I am getting ready to put together my solar in a van. I have 4 100ah batteries each with a bms that I'll wire in parallel. I am lookin at the redarc bcdc1250 and the renogy dc/dc50amp with mppt controller. I believe I can get 400 watts of panels on the roof but may have to go with 300 watts. I calculated the daily usage to be about 350ah so I think I'm ok there. I plan on a 2000w inverter and no shore power as we plan to drive most every day but I am considering adding a 110v charger (10amp) to the battery bank so I have the option for that if needed which I would likely put a switch in so I could disable the solar panels if plugged in. Any opinions on this setup? renogy vs. redarc etc.
redarc vs, renogy with 300 or 400 watt panels
- Thread starter Soggy Man
- Start date
You haven't mentioned voltage but ill assume 12v.
If you estimate 350Ah consumption daily that is 12.8V * 350AH = 3200Wh per day
300-400W of solar is pretty undersized for this. Even if we assume perfect efficiency and conditions and 100% of rated output (which are unrealistic assumptions to plan on) it would take between 8-11hrs of full sun to generate what you use everyday.
You'll be pretty dependent on your secondary charge sources, but even then, 350Ah / 50A = 7hrs minimum to charge via alternator, or 350Ah / 10A = 35hrs to charge via 10A wall charger.
If you estimate 350Ah consumption daily that is 12.8V * 350AH = 3200Wh per day
300-400W of solar is pretty undersized for this. Even if we assume perfect efficiency and conditions and 100% of rated output (which are unrealistic assumptions to plan on) it would take between 8-11hrs of full sun to generate what you use everyday.
You'll be pretty dependent on your secondary charge sources, but even then, 350Ah / 50A = 7hrs minimum to charge via alternator, or 350Ah / 10A = 35hrs to charge via 10A wall charger.
John Frum
Tell me your problems
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Max pv voltage is 25 volts
www.renogy.com
Max pv voltage is 32 volts
redarcelectronics.com
Here is a 3rd option
Max pv voltage is 50 volts
DCC50S 12V 50A DC-DC On-Board Battery Charger with MPPT
Make sure your service battery has all the juice it needs with Renogy's DCC50S DC-DC MPPT On-Board Battery Charger. 10% off: Renogy10off. Free shipping
www.renogy.com
Max pv voltage is 32 volts
BCDC Classic 50A In-vehicle DC Battery Charger
The REDARC BCDC1250D is a 12V, 50A In-vehicle DC to DC Battery Charger designed to keep your auxiliary battery charged when driving or with portable solar panels when parked.
redarcelectronics.com
Max pv voltage is 50 volts
KISAE DMT1250 Abso 50A DC-DC Battery Charger | DonRowe.com
The KISAE DMT1250 DC to DC Battery Charger is a multi-stage, multi-input battery charger capable of charging different types of batteries commonly installed in boats, RV's, 4WD's and commercial vehicles.
www.donrowe.com
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Going back and looking... I could be off on that 350ah. I've tried using a spreadsheet I found online that supposed to give you the daily ah but honestly I'm not really sure. I really guessed at what I thought it may be...rookie mistake I know. I'm just having trouble wrapping my head around this stuff. It is a 12v system. I really thought 400ah of battery would be plenty.
I feel your pain. Guestimating may not be the ideal approach but, but in the real world. Putting together a detailed spreadsheet is doable if you have a van/camper/etc that is already partially or fully built and used/lived in, but when you are building from scratch, its near impossible to avoid guestimating and downright guessing at some things. There can be a lot of variables and unknowns. But its still important to do the best you can (and err on the side of caution when you don't know).
Another approach would be to figure out your bottleneck (in your case its almost certainly generation/solar+secondary charge sources, and work backwards from there. (basically the reverse of the normal approach of figuring out how much power you will use and building your system around your needs--in other words figure out how much you can reasonably expect to generate per 24hrs in real world unideal circumstances and mold the rest of your system and your usage patterns around that limitation).
It might be, it can be, and it should be for a smallish system unless you are attempting to go all electric or use A/C.
