A 12V UPS & backup system lives or dies by its charger. JUXON Power, a Shenzhen charger manufacturer since 2014, builds switched-mode Lead-acid units from 48W to 8000W, tuned to the exact pack rather than a generic curve. For a 12V UPS & backup pack the real numbers are 2 cells in series — 12V nominal, 14.4V at full charge — charged at roughly 3.0A. The guide below uses our product sheet values, not marketing round numbers.
What a 12V UPS & backup buying guide actually is
It is a CC/CV (constant-current / constant-voltage) power supply that takes 100-240V AC and delivers a controlled Lead-acid charge. In a 12V system the pack is 2 cells in series (12V nominal, 14.4V full). The charger must terminate precisely at that point: overshoot cooks cells, undershoot leaves the pack shallow and the vehicle short-ranged. A purpose-built 12V UPS & backup unit holds the curve across temperature and pack age, which is why a generic laptop brick is a poor substitute.
Specifications that matter (from our product sheet)
Output voltage: 12V (Lead-acid)
Pack configuration: 2S (12V nominal / 14.4V full)
Typical output: 3.0A (36W)
Chemistry: Lead-acid (also Lead-acid)
Input: 100-240V AC, 50/60Hz
Charging mode: CC/CV
Cooling: Natural convection or fan
Housing: Black flame-retardant ABS (UL94 V-0)
Protection: OCP, OVP, OTP, reverse polarity
Connector: SAE 2 / / (service type) DC 5.5×2.1 / 2.5mm (low-voltage <=5A) M16 / C091 2–3 AMASS XT30 / LC30
Reference models: Juxon010-180A, Juxon010-180F, Juxon010-300A, Juxon010-450A and more
How a 12V Lead-acid pack should be charged
The charger ramps current to the set value, holds it while voltage climbs (constant current), then holds voltage at 14.4V while current tapers (constant voltage) until the pack is full. That CC/CV profile is what keeps a 2S Lead-acid pack healthy over hundreds of cycles. JUXON adds OVP, OTP and reverse-polarity protection so a wiring mistake trips the supply instead of the battery, and the black UL94 V-0 enclosure keeps it safe in a dusty workshop or a wet marine bay.
Connector: get this right and the rest is easy
For UPS & backup builds we see Bosch 3-pin eBike System 2 on many units — Bosch 36V daily slow-charge, onboard backup and store service charging; city, touring, mountain and cargo e-bikes. Typical compatible families: PowerPack 300 / 400 / 500 PowerTube 400 / 500 / 625 Smart System Trek Verve+ / Allant+ Cube Touring Hybrid / Reaction Hybrid Haibike Trekking / AllMtn Riese & Müller Charger / Nevo Gazelle Ultimate / .
For UPS & backup builds we see XLR 4-pin ION PMU4 on many units — Sparta / Batavus / Koga 36V ION PMU4 home slow-charge, store service and backup charging. Typical compatible families: Batavus Adagio Easy 2014–2015 Legato Easy 2015–2016 Mont Blanc Easy 2014–2016 Tourmalet E-go 2016 Koga E-Deluxe / E-Extension 2014–2016 E-Special / E-Tour 2015–2016 E-Xtension 2014–2015 Sparta Avantga.
Where a 12V UPS & backup charger is used
Ups & Backup charging covers UPS and standby backup banks. From the product sheet: indoor home, office, service stores and small-equipment; daily charging of small packs and prototype support; requires matched lead-acid cycle / float curve. JUXON's standard catalog shows e-bike, forklift, mobility and marine models, but we regularly design UPS & backup units to a customer's exact voltage, current and connector — see the UPS & backup product page.
How JUXON builds it (OEM / ODM)
JUXON Power is a professional lithium battery charger manufacturer based in Shenzhen, Guangdong, China, operating since 2014 across 48W to 8000W with 400+ charger models shipped to 60+ countries. The engineering team runs the full chain — schematic, PCBA, thermal management, enclosure tooling and end-to-end certification — so a 12V UPS & backup charger arrives as a drop-in unit matched to your chemistry and form factor. Low-moq runs with fast sampling (prototypes in 7-10 days).
Certifications for your market
For this Lead-acid 12V class, typical certifications on the build are CE, RoHS. The full portfolio JUXON supports end-to-end includes CE (EU), RoHS (EU/eco), UKCA (UK), UL (USA/Canada), TÜV (Germany/EU), TÜV GS (Germany), PSE (Japan), KC (South Korea), plus ISO 9001 / ISO 14001 factory systems. Tell us the target market and we map the exact marks before tooling.
How to size a 12V UPS & backup charger
Rule of thumb: charge at 0.2C-0.3C of pack capacity. A 20Ah Lead-acid 12V pack → about 4-6A; a 100Ah bank → 20-30A. Size the charger to the pack, not the vehicle's peak draw, and leave thermal margin for summer parking or sealed enclosures. If you are unsure, send the pack label — we return a matched model and a quote, usually within one business day.
Pre-production checklist
Before committing to a 12V UPS & backup build, lock down four things: (1) pack nominal and full-charge voltage; (2) cell count and chemistry (Lead-acid); (3) the exact mating connector, polarity and any communication pins; (4) target-market certifications. Email those on one line and we return a matched Juxon010-series model with a quote, usually within one business day.
FAQ
Q: What voltage does a 12V Lead-acid charger actually output?
A: It charges to the pack's full-charge voltage — 14.4V for a 2S Lead-acid pack (nominal 12V). The 'charger voltage' is always higher than the nominal rating.
Q: Can one 12V charger serve both Lead-acid and other chemistries?
A: No. Lead-acid needs its own CC/CV cutoff. Mixing chemistries on one curve damages cells; we build separate profiles or a selector.
Q: Which connector fits a UPS & backup pack?
A: It depends on the mating plug. Our sheet lists candidates per pack (XLR, Anderson, DC barrel, M16/GX16 and more); send a photo of the connector and we confirm polarity and pinout.
Q: What certifications apply to my market?
A: CE, RoHS are typical for this class; CE, RoHS, UL cover EU/US broadly, with PSE (Japan), KC (Korea), SAA (AU/NZ) and CCC (China) by market.
Q: What is the MOQ and lead time?
A: JUXON runs low-MOQ runs with fast sampling (prototypes in 7-10 days); standard OEM runs ship in roughly 15-25 days after sample sign-off.
> Get a matched 12V UPS & backup charger quote
> Share your battery pack voltage, capacity and connector. JUXON replies with a matched model and quotation within 1 business day.
> Request a Quote · WhatsApp +86 19501872679 · kevin@juxonpower.com / lee@juxonpower.com