For the cell balancing resistor in an EV battery pack built in Thailand, Walsin Technology (Walsin) lists 14 automotive-labelled part numbers at 100 ohm and 1 percent rated 1 W or more, from 2010 to 2512 and up to 3 W. Venatech, Walsin’s authorised distributor in Hong Kong, crosses your balancing resistor to them free.
Venatech Limited, an authorised Walsin distributor in Hong Kong, wrote this for a battery management system (BMS) engineer or buyer in Chonburi who is sizing the resistors that bleed charge from the highest cells during passive balancing. We parsed the 137 Walsin chip resistor export files in our data folder (234,815 rows in the 64 that hold data, from Thick_Film_High_Power_Chip_Resistor_1_1W.xlsx to Thick_Film_General_Purpose_1_1_10W.xlsx), kept every series labelled automotive, and read the Resistance, Size, Rated Power, Tolerance and TCR columns. We checked our stock list as at 23 September 2026 and re-measured every figure on 11 November 2026.
What did electrive report about GAC battery production in Thailand?
Production has started in Chonburi. According to electrive on 31 October 2026, Inpow Battery Technology, the battery division of the Chinese carmaker GAC, officially began production on 29 October at a plant in Si Racha, Chonburi Province, east of Bangkok.
The report says Inpow’s cumulative global output has reached 300,000 battery packs and that its batteries are used in the GAC Aion i60, N60 and UT models; it links to GAC Aion’s vehicle plant in Thailand, which opened in July 2024. It gives no capacity, chemistry or investment figure for the new plant, so we give none. Those are electrive’s figures, not ours. Our reading is that pack assembly in Thailand now sits next to vehicle assembly, and every pack needs a BMS. We have no relationship with GAC or Inpow and say nothing about what either buys.
What does a cell balancing resistor have to survive?
Hours of steady heat. In passive balancing, a resistor across a 4.2 V lithium cell dissipates about 0.18 W at 100 ohm, and a bank of them runs for hours at the end of charge, so the part needs power margin, stable TCR and an automotive-grade qualification.
The arithmetic is V squared over R: 4.2 V across 100 ohm gives 42 mA and about 0.18 W. A designer who wants faster balancing lowers the resistance and the power climbs, so many packs use 33 to 100 ohm in 1206 to 2512 bodies, often two in parallel to spread heat. Because the parts sit inside a sealed pack for its whole life, power derating with board temperature matters more than the headline rating. Our guide to passives for a battery management system covers the rest of the BMS.
How many automotive-labelled Walsin chip resistors are rated 1 W or more?
15,526. We counted 102,850 distinct Walsin chip resistor part numbers in series labelled automotive, and 15,526 of them are rated 1 W or more, across 10 series from general purpose and anti-sulfuration to high power, triple power surge and high voltage.
The biggest contributor is the Thick Film High Power Chip Resistor (Automotive) series, with 4,985 parts at 1 W or more, followed by the general purpose automotive series with 2,907. For a Chonburi BMS team that means the balancing position, the precharge position and the bleeder position can all sit on automotive-labelled Walsin parts. The chip resistor range lists the families, and our note on Walsin automotive chip resistors and the AEC-Q200 split explains how the labels map to qualification.
Which Walsin 100 ohm automotive resistors cross a 1 W balancing brief?
Thirteen of fourteen. We filtered the automotive-labelled rows to 100 ohm, 1 percent and 1 W or more and found 14 part numbers in 2010, 1218 and 2512; 13 carry a TCR of 100 ppm or better, the brief we set for a balancing bank.
Your incumbent goes in the last column.
| Walsin part | Family as the export names it | Size | Rated power | TCR (ppm/K) | Match / mismatch with the brief | Your incumbent |
|---|---|---|---|---|---|---|
WF25A1000FZLJ |
High Power (Automotive) | 2512 | 3 W | 100 | Match, highest power | |
WF25P1000FTLJ |
High Power (Automotive) | 2512 | 2 W | 100 | Match | |
MF25P1000FTL |
High Power (Automotive) | 2512 | 2 W | 100 | Match | |
MF25E1000FTL |
Triple Power Surge (Automotive) | 2512 | 2 W | 100 | Match, surge-rated | |
WF20A1000FTLJ |
High Power (Automotive) | 2010 | 1.5 W | 100 | Match, smaller body | |
WF20P1000FTLJ |
High Power (Automotive) | 2010 | 1 W | 100 | Match | |
MF20P1000FTL |
High Power (Automotive) | 2010 | 1 W | 100 | Match | |
MF20E1000FTL |
Triple Power Surge (Automotive) | 2010 | 1 W | 100 | Match, surge-rated | |
MR18X1000FTL |
General Purpose (Automotive) | 1218 | 1 W | 100 | Match, 1218 body | |
MR25X1000FTL |
General Purpose (Automotive) | 2512 | 1 W | 100 | Match | |
SR25X1000FTL |
High Grade Anti-Sulfuration (Automotive) | 2512 | 1 W | 100 | Match, adds anti-sulfuration | |
WK25V1000FTLJ |
High Voltage (Automotive) | 2512 | 1 W | 200 | Mismatch: TCR is above the brief |
Two further matches, WR25X1000FTLJ and SR25X1000FTLW, are packing and family variants of the 2512 1 W rows. A match is a match on export fields; confirm AEC-Q200 status and the derating curve against Walsin’s own datasheet, which we hold for the MR family as Walsin_MR_Automotive_Thick_Film_Chip_Resistor.pdf.
