Cold-Chain & Refrigerated Truck Batteries
A refrigerated truck carries two electrical loads that need two different batteries: the engine's cold-start burst and the reefer unit's continuous, hours-long draw. Confusing the two strands drivers mid-route.
Direct Answer
A refrigerated truck needs two separate systems: a starting battery with 850–1100+ CCA for the engine, and a deep-cycle or AGM auxiliary bank for the refrigeration unit — one battery cannot serve both jobs. The engine wants a short cold-crank burst; the reefer wants a continuous, hours-long draw that deep-discharges a starting battery and strands the driver. Size the auxiliary bank to the reefer’s specified draw and depth-of-discharge limit.
Key Takeaways
- Two loads demand two battery types — a starting (SLI) battery for the 850–1100+ CCA crank, and a separate deep-cycle bank for the reefer's continuous draw.
- Never run the reefer off the starting battery — a 25 A unit draws ~200 Ah over 8 hours and deep-discharges the plates; the truck starts fine on the lot, then strands the driver after an overnight stop.
- Isolation is not enough — a basic isolator only blocks reverse current and drops ~0.3–0.7 V; a DC-DC charger also applies a proper multi-stage charge the cycled auxiliary bank needs.
- Size the bank to the draw — a 25 A/8-hour duty needs ~200 Ah usable, or ~400 Ah of bank at the 50% depth-of-discharge limit.
Why a Reefer Needs Two Systems
The two loads are fundamentally different. The engine needs a short, high-current burst — 850–1100+ CCA for a large diesel — delivered in seconds. The refrigeration unit needs a modest but continuous current for hours while the truck is parked overnight or loading.
A starting battery is built for the first job: thin plates that deliver high current briefly. Drawing that battery down continuously for hours — as a reefer does — discharges it deeply and permanently damages the plates. The result is a vehicle that starts fine at the depot but won't crank the next morning. The fix is a separate deep-cycle or AGM bank dedicated to the reefer, with the two banks isolated so neither can drag the other down.
Duty Cycle & Environment
| Factor | Cold-chain duty |
|---|---|
| Duty cycle | Two separate loads: an intermittent engine-start burst and a continuous, hours-long reefer draw (often parked overnight). |
| Starting demand | 850–1100+ CCA for a large diesel tractor. |
| Environment | Continuous refrigeration current draw regardless of ambient temperature; long engine-off periods during loading and overnight stops. |
| Battery requirements | A starting (SLI) battery for the crank plus a separate deep-cycle or AGM auxiliary bank, isolated from the starting battery. |
| Recommended characteristics | High CCA for the engine, and an auxiliary bank sized to the reefer’s draw at ~50% depth of discharge — confirm the unit’s specified current and runtime. |
Recommended Specifications
| Load | Battery type | Key figure |
|---|---|---|
| Engine starting | Starting (SLI) battery | 850–1100+ CCA |
| Refrigeration unit | Deep-cycle or AGM auxiliary bank | ~200 Ah usable per 25 A / 8 h |
| System voltage | 12V or 24V per vehicle | Matched pair rule applies |
| Auxiliary depth of discharge | ~50% limit | ~400 Ah bank for 200 Ah usable |
Figures are representative. Exact CCA, bank capacity and runtime depend on the reefer unit's specified draw — contact us for a datasheet matched to your fleet.
Product Lines for Cold-Chain Fleets
Starting Batteries (N150/N200 / DIN)
High-CCA starting batteries for the tractor — JIS 145G51/190H52 or DIN 58827/60038.
View JIS Heavy-Duty →Auxiliary & AGM Banks
Deep-cycle and AGM for the reefer's continuous draw — sealed, maintenance-free.
View Fleet & AGM →Related DINWEYS model pages (starting): 145G51 (N150) — 900 A CCA · 190H52 (N200) — 1100 A CCA. The two-battery split explained: CCA vs capacity (Ah). Match a vehicle with the battery selection tool.
Frequently Asked Questions
What battery does a refrigerated truck need?
A refrigerated truck needs two separate systems: a starting battery with 850–1100+ CCA for the engine, and a deep-cycle or AGM auxiliary bank for the refrigeration unit. One battery cannot serve both jobs.
Can I run the reefer off the starting battery?
No. A 25 A refrigeration unit draws roughly 200 Ah over 8 hours and will deep-discharge a starting battery, damaging it and risking a no-start mid-route. Use a separate auxiliary bank.
What type of battery is best for a reefer unit?
Deep-cycle or AGM batteries are best for the reefer's continuous draw — they tolerate repeated discharge to about 50% without the plate damage a starting battery suffers.
How do I size a reefer auxiliary bank?
Size it to the reefer's continuous current draw and required runtime. A 25 A unit over 8 hours needs about 200 Ah usable — roughly 400 Ah of bank at the 50% depth-of-discharge limit. Confirm the unit's draw from its specification.
📚 Read the full guide: Cold-Chain & Refrigerated Battery Selection
Technical review — Reviewed by the DINWEYS technical team. Manufacturer: Chengguang Power Tech Co., Ltd. Data source: manufacturer specification and test documentation. Specifications vary by model and standard; confirm final values with the manufacturer.