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Welcome!

#VanLife, is that a thing? Is this temporary until your trip is finished or are the US full of people living in their cars all the time? :)
 
Definitely something in the back of my head makes me want to run away and do the same thing in Australia... Good on you for getting out and doing it .
 
MotoBitCrush said:
Its a thing, people do it for years in US, Canada, Europe, Asia, And Australia. There is one German couple who's been doing it for over a decade
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That's really interesting! I think you aren't even the first one here, we have a gentleman around here somewhere who is looking at converting the back of a delivery van into his home.
 
You've totally come to the right place. Doesn't really matter whether you live in a car or not, basically everything you find here applies to your case as well. The only difference is probably that you have to take vibration into consideration but apart from that there is really virtually no difference.

I've quickly converted your available space to metrical units, so you have 30x119x12cm available. A pack of 30 cells sits on my table right now and it happens to be 30x5x7cm so you would be able to fit 23 of them. 21 make a nice 7S90P setup, so 24V system and about 6kWh of energy. Obviously there are alot of details to be worked out and the result may differ, maybe you could even use the space more efficiently, but just so you have some numbers to imagine what your system may look like once finished.
 
It doesn't really matter as it was only an example anyway. All I wanted to say is that in the space you have available you can store about 6 kWh worth of batteries. The exact details still have to be worked out anyway.
I think you have added a picture to your post? Something went wrong apparently, it just shows a blank area with an error sign. But 28Ah at 12V is about 0.33 kWh so with lithium cells you can fit about 18x the energy to your car :)
 
cool stealth setup! how do you get money? savings? odd jobs? freelance?
 
That's correct, 6 kWh at 12V is 500Ah. 6 kWh is what I use daily at home. There are people here, mostly from the US, that use between 30 and 60 kWh for their house. These are likely cases with several people living in the house and stuff like AC running for extended periods of time. Just to put this into perspective. If we're talking about small stuff, like charging smartphones, then 6 kWh is enough for a full charge every day for a year.

To know what you need is definitely important, otherwise you can't size your system properly.
Another important thing is that lithium cells don't make good 12V batteries. 7S / 24V is the way to go.
 
Well, I saw that one coming. This is a very common misunderstanding. The car runs on 12V anyway so this seems reasonable. And it is, but only for lead acid batteries. 4S lithium isn't 12V though and 3S isn't either. You need 3.5S, but that doesn't exist obviously. 3S is 9.0V to 12.6V, too low for 12V. 4S is 12.0V to 16.8V, too high for 12V. So with 3S you can't use the capacity of the battery because your 12V devices will cut off too early. And with 4S you are either forcing your devices into overvoltage protection or just frying them straight away or you don't charge the battery all the way and sacrifice capacity that way.
So recommendations to go for 12V are only valid for lead acid systems. If someone recommends a 12V system with lithium batteries either he has no clue what he is on about or he is talking about LiFePo cells. These have a nominal voltage of 3.2V and fit 12V is 4S configuration.

7S is much more reasonable with all kinds of LiIon and LiPo as it fits the 24V system nicely. It is 25.9V nominal and ranges from 21.0 to 29.4V. You can always use a 24V to 12V DC-DC converter to use your existing 12V equipment if you don't want to buy new devices or if 24V versions simply don't exist.
 
This is the notation for the configuration of the battery. S means Series, P means Parallel. xSyP means x cells in series (to get the desired voltage) and y cells in parallel (to get the desired capacity). If xS or yP is missing then it is either to be read as 1S or 1P respectively or it isn't important for what is meant to be said.

Examples:
- Car batteries are usually 6S lead acid batteries for a total voltage of 12V. A lead acid cell has a nominal voltage of 2V, 6x2V is 12V. There are no cells in parallel, so it is just 6S.
- Lithium batteries for small/medium RC vehicles are usually 3S or 4S, again no cells in parallel.
Technically these batteries can be called 3S1P, 4S1P and 6S1P. But that is not very common since the 1P part has no meaning in this case. Also, lead acid batteries are the reference when talking about 12V/24V/48V systems. They define these systems. That is why they are usually called 12V, 24V and 48V batteries instead of 6S, 12S or 24S.

- If someone says "Use a 7S battery" then there is no yP since this is not relevant in this case. It means you should use a battery with seven cells in series (of that given chemistry that is talked about, in this case lithium ion cells) and the number of cells in parallel is yet to be decided on available space, current draw and so on.

- Similar thing, "Use 90P packs" means you should take packs of 90 cells in parallel and add as many of them in series until you have the desired voltage.

- And finally, 7S90P as an example, is a complete electrical specification of a battery. It uses seven cells in series and 90 in parallel, so a total of 7x90 = 630 cells are needed. You know the voltage, it is seven times the nominal voltage of an individual cell, and the capacity, it is 90 times the capacity of the individual cell. Its energy is its voltage times its capacity and its maximum discharge current is 90 times the maximum discharge current of the used cells.

Did that became clear, more or less? It is not unusual that this is a bit confusing for people that are new to the business :)

And regarding you question about conversion losses from 24V to 12V: Not much is lost, the conversion efficiency of DC-DC converters is rather high so the losses are small. Efficiency can be as high as ~98% and is rarely under 90%. I usually use 95% as an example if no real figures are available.
 
Excellent welcome!

Fellow #vanlife person here, but only on weekends and holidays :) Sounds like you have a cool idea, especially with travelling as well and seeing the country.

Here is my van:


image_khvcdn.jpg


It has a 100 watt flexible panel and currently a 160ah lead acid battery. Its a beast and can last for days with the TV and mini fridge on! I may upgrade to Li-ion after my home powerwall is complete. I have a small charge controller and 1000 watt inverter but most things run off 12volt for now. Don't forget ventilation if you have a lead acid battery.

Oh and if you use Kodi I made a vanlife add-onto browse dedicated youtube channelsnicely on a TV. I can add your channel if you post it here? :)

Good luck in your adventure! Thats a very small van!!
 
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