Alloys for soldering lead-acid battery posts and straps

No. The 50/50 alloy for sheet-metal work is too rich in tin and is not formulated for the gas-generating impurity limits (Ni, Te, Co, Fe, Mn) required by batteries. It can cause gassing, abnormal self-discharge, grid corrosion and reduced service life. A dedicated battery grade formulation with controlled purity is available: contact us for the specifications.

Typical specification limits for sealed VRLA batteries: nickel, tellurium and manganese 1-5 ppm; cobalt and chromium 5 ppm; iron 5-10 ppm; copper 50-100 ppm. Zinc and cadmium are normally limited to 5 ppm, although they have little effect on gassing. Antimony, arsenic and selenium are often intentional additives (not impurities) and follow formulation specifications (e.g. Pb-Sb 3% for posts). Bismuth and silver are tolerated at higher levels. The values to be met are those of the battery manufacturer's specification; for every lot we supply the spectrometric analysis certificate.

They are three different products: (1) Post/terminal alloy = Pb-Sb 2.75-3.25% / As 0.18-0.28% / Sn 0.20-0.35%, high hardness for mechanical resistance to the cable clamp; (2) COS strap = Pb-Sb 3.0-3.5% / Sn 0.2-0.4% / Se 150-250 ppm, optimised for automatic Cast-On-Strap of the internal cells; (3) Active oxide = pure Pb 99.97-99.99%, raw material for the oxide of the active material, NOT used for soldering.

Gassing is the production of hydrogen (H₂) and oxygen (O₂) by electrolysis of the water in the sulphuric acid electrolyte. Some metallic impurities (Ni, Te, Mn, Co) lower the hydrogen evolution overpotential: electrolysis occurs at lower voltages, even during simple storage. Effects: accelerated water consumption in flooded batteries, pressure build-up in sealed VRLA batteries (risk of explosion), reduced capacity.

They are equivalent trade names for refined lead suitable for battery production. 'Soft lead' refers to lead with low mechanical hardness (free of antimony or calcium hardeners). '99.97%' corresponds to grade PB970R of BS EN 12659 and to the Refined Pure Lead grade of ASTM B29. It is the starting point for formulating battery grade alloys by adding controlled intentional additives.

Yes, every lot of Dickmann battery grade alloy is supplied with a chemical analysis certificate by optical emission spectrometry (spark OES) on 14+ elements: Sn, Pb, Sb, As, Bi, Cu, Fe, Ni, Ag, Zn, Te, Co, Mn, Cr, Cd. The certificate shows the lot number, production date and signature of the laboratory manager. Paper or digital documentation, available for audits by customers and certification bodies. ISO 9001:2015.

Yes, we formulate custom alloys to customer specification. Typical procedure: the customer sends a specification sheet with the target composition and impurity limits for each element, we produce a pilot lot, the certificate of analysis is sent to the customer for validation, and after approval we start series production. For recurring orders we guarantee lots that are consistent over time (lot-to-lot deviation < 5%) for stable in-line QC.

No. Batteries fall outside the scope of the RoHS Directive 2011/65/EU (recital 14): they are governed by Regulation (EU) 2023/1542, which repealed Directive 2006/66/EC as of 18 August 2025. The use of lead alloys for battery soldering is therefore permitted.

Italian Legislative Decree 81/2008 requires: (1) local exhaust ventilation at the soldering points; (2) PPE selected on the basis of the risk assessment, such as heat-resistant gloves, goggles, dedicated clothing and FFP3 filtering facepieces against lead dust and fumes; (3) health surveillance with blood lead testing above the thresholds of Annex XLIII-bis, at intervals set by the occupational physician; (4) a limit value of 0.15 mg/m³ and a biological limit value of 60 µg/100 ml. Directive (EU) 2024/869 provides for lower values, which apply once transposed into national law. Safety data sheets are available on request.

For battery manufacturers we offer: ingots (standard format 12-25 kg/piece), sticks for torch soldering (41 cm long or custom), solid wires for induction soldering (from 0.5 to 4 mm on spools), custom formats to customer drawing. Packaging from 25 kg/box to pallets of 50-1000 kg. For continuous supply we agree a monthly or quarterly delivery schedule priced on the average LME.