# Can someone help me figure out how long this battery will last? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [October 2, 2023, 5:05pm UTC](https://boards.straightdope.com/t/can-someone-help-me-figure-out-how-long-this-battery-will-last/991016 "2023-10-02T17:05:02Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![FloatyGimpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/floatygimpy/32/7750_2.png) [@FloatyGimpy](https://boards.straightdope.com/u/FloatyGimpy)\ **Post date:** [October 2, 2023, 5:05pm UTC](https://boards.straightdope.com/t/can-someone-help-me-figure-out-how-long-this-battery-will-last/991016/1 "2023-10-02T17:05:03Z")
I need help trying to figure out if this power station would run some things on my fish tank. I can’t seem to figure out/understand volts/watts etc. I have a heater and an air pump. There are some other things as well like lights etc but, in a power outage, I’m just concerned with those two things: > **[Top Fin® Compact Aquarium Heater](https://www.petsmart.ca/fish/heating-and-lighting/heaters/top-fin-compact-aquarium-heater-5282573.html?gclid=Cj0KCQjw1OmoBhDXARIsAAAYGSFtxyZ-0sE70tRaVNPIgWD3FldjGP1oDZmeGbOXYliUm0MVivKN_SEaAtsDEALw_wcB&gclsrc=aw.ds)** > > null > **[Tetra Whisper Air Pump 10-30 Gal Aquarium | Walmart Canada](https://www.walmart.ca/en/ip/tetra-whisper-air-pump-10-30-gal-aquarium/6000135667544)** > > Buy Tetra Whisper Air Pump 10-30 Gal Aquarium from Walmart Canada. Shop for more Aquarium Air Pumps available online at Walmart.ca This is the portable power station that I am thinking of buying. I’ve done some research and read reviews but I honestly can’t figure out how long it would last with those two items running. > **[Jackery Explorer 500 Portable Power Station, 518Wh Outdoor Solar Generator...](https://www.walmart.ca/en/ip/Jackery-Explorer-500-Portable-Power-Station-518Wh-Outdoor-Solar-Generator-Mobile-Lithium-Battery-Pack-110V-500W-AC-Outlet-Solar-Panel-Not-Included-Ho/70YRC4R8BK09?skuId=43N9OGYKYGKF&offerId=C649F5BE355E4BFEAAD24FF7F3BD9B37&cmpid=SEM_CA_32614_SA6NM5M1QX&utm_id=SEM_CA_32614_SA6NM5M1QX&utm_medium=paid_search&utm_source=google&utm_campaign=always_on&gclid=Cj0KCQjw1OmoBhDXARIsAAAYGSENEde481m6ZQdCFVjzPuHIBFUHR0lhZPIWT_GLuX0DD2P8qBwmJn4aAnOfEALw_wcB&gclsrc=aw.ds)** > > Buy Jackery Explorer 500 Portable Power Station, 518Wh Outdoor Solar Generator Mobile Lithium Battery Pack with 110V/500W AC Outlet (Solar Panel Not Included) for Home Use, Emergency Backup from Walmart Canada. Shop for more Generators available... I have a large generator but it’s honestly embarrassingly loud. It’s good for prolonged outages but I just want something for if the power goes out for a few hours and I need to keep the fish/frogs warm. ---
**Author:** ![Al128](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/al128/32/16541_2.png) [@Al128](https://boards.straightdope.com/u/Al128)\ **Post date:** [October 2, 2023, 5:12pm UTC](https://boards.straightdope.com/t/can-someone-help-me-figure-out-how-long-this-battery-will-last/991016/2 "2023-10-02T17:12:45Z")
as per your link, the heater claims “50w of power” … (=consumption) no info on the airpump … but air isnt that heavy - so lets assume 10w having a total of 60w if both on … assuming this is constant, you’d have a consumption of 60Wh, conveniently below the 518Wh provided by the generator … so, yes this should work and has lots of reserve for other non-mentioned consumes (light,…) ---
**Author:** ![Dorjan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dorjan/32/12440_2.png) [@Dorjan](https://boards.straightdope.com/u/Dorjan)\ **Post date:** [October 2, 2023, 5:14pm UTC](https://boards.straightdope.com/t/can-someone-help-me-figure-out-how-long-this-battery-will-last/991016/3 "2023-10-02T17:14:36Z")
You need to know how much power or current each device draws. I don’t see that info for the air pump, but the heater draws 50 watts at max power so the battery will be able to power it for about 10 hours. ---
