Most of these yards start on one 125 kW or 250 kW cabinet. Then a second line comes up, the compressor stays on through the outage, or two feeders have to island together. The protected hall is now several hundred kilowatts, and the signed backup may run for hours. That is when the comparison moves to a 750 kW or 1 MW BESS. Open KRL-B2M6L 1-2 MW / 2-6 MWh and put the string on the inquiry: KRL-B1M5L-750H3S-720M6-HX1 or KRL-B2ML-1MH3S-960M8-HX1.
Keep KRL-B261L 125 kW / 261 kWh or KRL-B522L 250 kW / 522 kWh when one feeder still fits 189 A or 375 A after the start review. Those cabinets parallel to 10 and 6. Their PV ports stay at 120 kW or 240 kW, and the lift stays at 2.6 t or 4.9 t. Stack them past that and you are still buying yard current, not a plant converter.
| Buy this string | Power / energy | Max AC current | Max PV | Mass | Box |
|---|---|---|---|---|---|
| KRL-B1M5L-750H3S-720M6-HX1 | 750 kW / 1.5 MWh | 1130 A | 720 kW, 6 × 200 A | about 15000 kg | 6058 × 2438 × 2896 mm |
| KRL-B2ML-1MH3S-960M8-HX1 | 1000 kW / 2 MWh | 1500 A | 960 kW, 8 × 200 A | about 19500 kg | 6058 × 2438 × 2896 mm |
On-grid rated power and off-grid rated power use the same figure on each string. Read the off-grid column as the same converter. If the published specification does not list extra off-grid current, the quote should not invent it.
KRL Power puts the yard class and the plant class on one outdoor list. Once one plant bus has moved beyond the practical 125 kW / 250 kW yard-cabinet arrangement, the plant string belongs on the comparison sheet.
What the yard class will still do
B261L publishes 125 kW, 261 kWh, 189 A, 120 kW PV, parallel 10, about 2600 kg on 980 × 1300 × 2320 mm.
B522L publishes 250 kW, 522 kWh, 375 A, 240 kW PV, parallel 6, about 4900 kg on 2480 × 1400 × 2050 mm.
If one protected feeder fits after the start review, those two cabinets remain the buy. The 125 kW motor-start review covers the start sequence, while the two B261L vs one B522L comparison covers the 125 kW / 250 kW cabinet decision.
| Limit that stays on the yard | B261L | B522L | What happens if you ignore it |
|---|---|---|---|
| Converter current | 189 A | 375 A | Six B261L cabinets or four B522L cabinets still hand the bus many 189 A or 375 A converters |
| Parallel published | 10 | 6 | The tenth B261L or the sixth B522L is the last yard unit on that sheet |
| PV port | 120 kW | 240 kW | A 600 kW roof wants the 720 kW or 960 kW map |
| Lift | about 2600 kg | about 4900 kg | Six B261L lifts or four B522L lifts mean repeated crane handling |
| Pad width | 980 mm | 2480 mm | A 20-ft box needs a 6058 mm pad and a 15 t or 19.5 t note |
A lot of lines look identical across the three product pages: LiFePO4, 832 V, battery liquid cooling, PCS intelligent cooling, fire protection listed Yes, IP65 on the battery, diesel port Yes, RS485 / WiFi, under 10 ms switching, -10 C to 55 C, 5-95% humidity, altitude under 2000 m. Those shared lines sit on all three pages. Class still follows 125 kW, 250 kW or 750 kW / 1000 kW.
What pushes a site out of the yard-cabinet class
Take a hall that has to ride 400-600 kW through an outage. Six B261L cabinets add up to 750 kW and 1.566 MWh on paper. They also add six 189 A converters, six 120 kW PV ports, six RS485 / WiFi nodes and six 2600 kg lifts. The plant asked for one 750 kW converter. KRL-B1M5L-750H3S-720M6-HX1 puts 750 kW, 1130 A and 1.5 MWh in one 6058 mm box.
800-900 kW overlap is messier. Two lines and the compressors come up together. Four B522L cabinets reach 1000 kW and 2.088 MWh, and they leave four 375 A converters plus four 4900 kg pads on the yard. KRL-B2ML-1MH3S-960M8-HX1 keeps 1000 kW, 1500 A and 2 MWh in the same 6058 mm footprint, on one heavier lift.
