2ft tall.
I got antsy and ordered a 300ah (280ah? Whatever its better than what I have.) 12v dumfume from Amazon a few days ago, so now I have a fire under my ___ to put that thing to work when it gets here, and possibly get a second one and upgrade to 24v, or return it and get a different battery setup. I should be able to fit 2 of those 300ah dumfumes in the battery spot at 15.04”L x 7.6”W x 9.82”H each
I like the 24v architecture, but none of my runs would really benefit from it. The DC parking Air Conditioner would only have a 6’ run from the batteries. Might get more capacity out of my charge controller as its nominal output at 12v is 290W and 24v is 590W. 48v seems a bit absurd, but why not. If I’m already converting most of my house loads to 12v, why not skip 24 and go straight to 48v then I can get 1160w out of the charge controller, probably the parking AC will be more efficient, and charging off of generator or shore power will go faster, and and upgraded inverter will be more efficient. But that sounds like a headache unless its really worth it, so Probably just stick with 12v.
Interested in building my own battery out of prismatic cells, but for ease of install and time and work location constraints, Id probably just get a cased battery.
Pretty sure those 12v AC minisplits usually consume around 55a spiking to 70a at startup, and Ive been told that as long as my van is well insulated and im really only cooling the sleeping area consistently i can get away with 300w of solar and 3-400ah of battery. of course I would like more power, and if I'm getting in there and mucking about, I might as well expand the system as much as feasible.
My current plans/ideas
• Keep it 12v
⁃ Install 1 more 100w Renogy panel in series on the roof for 300w of solar on roof
⁃ I think I could also just put 2 100w panels on a second string and it would work, just be super over paneled.
⁃ Just one 300ah battery right now, another later.
⁃ or get the LiTime 460ah 12v
⁃ or some other battery the hive mind can point me to that will fit in the space. The larger and more monolithic the better.
⁃ Keep the alternator charging situation and manually connect it when the lithium is discharged and I’m going on a drive. But usually just rely on shore power and solar
⁃ or get a dc dc charger, that new Victron XS 1400 looks tasty, but I’m open to other opinions.
⁃ or get a Victron bms and the Cyrix-Li-ct
⁃ Get a RV lithium converter charger, 50a or 60a for shore power/ generator fillups
⁃ or get some sort of inverter/charger like the AMIS 1000w/2000w peak with 55a charger or similar
⁃ or the Victron 30a 12v battery charger and just have it be slower but work with the rest of the syste
• Go 24v
⁃ 2 more 100w Renogy panels in a second string 400w solar on roof
⁃ return the dumfume and get the LiTime 8d 24v 230ah battery,
⁃ or get a second dumfume and wire it up as a 24v system
⁃ or get something else.
⁃ New inverter/charger
⁃ or just get an inverter and charger separately
⁃ get a 24/12 dc dc buck converter for the house loads
⁃ Get a switched DC DC charger for alternator charging. Like the Victron Orion or similar
• Go 48v
⁃ 2 more 100w renogy solar panels all in series. Max voltage in that config is like 101v max so that might not work on the 100/20
⁃ or some sort of wildly different solar panel situation, haven’t really explored that yet
⁃ 48v 100ah battery of some sort, they seem to come in 8d sizes,
⁃ new inverter/charger
⁃ or just get an inverter and charger separately
⁃ get a 48/12 dc dc buck converter for the house loads
⁃ Get a DC DC charger for alternator charging.

Anyway, just fishing for validation or criticism of my plans. I honestly hadn’t even thought of going 48v until I started writing this. So I am sure I still have a lot of planning to do. Thanks.

 

[RV8R]

Hi @ampsoma

It has been a few days & no response yet for you .