**Author:** ![FloatyGimpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/floatygimpy/32/7750_2.png) [@FloatyGimpy](https://boards.straightdope.com/u/FloatyGimpy)\ **Post date:** [October 2, 2023, 5:14pm UTC](https://boards.straightdope.com/t/can-someone-help-me-figure-out-how-long-this-battery-will-last/991016/4 "2023-10-02T17:14:53Z")
Does that mean it would last about 8 hours? The power goes out regularly here and is usually out for about four hours. ---
**Author:** ![Al128](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/al128/32/16541_2.png) [@Al128](https://boards.straightdope.com/u/Al128)\ **Post date:** [October 2, 2023, 5:16pm UTC](https://boards.straightdope.com/t/can-someone-help-me-figure-out-how-long-this-battery-will-last/991016/5 "2023-10-02T17:16:13Z")
just reckoned: the “Generator” is odd description … for a battery pack … so, yes you get about 8 hours of runtime before depleting the batteries ---
**Author:** ![Al128](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/al128/32/16541_2.png) [@Al128](https://boards.straightdope.com/u/Al128)\ **Post date:** [October 2, 2023, 5:18pm UTC](https://boards.straightdope.com/t/can-someone-help-me-figure-out-how-long-this-battery-will-last/991016/6 "2023-10-02T17:18:13Z")
> [@FloatyGimpy](#): > > Does that mean it would last about 8 hours? The power goes out regularly here and is usually out for about four hours. yes … and that is a good size battery for your application, as you dont want to deplete your battery to 0% too often … but your scenario seems indicative of using roughly 50% of the battery ---
**Author:** ![Dorjan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dorjan/32/12440_2.png) [@Dorjan](https://boards.straightdope.com/u/Dorjan)\ **Post date:** [October 2, 2023, 5:18pm UTC](https://boards.straightdope.com/t/can-someone-help-me-figure-out-how-long-this-battery-will-last/991016/7 "2023-10-02T17:18:38Z")
Looking around, the air pump draws around 3 Watts. So 518/53 = 9.7 hours assuming peak efficiency (which it wont get). Generally you don’t want to run a battery below 50% of it’s rated capacity either, but ignoring that you can get 8-9 hours runtime. ---
**Author:** ![FloatyGimpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/floatygimpy/32/7750_2.png) [@FloatyGimpy](https://boards.straightdope.com/u/FloatyGimpy)\ **Post date:** [October 2, 2023, 5:19pm UTC](https://boards.straightdope.com/t/can-someone-help-me-figure-out-how-long-this-battery-will-last/991016/8 "2023-10-02T17:19:55Z")
> [@Dorjan](#): > > Generally you don’t want to run a battery below 50% of it’s rated capacity How come? I thought it was good to fully drain the battery before recharge? ---
**Author:** ![Dorjan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dorjan/32/12440_2.png) [@Dorjan](https://boards.straightdope.com/u/Dorjan)\ **Post date:** [October 2, 2023, 5:22pm UTC](https://boards.straightdope.com/t/can-someone-help-me-figure-out-how-long-this-battery-will-last/991016/9 "2023-10-02T17:22:15Z")
Nope. the lower you let your battery get, the less charging cycles you will get out of it for that type of battery. You will also loose about 5-15% capacity from converting from DC to AC, but i’m assuming that’s accounted for in the Watt-hour rating for that power pack. ---
**Author:** ![FloatyGimpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/floatygimpy/32/7750_2.png) [@FloatyGimpy](https://boards.straightdope.com/u/FloatyGimpy)\ **Post date:** [October 2, 2023, 5:23pm UTC](https://boards.straightdope.com/t/can-someone-help-me-figure-out-how-long-this-battery-will-last/991016/10 "2023-10-02T17:23:46Z")
> [@Dorjan](#): > > Nope. the lower you let your battery get, the less charging cycles you will get out of it for that type of battery. Good to know, thank you. Should it be kept fully charged when not in use? Leave it plugged in? ---
