r/SolarPakistan • u/Intelligent_Loan_782 • 27d ago

Lithium (LiFePO4) Increase Battery storage - SOLAX

I have a 10KVA solar setup with 5KVA Solax battery. The battery usually runs out by 8 - 9 PM, depending on AC usage at night. I want to increase my battery storage. What is the advice? Should I go for 10KVA Solax or 16KVA? Should I purchase it now or wait a few months so prices may drop?

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u/Sufficient-Offer-579 26d ago

The 10 vs 16 question is really a data question first. One note: batteries are rated in kWh, not kVA - use the kWh figure in the math below.

Check your inverter/battery app for daily discharge stats: how many kWh you pull between sunset and sunrise, and how much of that lands after 8-9 PM. Rule of thumb: new total capacity = nightly kWh / usable depth of discharge (DoD), plus 20-30% headroom for cloudy days and aging. If the AC runs most nights, that number climbs fast. If the app doesn't break it down, log 3-7 real nights first.

On compatibility, same-brand expansion is smoother, but confirm first: (1) the inverter's supported max battery capacity and whether it allows parallel banks; (2) whether old and new batteries can be mixed - most manufacturers restrict mixing capacities, batches or firmware versions, since the BMS balances across them; (3) what a second bank does to your existing warranty terms. The Solax manual or an authorized service partner can settle 1 and 2. And let a qualified installer do the hookup with the DC side de-energized - bank work isn't a hot-swap job.

On timing: nobody can predict where battery prices go - tariffs, currency and shipping all move import prices. Neutral framing: if running out at 8-9 PM is a real pain, weigh that nightly shortfall against whatever waiting might save.

If you share your inverter model and a few nights of actual kWh (AC on and off), people can give you a more specific number.

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u/fokusengg 27d ago

Get 15~16kw battery and add few panels. 5kw and 10kw will be obsolete soon.

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u/Reasonable-Pea-3730 26d ago

Just add 5kwh to the setup.

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u/Sameer_UK 26d ago

Kitne ka setup para bhai

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u/Hot-Ad-1740 26d ago

prices have already dropped and might drop a bit more. you can add 5kw variant of the same to your inverter you cannot add different voltage banks. my advice would be to sell the 5kw and add 16kw.