East Penn Manufacturing Deka Fahrenheit HT series high-temperature AGM blocks

The only line here that puts a number on heat, with warranty months falling from 72 to 30 as ambient rises

East Penn Manufacturing Deka Fahrenheit HT series high-temperature AGM blocks is one of 7 battery systems tracked in the SecondWatt catalogue, each with specifications, lead times and indicative secondary-market pricing.

East Penn Deka Fahrenheit dossier: high-temperature AGM blocks, published life at 25 and 35 degrees C, warranty scaled to ambient, and inspection guidance.

Why it matters

Published ohmic baselines against named instruments change what a used inspection can prove. Most manufacturers publish a design life and nothing else, so a buyer measuring internal resistance has no reference to compare against. East Penn gives four, at 2242 millisiemens on one instrument and 2.948, 2.384 and 2.584 milliohms on three others for the HT200ET.

Who buys it

Telecom and utility operators with outdoor or unconditioned cabinets, and data center operators putting batteries somewhere the cooling does not reach. The line exists because standard VRLA product loses half its life for every 8 to 10 degrees C above 25, and Fahrenheit is the answer to sites that cannot fix the ambient.

Role in the data center

Battery strings in unconditioned or partially conditioned spaces, outdoor cabinets and telecom shelters, where the ambient cannot be brought down to the 20 to 25 degree band standard VRLA wants.

Key specifications

Technical summary

Nominal voltage: 12 V, front access Capacity, HT200ET: 190 Ah at the 8-hour rate to 1.75 volts per cell Watts per cell, HT7500ET: 750 W at 15 minutes and 287 W at 1 hour Design life: 12 years at 25 degrees C on the HT200ET; 10 years at 25 and 5 years at 35 on the HT7500ET Weight: 151 lb or 68.5 kg on both blocks Dimensions: about 24 by 4.97 by 12.74 in Terminals: front access quarter-inch threaded insert at 100 inch-pounds plus or minus 5 Float and equalize: 13.50 V per 12 V unit; equalize 14.40 V for 24 hours Temperature compensation: 12 millivolts per degree C per 12 V unit Maximum charge current: 36.4 A on the HT200ET and 35.4 A on the HT7500ET Ohmic baselines, HT200ET: 2242 mS, 2.948 milliohms, 2.384 milliohms and 2.584 milliohms by instrument Listings: UL 1973 for energy storage applications with a UL 94 V-0 flame-retardant case

Configurations and options

Front-access blocks in relay racks or cabinets, series-connected to the site bus. The optimal band is 10 to 35 degrees C with an extended range from minus 40 to 40, and equalisation at 14.40 V for 24 hours is the published recovery routine.

Compatibility and dependencies

Ohmic baselines are published per model and per instrument, so a meaningful test needs the matching instrument rather than a generic reading. The HT7500ET has no published baseline in the retrieved table, where East Penn directs the reader to contact the manufacturer. Charger temperature compensation must be set to 12 millivolts per degree C per block.

Pricing and availability

Published price range: $722 - $1,459 per 12 V block depending on model. Trend: flat Lead time, new: Distributor stock at common model numbers; one channel quotes on request.

Lifecycle and maintenance

Valve-regulated lead-acid batteries age on the calendar rather than on cycles, and temperature sets the clock. The industry convention is a design life quoted at 25 degrees C with service life roughly halving for every 8 to 10 degrees C above that, which is why the same block lasts a decade in a conditioned data hall and half that in an unconditioned telecom cabinet. IEEE 1188, whose 2025 edition supersedes the 2005 standard, governs maintenance and testing and sets 80% of rated capacity as the replacement trigger. At a NERC-registered facility the obligations are explicit: 4-month voltage and ground checks, 6-month internal resistance checks, 18-month connection checks and a 3-year capacity test, which is the one paper trail that makes a used string assessable at all.

Common failure points

• Dry-out — A sealed cell loses electrolyte through the valve and capacity falls with no way to top it up
• Thermal runaway — Charging current and cell temperature climb together until the case swells or vents
• Grid corrosion — Positive grid corrodes over calendar time and capacity fades regardless of cycling
• Temperature ageing — Service life roughly halves for every 8 to 10 degrees C above 25, so a hot cabinet destroys a string early
• Post and terminal corrosion — Sulphate creep at the posts raises resistance and heats the connection
• String mismatch — Mixing ages or manufacturers lets one weak block set the capacity of the whole string

Inspection checklist

Manufacture date — read the date code on every block, because a stationary battery is priced on age against a design life quoted at 25 degrees C Ambient temperature history — service life roughly halves for every 8 to 10 degrees C above 25, so a hot cabinet consumes a 10-year battery in 5 Capacity test record — request the most recent discharge test, since IEEE 1188 sets 80% of rated capacity as the replacement trigger Test interval compliance — a NERC-registered site owes VRLA a 3-year capacity test, 6-month internal resistance checks and 18-month connection checks Internal resistance or conductance — compare every cell against the manufacturer baseline and against the string average rather than a generic number String matching — never mix ages or manufacturers in 1 string, because a single weak block drags the whole string down Float voltage and temperature compensation — verify the charger setting against the manufacturer's published coefficient Case condition — look for swelling, distortion and heat marks across all 6 faces, which indicate thermal runaway or chronic overcharge Post and terminal corrosion — inspect for creep and sulphate growth, and check torque against the published value Dry-out — a VRLA cell that has lost electrolyte cannot be topped up, so weight loss against the published figure is terminal Rating basis — confirm whether the model number encodes amp-hours or watts per cell; UPS12-490MR is 490 watts per cell at 15 minutes and 141.2 Ah at the 20-hour rate Warranty transferability — get the remaining term in writing, because EnerSys credits against 80% capacity rather than on a classic pro-rata schedule Shipping classification — sealed VRLA moves as UN2800 Class 8 with terminal protection and separation requirements Scrap floor — lead is about 60% of block weight, so a 132 lb block carries roughly 12 to 17 USD of scrap value at current prices Recycler channel — confirm a certified recycler will take the pull, since spent lead-acid falls under 40 CFR 266 Subpart G rather than the universal waste rule