Easiest Budget Setup for Van Conversion?

[reecetas7196]

This may be a dumb question, but could I use two 100w panels for the 202ah lifepo bank? Wouldn't it just take longer to recharge?

 

[MisterSandals]

This may be a dumb question, but could I use two 100w panels for the 202ah lifepo bank? Wouldn't it just take longer to recharge?

Yes
202Ah x 12.8V = 2585Wh

2585Wh / 200W = 12.93h to recharge

 

[Browneye]

Only if it was all the way discharged.

 

[Dzl]

This may be a dumb question, but could I use two 100w panels for the 202ah lifepo bank? Wouldn't it just take longer to recharge?

Longer to recharge, or never recharge, it depends on your consumption more than your battery bank size.

Lets switch from calling it/thinking of it as a 202Ah lifepo4 bank to calling a 2600 Watt-hour lifepo4 bank (12.8V x 202Ah = 2585Wh), to simplify the units.

Thinking about things in Watt-hours may make it easier your logic above may not make sense. While it is true 200W of solar could charge your 2600Wh battery bank, given enough time, it would take multiple days of perfect conditions (2600Wh / 200W = 13hrs) of perfect conditions to charge from 0-100%, or probably closer to roughly double that time in real world conditions. And that is assuming that you have nothing consuming power during charging.

Now if your consumption is very low, and you maybe only use 20% or maybe of your battery capacity in a day, a small array like that might be fine, your battery would basically be a big reserve for back to back days of crap weather, and it would take many back to back days of sun (or a separate charge source) to recharge to full after that, but in sunny conditions your small array might be enough. On the other hand if your consumption is not that low, 200W may well never be able to recharge your batteries as you would be consuming more over a 24hr period than you can generate. And considering that you want a 2000W inverter, I assume your consumption may not be that modest (2000W inverter at full load for 5 minutes would consume the max of what your 200W panels produce in an hour).

But to some extent a lot of this depends on your use case / design goals, and the type of travel you do. Weekends? Weeks? Full-time? Other charge sources? And especially depend on how much energy you will consume on average and in worst case.

Or put more succinctly, energy in must be greater than or equal to energy out, and you cant count on perfect conditions.

You've basically got 3 big variables.

1. Generation (Solar panels * number of hours of sun + other methods of charging/generation)
2. Stored Energy (batteries)
3. Energy Consumed

Its more important to size your solar array (#1) for #3 than #2 but both are considerations.

If we talk just in Watts and Watt-hours the math is much more clear

 

[John Frum]

If we talk just in Watts and Watt-hours the math is much more clear

Watt hours is also divorced from system voltage which I don't think is a settled issue yet.
@reecetas7196 I urge you not to buy components or even kick tires until you have defined your requirements.
Make a plan first... lest you annoy the sun deity.

 

[reecetas7196]

What would you all recommend for a charge controller for two of these?

 

[Dzl]

What would you all recommend for a charge controller for two of these?

Something like the Victron Smartsolar 75/15 would do the trick.

 

[12VoltInstalls]

What would you all recommend for a charge controller for two of these?

urge you not to buy components or even kick tires until you have defined your requirements.

What is it you plan on running with your system is what he’s saying.

I’ve been reading along. While the questions of will this X and that Y work can be answered narrowly, not only is it very random it doesn’t answer the most important question of, “will this meet my needs?”

Did I miss where your planned loads were listed?

 

[reecetas7196]

What is it you plan on running with your system is what he’s saying.

I’ve been reading along. While the questions of will this X and that Y work can be answered narrowly, not only is it very random it doesn’t answer the most important question of, “will this meet my needs?”

Did I miss where your planned loads were listed?

No, you didn't miss it. I've done my calculations of planned loads. I did not post. I'm just piecing together the system, yes. Not the best practice, but when you're on a hardcore budget, you'll do what you gotta do. I'm building out a mercedes sprinter van. It's a 2002 e150 conversion van high top. I'm just trying to piece a working system together. Currently, I have my 100ah 12v lifepo4 battery and two 100w solar panels that I may eventually add two more for a total of 400w. I asked about the charge controller because I want one that is a good fit for the two SP's I have and one that will support me adding two more down the road. Nothing is wired, I'm just piecing it all together and will wire it all up sometime soon down the road.

 

[MisterSandals]

100ah 12v lifepo4 battery and two 100w solar panels that I may eventually add two more for a total of 400w.

400W / 12.8V = 31.2A max charge capability

Configuring 4 panels in a 2S2P manner (quite popular), you could get by with a Victron 100/30 since your panels will be laying flat and never quite produce their listed watts.

 

[McCarthy]

What van are you converting? I put one commercial grade 465 watt panel on my minivan. That's much better than 4 of those China made hobby level panels.

You can find the overkill BMS on eBay for a better deal. Get one with lugs, not with soldered wires.

 

[reecetas7196]

What van are you converting? I put one commercial grade 465 watt panel on my minivan. That's much better than 4 of those China made hobby level panels.

You can find the overkill BMS on eBay for a better deal. Get one with lugs, not with soldered wires.

