Need Solar Guru Help!

The 1.8 amps sounds more like the 120v side. 13.2 is more than 70% on any chart I've seen. I did not know any Li battery needed absorption.

Rotated OP's 12v system link.

I'd suggest checking/verifying load/discharge (-) and charge (+) current separately by measuring current on the appropriate wires/cables with a DC clamp-on ammeter (during the day and at night). Your battery monitor only provides the sum total of both, which doesn't give you a clear picture of what's going on. It's also possible your battery monitor is inaccurate or mis-calibrated. A DC clamp-on ammeter would help confirm the accuracy of the battery monitor's current readings.

So there was one connection wrong that was affecting the amps reading....the Neg of the inverter was not on the shunt! I have now switched them.
Now it's just the charge issue, I think.

2oldman wrote:
The 1.8 amps sounds more like the 120v side. 13.2 is more than 70% on any chart I've seen. I did not know any Li battery needed absorption.

Can you please post a chart that shows 13.2v is not 70% for Lithium batteries? If it's not 70% what is it?

See my post above this one, I found/fixed an issue that should fix the amps issue.

13.3 to 13.4 is 100%, so I guess 13.2 could be 70%, but that does surprise me.

2oldman wrote:
13.3 to 13.4 is 100%, so I guess 13.2 could be 70%, but that does surprise me.

Yup, can't figure out why it's that low!

campermama wrote:

2oldman wrote:
The 1.8 amps sounds more like the 120v side. 13.2 is more than 70% on any chart I've seen. I did not know any Li battery needed absorption.

Can you please post a chart that shows 13.2v is not 70% for Lithium batteries? If it's not 70% what is it? . . .

Many 12v lifepo4 voltage/SOC charts show 13.20v (resting voltage) as equivalent to 70% SOC. The key here is "resting voltage".

If you're going to use a lifepo4 voltage/SOC chart to determine SOC, you must have zero charge/discharge current (ideally by disconnecting the battery entirely). Then you must let the voltage stabilize to a final resting voltage before taking a voltage reading. Depending on the situation, it can take anywhere from a few minutes to a few days to reach the final resting voltage.

As for 2oldman's comment about lifepo4's not needing absorption---that was the lifepo4 charging philosophy a 2-3 years ago when nearly all lifepo4 converters/chargers were single-stage 14.6v (no absorption or float stage). These days it's common knowledge you can damage a lifepo4 subjecting it to a 14.6v bulk mode indefinitely. Thus, the need for an absorption voltage. Many recommend 13.2v - 13.6v. There are still a lot of single-stage 14.6v lifepo4 converter/chargers on the market. Highly recommend purchasing a 2-3 stage converter/charger instead.

otrfun wrote:
As for 2oldman's comment about lifepo4's not needing absorption---that was the lifepo4 charging philosophy a 2-3 years ago when nearly all lifepo4 converters/chargers were single-stage 14.6v (no absorption or float stage).

Okay, I guess things have changed. My 5yo 48v pack only has bulk and float, but the specs for 12v Battleborns do specify an absorb voltage. I adjusted my solar controller's absorb to almost nothing.

Many 12v lifepo4 voltage/SOC charts show 13.20v (resting voltage) as equivalent to 70% SOC. The key here is "resting voltage".


Ok so the 13.2 is not really "resting", then would the actual "resting" voltage show a higher voltage or less?