描述了一个离网太阳能设置，20年前有人会想象树林里的偏远机舱，带有铅酸电池和用作备用电源的柴油发电机。但在2020年代，离网家可能比你想象的更接近 - 就在隔壁。许多社区是因为它们的地理或限制存在于现有网格，正在翻转脚本并单独使用电网作为紧急备份。
“The newest thing is grid defection,” said David Norman, director of solar product and business development at lead-acid and lithium battery providerDiscover Battery.
Doomsday bunkers aren’t present in either of these situations — off-grid setups already exist in many urban neighborhoods. Today’s power needs require battery technologies to keep up.
An electric battery, by definition, is a device that stores energy that can be converted into electrical power. In that sense, all battery types are equipped to handle off-grid storage needs, but some are better than others at satisfying today’s electricity demands and cycling schedules.
“Off-grid is less about the battery and more about the use-case,” Norman said. “If you’re only doing backup power, lead-acid works. It’s not cycling regularly, and it’s primarily just sitting in reserve for a power outage or failure. But for demand charge applications, any lithium battery is better.”
Lead-acid batteries do work well for occasional, short-term backup needs. But if someone wants to switch power sources to take advantage of utility time-of-use rates or avoid the grid for an extended period of time, more frequent and deeper cycles are needed than what lead-acid can provide.
“Lithium is changing off-grid,” Norman said. “You still can live off-grid on lead-acid, but lithium is more efficient.”
This all boils down to the number of cycles a battery has and its depth of discharge — how many times the battery can be drained, and how much power can actually be used.金库还提供铅酸和锂基电池，销售和销售杰伊加索的VP通常解释了两种化学类型的充电规范。
Lead-acid batteries degrade more with every cycle. Where a lithium battery may come with a 10,000-cycle guarantee, a lead-acid battery may peak at 2,500 cycles when discharged to 50%. Lithium batteries can be discharged to near-zero, or basically, all the juice in a lithium battery can be used in one cycle, where a lead-based battery can only use half of its juice before degrading even faster.
“Lead-acid batteries are lower in cost for the same voltage and capacity but do not last for many cycles,” Galasso said. “[Lithium-based] designs can use fewer batteries for a given application because of the higher charge/discharge rates, resulting in lower initial costs.”
Simpliphi Power.was founded in the early 2000s and has always been a lithium battery provider. The company knows the value of lithium batteries in off-grid applications since its original market was remote power scenarios.
“Lead-acid is a legacy product used in off-grid. It’s where the solar industry originated. You couldn’t have a PV system without lead batteries in those early days,” said Sequoya Cross, director of global sales and business development for SimpliPhi. “Why we see more people scaling to lithium: you have more usable capacity in a smaller space, you can pull them to 100% depth of discharge.”
当有人想要其积极的家庭off the grid today, that usually means they want the refrigerator to work, along with computers, internet, televisions, lights and everything else, all at the same time. Just backing up one emergency load can’t cut it anymore, especially in places like California where life must go on when the utility turns off the power. This requires larger battery capacity, faster charging rates and deeper depth of discharge — things lead-acid just can’t provide.
用于住宅应用的两个主要锂电池类型是锂镍锰钴氧化物（NMC）和磷酸铁锂（LFP）。Tesla PowerWall，Generac PwrCell和LG Resu电池都使用NMC化学，而许多供应商使用LFP（包括Discover，Eguana，Electriq Power，Enphace，Kilovault，SimpleIphi，Sonnen）。虽然两种电池类型在需求套利情况下工作很大，但LFP在近网上有一个边缘。这可能是为什么更多公司提供无钴化学。
Aric Saunders, EVP of sales and marketing for NMC and LFP battery providerElectriq Power, explained the differing charge-rates for the two lithium chemistries. NMC batteries have a charge-rate of 0.5C while LFP batteries are 1C. If it takes an LFP battery one hour to charge, the NMC battery takes twice as long because it accepts current more slowly. LFP batteries can be charged in half the time as NMC.
“Because of [the faster charging rate], LFP batteries can provide a higher power output to the grid or home. This feature allows the battery to back-up larger loads with a smaller battery than would be needed with NMC,” Saunders said.
“Time is money. If I’m charging on solar and I’ve only got a six-hour solar day, I want to get as much into those batteries as I can,” Norman said. An off-grid solar + storage system would benefit most from the fast-charging properties of LFP.
“Off-grid is around us all the time. It’s not just people in the woods anymore,” SimpliPhi’s Cross said. “It isn’t necessarily possible to completely disconnect or pull your meter, but it is possible to design around an off-grid lifestyle.”