I suspect it has somewhat due to the mini novel you wrote. You might get more action if you provide pictures rather than words or schematic sketches rather than words. Maybe schematics of;

Current System
Vs
New System (or the changes you want to make)

A “Load Spreadsheet” can also be very helpful when asking for advice from the forum. But if you don’t have that, maybe a list of your intended loads ,,, what do you wish to use the electricity for ,,, just a simple list of the loads in voltage category if you can; 12vdc / 24vdc / 120vac

If you present your information & questions in a clear concise format, I assume you will get more than just me responding .

I note 1984 Dodge Van.

 

[Aussieguy]

It’s very simple
You need more panels …. While you not driving or hooked to a power pole

You don’t have enough panels to go higher battery voltage… very doubtful roof would ever hold enough panels to consider going higher volts

12v will work just fine even for inverter use

You won’t be able to use a big inverter anyways as battery capacity is limiting

Keep it simple
You want at minimum 600-800w of panels
Roof mount and ground mount combo

Small 12v inverter to power a outlet or tv

Consider using 12v to 19v converter to charge laptops and watch tv … look for tv with a 19v power brick

Get Biggest capacity battery you can fit
So you’ll have more days … not more power usage per day

Get a stand alone 55 amp rv converter for when you have some shore power
BTW these converters only use about 5 amps of shorepower when battery is discharged somewhat…. Fullly charged converter uses virtually no shorepower unless you turn on a 12v load

It’s a van…. You can turn it into a power station with no room to live in
or ….. live within the power restrictions the van size sets

I can camp indefinitely using 2x 370w panels
Which may just fit your roof
Can use a small inverter… but so far have not bought one… coffee is made on the stove

 

[HarryN]

Thanks for the details - it actually helps a lot.

An older vehicle just does not have a very strong alternator, and often they are unavailable in larger models.

Being practical, air conditioning will run over everything that you have in place today, and blow nearly any budget under $5 - 10K of upgrades. I have done this and it is completely technically possible, but not cheap.

Your most economical path that is actually practical is to buy a generator. A good example for your use is a honda or similar 7000 size - with the fuel tank large enough to be useful. The nice thing about that size is that it holds enough fuel for more than one day of use, so you might not need to carry additional fuel.

There are also 12 or 24 volt DC generators if your goal is to charge up a battery pack ( at least 5 kW-hrs needed ) and new inverter sized for the air conditioning.

 

[SplitUniverse]

Start with figuring out your panel mounting space, your generating capacity will dictate EVERYTHING else.
Make an energy budget to see what fits in it, I doubt an AC will be an option unless you can install at least 1KW of panels, more like 2-3 times that.
That victron is self adapting for up to 48V unless I misread the model number.

 

[Isaac-1]

First a little background, I have been playing with small solar for sailboat, RV, storage sheds, remote security cameras, etc. for over 20 years, doing over half a dozen installs, so I am no expert, but have dipped my toes in the water.

Having said that I feel 12V is the way to go until you need over a 2,000 - 3,000 watt inverter. Bang for the buck your best to ditch the current panel and fit larger residential style panels to the roof of your van.

You say you have 50x60 inches of space, this is enough room for a single circa $150 400 watt panel, though finding one that is short and wide vs long and skinny may be a challenge, add in an RV Lithium compatible converter in the 80 amp size range and a good Victron MPPT controller probably 100/30 or 100/50 depending on if you can fit over 400 watts of panels or not, plus your choice of LiFePo4 batteries in the 400AH size ballpark and you are done.

Call it $200 for solar and mounting brackets, $20 for MC4 cables, Victron 100/30 Smart Solar MPPT (Pay the extra $25 for the Smart with Bluetooth over the Blue Solar without) $125, and $150 for a 75A PowerMax PM3 Lithium converter for charging when you have shore power. I would say the the 100A PM3, but if you are at the end of a long extension cord plugged into a residential 15 amp outlet you might trip the breaker or melt the cord. The 75A model will draw over 1,150 watts from the 120V outlet, probably over 1,250 watts.