Several feeders can stay on yard cabinets when each feeder remains inside 125 kW or 250 kW. Once those feeders have to island as one plant, the EMS and the current on the incoming bus belong on the 750 kW or 1000 kW row.
A 25 August 2026 field comment described a warehouse that added robotics and then had to upgrade the hookup and substation because the original building supply had been sized for minimum expected use (X post, 25 Aug 2026). That is an incoming-side limit. The plant-class box sits behind whatever transformer already exists.
The rest of the outdoor map lives in the commercial and industrial energy storage system selection guide. The jump off the yard list is the only question this page answers.
Current on the plant bus
1130 A is the published ceiling on the 750 kW string. 1500 A is the published ceiling on the 1000 kW string.
At 400 Vac three-phase, 750 kW near unity power factor sits around 1083 A. Rated data gives 1130 A. 1000 kW sits around 1443 A. Rated data gives 1500 A.
The energy totals can look close to the plant strings. Spare parts and firmware updates still follow how many converters landed on the purchase order.
Run the motor-start check on 1130 A or 1500 A. The MWh figure will not catch a simultaneous start.
- DOL motors on one hall bus: check the first two seconds against 1130 A or 1500 A
- Soft starter or VFD: write which machines close together
- Two halls that island as one plant: one event on the logger
- Chargers or welders that wake together: treat the wake as a start
A 300 kW plastic line or a 500 kW welding hall already lives above one B522L. Those project files sit on the 300 kW plastic-plant battery storage page and the 500 kW welding-plant energy storage page. Use this page if those halls already grew and the yard is filling with 125 kW and 250 kW boxes.
On-grid rated power and off-grid rated power are both 750 kW on the first string and both 1000 kW on the second. Copy both columns. There is no third power rating on that sheet.
PV ports and the diesel handshake
KRL-B1M5L-750H3S-720M6-HX1 lists 720 kW PV, 950 Vdc max, 250-850 Vdc MPPT, six channels at 200 A each.
KRL-B2ML-1MH3S-960M8-HX1 lists 960 kW PV, the same voltage window, eight channels at 200 A each.
Six B261L cabinets reach 720 kW only if every 120 kW port is used and the roof is split six ways. Four B522L cabinets reach 960 kW only if every 240 kW port is used. Feed one yard cabinet from a single string and the port is the yard port.
Price the extra combiners and the extra trenches first. A stack of yard cabinets can look cheaper until the roof crew counts six trenches. A roof already drawn as one 800 kW array wants the plant-class port count.
Diesel is listed Yes on B261L, B522L and both B2M6L strings. Two ports, six ports or eight ports need one start owner. One plant-class port needs that name too: EMS, PLC, or a person. Under 10 ms is the published changeover on the B2M6L sheet. A diesel set needs seconds. In those seconds the signed load rides on the battery or it drops. Extra yard cabinets will not start the generator any sooner.
Once class is fixed, night diesel hours sit on the industrial battery storage for diesel cost reduction page.
Pads, cranes and the 20-ft box
Both B2M6L strings use the same envelope: 6058 × 2438 × 2896 mm. That is a 20-ft high-cube footprint. The 750 kW string lands at about 15000 kg. The 1000 kW string lands at about 19500 kg.
| Buy | Envelope | Mass | Civil pack |
|---|---|---|---|
| One B261L | 980 × 1300 × 2320 mm | about 2600 kg | one small pad, one light lift |
| One B522L | 2480 × 1400 × 2050 mm | about 4900 kg | one wider pad, one medium lift |
| Six B261L | six of those | about 15600 kg | six pads, six lifts, six cable sets |
| Four B522L | four of those | about 19600 kg | four pads, four lifts |
| KRL-B1M5L-750H3S-720M6-HX1 | 6058 × 2438 × 2896 mm | about 15000 kg | one 20-ft pad, one 15 t lift |
| KRL-B2ML-1MH3S-960M8-HX1 | 6058 × 2438 × 2896 mm | about 19500 kg | one 20-ft pad, one 19.5 t lift |
A door that accepted the 980 mm cabinet will not accept a 6058 mm box. A pad poured for 2.6 t will not hold 15 t. A route that walked a 4900 kg cabinet past a canopy may reject a 19.5 t lift. Walk the truck path and the crane radius before the salesman leaves.
Six light cabinets can look easier to walk onto a tight yard, and they can also book six crane visits and six earths. One 15 t box is one visit and one set of anchors.