What are your largest energy consumers?
Will you have propane on board?
Cajunwolf
Solar Enthusiast
Well, 400ah is a reasonably large battery bank for a van.
Edit: Maybe instead of 350ah, you meant 350wh, which equates to around 30 amps, which sounds more right.
My guess is not, 350Wh is pretty damn minimal even for a van. In the last ~5 years or so, there has been a lot of inflation in the typical size of van electrical systems driven by the more glamping oriented sprinter crowd. A lot of people pursue all electric, or mostly electric, and expect a lot of creature comforts, compared to what was the norm 10 years ago.
The house electrical system in my van was only (1) compressor fridge (2) low wattage lights (3) a small inverter. Today I frequently talk to people designing for A/C, induction cooking, microwaves, electric water heating, and kitchen appliances like instapots, slow cookers, blenders, and electric kettles.
Cajunwolf
Solar Enthusiast
All of that being said, and from the information provided, here's my $.02's worth.
He's going to be driving most of the time. Sounds like a job for an alternator-driven charging system.
When stopped for some sleep, and a 120AC socket available, a good high amperage 12-volt DC charger (Aims), and an extension cord (10ga) to the rescue.
For the load the OP is talking about, there isn't real estate on the roof of a standard van for enough panels to charge in a reasonable amount of time.
He's going to be driving most of the time. Sounds like a job for an alternator-driven charging system.
When stopped for some sleep, and a 120AC socket available, a good high amperage 12-volt DC charger (Aims), and an extension cord (10ga) to the rescue.
For the load the OP is talking about, there isn't real estate on the roof of a standard van for enough panels to charge in a reasonable amount of time.
Most days*, its unclear to me how much actual time will be spent driving. I've lived and traveled long term in a van a few times in my life, driving most days does not always mean a lot of driving time, in fact sometimes it means the opposite. I average probably 1.5-4hrs per day , with occasional 6+ hr days and many <1.5 hr days, as well as many non-driving days.
Point being OP needs to consider their driving and camping patterns to determine how feasible alternator charging will be for their expected consumption. 350Ah / 50A works out to minimum of 7hrs driving per day, everyday, just to break even assuming consistent 50A charging. I don't know enough about OP's scenario to know how realistic this is or isn't, but for me, it would be incredibly unrealistic. Over 1000+ days living on the road, I would guestimate maybe 2-3% were 7+ hr days. For someone doing 1-3wk cross country roadtrips, or long weekends with lots of driving, 7+ hrs everyday might be totally normal and doable.
That said, I agree with you that:
I think we are of a similar mind here, for a small van sized system with heavy expected consumption, having multiple power sources, and maximizing the power of each source is probably the only realistic path forward (apart from reducing consumption, which is the cheapest and simplest strategy in many cases).
Cajunwolf
Solar Enthusiast
Cajunwolf
Solar Enthusiast
I wish OP would clarify the 320ah figure; that's a lot of amps/hour; dang, what are we running, a sawmill? @Soggy Man Jokin, of course.
Alternator charging while driving with solar during daylight hours work well for me because I like to travel. I'm only limited by how much money I have for gas. Therefore, a Class C Rv with a 460 can limit my range depending on terrain and weather. When in the oilfields, I often drove 3, 4 hours both ways, and sometimes 20 hours at a time when crossing multiple states fueled by coffee and junk food. My favorite times were out on the open road at 3 am listening to the radio, if you could pick up a station while on overtime, and my truck making $.60/mile. Many moons ago, to be sure, but I still love to drive/travel, and when you're traveling in your cozy little home, it's so much better.
Back on topic, my bad.
I have 400ah at 24-volts with a 4kW Giandel, and I'm only doing 30ah max, and that's only 60 amps at 12-volts. That would be with my 6000 BTU window unit running with a thermostat, so it doesn't run constantly; I'm guessing 60 percent of the time. I have a dual fuel 4.3kW generator for anything heavy. I have a ten cu ft apt style fridge, but if you only open the door every so often, it barely uses any juice. I'm not big on the microwave; I use it to reheat coffee or tea along with certain heat-up meals (it's only 900 watts). I have a sweet 4-burner propane stove with a nice oven and a 12k BTU propane furnace. I carry a lot of propane. The other thing would be the TV (32") and my laptops; that's diddly squat. I have other electrical appliances, but I use them when plugged into 30a shore power or while running the (noisy) generator.
