Sea Ray 340 Express — Lake Tahoe 24V Upgrade
powerboat · 24V system · Lake Tahoe, CA
Express cruiser retrofit with 400Ah 24V LiFePO4 for silent overnights on the lake. Marine A/C stays on the genset, but all house loads run off the bank. Ice maker, residential fridge, Starlink TV evening at anchor.
Daily load
4,561 Wh
Daily Ah
190 Ah
Battery
500 Ah LiFePO4
Solar
1200 W
Load budget
| Load | Watts | Qty | Hrs/Day | Wh/Day |
|---|---|---|---|---|
| Residential Fridge (Inverter) | 150 | 1 | 10 | 1,500 |
| Ice Maker | 120 | 1 | 3 | 360 |
| Microwave | 1000 | 1 | 0.25 | 250 |
| Coffee Maker | 900 | 1 | 0.25 | 225 |
| TV / Monitor | 60 | 1 | 4 | 240 |
| Stereo / Speakers | 25 | 1 | 4 | 100 |
| Starlink | 75 | 1 | 16 | 1,200 |
| Chartplotter | 25 | 1 | 4 | 100 |
| LED Cabin Light | 5 | 5 | 4 | 100 |
| Interior LED Strip | 12 | 1 | 5 | 60 |
| Freshwater Pump | 60 | 1 | 1 | 60 |
| Phone Charger | 10 | 2 | 3 | 60 |
| Laptop | 60 | 1 | 3 | 180 |
| VHF Radio (Standby)CRITICAL | 5 | 1 | 24 | 120 |
| Bilge PumpCRITICAL | 30 | 1 | 0.2 | 6 |
Battery bank
10 × 100Ah (2S5P) for 24V/500Ah
Your daily consumption is 190Ah. With 2 days of autonomy, you need 380Ah of usable capacity. LiFePO4 (Lithium Iron Phosphate) batteries should only be discharged to 80% depth of discharge, so you need 475Ah of total capacity. We recommend a 500Ah bank (10 × 100Ah (2S5P) for 24V/500Ah), giving you 400Ah of usable capacity — enough for 2 days without any charging.
Solar array
6 × 200W panels · 63A charge controller
Your daily consumption is 4561Wh. With 5.3 peak sun hours, a 75% system efficiency factor, and LiFePO4 (Lithium Iron Phosphate) round-trip efficiency of 96%, you need 1195W of solar panels. We recommend 6 × 200W panels (1200W total). This array will produce approximately 199Ah per day at 24V. You'll need a charge controller rated for at least 63A. MPPT recommended — higher efficiency at this array size.
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