FLA Battery Maintenance

[tanglewood]

Originally Posted by john61ct

Thanks, will try to find my source notes on the rest.
Just residual capacity, industry standard EoL spec is 80%, when a 20-hr load test shows a bank spec'd at 500AH is now actually 400AH.

At the consumer level, except for mission-critical cases, long offshore / RTW sailing, pushing EoL to 70% should be fine.

Ok, well understood. Just never heard it referred to as SOH.

Part of my point is that lost capacity due to sulfation is often recoverable, more so the earlier it is detected. And it is often accumulated early on because of incorrect charge parameters or extensive PSOC operation.

Once there is an accumulation of SO2, your batteries will appear charged if you only judge based on return current, even though there is still unreacted SO2. SG will show that immediately, and more aggressive charging (aka equalizing) can recombine it if it hasn’t crystallized too badly.

Periodic SG sampling will let you know where you are is real SOC, and hopefully signal you early enough to take corrective action before it’s too late.

And I agree this is for FLA only, but that is the thread subject, and the big advantage of FLA over other lead techs.

[tanglewood]

Originally Posted by daveNZ

From the top of the plates to a little under the fill spout, on my 12V battery (USBattery) is, at a guess, 10 to 15 mm. That seems like a ‘lot’ of water to add. Is the SG valid only when the electrolyte is at the correct level? (Assume it is mixed and I am not measuring recently added water sitting at the surface). I assume adding water, diluting the electrolyte will be affect the SG??

Good points.

If you just added water, mixing time will be required to get good SG readings.

And SG readings on a battery requiring a top up of water will read high, but in my experience only a tiny bit so. But not enough the really throw you off.