Generac — Checking and Testing the Battery
Maintenance
From a Generac service manual covering: 0D3358, 0D7675, 0D9033, 0D9708, 0E0038, 0E3342, EVT-04174-0, EVT-04198-0, EVT-04629-0, EVT-04629-1, EVT-04630-0, EVT-04712-0…. Check it applies to your exact model before use.
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Before you start
- Wear eye protection when servicing the battery; avoid skin contact
- Batteries produce hydrogen, an explosive gas - do not store or charge near open flame or spark
- Before servicing battery, disconnect negative (-) cable then positive (+) cable
- Do not crank starter motor for more than 15 seconds without allowing it to cool at least 2 minutes
Procedure
- Make a physical check - clean corrosion and dirt; check terminals and clamps are secure and in good condition
- Bring battery to full charge using a taper charge and do not exceed charge rate of 1/10 ampere for every ampere of battery rating
- Fill non-sealed battery cells with distilled water after charging
- With battery fully charged, check specific gravity readings of each cell with a battery hydrometer
- Replace battery if specific gravity readings varied 0.50 or if all cells read less than 1.225
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- All specific gravity readings should be above 1.250 (compensating for temperature)
- Battery size recommended 525 CCA @ 0
- Meter should display 9 volts or more while cranking
Source: Generac service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.