**Author:** ![Dorjan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dorjan/32/12440_2.png) [@Dorjan](https://boards.straightdope.com/u/Dorjan)\ **Post date:** [October 2, 2023, 5:25pm UTC](https://boards.straightdope.com/t/can-someone-help-me-figure-out-how-long-this-battery-will-last/991016/11 "2023-10-02T17:25:04Z")
It really depends on the chemistry of the battery. Lithium-ion batteries are much more tolerant of deep drawdowns than lead-acid, for example. but as a general rule for optimum battery health and longlevity you shouldn’t let it drop below 50% very often. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [October 2, 2023, 5:25pm UTC](https://boards.straightdope.com/t/can-someone-help-me-figure-out-how-long-this-battery-will-last/991016/12 "2023-10-02T17:25:18Z")
> [@Al128](#): > > no info on the airpump … but air isnt that heavy - so lets assume 10w Air isn’t heavy, but that air has to get pushed down through some water before it’s allowed to bubble up again. Not much air though. **[It turns out these pumps only use 2-3 watts](https://www.google.com/search?q=tetra+whisper+air+pump+wattage&sca_esv=570067020&rlz=1C1GCEA_enUS930US931&sxsrf=AM9HkKmTqLxAB_kIrACqxGip1y2OEZMCYA%3A1696266967547&ei=1_oaZbWAIajE0PEPzuOB8Ag&oq=tetra+whisper+air+pump+watts&gs_lp=Egxnd3Mtd2l6LXNlcnAiHHRldHJhIHdoaXNwZXIgYWlyIHB1bXAgd2F0dHMqAggAMgYQABgWGB4yBhAAGBYYHjIGEAAYFhgeMgYQABgWGB4yBhAAGBYYHjIIEAAYigUYhgMyCBAAGIoFGIYDMggQABiKBRiGA0jIFVDKBVjtCnABeAGQAQCYAWigAYwEqgEDNC4yuAEDyAEA-AEBwgIKEAAYRxjWBBiwA8ICChAAGIoFGLADGEPCAg4QABjkAhjWBBiwA9gBAcICGRAuGIoFGMkDGMcBGNEDGMgDGLADGEPYAQLCAhYQLhiKBRjHARjRAxjIAxiwAxhD2AECwgIHEAAYigUYQ8ICBRAAGIAE4gMEGAAgQYgGAZAGEboGBggBEAEYCboGBggCEAEYCA&sclient=gws-wiz-serp)**. > [@Al128](#): > > just reckoned: the “Generator” is odd description … for a battery pack … > > so, yes you get about 8 hours of runtime before depleting the batteries I thought the same as you, but it turns out there’s an optional solar panel for recharging: > **[Jackery Explorer 500W Portable Power Station](https://www.jackery.com/products/explorer-500w-portable-power-station)** > > Jackery Carrying Case is a premium EVA bag designed to fit and protect the Explorer 500 Portable Power Station from damage. Stylish, practical, and durable. It can recharge the battery in 7.5 hours, so figure 518 Wh divided by 7.5 hours = 69 watts provided by the solar panel. Factor in the battery-charging inefficiency, and it means the solar panel is putting out a good bit more than 69 watts; it could keep the OP’s equipment running without depleting the battery at all, as long as it’s getting direct sunlight. ---
**Author:** ![Dorjan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dorjan/32/12440_2.png) [@Dorjan](https://boards.straightdope.com/u/Dorjan)\ **Post date:** [October 2, 2023, 5:26pm UTC](https://boards.straightdope.com/t/can-someone-help-me-figure-out-how-long-this-battery-will-last/991016/13 "2023-10-02T17:26:41Z")
> [@FloatyGimpy](#): > > Good to know, thank you. Should it be kept fully charged when not in use? Leave it plugged in? Overcharging is not good either 😃 If it’s well made it should have charge protection circuitry built in that will “turn off” charging internally once it’s charged, and “back on” if needed. Or you can keep it on a trickle-charger which will do the same thing externally. ---
**Author:** ![Dorjan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dorjan/32/12440_2.png) [@Dorjan](https://boards.straightdope.com/u/Dorjan)\ **Post date:** [October 2, 2023, 5:28pm UTC](https://boards.straightdope.com/t/can-someone-help-me-figure-out-how-long-this-battery-will-last/991016/14 "2023-10-02T17:28:53Z")
> [@Machine\_Elf](#): > > It can recharge the battery in 7.5 hours, so figure 518 Wh divided by 7.5 hours = 69 watts provided by the solar panel. 7.5 hrs is charging time plugged in. They claim the panel can charge it in 9.5 hours, which I suspect is very optimistic. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [October 2, 2023, 5:30pm UTC](https://boards.straightdope.com/t/can-someone-help-me-figure-out-how-long-this-battery-will-last/991016/15 "2023-10-02T17:30:19Z")
> [@Dorjan](#): > > Lithium-ion batteries are much more tolerant of deep drawdowns than lead-acid, for example. but as a general rule for optimum battery health and longlevity you shouldn’t let it drop below 50% very often. Battery University suggests that you get better longevity if you run a battery between 85% and 25% than you do running it between 100% and 50%. See Figure 6 at this link: > **[BU-808: How to Prolong Lithium-based Batteries](https://batteryuniversity.com/article/bu-808-how-to-prolong-lithium-based-batteries)** > > BU meta description needed... ---