Alternator charging while driving with solar during daylight hours work well for me because I like to travel. I'm only limited by how much money I have for gas. Therefore, a Class C Rv with a 460 can limit my range depending on terrain and weather. When in the oilfields, I often drove 3, 4 hours both ways, and sometimes 20 hours at a time when crossing multiple states fueled by coffee and junk food. My favorite times were out on the open road at 3 am listening to the radio, if you could pick up a station while on overtime, and my truck making $.60/mile. Many moons ago, to be sure, but I still love to drive/travel, and when you're traveling in your cozy little home, it's so much better.
Back on topic, my bad.
I have 400ah at 24-volts with a 4kW Giandel, and I'm only doing 30ah max, and that's only 60 amps at 12-volts. That would be with my 6000 BTU window unit running with a thermostat, so it doesn't run constantly; I'm guessing 60 percent of the time. I have a dual fuel 4.3kW generator for anything heavy. I have a ten cu ft apt style fridge, but if you only open the door every so often, it barely uses any juice. I'm not big on the microwave; I use it to reheat coffee or tea along with certain heat-up meals (it's only 900 watts). I have a sweet 4-burner propane stove with a nice oven and a 12k BTU propane furnace. I carry a lot of propane. The other thing would be the TV (32") and my laptops; that's diddly squat. I have other electrical appliances, but I use them when plugged into 30a shore power or while running the (noisy) generator.
I really do appreciate all the input. And yes this is an empty van to start with and some things I did guess at because I don't really know how much usage there will be from various items. I do plan on installing a dc/dc charger to supplement when driving. And yes actual drive time is likely 4hrs or less per day with some days of no driving. I will not have an air conditioner but I do plan on running two (2) fridges 12v. Propane but only for cooking and hot water (no water heater)...and a webasto heater. I do plan to have 2-3 a/c outlets as well connected to a 2000w inverter. That being said here is a list of what I think the main draws will be.
2 fridges (we cook a lot) This is the largest draw
2 laptops
2 Cell phones
2 ipads
1 max air fan
Webasto Heater (part time use of course)
H2O pump
Propane solenoid
4-6 camera batteries (some use d/c some use a/c)
6-10 L.E.D. puck lights
There may be some incidentals but not much and only momentary usage.
I did recalculate and come up with about 250wh ish. I am trying to guesstimate and err on the side of more than may be needed but as another said space is limited inside and out.
2 fridges (we cook a lot) This is the largest draw
2 laptops
2 Cell phones
2 ipads
1 max air fan
Webasto Heater (part time use of course)
H2O pump
Propane solenoid
4-6 camera batteries (some use d/c some use a/c)
6-10 L.E.D. puck lights
There may be some incidentals but not much and only momentary usage.
I did recalculate and come up with about 250wh ish. I am trying to guesstimate and err on the side of more than may be needed but as another said space is limited inside and out.
You appear to be getting confused between Amp Hours (Ah) and Watt Hours (Wh), they are not the same thing. In your first post you mentioned an estimate of 350 Ah, in this last post you mention 250 Wh, These are different units, and if you convert to like units (3200Wh = 350Ah @ 12V) a difference (reduction) of nearly 92%.
Are you sure you are getting the units and the math right? Something seems off. For the loads you have listed the first estimate of 3200Wh seems pretty high, but the 250Wh estimate seems unrealisticically low.
The good news is that the loads you have listed sound reasonable and doable, no obvious super high draw items, how are you estimating the consumption of the fridges?
Are you sure you are getting the units and the math right? Something seems off. For the loads you have listed the first estimate of 3200Wh seems pretty high, but the 250Wh estimate seems unrealisticically low.
