One range, three uses
Sizing guide
Homes, RVs and boats share this catalogue. The difference is how many watt-hours you use in a day, the largest load that can be on at once, and whether the battery must charge below freezing.
| Load | Watts | Hours | Wh | |
|---|---|---|---|---|
| 960 | ||||
| 200 | ||||
| 160 | ||||
| 240 |
Energy for this list
1,560 Wh
If they run together
260 W
Suggestion
1 × 200Ah
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1 × 12.8V 200Ah · closest fit
R12,250 for 1. About 8.9 h at 260 W together. Continuous limit 2,560 W. Charges from −20°C.
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1 × 12.8V 300Ah
R15,850 for 1. About 13.3 h at 260 W together. Continuous limit 2,560 W. Do not charge below about 0°C.
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1 × 12.8V 300Ah Self-Cooling
R22,450 for 1. About 13.3 h at 260 W together. Continuous limit 3,840 W. Charges from −20°C.
Uses 90% of nameplate watt-hours and assumes the listed loads can be on at once. Estimates only — inverter losses (about 10–15%), start-up surges and temperature are not included. Real fridge and trolling-motor draw cycles. Resting voltage, not inverter load, is how the manuals say to read state of charge. Ask Danie for this setup.
Home backup
Add the appliances you actually keep on. A 120W fridge for 8 hours is already about 1kWh before lights and Wi-Fi. Match the inverter to the battery’s max load: 1,920W on the 100Ah, 2,560W on the 200Ah and the standard 300Ah, 3,840W on the rest.
RV and camper
A weekend with a compressor fridge, lights and a laptop often sits on a 300Ah. Longer off-grid stays and inverter cooking move you to 460Ah, 560Ah or 600Ah. If you charge on cold mornings, pick a model rated to charge from −20°C: the 200Ah, the 300Ah cooling fan, or the 560Ah.
Boat
House loads are similar to an RV. A trolling motor is the number that blows the watt limit — 300W for a few hours is fine on the larger packs; a heavy motor may need two identical batteries in parallel so the current adds up.
Which cold behaviour
| Charges from −20°C | Low-temp cut-off | |
|---|---|---|
| Models | 200Ah, 300Ah cooling fan, 560Ah | 100Ah, 300Ah 1500 CCA, 460Ah, 600Ah |
| Charging | Charge range −20°C to 50°C. Discharge still cuts off near −20°C. | Charging stops near 0°C ± 4°C. Do not force a charge in a frost. |
| Discharging | Both families cut discharge off near −20°C. | |
A resting-voltage sketch
Approximate resting-voltage guide (not from the Vatrer manuals). Measure at the posts 15 minutes after everything is disconnected, with no current flowing.
- 100%13.5V
- 90%13.3V
- 70%13.2V
- 30%13.0V
- 10%12.8V