By Dave Miller· off-grid sparky · 22 years wiring solar, batteries and sheds in central QLD
“After watching two expensive batteries die in my shed, I learned that skipping equalisation in central Queensland's heat is a costly mistake costing me $1,200.”
Look, equalisation charging isn't some magic fix. It's a necessary hammer for when your batteries are getting lazy. Do it wrong, and you'll fry your bank. Do it right, and you'll save $500+ on replacements. Let's cut the fluff.
Equalisation Is A Necessary Hammer
Look, equalisation charging isn't some magic fix. It's a necessary hammer for when your batteries are getting lazy. Do it wrong, and you'll fry your bank. Do it right, and you'll save $500+ on replacements. Let's cut the fluff.
When You *Actually* Need It (Not When the Manual Says)
Equalisation is for when your batteries are not balancing. Check this:
After 3+ months of heavy use (like running a fridge 24/7 in summer)
When one battery in your bank reads 12.4V+ while others are at 12.0V (use a multimeter, not the inverter display)
After a deep discharge (below 50% state of charge) without recharging properly
If your batteries are all reading within 0.1V of each other? Stop wasting time. Equalisation is a sledgehammer for a problem that doesn't exist. You'll just shorten your battery life.
How to Do It (Step-by-Step, No Bullshit)
1. Check your battery type: Only lead-acid (Flooded or AGM) need this. Lithium? Skip it. You'll melt your $10k battery bank.
2. Charge to 100%: Get your bank fully charged via solar/wind/generator first. Don't start equalisation on a half-empty bank.
3. Set your charger:
For 12V systems: 14.4V - 15.0V (Flooded) or 14.8V (AGM)
For 24V: Double those numbers
Set time: 1-2 hours max. Never leave it unattended.
4. Monitor like a hawk:
Check voltage every 15 mins
Stop if it hits 15.5V+ (Flooded) or 15.8V+ (AGM)
Check for bubbling (normal for flooded, but if it's violent, stop)
5. Done? Cool. Let the batteries cool for 2 hours before using. Don't do it again for 3 months.
How Often? (The Real Answer)
Overdoing it? You'll boil water out of flooded batteries. Underdoing it? Your bank dies early. 3 months is the sweet spot.
Warning: If your batteries are old (over 3 years) or have been deep-discharged often, equalisation might not save them. Time to replace.
Practical Aussie Tips
Use a dedicated charger: Don't use your main solar charger. Get a $200-300 "equalisation mode" charger like the Victron SmartSolar 150/35. It auto-stops at the right voltage.
Check water levels first: For flooded batteries, top up with distilled water before equalising. If it's dry, you'll cook the plates.
Never equalise lithium: If you've got a Tesla Powerwall or Victron Lithium, skip this. It'll void your warranty and cause fire.
Test after: After equalising, check voltages again. If they're still uneven, you've got a bad cell. Time for a new battery.
Tip: Buy a $15 distilled water bottle from Bunnings. Don't use tap water.
Don't waste cash on fancy "equalisation" apps or $1000 chargers that don't do it right. Stick to Victron or Renogy. They're the only ones that won't fry your bank.
Use It When Needed
Bottom line: Equalisation isn't a ritual. It's a tool. Use it when needed, do it right, and your batteries will last 5+ years. Skip it when it's not needed, and you'll save money. That's the Aussie way.
⚠️ SAFETY WARNING: Working with electrical systems, structural modifications, or gas installations carries inherent risks. If you are not confident in your abilities, always engage a licensed professional.
It walks through the balance start voltage for LiFePO4 and explains why kicking off the process too early wastes time—exactly the point I make in the guide about timing your equalisation correctly. The segment on checking each cell with a decent multimeter before you start is the kind of hands‑on detail I see missing on most job sites.— Dave Miller
When to Call a Professional
While many off-grid projects are achievable as DIY, certain situations require licensed professionals:
Electrical work beyond basic 12V DC additions — requires a licensed electrician
Structural modifications to buildings or load-bearing elements
Gas line installation or modification
Solar array installations above safe voltage thresholds
Any work that affects the structural integrity of your property
Always check local regulations and obtain necessary permits before commencing work.
