#5 · Standard or Power Pack: Which One to Choose?

When choosing a battery, voltage and capacity usually come first. Yet even batteries of the same voltage and capacity can differ in the current that can be drawn at once and the current that can be accepted during charging. That is why the discharge and charge current specifications need to be checked alongside capacity. POWERCRAFT organises its standard battery packs into standard and power versions on the basis of this difference.

1. C-rate — reading current against capacity

The C-rate, which expresses charge and discharge current relative to capacity, is defined as follows.

C-rate = current (A) ÷ capacity (Ah)

1C is a current equal in size to the capacity. For a 100Ah battery pack, 1C = 100A, 0.5C = 50A and 0.2C = 20A. The C-rate shows whether a battery is built for high discharge.

2. What is different — discharge current and charge current

Here are two POWERCRAFT standard battery packs at 12.8V 100Ah side by side.

• Continuous current (Max Discharge Current) — standard 50A (0.5C) · power 150A (1.5C)
• Peak current (Instantaneous Discharge Current) — standard 100A · power 200A
• Continuous max power — standard 640W · power 1,920W
• Charge current (normal / fast) — standard 20A (0.2C) / 50A (0.5C) · power 50A (0.5C) / 100A (1C)
• Size and weight — both about 15kg, identical dimensions

12.8V 100Ah — standard vs power

StandardDM-STD-12.8V-100Ah

PowerDM-PWR-12.8V-100Ah

Continuous —
Max Discharge Current

50A

150A

Peak —
Instantaneous Discharge

100A

200A

Fast charge —
Max Charge Current

50A

100A

Standard models have a continuous current of 0.5C, and power models up to 1.5C (*some high-capacity models are set lower, so the spec sheet of each model must be checked). For charging, standard models take 0.2C normal and 0.5C fast, and power models 0.5C normal and 1C fast.

Capacity (100Ah) and energy (1,280Wh) are the same, so when discharged at the same current the runtime is also the same (article #3). What changes is how much current can be drawn at once and how fast the pack can be charged. How to read continuous and peak current is covered in article #4.

3. How to choose — start with the machine's current

The steps are the same as in article #4. Confirm the machine's normal current and peak current first, check them against the standard model's spec sheet, and consider a power model if they exceed its range. For continuous current, a 1.2–1.3× margin is recommended rather than running close to the limit (article #4).

Worked example 1. A 12V-class machine drawing 30A normally and 80A for 1 second when starting off is within the spec sheet of the DM-STD-12.8V-100Ah (continuous 50A · peak 100A); even with a 1.3× margin, 30A becomes 39A, still within the continuous 50A. A standard pack is enough here.

Worked example 2. If a 12V-class machine draws 70A normally and 180A for 1 second when starting off, it exceeds the standard pack's continuous 50A. With the DM-PWR-12.8V-100Ah (continuous 150A · peak 200A), it is within the spec sheet.

4. Line-up — the mix differs by voltage

Across the 49 POWERCRAFT standard battery packs, standard and power versions are offered as follows.

• 12.8V — standard and power line-ups
• 25.2V · 50.4V (lithium-ion) — standard and power line-ups
• 25.6V · 51.2V (LiFePO4) — power line-up only

In the lithium-ion line, the capacity steps of standard and power packs differ slightly (ex) 25.2V standard 100Ah · power 108Ah). In that case, please compare products of similar capacity. The 25.2V 100Ah standard pack has a continuous current of 0.5C (50A), the 108Ah power pack 1.5C (162A), and both weigh about 20kg.

If a standard pack is needed at the 24V or 48V class, the choice falls to the lithium-ion line, so please also see article #2 on the difference between battery types. Voltage selection is covered in article #1.

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