Member Avatar for Duki

Hey guys,

I need to know about Lithium-Ion batteries and where I can buy them. I'm not really talking about laptop batteries. I need something that can power a desktop for well over an hour (more like half a day). Does anyone know where I can get information on this?

Thanks

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Short primer for (and thanks to for the UPS idea): amp-hours (Ah) alone don’t tell you how much energy you have — you must multiply Ah by the nominal voltage to get watt‑hours (Wh), which is the energy that actually runs stuff. Example: 60 Ah at 12 V = 720 Wh; usable energy will be less once you allow for inverter losses and depth‑of‑discharge limits. (batteryuniversity.com)

Pick your target runtime by measuring real load, not guesses. Use a plug‑in power meter or monitor the PSU under typical use to get continuous watts, then multiply watts × hours = Wh required. Desktop draw varies a lot (modern office towers average tens-to‑low‑hundreds of watts; gaming/workstation rigs can be several hundred watts or more), so a 12‑hour desktop backup can need 1–3 kWh depending on the machine; a 3‑hour robot run at 100–200 W only needs 300–600 Wh (so 60 Ah at 12 V can easily cover light robots). Measure first (Kill‑A‑Watt or similar) and size Wh, then convert back to Ah for your chosen pack voltage. (researchgate.net)

Chemistry and safety: for long runtime, frequent cycling and on‑platform use (robots, vans, backups) LiFePO4 (LFP) is a strong choice — far better cycle life and thermal stability than older Li‑ion chemistries — but always use a proper BMS, charger and rated continuous discharge current. If weight is the priority and you accept more careful thermal management, higher‑energy NMC packs exist, but they need stricter pack engineering. (batteryuniversity.com)

Where to look: established vendors now sell ready 12 V LiFePO4 modules (100 Ah ≈ 1.28 kWh is common) and distributors carry cells and BMS parts if you build a pack yourself — e.g., Renogy/BattleBorn style packs or electronics distributors for cells and management boards. A consumer UPS (as suggested) is easiest for short runtimes, but most consumer UPS units use sealed lead‑acid cartridges (heavy, low energy density) so for multi‑hour runtime a dedicated LiFePO4 pack + inverter is usually the better solution. Measure your watts, calculate Wh needed (add ~25% for inverter & aging), pick a pack with a BMS rated above your continuous draw, and buy from reputable suppliers. (renogy.com)

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Member Avatar for GrimJack

Almost any office supply store will sell you a UPS - do you need more than that? The more money you spend on it, the longer it will last (within reason). You might be able to find recommendations in the hardware section here on DaniWeb.

Member Avatar for Duki

I need something with at least 60Ah. Also, it has to be able to sustain a robot for well over 3 hours.

Member Avatar for GrimJack

What is your weight limit? I found a couple 2700mAh

Member Avatar for GrimJack

I just found this site: here

Member Avatar for Duki

thanks for the site. lithium-ion may be a little to pricey for us. we just wanted to make sure.

the battery we would require is around $1200.
thanks for the help.

Member Avatar for GrimJack

Have you looked inside a UPS - the batteries are often replaceable 'packs' - just a thought.

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