How should a Chonburi team choose between 1 W, 2 W and 3 W?
By temperature, not by the headline. In our 14-part set, 9 parts are rated 1 W, 1 is 1.5 W, 3 are 2 W and 1 is 3 W, so a designer can hold 100 ohm and step up power in the same 2512 footprint from 1 W to 3 W.
Inside a sealed pack the board can run hot, and chip resistor ratings are derated above a stated terminal or ambient temperature, so a 0.18 W load per cell can still need a 1 W body once two or three balancing resistors share copper. Moving from a 1 W to a 2 W part in the same 2512 pad costs no layout change. Triple power surge parts add margin if the balancing path also sees hot-plug transients. Test the hot spot on your own board before you fix the choice.
What does Venatech hold in Hong Kong for automotive resistors?
Four automotive-labelled Walsin surge resistors. Of the 1,125 distinct part numbers on our stock list as at 23 September 2026, 4 are Walsin Triple Power Surge (Automotive) parts in 1206: MF12E1R00FTL, MF12E2200FTL, MF12E3300FTL and MF12E3902FTL.
Those suit prototype boards that need automotive-labelled surge parts in a hurry, and the snapshot as at 23 September 2026 is the list we quote them from. For the 100 ohm balancing parts above, request a quote and we source them through our authorised Walsin channel. The ready-stock list is a dated snapshot, never live-synced; we give no lead time or stock promise.
How Venatech helps: what should a Thai battery team send us?
Your BMS resistor lines and the grade you need. Venatech is Walsin’s authorised distributor in Hong Kong, and VenaMatch decodes 18 manufacturers’ part numbers and crosses 800,000+ parts to Walsin, with every difference from your original stated.
Paste up to 500 part numbers into the free cross-reference tool and filter by automotive grade, or upload a BOM and request a quote for small lots. Worked example from our own export: a 100 ohm, 1 percent, 1 W or more, automotive-labelled brief returned 14 parts and 13 matches at 100 ppm. We hold no office in Thailand, hold no IATF 16949 certificate and give no legal or customs advice. Walsin is the line we are authorised for; Stackpole and Viking are lines we supply.
The short version
For an EV battery pack built in Chonburi, Thailand, Walsin covers the cell balancing resistor position with 14 automotive-labelled parts at 100 ohm and 1 percent, from 1 W to 3 W, inside a range of 15,526 automotive-labelled parts rated 1 W or more. Venatech, Walsin’s authorised distributor in Hong Kong, crosses your resistor and quotes it.
Send us your balancing, precharge and bleeder resistor lines with the grade you need, and we will return the Walsin crosses with every difference stated. How hot does your balancing bank run?
Related reading
- Passives for a battery management system
- Walsin automotive chip resistors and the AEC-Q200 split
- Chip resistor power rating by case size
- Free cross-reference tool and ready-stock snapshot
Last reviewed 11 Nov 2026.
Sources
Fetched 11 November 2026.
- electrive, “GAC launches battery production in Thailand”, 31 October 2026: https://www.electrive.com/2026/10/31/gac-launches-battery-production-in-thailand
Frequently asked questions
Where has GAC started battery production in Thailand?
electrive reported on 31 October 2026 that Inpow Battery Technology, GAC’s battery division, began production on 29 October at a plant in Si Racha, Chonburi Province. The report gives no capacity figure.
Which Walsin 100 ohm automotive resistors are rated 1 W or more?
We counted 14 automotive-labelled parts at 100 ohm and 1 percent rated 1 W or more, including WF25A1000FZLJ at 3 W, WF25P1000FTLJ and MF25P1000FTL at 2 W, and MR25X1000FTL at 1 W.
How much power does a cell balancing resistor dissipate?
Power is voltage squared over resistance, so 100 ohm across a 4.2 V cell dissipates about 0.18 W. Derate for board temperature inside the pack and check Walsin’s derating curve.
Are Walsin automotive-labelled resistors AEC-Q200 qualified?
The export labels series as automotive. Ask for Walsin’s qualification documents for the exact part before treating it as AEC-Q200 for your programme; compliant is not certified.
Does Venatech stock automotive resistors in Hong Kong?
As at 23 September 2026 our snapshot holds four Walsin Triple Power Surge (Automotive) 1206 lines. For other parts, request a quote and we source them through our authorised Walsin channel.
Is Venatech an authorised Walsin distributor?
Yes. Venatech Limited is Walsin’s authorised distributor in Hong Kong and serves Thailand from Hong Kong.