Surlon Power LFP | SLA Replacement batteries,12.8V100Ah

A 12V Block That Holds Voltage Under Load

Most 12V installations are limited by current before they are limited by stored energy. A trolling motor, a 1.5kW inverter or a small traction controller asks for a surge the moment it starts, and a block that sags under that demand drags every load on the circuit down with it. This is the 12.8V 100Ah LiFePO4 battery Surlon Power builds for that duty: 1,280Wh of lithium iron phosphate storage in a sealed IP65 case, rated at 150A continuous discharge and 1,920W maximum output.

The case carries M8 threaded inserts on the top face and a fabric strap across the top, and it stays compact enough to fit a tray built around a conventional 12V block. Inside, an integrated battery management system tracks cell voltage, pack current and temperature and opens the circuit on overcharge, over-discharge, short circuit or over-temperature, so the protection travels with the pack rather than living in the charger.

As a 12.8V drop-in SLA replacement battery it suits systems that were originally laid out around a large 12V lead-acid block: boat and RV house banks, off-grid solar storage, UPS and telecom cabinets, low-speed electric vehicles. Fit, cable gauge and charging profile are the three things worth checking before the first cycle — get them right and the changeover is uneventful; skip them and the pack spends its life arguing with the installation.

Compared with the smaller capacities in the same 12V family, the point of this block is headroom. Where a 50Ah or 10Ah unit serves lighting, instrumentation and standby duty, the 100Ah carries the motor, the inverter and the traction load without running at its own ceiling.

What 150A Continuous Actually Runs

• 150A continuous is a working rating, not a momentary peak. The figure holds for as long as the load holds, so equipment that stays inside it runs without the BMS stepping in.
• 1,920W maximum output at 12.8V. A 1,500W inverter pulls roughly 117A before its own losses, which leaves room; a 2,000W inverter sits right on the ceiling, so keep headroom for start-up surge.
• Start-up current matters more than running current. Pumps, compressors and winches draw several times their rated current for a fraction of a second — describe that surge and the pack, cable and protection can be matched to it.
• The cable is part of the rating. M8 inserts take a standard ring lug, and the cable has to carry the full current without excessive volt drop; undersized cable turns a capable pack into a warm one.
• 1,280Wh sits behind the current. A 200W average load runs for around six hours on paper, less once inverter losses and the reserve kept for cell health are counted.
• What the rating does not replace: a fuse, a breaker or a correctly sized DC circuit. The BMS is the last line of protection for the cells, not the electrical design of the installation.

Where the 5,000-Cycle Rating Comes From

Up to 5,000 cycles is the rating for this model under recommended conditions, and the conditions are part of the number: depth of discharge, charge and discharge rate, ambient temperature and the capacity-retention threshold that defines end of life. Cycled shallow in a cool locker, a pack goes further than the rating; run flat in a hot engine bay, it will not.

The commercial comparison that matters is cost per cycle rather than the invoice at delivery. A lead-acid block in daily duty gets replaced on a calendar whether or not it has failed; this pack is specified to carry the same installation through several of those replacement intervals, and the labour and downtime go with them.

Three habits shorten the count faster than anything else: charging outside the permitted window, leaving the pack at a low state of charge for months, and repeated high-current work at the top of the rating. None of them is a defect — they are simply the conditions the rating assumes you avoid.

Specifications for the LFP 12.8V100Ah

Where a 1.28kWh Pack Earns Its Place

• Boat house banks with real loads. A fridge, a pressure pump, navigation electronics and a trolling motor that draws hard for hours; the 150A rating is what separates this block from the smaller packs in the range.
• Camper and motorhome electrical systems. Because the case is sealed, a 12.8V drop-in SLA replacement battery can sit under a bench where a vented lead-acid box would need its own compartment and vent.
• Off-grid solar and cabin storage. Set the MPPT to a lithium profile and the pack cycles through lighting, communications and small appliance loads day after day.
• UPS, telecom and access-control cabinets. Standby duty, where the pack sits at partial charge for weeks and has to take over without warning.
• Low-speed electric vehicles. Four units in series give a 51.2V pack for mobility scooters, utility carts and small EV platforms built around 48V lead-acid — the case layout is close enough to the original blocks that the pack sits in the existing tray once the hold-down and charger are checked.
• Jobsite and portable power boxes. The strap and the sealed case matter as much as the energy rating when the pack moves between sites.

