EV battery electronics in Debrecen, Hungary, that use a 47 ohm resistor to bleed a cell at 4.2 V dissipate about 0.375 watt, and only 31 of the 180 Walsin Technology (Walsin) 1 percent rows at 47 ohm are rated at twice that or more. Neither of the 2 stocked 47 ohm lines is.
Venatech Limited, an authorised Walsin distributor in Hong Kong, wrote this from the Walsin chip resistor exports (234,707 rows, 234,294 distinct part numbers, jumper files excluded) and our stock list as at 23 September 2026. It is for a design engineer at a battery-management or pack-electronics supplier near Debrecen who is choosing a balancing or bleed resistor. Every part number is real and every count is ours. The market statements name their sources and the day we fetched them, 10 November 2026.
What did EV Powered and electrive report from Debrecen?
They reported two large plants, one ramping and one starting. According to EV Powered on 28 September 2026, CATL began trial production at its Debrecen plant, a 7.3 billion euro project planned at 100 GWh when complete, with the first two lines put at 34 GWh.
On 18 September 2026 electrive reported that BMW moved iX3 production at its Debrecen plant from two shifts to three, after series production began in October 2025, and that the 50,000th iX3 had come off the line. The same report gives the plant’s workforce as about 5,000 and the investment as over 2 billion euros. Those are the reports’ figures, not ours. We have no relationship with either company and say nothing about what they buy.
How much power does a cell-balancing bleed resistor dissipate?
It is the cell voltage squared over the resistance. At an assumed 4.2 V per cell, a value for you to replace with your own chemistry and pack design, a 47 ohm bleed dissipates 0.375 watt, a 100 ohm bleed 0.176 watt and a 220 ohm bleed 0.080 watt, all continuously.
Balancing is often pulsed, and a duty cycle cuts the average, but the resistor still has to survive the on-time. We apply a rule of rated power at least twice the continuous dissipation, which is our assumed design rule and not Walsin’s or anyone’s standard. Under that rule the required rating is 0.75 watt at 47 ohm, 0.35 watt at 100 ohm and 0.16 watt at 220 ohm. A chip rated 3/4 W, 0.75 watt, misses the 47 ohm requirement by under a milliwatt, and 11 of the 47 ohm rows are exactly that. Our post on chip resistor power rating by case size covers why the case size sets the ceiling.
How many Walsin 1 percent chip resistors carry that bleed with margin?
Fewer than a fifth at the lowest value, and the share rises with resistance. We counted every plus or minus 1 percent row at six round values across the Walsin chip resistor files: at 33 ohm 12 of 165 meet the 2x rule, at 47 ohm 31 of 180, at 68 ohm 42 of 181, at 100 ohm 65 of 185, at 150 ohm 96 of 185 and at 220 ohm 98 of 185.
| Resistance | Dissipation at 4.2 V | Rating needed (2x) | Plus or minus 1% rows | Rows that meet it | Stocked lines at this exact value | Stocked lines that meet it |
|---|---|---|---|---|---|---|
| 33 ohm | 0.535 W | 1.07 W | 165 | 12 | 0 | 0 |
| 47 ohm | 0.375 W | 0.75 W | 180 | 31 | 2 | 0 |
| 68 ohm | 0.259 W | 0.52 W | 181 | 42 | 0 | 0 |
| 100 ohm | 0.176 W | 0.35 W | 185 | 65 | 2 | 0 |
| 150 ohm | 0.118 W | 0.24 W | 185 | 96 | 2 | 1 |
| 220 ohm | 0.080 W | 0.16 W | 185 | 98 | 3 | 1 |
At 47 ohm the 31 qualifying rows are all 1 W or more, and they sit in six sizes only: 17 in 2512, 7 in 2010, 3 in 1218, 2 in 1225, 1 in 1020 and 1 in 0612. They come from five series groups: 13 High Power, 9 General Purpose, 4 Wide Terminal, 3 High Voltage and 2 Anti-Surge. No 1206, 0805 or smaller part qualifies. The table is built from those .xlsx exports and the stock list as at 23 September 2026.
Which Walsin parts answer a 47 ohm, 1 percent, 4.2 V bleed brief, and what differs?
Parts in 2010 and 2512 do; the stocked ones do not. For a 47 ohm, plus or minus 1 percent brief needing at least 0.75 watt, the export returns parts such as WF20P47R0FTL in 2010 at 1 W and WF25P47R0FTL in 2512 at 2 W, while both stocked 47 ohm lines are rated 1/10 W and 1/16 W.
| Walsin part | Series / size | Rating | On shelf 23 Sep 2026 | Match / mismatch with the 47 ohm, 1%, at least 0.75 W brief | Your incumbent |
|---|---|---|---|---|---|
WF20P47R0FTL |
High Power, 2010 | 1 W | No | Match on value, tolerance, rating | |
WF25P47R0FTL |
High Power, 2512 | 2 W | No | Match on value, tolerance, rating with more headroom; mismatch in footprint size | |
MF20E47R0FTL |
Anti-Surge, 2010 | 1 W | No | Match on value, tolerance, rating; Anti-Surge is a different series | |
WF12A47R0FTL |
High Power, 1206 | 3/4 W | No | Mismatch: 0.75 W misses the 2x rule of 0.7506 W by under a milliwatt | |
WR06X47R0FTL |
General Purpose, 0603 | 1/10 W | Yes | Mismatch: a tenth of the rating needed | |
WR04X47R0FTL |
General Purpose, 0402 | 1/16 W | Yes | Mismatch: under a twelfth of the rating needed |
A match in the table is a match on the export fields and nothing more. Confirm against both datasheets and qualify in your own circuit. Chip resistors in these sizes have a power derating curve with ambient temperature that the export does not carry; read it in the datasheet.