 

[Aussieguy]

You say you have 50x60 inches of space, this is enough room for a single circa $150 400 watt panel, though finding one that is short and wide vs long and skinny may be a challenge

I found 370w were good fit for rv roofs
39-40 inches wide can fit 2 side by side plus a small walkway

 

[Bone 1]

Thanks for the details - it actually helps a lot.

An older vehicle just does not have a very strong alternator, and often they are unavailable in larger models.

Being practical, air conditioning will run over everything that you have in place today, and blow nearly any budget under $5 - 10K of upgrades. I have done this and it is completely technically possible, but not cheap.

Your most economical path that is actually practical is to buy a generator. A good example for your use is a honda or similar 7000 size - with the fuel tank large enough to be useful. The nice thing about that size is that it holds enough fuel for more than one day of use, so you might not need to carry additional fuel.

There are also 12 or 24 volt DC generators if your goal is to charge up a battery pack ( at least 5 kW-hrs needed ) and new inverter sized for the air conditioning.

Just a couple of thoughts. Like you said your amount of battery storage is way to small and is more frustrating than anything else. I've had great luck with the Newtipower batteries on Amazon. I've been running 2 of the 280ah (before the 300) for over 2 years straight in my '90 Winnie. Powers my 10cf Magic chef residential fridge with plenty of room leftover for everything else (32in led tv, charge laptop and phone, all cabin led lights, water pump, furnace and bath fans, etc). Can typically go a couple of days with no sun. They have a 12v 300ah with a 200ah bms for $327. This is roughly 4-5 times (maybe more depending on age) of your worn flooded batteries.

On another note I've had several of those old Dodge van's (currently have an 02). Stock they come with an 80 amp alternator but I was able to get a 120a alternator at the Autozone for a '96 with the 360cid. I think it was about $140.

Finally, I agree with some others on here about more solar. Max out the roof (great deals on FB Marketplace) and wire an exterior port for portable panels for when your set up. I hope this helps.

 

[0truck0]

Wow, long post with prob too much info....

I have a 12v parking air cond. People say they consume 50 amps but I have not seen anything over 22 amps at 12 volts yet. I was on long trip in 4-corners states with near 100 degrees even and still only saw 22-23 amps at the peak, settling to 15-18 amps while running. Even less with solar panels feeding in the amps, usually 7-8 running out of the battery since solar is coming in. Be careful charging them as they can be fickly if over-charged. Use proper manifolds to fill.
Praking ac's are great. See if you have room for the underneath type, so it tucks away out of sight and out of the way. mine is on the back wall and is very out of the way, but Id prefer an undermount.
I have 600 amp hrs for the ac and never got below 85% on batteries so mine is a bit over done for the sunny west, but might be just right for shady or cloudy east.
If all you want is to be cool while sleeping then smaller ac's could work to just blow on the bed. The parking ac is prob 5000-6000btu's despite any false claims by the china (lier) seller that just wants your dollars. For a van this is plenty unless it is uninsulated and all glass.

Water pump power and led power is nothing. For fans those are 1.5-3 amps so DO get a PWM type speed controller. Maxair should be brushless, so you need to get specific controllers for brushless or ones for brushes, they are not compatible.
I typically now can run vent fan at 0.5 amps or less, so like led lights, this is nothing.

Put DC outlets all over, not just one or two. These are useful. The usb outlets are convenient but will always consume power.
Your inverter will always consume power while on but not being used. Consider a DC fridge, or have very few things that need the inverter so you can have it off most of time.

Will 350 watt panels fit on roof? Would b better than a bunch of 100w tied together.
The more solar the better and yes, it will keep your roof/ceiling way way more cool inside, reducing need for ac.

You will need some fold out or slide out panels when parked so your roof system can expand when running ac.
I did 6 week trip out west and never once needed alternator or generator or shore power, solar did it all including air cond, a DC fridge/freezer that ran all the time and the little things liek fans and lights and phone charging, occcasional inverter laptop charging for movies and a cradle point at night.

