Battery bank — LiFePO4 · battery monitor required · 12V system
Total capacity
300 Ah
Rated LiFePO4
Usable capacity
240 Ah
80% DoD limit
Starting SOC
100%
Your battery monitor reading
Available today
240 Ah
From current SOC
Battery settings — adjust to match your battery monitor reading and configuration
Battery capacity
300 Ah
Total rated Ah of your LiFePO4 battery or bank.
Starting SOC
100%
Set to your battery monitor reading. 100% = fully charged after shore power or a full solar day.
Min usable SOC
20%
LiFePO4: 20% recommended floor. BMS hard cutoff ~10%. Do not cycle below 20% regularly.
System losses
10%
Wiring resistance, BMS, connections. Typical 8–12%.
Charging sources — adjust drive time, solar size and day conditions
Drive time today
4.0 h
Hours engine running. DC–DC charger feeds aux battery whenever alternator is above ~13.2V.
DC–DC charger output
23 A
DC–DC charger output in Amps. Common units: 20A, 25A, 40A. Set to 0 if no DC–DC charger fitted.
Solar panel watts
200 W
Total rated watts of your solar panel or blanket (MPPT controller assumed). Set to 0 if no solar deployed.
Peak sun hours
5.0 h
Southern & East Africa clear day: 4.5–6.5 h. Overcast: 1–2 h. Heavy overcast: 0.5–1 h.
Panel efficiency factor
72%
Combined derating: heat, angle, dust, MPPT losses. Blanket on hot roof: ~70–75%. Clean panel, cool: ~85–92%.
Load profile — select a preset or edit the table directly
| Appliance / Item | Draw (A) | Hrs/Day | Note | Ah/Day | |
|---|---|---|---|---|---|
| TOTAL DAILY LOAD | — | ||||
Daily energy balance — calculated from all inputs above
Available today
—
Ah from current SOC
Total daily load
—
Ah consumed today
Total charging
—
Solar + DC–DC Ah
Solar input
—
Effective Ah today
Alternator input
—
Via DC–DC today
Battery autonomy
—
Days without charging
Calculation breakdown
Battery capacity—
Usable capacity (DoD range × system efficiency)—
Available from starting SOC—
Solar — —
DC–DC alternator — —
Total daily load—
Net balance (total charging − load)—
End-of-day SOC—
Battery autonomy (zero charging scenario)—
System notes — LC76 power configuration
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National Luna 52L compressor fridge: Draws 1.2A at low speed to 2.8A at high speed. In SA summer heat (38°C ambient) at mid-speed, the compressor runs roughly 55% of the time — about 13 hours out of 24 at an average of 3.75A, giving 45 Ah/day. Pre-cool the fridge to 4°C on shore power before leaving for a wild camp — this saves 10–15 Ah on day one. Shade the fridge when stationary. In cooler conditions (25°C), the same fridge draws ~25–30 Ah/day.
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DC–DC charger (alternator charging): At 23A output and 88% efficiency, 2 hours of driving delivers ~40 Ah to the aux battery. A full 8-hour drive day delivers ~162 Ah — enough to recover a heavily depleted 300 Ah bank. The 1HZ alternator has ample headroom for a 20–40A DC–DC charger. Use driving time efficiently — the first two hours deliver the most benefit.
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Solar panel or blanket: A 200W panel at 5 peak sun hours with 72% combined efficiency (heat, angle, dust, controller losses) delivers ~60 Ah/day on a clear African day. At the 77 Ah/day reference load, solar alone leaves a 17 Ah daily deficit — covered by about 55 minutes of driving. Dust on the panel or blanket costs 10–30% output — clean every 3–5 days. Park solar-side in full sun.
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Reference load ~77 Ah/day (from R5 Battery Training Guide): Fridge 45.0 Ah · Laptop 5.0 Ah · iPhone ×2 5.0 Ah · GPS nav 2.5 Ah · Camera charging 2.7 Ah · Fan charging ×2 1.5 Ah · LED lights & misc 3.6 Ah. This reflects actual daily draw at camp in SA summer conditions.
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How to calculate any appliance’s daily load — three steps:
Step 1 — Find the current draw in Amps. Check the device label or manual for rated watts, then divide by 12: Amps = Watts ÷ 12V. A 30W laptop charger draws 30 ÷ 12 = 2.5A. If the spec sheet lists Amps directly, use that figure.
