Short, field‑tested guide to size your EV camping battery bank. Learn how to budget daily Wh, convert to Ah at 12.8V, choose between 200Ah and 300Ah LFP, and run a pure sine 3kW inverter with ATS safely.
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Alt: EV camping power Q&A LFP 200-300Ah core: LFP battery, pure sine 3kW inverter, ATS
Caption: Apply the 1.3 safety margin to your daily Wh and convert to Ah at 12.8V. |
EV Camping Power Q&A: Field‑tested answers you can apply tonight
Hook. If you can write down your devices and hours, you can size your system in one page. This post is my compact EV camping power Q&A LFP 200-300Ah playbook built from real weekends, cold mornings, and that one dawn when the fridge stopped and coffee went lukewarm.
Plain words first
LFP = lithium iron phosphate (safer, long life).
Wh = energy you use (watts × hours).
Ah = how big your “water tank” is at 12.8V.
Pure sine inverter = clean 220V like at home.
ATS = automatic switch between outside AC/V2L and inverter so both never tie together.
A) Quick Answers (the essentials you keep open on your phone)
Q1. How do I calculate the battery size in minutes?
List each device, write W × h = Wh, add all Wh, multiply by 1.3, then convert to Ah at 12.8V.
Formula: Ah = (total Wh ÷ 12.8) × 1.3.
This one line drives the whole EV camping power Q&A LFP 200-300Ah method.
Q2. 200Ah vs 300Ah — which one first?
If your day totals around 70–95Ah, 200Ah is fine. If you cook often, work on a laptop for hours, or want a relaxed margin (~90–120Ah/day), go 300Ah. That choice alone prevents 80% of headaches.
Q3. Why a pure sine 3kW inverter as the baseline?
Heaters and motors surge at start‑up. A 3kW rating with ≥2× surge handles those spikes and keeps electronics quiet. Check idle draw (lower is better at night).
Q4. Where does ATS fit and why should I care?
Path: Shore/V2L AC → ATS → charger/inverter/battery → distribution.
ATS makes sure two AC sources never touch. It’s the cheap insurance that protects gear and you.
Q5. Can V2L alone cover a weekend?
Yes for light loads. If you also cook and edit video, mix sources: V2L + shore power when available + a drive‑charge + a bit of solar. The EV camping power Q&A LFP 200-300Ah approach is hybrid on purpose.
B) Sizing & Runtime (with one real case you can mirror)
Case I actually logged (work + simple coffee):
Table 1. One‑night power budget (example)
| Device | Watts | Hours | Daily Wh | Cumulative Wh | Ah @12.8V (×1.3) |
|---|
| Fridge (small) | 40 | 8.0 | 320 | 320 | 25.0 |
| Laptop | 60 | 3.0 | 180 | 500 | 39.1 |
| LED lights | 10 | 5.0 | 50 | 550 | 43.0 |
| Vent fan | 15 | 8.0 | 120 | 670 | 52.3 |
| Coffee machine | 800 | 0.3 | 240 | 910 | 71.1 |
| Safety margin ×1.3 | | | 1183 | | ≈92Ah/day |
With ~92Ah/day, I ran 200Ah fine when cooking was short and sharp. On rainy days with longer indoor time, 300Ah felt right. That is the practical spirit of EV camping power Q&A LFP 200-300Ah—numbers first, shopping second.
Table 2. Situational recommendation (summary)
| Pattern | Daily Ah (12.8V) | Recommended LFP | Note |
|---|
| Light overnight | 70–95 | 200Ah | lean and affordable |
| Frequent cooking / long laptop work | 90–120 | 300Ah | better surge headroom |
| 2‑day autonomy (no charging) | 140–190 | 300Ah+ | plan mixed charging |
Blank you can fill (copy this one):
Table 3. One‑night budget (template)
| Device | Watts | Hours | Daily Wh | Cumulative Wh | Ah @12.8V |
|---|
| Fridge | | | | | |
| Laptop | | | | | |
| Lights | | | | | |
| Vent fan | | | | | |
| Cooktop/coffee | | | | | |
| ×1.3 margin | | | | | |
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Final Ah = (total Wh ÷ 12.8) × 1.3
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≤92Ah/day → start with 200Ah; above that → 300Ah.
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Update this table after your first trip to keep the EV camping power Q&A LFP 200-300Ah plan honest.
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Alt: Power calculation memo, simple system flow, wiring/safety checklist
Caption: Wh = W×h, total×1.3 → Ah(12.8V). Keep fuse/breaker near the battery and ensure ventilation. |
C) Hardware & Safety (straight‑ahead checklists you can tick)
Q6. What spec list should I use to choose an inverter?
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Rated 3kW, surge ≥2×
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Idle draw clearly stated
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Pure sine output, low noise
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Terminal size and recommended cable gauge listed
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Thermal/over‑current protections, decent manual and support
Q7. How do I connect ATS correctly?
Use the simple path above. After wiring, test switching with power on/off, then test ground‑fault/ELCB. The EV camping power Q&A LFP 200-300Ah baseline assumes ATS is your “always‑on guard”.
Q8. What are the non‑negotiable wiring rules?
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Fuse/breaker close to the battery terminal
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Keep runs short, size thick enough to avoid voltage drop
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Proper busbar/terminal torque and labels
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Ventilation around the battery/inverter bay
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Keep heavy items on the floor; top load ≤15 kg
Q9. Charging strategy that actually works?
Blend sources:
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V2L for simplicity (set a lower SoC limit in car settings)
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Shore power at camp/home for a full top‑up
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DC‑DC while driving to recover during transits
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Solar as a helper (season and shade matter)
Q10. Real‑day timeline I follow (you can copy):
18:00 arrive → lights + fan only
19:00 cook within 15 minutes (brief hot loads)
21:00 2‑hour laptop session, glance at inverter temp
23:30 sleep with fridge + fan running
07:00 coffee, pack, drive—charge topped by the road
Q11. Top 5 beginner mistakes to avoid?
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Inverter undersized vs surge
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Long thin cables causing heat/drop
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No fuse/breaker near battery
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BMS and charger spec mismatch
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Grounding confusion between V2L and inverter (back‑feed risk)
Q12. Pre‑departure 10‑point checklist (print this):
Battery‑side fuse/breaker; cable gauge/length; busbar torque; ATS switching test; GFCI/ELCB test; V2L SoC floor set; inverter idle draw confirmed; airflow clear; top load ≤15 kg; two extinguishers + CO/LP gas/smoke alarms.
Internal links
External references
Author box (signature)
Molracha | Practical EV‑Camping Editorial
We follow field practice and manufacturer documents. If electrical work feels uncertain, let a professional check your wiring for safety.
Watch related YouTube videos here ^^*
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