Charge Limits, Heat and the Right Charger

Charging is rated from 0 °C to 60 °C (32 °F to 140 °F) and discharging from -20 °C to 65 °C (-4 °F to 149 °F). The charge window is the narrower one for a reason: pushing current into a lithium cell below freezing plates lithium on the anode and quietly removes capacity, so a cold locker or an unheated shed needs the pack warmed or the charge deferred.

The 65 °C figure is a ceiling, not a target. A dark case in summer sun, a compartment beside an engine or a closed cabinet all run hotter than the air outside, and the BMS will interrupt rather than let the cells cook. Leave air around the case and shade it where the installation allows.

At 20A continuous charge current, a full recharge from empty takes roughly five hours before the constant-voltage tail, so plan an overnight window or a shift change rather than a coffee break.

Compatibility is where conversions go wrong. Surlon chargers and approved chargers suit the pack; an existing lead-acid charger is not automatically a match for a 12.8V 100Ah LiFePO4 battery, because equalisation and desulphation stages push voltage past what the BMS will accept and the pack never finishes a cycle. Send the charger model and its current profile before treating the pack as a straight swap for the lead-acid block rather than something that needs a different charger.

Installation Steps, Terminals and Bank Wiring

1. Measure against the drawing before lifting, and add clearance for lug bodies, cable bend and lid closure. The layout follows the large 12V lead-acid blocks this range replaces, which is what makes a 12.8V drop-in SLA replacement battery practical in an existing tray — but only once the lid, lugs and cable bend are confirmed to clear.
2. Lift by the strap and set it upright. The pack is a one-person carry when it is handled by the strap rather than the posts, and the case goes in the orientation printed on the label.
3. Bolt the M8 inserts with ring lugs. Clean mating faces, correct polarity, insulated tools, and the covers back on afterwards; torque to the figure on the datasheet rather than by feel.
4. Strap the case down. Vibration works a loose block against its cables, so reuse the original hold-down or fit a bracket across the base, never a clamp across the case faces.
5. Build series strings before parallel groups. Four units in series make a 51.2V string for 48V-class equipment; ten in parallel raise capacity at 12.8V. Match model, rated capacity and state of charge, charge each unit to full on its own, then wire it in.
6. Commission with a meter. Check open-circuit voltage and polarity at the far end of the cable, confirm the charger profile, then bring loads on one at a time. Fit the optional CANBus or Bluetooth link last, once the DC side checks out.

Custom Builds Alongside the Catalogue Model

Catalogued as LFP 12.8V100Ah, the pack is a baseline rather than a fixed item. Capacity, case dimensions, terminal configuration and the BMS itself are open to a project — a compartment too tight for the standard block, a controller that wants to read state of charge over CANBus or Bluetooth, a protection threshold that has to line up with the equipment it feeds. Labels and branding are part of the same discussion for distributors running their own range.

As a lead acid replacement battery supplier we keep the 12V family on one terminal layout and one BMS logic, from 7Ah to 100Ah, so a distributor can stock several capacities without teaching installers a new block each time.

Where a build differs from the catalogue version, the work starts from your drawing and your load profile: enclosure, mounting points, connector position and cable length are agreed, sampled and tested before a production run.

What to Send Before an Order

• The equipment it powers, with continuous and start-up current for each load on the circuit.
• The charger model, the profile it currently runs, and the charging window available between duty cycles.
• Compartment dimensions, mounting points, cable route and lug type; a sketch and a photo usually cover it.
• The destination market and its documentation — certificates, test reports and transport papers are prepared for the exact configuration, because a lead acid replacement battery supplier shipping into the EU, Australia or Japan has to match the file to the market.
• Whether the standard 100Ah build fits, or capacity, terminals, case size or communication need to change.
• The documentation you need for approval: datasheet, dimensional drawing and test reports for the exact build.
• Whether a first article is wanted for bench testing before volume.

Technical Support & Model Matching

Technical questions reach the people who build the packs. Our engineering group in Shenzhen reviews your device's voltage window, load profile, enclosure space and charger before proposing a configuration; our sample group then builds units so you can validate fit and runtime before production. Cell selection, BMS design and pack assembly stay in-house, with quality checks in process and at final inspection, and a documentation team handling certificates, test reports and shipping papers. When a unit behaves unexpectedly in the field, our engineers help trace the fault and advise on installation and commissioning.

FAQ