Want to know how and why to connect two 12-volt (or 24-volt) batteries in parallel? This tutorial will demonstrate how to connect two 12-volt batteries in parallel properly. I’ll be using the Power Queen 12.8 volt, 100 amp-hour, 1280 watt-hour lithium iron phosphate batteries for the demonstration.
Purpose of parallel batteries
For the off-grid ham shack project, the purpose of dual batteries in parallel is to add capacity. As I’ve mentioned previously, the goal has always been to reach 400 amp-hours of battery storage. In a perfect world, that would have happened all at the same time. Either with 4x batteries in parallel, or with one large 400ah battery. I prefer the redundancy!
Benefits
Parallel batteries offer several benefits, including:
- Increased capacity: Combining batteries in parallel increases the overall capacity, allowing for longer runtimes between charges. Several cloudy days with now sun, no problem.
- Redundancy and reliability: If one battery fails, the others can continue to power the system, providing redundancy and improving overall reliability.
- Enhanced power delivery: Parallel batteries can supply higher current levels, making them suitable for applications with high current demands.
- Flexibility: Parallel battery configurations can be adapted to different voltage and capacity requirements, offering flexibility in designing power systems.
Overall, parallel batteries can improve energy storage, reliability, and flexibility in various applications.
Solar charging in winter
For the off-grid ham shack, the dark winter days 4 weeks before and after winter solstice make solar recharging almost impossible. Charging with solar during winter at high latitudes is challenging, as the days are shorter, the sun is barely above the horizon, and there just isn’t enough sunlight. Moreover, snow and overcast skies can reduce the efficiency of solar panels. However, with proper planning (ie enough solar panels, and battery storage, it is still possible to generate and store solar energy during the winter months. Implementing strategies such as adjusting the angle of the panels, ensuring they are clean and free from snow, having alternative ways of recharging such as a wind turbine and handcrank generators, and having sufficient battery capacity for days without daylight can help optimize solar charging during this time.
Related Posts
Building a solar-powered Off-Grid Ham Radio Station for beginners
https://oh8stn.org/blog/2023/12/21/building-an-off-grid-solar-powered-ham-shack/
Radio friendly MPPT charge controller:
https://oh8stn.org/blog/2023/11/30/radio-friendly-mppt-charge-controller-for-off-grid-comms-genasun/
Current consumption and off-grid communications
https://oh8stn.org/blog/2023/11/20/off-grid-grid-down-comms-current-consumption/
Power Queen LiFePO4 Batteries
https://oh8stn.org/power-queen-lifepo4/
Power Queen LiFePO4 batteries.
Use coupon code: “JULIANOH8STN” in Europe, the USA and the UK, and Canada.
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Friendly advice: when paralleling batteries of any kind with large Amp draws/intake remember to cross the feed to allow even charge distribution.
Correct:
(+) ———…..–
B1 B2 Bx
———…..——- (-)
Incorrect:
(+) ———…..–
B1 B2 Bx
(-) ———…..–
For light loads this is unnecessary, but when you reach tens of A of draw this will extend your battery life noticeably.