12vdc camper van build (EFFICIENCY!!!)

[butchandmungo]

Budget (including currency):  pounds sterling (£)

Country: uk

Games, programs or workloads that it will be used for: starsector (heavily modded), battle brothers, underrail, mount and blade, morrowind (heavily modded), plus others less often

Other details (existing parts lists, whether any peripherals are needed, what you're upgrading from, when you're going to buy, what resolution and refresh rate you want to play at, etc):  currently have an 7600x in a asrock b650m m.2/hdv motherboard and a powercolor fighter rx 7800. With moving to 12vdc, i will need a pico psu and 12v monitor.

 

The main question i have is should i keep my current setup and replace the rx 7800 (bought to play helldivers, but far too much for a 12vdc build) with something like an rx 6600 (and undervolt the snot out of it).

 

Or should i look at getting an apu like the 8700g?

 

If i could get the descreet gpu and cpu down to a similar power draw as the apu, then i surely that would be a better option? Is it even possible to bring them down so far? Apu ~65w tdp  :  gpu + cpu ~200w tdp

 

12w is 1ah @ 12v, so even the smallest savings will make a big difference.

 

Basically with battery power being at a premium in a camper van, efficiency is king.

 

 

 

[keskparane]

get a generator and not worry about how much power you use?

[butchandmungo]

Genny is not possible. Needs to run off solar and battery

 

Biggest battery i can afford is around the 100 ah mark

 

Obviously this needs to run other things in the van, 8/10ah for the computer is about what i consider reasonable.

 

Edit: but less is always more desirable!!!

[DoctorNick]

50 minutes ago, butchandmungo said:

Genny is not possible. Needs to run off solar and battery

 

Biggest battery i can afford is around the 100 ah mark

 

Obviously this needs to run other things in the van, 8/10ah for the computer is about what i consider reasonable.

 

Edit: but less is always more desirable!!!

You can try undervolting your CPU with PBO, set limits. Should be able to get about the same power draw as 7600. https://www.techpowerup.com/review/amd-ryzen-5-7600-non-x/22.html

 

For GPU this chart is pretty useful: https://www.techpowerup.com/review/nvidia-geforce-rtx-4080-super-founders-edition/41.html

 

A 200Wh load is 16.667Ah @12v

[butchandmungo]

Hmm yea it seems getting anywhere near the 8700g 65w im gonna sacrafice a lot of performance.

 

Even limiting the cpu to 35w and undervolting a 6600, it still isnt close.

 

Might just go for the apu seeing as its low power and simple.

 

Plus a gpu in a moving vehicle seems like a bad idea. Pcie slots arent exactly indestructable

 

P.s. thanks for your replys! Appreciate the input

[Nuzicx]

Create a power management spreadsheet (I've attached one to get you started), figure out all electrical items, edit fields: name, wattage, day runtime, night runtime (in hours). This spreadsheet has 4480ah (1120ah @ 48v) and can be changed in the depth of discharge 100% field, this field is in 12V for calculations. This projects is not quite finished and you'll notice not enough solar being produced to keep up with the electrical demand (as shown in 'Balance on yield' in the Solar Panel Info, here's where an alternator comes into use. Alternators are a fast & cheap way of using your van/boat engine to produce power to the batteries. I'm in Australia and we use 220/240V for inverter, that will need to change if you use different voltage for your inverter system. The field 'Inverter (Loss inc 10%)' this calculates the load of the inverter system back into 12V for calculations on the overall draw of the system, leave untouched '5% - Loss in wires' as wires lose energy they are 'transporting'. Solar panel info 'Yield day AVG Wh' is a calculation of how much solar panels produce in my area, it may be different to yours, use a solar calculator to get your result, from memory its got 3 x 290w panels.

 

Apologies for it being very messy.

 

Electrical.xlsx

 

 

Build your system with a great capacity then required.

ChatGPT: Is it's better for the batteries if your not drawing a lot of volts/amps?

Spoiler

Yes, generally speaking, it's better for the longevity and health of batteries if you avoid drawing high amounts of voltage or current (amperage) from them. Here are a few reasons why:

1. Heat Generation: High current draw can generate a lot of heat. Excessive heat can damage battery cells, reduce their lifespan, and even cause them to fail prematurely.

2. Voltage Sag: High current draw can cause a significant drop in voltage, known as voltage sag. This can affect the performance of the device powered by the battery and can lead to a shorter effective battery life.

3. Cycle Life: Batteries have a limited number of charge and discharge cycles. Drawing high currents can reduce the number of effective cycles, thereby shortening the overall lifespan of the battery.

4. Internal Resistance: High current draw can increase the internal resistance of a battery over time. Higher internal resistance means less efficient operation and more energy lost as heat.

5. Capacity Loss: High discharge rates can reduce the effective capacity of the battery. This means the battery will provide less energy over time compared to when it's discharged at a lower rate.

6. Chemical Stress: High currents can stress the chemical components of the battery, potentially leading to issues such as dendrite formation in lithium-ion batteries, which can cause short circuits and battery failure.

To maximize battery life, it's generally best to:

• Use batteries within their recommended current and voltage ranges.
• Avoid deep discharges and overcharging.
• Maintain batteries at a moderate temperature.
• Store batteries at partial charge if they are not going to be used for an extended period.