B2M6L does not publish a parallel number like 10 or 6. Expansion past one 750 kW or 1000 kW box is project design. Ask for the incoming-transformer rating and the next hall date. The product table has no next count to copy.
Where the wrong class shows up
A hall that already overlaps at 400 kW does not get safer because more B261L energy landed on the yard. Each box stores kilowatt-hours. The incoming bus now owns six current limits. A fault on cabinet three can leave cabinets four to six holding a feeder they were never sized to hold alone. Night-shift plants have already walked a single-cabinet dropout on the 2 a.m. factory blackout recovery page.
If the array is already one 800 kW drawing, four B522L cabinets can add up to 960 kW at the ports. The PV crew then inherits four combiners and four trenches. The 960 kW map on KRL-B2ML-1MH3S-960M8-HX1 was the drawing they asked for.
A 90 kW feeder with no overlap does not need the 1000 kW string. That quote paid for 1500 A and 19.5 t on a site that fits 189 A and 2600 kg.
Tender language hides another miss. Six B261L cabinets written as a 750 kW plant package leave spare parts, firmware and the diesel handshake on six nodes. The storeman then orders 1884 Ah pack language against six 314 Ah cabinets.
Altitude gets missed. Leave it off the inquiry and someone parks the box above 2000 m. The B2M6L sheet caps altitude under 2000 m. Higher than that, ask for derating in writing. The factor is not on the published table.
On 30 August 2026 one engineer wrote that large power transformers still run three to four years, with output described as fully committed (X post, 30 Aug 2026). That thread is commentary, not a KRL schedule. Check the existing transformer rating before a seventh yard cabinet goes behind it.
What locks class in the meeting
Name the incoming transformer and the halls that must island together. If the meeting keeps adding a new building every ten minutes, class is open.
Bring a logger that includes a bad day: running kW, kVA and power factor. Add each large motor, its kW and DOL / soft / VFD, and which motors close in the same two seconds. Add the first ten seconds after the grid dies. Add PV target, 720 kW or 960 kW, and whether the roof arrives as one array or six. Add diesel kept or removed, and the name of the start owner. Add pad access for 6058 mm and a 15 t or 19.5 t lift. Put that pack next to 1130 A and 1500 A.
Each protected feeder inside 189 A or 375 A after the start review stays on B261L or B522L. A plant bus that needs 750 kW / 1130 A, or 1.5 MWh in one 20-ft box with a 720 kW PV map, opens KRL-B1M5L-750H3S-720M6-HX1. A plant bus that needs 1000 kW / 1500 A, or 2 MWh in one 20-ft box with a 960 kW PV map, opens KRL-B2ML-1MH3S-960M8-HX1.
Before the price column, confirm which converter actually carries 1130 A or 1500 A. The vendor should also show how PV lands, who owns the diesel start, and what crane note sits beside 15000 kg or 19500 kg. A second hall changes the expansion question, while usable hours still need a defined meter point after SOC reserve and conversion losses.
The outdoor list sits under KRL C&I energy storage systems. Drawing order before class is locked sits in how to design a commercial energy storage system. If the feeder is inside 250 kW, the project language also sits on the 522 kWh / 250 kW solar-storage-diesel cabinet page.
Send the single-line of the incoming bus, the motor list and the first-ten-second sheet. Class is usually obvious after those three files.
Table you can paste into the inquiry
| Site fact | Class that fits | Cost if the class is wrong |
|---|---|---|
| One feeder inside 125 kW / 189 A | one B261L | extra 15 t steel |
| One feeder inside 250 kW / 375 A | one B522L | extra 19.5 t steel |
| Hall overlap 400-600 kW on one bus | KRL-B1M5L-750H3S-720M6-HX1 | six 189 A converters on a 750 kW bus |
| Hall overlap 800-900 kW on one bus | KRL-B2ML-1MH3S-960M8-HX1 | four 375 A converters on a 1000 kW bus |
| Roof already planned at 720 kW into one box | 750 kW string | six 120 kW ports and six trenches |
| Roof already planned at 960 kW into one box | 1000 kW string | four 240 kW ports and four trenches |
| Pad and crane already limited to 5 t | stay on B522L or below | 15 t box rejected at the gate |
| Next hall date already on the capex sheet | project design past one B2M6L box | no published parallel count to copy |
