LFP longevity

[Delfin]

I'd forgotten when we installed our lithium bank, so looked it up and voila, we are celebrating our 7th year. Around 25,000 miles of cruising with daily charging when we're out and they have the same capacity they did when new. Pretty amazing, if you axe me. Rod Collins no doubt has the record, what with his official lithium pioneer status, but I am starting to wonder if LFP banks won't turn out to be a one and done installation under normal usage and sensible management protocols.

 

[sjisailor]

Amazing report, thanks for sharing! Could I ask about the brand and capacity (and the charger brand)?

 

[Delfin]

Amazing report, thanks for sharing! Could I ask about the brand and capacity (and the charger brand)?

They're from Lithonics, which at the time was one of a very few options except for DIY. 600 Ah @ 24vdc, which replaced 1280 Ah Northstar AGM. Underway, they're recharged from an Ample Power 120 A alternator derated to 90 A, plus 100 A from the genset via a Trace 4000 charger/inverter. At anchor, the genset powering the Trace, plus another 90 A from three 30 A Sterling chargers, so around .3 C for either option when charging.

Starter bank is 200 Ah @ 24 vdc lead acid. When the LFP is charged, the starter bank is selected via rotary switch for charge current from the alternator, and the LFP is taken offline via the external BMS.

We generally use around 300 Ah per 24 hour, so recharge takes 90 minutes. I just set a timer when recharging the LFP and turn off charging when the acceptance rate is less than 5% C - 30 A. Until Lithionics changed charging recommendations a short time ago, I was following their protocol for bulk voltage of 29.2 vdc, now 28.8. Never more than 5 minutes absorption, never floated. Stored usually around 50% C.

The LFP bank has a source of outside air to cool them when charging, or just keeping them cooler than the ER.

 

[sjisailor]

Great details, thanks again for sharing the experience! (Am thinking here about when to switch over but will be at least a year away.)

 

[Delta Riverat]

The perfect time is when you can't even get a whole day out of your LA. That will give you enough time to change before you can't even get a half day...

Which is when I did mine -