In my system I have a 55 amp wall plug charger, but have never needed it. I Have a tiny 70cc 900 watt 2-stroke generator at 35 pounds that can run the charger, but not needed it either, good thing it is so small.

In short, for long trips, your fridge is the king and must always run. Second is air cond when hot n humid. Get batts and solar to run these two. All other things are small and secondary almost. A DC fridge runs off batteries, while an ac fridge runs off the inverter that runs off the batteries and the inverter must always be on so it consumes power otherwise that could be saved if inverter was off. DC power is best on DC systems.
inverters can die, and that will kill downstream things that need an inverter, do you carry spare inverter?
Giandel inverters are junky, it just might die.

 

[ampsoma]

I want to thank everyone for their opinions and suggestions as to improving van the situation. I'm still watching this thread and gathering information, trying to make the best decisions. I've made some upgrades and looking at the path forward.

I installed a 30a Victron shore power charger, love this thing, I pigtailed it in to a 50a anderson plug and built a 12' 6ga extension so I can unplug it from the van system and charge any other battery within a few feet of the van fairly easily without modifiying the system to much. Love all the settings on the charger. Really quiet fans and was marginaly warm even after 9+hrs of solid charging.

I've upgraded the battery, with a 300ah Dumfume battery a few weeks ago, which has been excellent. From 100% SOC, it easily runs the fridge with the solar disconnected for upwards of 8-9 days in mild temps and no other loads. I performed a capacity test, and got 302ah from the battery before the inverter i have (a Giandel 600w pure sine) triggered a low voltage cutoff at around 10.2v under a 500w load (space heater on low). I was able to maintain that 500w load for 6-7hrs. Charging from this state on the 30a charger took an expected 10.5hrs.

I have swapped out the Cyrix battery combiner with a 200a manual relay, which enables alterator charging as long as I keep my eye on it. Still pulls only about 50-55a while driving. I am interested in a new alternator larger tho.

The future,
Focusing on upgrading the inverter right now to one that can support my current portable air conditioner. More solar is comming, but I think the needs of the build are more on the other side right now.

The portable air conditioner is a Hisense 8k btu, dual hose, inverte unit. It pulls max about 9a. Just upgrading to a 1500w, 3000w surge, inverter should run just the ac and fridge, which is fine. There are some interesting chinese 1500w pure sine inverters on amazon that have interal transfer switches, such as the OLTEANP for $170 currently, or there is a pure sine giandel with gfci for around 200. If anyone has anyother suggestions I am gamet, or if you think im undersizing the system, please let me know. I could go with a 2000w inverter, but I do not think I need the head room, and the extra idle watts when its just keeping the dorm fridge on. A 2000w invterter would also require alot more upgading of cabeling on the battery side, fuses, etc.

Also would like to get a second charger to bump up charging rates while mooching or on generator. 10hrs is too slow. I figure the victron is pulling around 500w to charge at 30a, the limit of a long extension cord and smaller generators is around 12-1500w, which leaves 800-1000w to fast charge with, or 50a-65a of 14v. I could get a 55a lithium rv converter/charger, or smaller 60a or 50a constant 14.6 voltage charger for around $100-200, and boost charging when needed, without resorting to two more victron chargers (at $150-$200 ea.) to get the same effect.

Once the inverter and the 120v charging system is built out, I'll invest in some more solar kit, more panels on the roof, and a second charge controller for a portable ground mount set up.

Thanks again everyone for your views and input!

 

[HarryN]

You need the ability to charge at least 2x as fast as the largest load, ideally 4x to have a viable system.

You are becoming lured into fake chinese specs and budget pricing.

Marine electrical on line stores have suffer if they sell their customers junk stuff, so they are much more careful vs amazon is increasingly scams.

Pick a couple of marine supply places on line - if they don't carry it - don't buy it.

My Dad had a wet / dry vac and put a brick in it to hold it from tipping over. He got suckered by import junk as well. I still remember telling him that the only useful aspect of that sweeper was the brick.