Step 2 — Estimate daily hours of use. For devices that run continuously (fridge, tracker), use 24h — but apply a duty cycle for compressor devices. A fridge compressor does not run 24/7; in SA summer heat it runs roughly 55% of the time, so effective hours = 24 × 0.55 ≈ 13h. For devices used in sessions (charging phones, laptop), use actual charging time.
Step 3 — Multiply: Ah/day = Amps × Hours. A fridge at 3.75A running 13h = 48.75 Ah/day. A phone charger at 1.67A for 1.5h = 2.5 Ah. Add up all appliances for your total daily load.
Key conversions: Watts ÷ 12 = Amps · Amps × Hours = Ah · Wh ÷ 12 = Ah · Ah × 12 = Wh. To find how many days your battery will last without charging, divide usable Ah by total daily load.
Step 1 — Find the current draw in Amps. Check the device label or manual for rated watts, then divide by 12: Amps = Watts ÷ 12V. A 30W laptop charger draws 30 ÷ 12 = 2.5A. If the spec sheet lists Amps directly, use that figure.
Step 2 — Estimate daily hours of use. For devices that run continuously (fridge, tracker), use 24h — but apply a duty cycle for compressor devices. A fridge compressor does not run 24/7; in SA summer heat it runs roughly 55% of the time, so effective hours = 24 × 0.55 ≈ 13h. For devices used in sessions (charging phones, laptop), use actual charging time.
Step 3 — Multiply: Ah/day = Amps × Hours. A fridge at 3.75A running 13h = 48.75 Ah/day. A phone charger at 1.67A for 1.5h = 2.5 Ah. Add up all appliances for your total daily load.
Key conversions: Watts ÷ 12 = Amps · Amps × Hours = Ah · Wh ÷ 12 = Ah · Ah × 12 = Wh. To find how many days your battery will last without charging, divide usable Ah by total daily load.
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SOC danger zones: Below 30% — reduce load, plan to drive or find shore power. Below 20% — fridge and essential loads only. Never below 10% — BMS hard cutoff. Always aim to arrive at camp with >50% SOC when heading into a wild camp with no shore power available.
Common appliance draw — reference
| Appliance | Draw (A avg) | Hrs/Day | Ah/Day | Notes |
|---|---|---|---|---|
| Compressor fridge 52L (SA summer 38°C) | 3.75A | ~13h run | 45.0 Ah | 55% duty cycle · pre-cool on shore power saves 10–15 Ah Day 1 |
| Compressor fridge 52L (mild 25°C) | 2.08A | ~12h run | 25.0 Ah | 40% duty cycle · cooler morning & evening conditions |
| Laptop (USB-C 30W) — full charge once/day | 2.08A | 2.4h | ~5.0 Ah | 49.9 Wh battery ÷ 12V ÷ 85% charger eff. = 4.9 Ah to fill from flat |
| Laptop — charge + active use (2h each) | 3.17A | 4h total | 6.7 Ah | 30W charge × 2h + 8W active × 2h ÷ 12V |
| Smartphone (USB-C 20W) — per phone | 1.67A | 1.5h | 2.5 Ah | 20W ÷ 12V × 1.5h per phone |
| GPS navigator (12V socket) | 0.42A | 6h | 2.5 Ah | 5W ÷ 12V × 6h |
| Camera batteries (dual charger) | 1.33A | 2h | 2.7 Ah | 16W ÷ 12V × 2h |
| Portable fan (internal battery, daytime top-up) | 0.38A | 2h × 2 | 1.5 Ah | Fan runs overnight on its own cell · 12V aux tops it up during day only |
| LED camp lighting | 0.6–1A | 3–5h | 2–5 Ah | Quality LED strips are a small load |
| 12V water pump | 5–7A | 0.2h | 1–1.5 Ah | Intermittent use only |
| Satellite tracker (10-min interval) | 0.08A | 24h | 2.0 Ah | Very low continuous draw |
| CB radio (receive only) | 0.5A | 6h | 3.0 Ah | Transmit adds 4–5A but only in short bursts |
| Inverter 300W at 50% load | 14A | 1h | 14.0 Ah | 150W AC output + ~10% inverter loss |