**Author:** ![FloatyGimpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/floatygimpy/32/7750_2.png) [@FloatyGimpy](https://boards.straightdope.com/u/FloatyGimpy)\ **Post date:** [October 2, 2023, 5:34pm UTC](https://boards.straightdope.com/t/can-someone-help-me-figure-out-how-long-this-battery-will-last/991016/16 "2023-10-02T17:34:12Z")
Thank you so much for your help. I purchased it through amazon because it was $100 less with their coupon. ---
**Author:** ![Dorjan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dorjan/32/12440_2.png) [@Dorjan](https://boards.straightdope.com/u/Dorjan)\ **Post date:** [October 2, 2023, 5:38pm UTC](https://boards.straightdope.com/t/can-someone-help-me-figure-out-how-long-this-battery-will-last/991016/17 "2023-10-02T17:38:37Z")
> [@Machine\_Elf](#): > > Battery University suggests that you get better longevity if you run a battery between 85% and 25% than you do running it between 100% and 50%. True, I should clarify that I’m talking more about large deep cycle batteries, not so much the small high capacity batteries like you’d find in drones and cell phones. Most of my DC electrical experience is with Deep cycle batteries on a 12V circuit like you would find on a boat or car. ---
**Author:** ![Al128](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/al128/32/16541_2.png) [@Al128](https://boards.straightdope.com/u/Al128)\ **Post date:** [October 2, 2023, 6:21pm UTC](https://boards.straightdope.com/t/can-someone-help-me-figure-out-how-long-this-battery-will-last/991016/18 "2023-10-02T18:21:19Z")
> [@Dorjan](#): > > Overcharging is not good either 😃 If it’s well made it should have charge protection circuitry built in that will “turn off” charging internally once it’s charged, and “back on” if needed. Or you can keep it on a trickle-charger which will do the same thing externally. those lithium batteries will come with a BMS (Battery Managment System) - no need for anything else … it will disconnect the battery from the PV before overcharged, and it will disconnect the load (pump,…) before the battery’s voltage gets drawn down too much so, in short: that already comes built into the battery - nothing to do manually ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [October 2, 2023, 7:26pm UTC](https://boards.straightdope.com/t/can-someone-help-me-figure-out-how-long-this-battery-will-last/991016/19 "2023-10-02T19:26:38Z")
Nitpick on the heater consumption: 50W tells you the power consumption when the heater is on, but the heater does not stay on all the time. The real measure is the rate of heat loss in the aquarium, which is a function of ambient temp, rate of evaporation of water, how warm the water needs to be, etc. A heater may only turn on a couple of times per hour for just a few minutes at a time to retain heat. It depends on the size of the heater compared to the size of the tank. However, you might as well assume it’s on all the time as a worst case scenario and plan for that, since it’s not that much power anyway. But realistically it’s probably more like 1/5 the rated power per hour or less. I’ll bet a 50W heater in a smallish tank consumes less than 10W per hour. ---
**Author:** ![FloatyGimpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/floatygimpy/32/7750_2.png) [@FloatyGimpy](https://boards.straightdope.com/u/FloatyGimpy)\ **Post date:** [October 2, 2023, 7:58pm UTC](https://boards.straightdope.com/t/can-someone-help-me-figure-out-how-long-this-battery-will-last/991016/20 "2023-10-02T19:58:24Z")
Very true. The tank stays quite warm and the heater only comes on a few times an hour. Also, during an outage, I put blankets on the aquarium to conserve heat. [Next page](https://boards.straightdope.com/t/can-someone-help-me-figure-out-how-long-this-battery-will-last/991016.md?page=2)