The good news is that the loads you have listed sound reasonable and doable, no obvious super high draw items, how are you estimating the consumption of the fridges?
Cajunwolf
Solar Enthusiast
I assume those are 12-volt fridges? They should have the amp/wattage draw on a label somewhere or in the manual under specifications. I looked into 12-volt fridges, and most use very little current. Being top loaders, you save from not having all of the cold air dump out when you open a door.
You say you cook a lot, on what? You mentioned a propane solenoid, perhaps a propane stove. You mentioned the Webasto Heater (diesel?), and I believe they have a small draw. They also have a cooktop.
Two laptops with chargers can pull a lot depending on the laptop. Only plug the charger in when the laptop needs charging. I see many folks leave them plugged in, and that's a consistent draw as the charger is trying to replace what you're using.
You say you cook a lot, on what? You mentioned a propane solenoid, perhaps a propane stove. You mentioned the Webasto Heater (diesel?), and I believe they have a small draw. They also have a cooktop.
Two laptops with chargers can pull a lot depending on the laptop. Only plug the charger in when the laptop needs charging. I see many folks leave them plugged in, and that's a consistent draw as the charger is trying to replace what you're using.
The way I guestimate laptop power consumption (or any other device with a battery), is lookup the specs for the battery (laptops and smartphone specs rarely state Watt-hours, but if you lookup the replacement part, it'll usually tell you. My laptop (which is pretty efficient and small) has a ~50Wh battery, my cell phone has a ~12Wh battery. So if I assume 1 charge per device per day, and maybe 50% charging efficiency to be safe, that is about 125Wh per day for a full charge for both devices. I like this method since most people are usually pretty in tune with how long a charge lasts them, and how many days per charge or charges per day is normal for them, so its rather intuitive I think.
Both fridges are top load. I did get average amp draw from the manufactures website. We will be cooking on a propane burner that is much like a camping stove. No power needed except propane. Webasto heater will be gasoline. 7.5 amps on start up for about 2 mins then on high 2.45a med 1.7a low1.25a. Chargers are to plugged in when needed only plus I plan to use switchable usb outlets so they can be turned off when not needed.
50ShadesOfDirt
Solar Enthusiast
- Joined
- Jan 8, 2021
- Messages
- 432
Consider adding these capabilities, as this is a van build:
1. beefed up alternator, as there will be *some amount of* driving; all bits and bobs & wiring to get this (free) power to the inverter/charger
2. both rooftop and portable solar panels (put these out when parked); mppt & bits and bobs to get this (free) power to the inverter/charger
3. portable genny and shore-power hookup; all bits and bobs & wiring to get this (absolutely necessary backup) power to the inverter/charger
400Ah of LFP is smart (as much Ah as can afford/fit into the van). just add the above to have multiple sources of power for recharging. All this assumes 12v inverter/charger (magnum) or some such.
hope this helps ...
1. beefed up alternator, as there will be *some amount of* driving; all bits and bobs & wiring to get this (free) power to the inverter/charger
2. both rooftop and portable solar panels (put these out when parked); mppt & bits and bobs to get this (free) power to the inverter/charger
3. portable genny and shore-power hookup; all bits and bobs & wiring to get this (absolutely necessary backup) power to the inverter/charger
400Ah of LFP is smart (as much Ah as can afford/fit into the van). just add the above to have multiple sources of power for recharging. All this assumes 12v inverter/charger (magnum) or some such.
hope this helps ...
williamsk913
New Member
- Joined
- Sep 27, 2019
- Messages
- 99
One benefit of the renogy combined mppt DC to DC chargers is that on the lifepo4 setting (if you have them), using the temp probe on lifepo4 setting, the charging will be cut off at low temps. Had a gentleman give up on it because of glitchy user setting issues and limitations on voltage, but was kind enough to pass it on. As I will use as just a DC to DC charger, the low temp charging protection is a nice little feature. Everyone stresses about charging protection for solar, but forget about safeguarding other sources. May not be an issue for you depending on your battery chemistry or bms, but may be. Something to check for if you do have lifepo4.