Got links for the panel and charge convertor and whatever else I'd need for for those type of panels?

 

[McCarthy]

Got links for the panel and charge convertor and whatever else I'd need for for those type of panels?

Search on google maps for a local solar panel dealer (not installer) and see what they have in stock. Get something that fits your roof and has the highest output / efficiency.

This is the 200 amp BMS I use for my 4 cell bank:

4S 12V 200A BMS Programmable Lifepo4 Battery Protection Board Same Port Balancer | eBay

Find many great new & used options and get the best deals for 4S 12V 200A BMS Programmable Lifepo4 Battery Protection Board Same Port Balancer at the best online prices at eBay! Free shipping for many products!

www.ebay.com

This one has only 150 amp but low temp cutoff:

Smart BMS 12V 4S 150A Lithium Lifepo4 Battery System w/Bluetooth US Stock 4S12V | eBay

4 x 3.65 =14.6V Lifepo4 Chemistry battery. Fully Programmable Smart BMS with Bluetooth with Android or iPhone App. Protection functions : This BMS is designed with a high quality IC chip specially for lithium battery protection.

www.ebay.com

 

[McCarthy]

I got my 465 watt panel for 220 bucks, no shipping, local dealer.

 

[Dzl]

If you are in Arizon or Georgia Santan Solar has great deals on new and used solar panels. If you are not in this area, shipping will be a dealbreaker for small orders of large panels. As others have mentioned finding something local is the way to go, Craigslist or a local solar seller or liquidator/reseller of some sort.

As to the charge controller. With a proper MPPT charge controller, its mostly irrelevant whether you have 3-4 100W panels or a single 300-400W panel. The same factors apply when sizing a controller to an array (1) max input voltage (2) max input current (3) max output power

All panels have a datasheet and/or sticker with the relevant details, and all charge controllers have a datasheet, once you narrow things down you can check the details, and/or ask here for confirmation.

The Victron 100/30 or a similarly sized Epever MPPT controller would be two options for a large 300-400W panel.

 

[12VoltInstalls]

when your on a hardcore budget, you'll do what you gotta do.

I hear that. Been there!
That’s why I first got going with solar- enabled me to live “normal” and look normal and show up to work every day but not spending the ~$1000/month on rent.

200W or 400W of panel on something like a P30L PWM controller will work fine, but in your case I think planning for 400W by buying one of the Epever mppt controllers now is the best 6-12 month spend for you. And there are benefits to a 2P or 2S2P system with an mppt.

If ‘bigger’ and inexpensive panels are accessible to you - great. While this can be less expensive per watt, to scale up over time it’s usually easier to obtain similar spec 100W commodity panels to add in whereas same-spec bigger panels may come and go or not be obtainable when you wish. Or not still be low cost.

I'm just trying to piece a working system together.

Configuring 4 panels in a 2S2P manner (quite popular), you could get by with a Victron 100/30

Although a bit more money Victron is a top shelf brand. It should last well.
Either way 2S2P with 400W is a good setup.

 

[reecetas7196]

Is there anything missing here or is this a pretty basic setup which really all I need?

 

[John Frum]

Should be over-current protection between the starter battery and the kill switch
Also 10 awg undersized for that long circuit and will cause excessive voltage drop

There is no provision for shore power

We usually like to see a double pole single throw switch between the panels and the solar charge controller

That 100amp hour agm battery would not even run that inverter for 30 minutes at full bore.

Its a very small system by today's standards

Are you in North America or other?

 

[reecetas7196]

Should be over-current protection between the starter battery and the kill switch
Also 10 awg undersized for that long circuit and will cause excessive voltage drop

There is no provision for shore power

We usually like to see a double pole single throw switch between the panels and the solar charge controller

That 100amp hour agm battery would not even run that inverter for 30 minutes at full bore.

Its a very small system by today's standards

Are you in North America or other?

I'm in California. This is just a diagram I found online. I have two 100w Solar Panels and a 100ah Lifepo battery. That's all I have right now. I need to figure out what I need to get a basic solar setup with a Fuse box to include my LED lights and MaxxFan for now. Also, eventually an inverter, probably 2000w. and the switch and whatever else is needed for switching between car battery charge and solar charge for house battery.

 

[John Frum]

I'm in California. This is just a diagram I found online. I have two 100w Solar Panels and a 100ah Lifepo battery. That's all I have right now. I need to figure out what I need to get a basic solar setup with a Fuse box to include my LED lights and MaxxFan for now. Also, eventually an inverter, probably 2000w. and the switch and whatever else is needed for switching between car battery charge and solar charge for house battery.

A 2000 watt inverter will draw...
2000 ac watts / .85 conversion factor / 10 volts low cutoff = 235.294117647 service amps
235.294117647 service amps / .8 fuse headroom = 294.117647059 fault amps

That means 2/0 awg wire and a 300 amp fuse for the inverter circuit.
4/0 awg and a 400 amp fuse for the main circuit.
You also will need a lot more battery to deliver ~235 amps continuous.