What does the Hong Kong shelf hold at these values?
Small parts, with two partial exceptions at higher values. At 47 ohm the stocked lines are WR06X47R0FTL and WR04X47R0FTL, and neither meets the rule; at 150 ohm WR12X1500FTL (1/4 W, 1206) does, and at 220 ohm MF12E2200FTL (3/4 W, 1206, Anti-Surge) does.
At 33 ohm and 68 ohm exactly, the shelf holds no line at all, though neighbouring E96 values such as 33.2 ohm and 68.1 ohm are stocked in small sizes. The shelf is 1,125 distinct part numbers in all, re-counted by us. The ready stock list is a dated snapshot and never live-synced, and the chip resistor range lists the families. A high-power 47 ohm part is a to-order enquiry, and we give no lead time or price.
What will we not tell you about battery plants?
Anything about their cells, their balancing method or their purchasing. Of the 28 Walsin datasheets we hold, 2 cover chip resistors, and neither covers the High Power, Wide Terminal or Anti-Surge series, so every rating here is the export’s field and not a datasheet value.
We make no claim that any part suits a battery pack, no part here is a certified part, and 4.2 V is our assumed example, not a figure from CATL, BMW or any pack maker. We hold no office, entity or stock in Hungary; our locations are Hong Kong, Shenzhen, Singapore and Jiangmen, with Chengdu in preparation. We hold no ISO 9001 or IATF 16949 certificate. We give no legal, customs or conformity advice; confirm with your compliance team.
How can Venatech help a Debrecen battery electronics buyer?
How Venatech helps starts with a free paste box. The cross-reference tool, VenaMatch, decodes 18 manufacturers’ part numbers across 800,000+ crossable parts, accepts up to 500 part numbers or an Excel or CSV file, and marks each field of a Walsin candidate as match or mismatch. Load a whole BOM for review. The ready-stock list is a Hong Kong snapshot dated 23 September 2026.
Worked example from our own exports: a 47 ohm, 1 percent bleed brief at 0.75 watt returned 31 qualifying rows, none stocked, plus 11 near-misses at exactly 3/4 W. Walsin is the only line we are authorised for. Stackpole and Viking are lines we supply. We serve from Hong Kong in small lots, we help cross-reference, and you request a quote through the site.
The short version
For a 4.2 V bleed, power rating, not value, narrows the Walsin range: at 47 ohm only 31 of 180 rows qualify, all in 2010 or larger and none on the shelf. Check the dissipation and the duty cycle before you fix the footprint.
Send us one bleed or balancing line from your BOM, with the dissipation you must meet, and we will return the Walsin parts with every difference stated. If the board area is fixed, which can move: the resistance or the duty cycle?
Sources
Fetched 10 November 2026.
- EV Powered, “CATL gigafactory begins battery trial production in Debrecen, Hungary”, 28 September 2026: https://evpowered.co.uk/news/catl-gigafactory-begins-battery-trial-production-in-debrecen-hungary/
- electrive, “BMW intensifies production in Hungary amid high iX3 demand”, 18 September 2026: https://www.electrive.com/2026/09/18/bmw-intensifies-production-in-hungary-amid-high-ix3-demand/
Related reading
- Chip resistor power rating by case size
- Anti-surge chip resistors
- Low-ohm current sense: thick film versus metal
- Free tools: VenaMatch cross reference and the ready stock list
Last reviewed 10 Nov 2026.
Frequently asked questions
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What did EV Powered report about CATL in Debrecen?
On 28 September 2026 it reported that trial production began at the Debrecen plant, a 7.3 billion euro project planned at 100 GWh when complete, with the first two lines put at 34 GWh. These are the report’s figures, not ours.
How much power does a 47 ohm bleed resistor dissipate at 4.2 V?
About 0.375 watt, from voltage squared over resistance. The 4.2 V is our assumed example. With a rule of twice the dissipation, which is also assumed, you need a rating of at least 0.75 watt.
How many Walsin 47 ohm, 1 percent chip resistors meet 0.75 watt with margin?
31 of 180, all rated 1 W or more and all in 2512, 2010, 1218, 1225, 1020 or 0612. Another 11 rows are rated exactly 3/4 W and miss the 2x rule by under a milliwatt. Check the datasheet derating curve.
Which Walsin 47 ohm parts are on the Hong Kong shelf?
WR06X47R0FTL (0603, 1/10 W) and WR04X47R0FTL (0402, 1/16 W). Neither meets the 0.75 watt rule. The snapshot is dated 23 September 2026 and is not live, so ask us about a to-order enquiry.
Does the export carry the power derating curve?
No. The export gives one rated power per row. The derating with ambient temperature is on the datasheet, and we hold datasheets only for the MR and WR families. Request the sheet for the exact series before you design in.
Do you hold stock or an office in Hungary?
No. We hold no office, entity or stock in Hungary; our locations are Hong Kong, Shenzhen, Singapore and Jiangmen. We hold no ISO 9001 or IATF 16949 certificate and give no legal, customs or conformity advice. Confirm with your compliance team.