LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

[sparrowhawk1]

Originally Posted by newhaul

Don't know your controller but my tracer is lfp fully programmable and to kick it on to charge only takes a few seconds below set voltage.

You have helped me so much in the past so please don't miss interpret my reaction as LOL..... my controller is a tracer also, working flawlessly for over 15 years but the Chinese named it that because Trace is a high-quality american-made electronics company. And I'm just trying to help you back and have no idea why anyone would set float voltage lower than bulk / absorb voltage with LiPO batteries after all I have shown why it's a bad idea. Next time my battery is goes to float (when I have time) I will momentarily put on a large load on and report back whether it cycles. That is something I never thought of and thank you for possibly solving my problem of having 13.2 as my float

[newhaul]

Originally Posted by sparrowhawk1

You have helped me so much in the past so please don't miss interpret my reaction as LOL..... my controller is a tracer also, working flawlessly for over 15 years but the Chinese named it that because Trace is a high-quality american-made electronics company. And I'm just trying to help you back and have no idea why anyone would set float voltage lower than bulk / absorb voltage with LiPO batteries after all I have shown why it's a bad idea. Next time my battery is goes to float (when I have time) I will momentarily put on a large load on and report back whether it cycles. That is something I never thought of and thank you for possibly solving my problem of having 13.2 as my float

No I don't take anything to seriously anymore I'm to old to give a s..@ about stuff that doesn't directly affect me . I usually heatmsome water for my French press in my rice cooker first thing . But I also have taken note today specificly I woke up at 89% and a 13.32v resting and no panel output. As in the sun was not up yet. As soon as the sun cracked the horizon panels reached up 2volts above battery and started charging . No load required. It is likely your specific model that is not allowing this . Or my specific that is allowing it .
BTW my inverter charger is a Trace 2512.

My controller

[newhaul]

Originally Posted by sparrowhawk1

You have helped me so much in the past so please don't miss interpret my reaction as LOL..... my controller is a tracer also, working flawlessly for over 15 years but the Chinese named it that because Trace is a high-quality american-made electronics company. And I'm just trying to help you back and have no idea why anyone would set float voltage lower than bulk / absorb voltage with LiPO batteries after all I have shown why it's a bad idea. Next time my battery is goes to float (when I have time) I will momentarily put on a large load on and report back whether it cycles. That is something I never thought of and thank you for possibly solving my problem of having 13.2 as my float

Something just dawned on me . Do you have the wifi or ble adapter and programming on your phone to set the parameters for lfp? That is a feature I have. May be time for a new controller on your end

[CatNewBee]

Originally Posted by mitiempo

My preference is no float at all. 13.2 gives me what I want - no current going in.

13.5V gives you no current in too, but at 95% SOC and powers your loads on board.

[secessus]

Originally Posted by sparrowhawk1

just telling you my experience of why having a float voltage lower than the bulk voltage is bad ( exactly what the video was about).

IMO the video was making the point that Li doesn't self-discharge in any meaningful sense during a single solar cycle. Therefore Floating in the lead sense isn't needed or even possible in the normal sense of offsetting self-discharge.

The rest was a refresher on how solar charge controllers behave. Regardless of battery chemistry, Vfloat is the voltage floor where the controller holds the bank as long as solar harvest > loads. The only difference with Li is that it's only holding the line against loads rather than loads+selfdischarge as with Pb.

approaches

If one has copious charging time (not always a given with solar) one might set Vabs = Vfloat = 3.35vpc as Andy did @15mins in the original video we are discussing.

People with limited charging windows might need higher Vabs (≥3.5vpc) to get the job done in the time available. Floating that high is uncommon and seems to be inadvisable. So in this scenario we can either have Vfloat < Vabs or (like Renogy Li profiles) have no float defined and let the bank run between Vabs and the absorption restart setpoints.

Or something in between, whatever serves our particular needs. We all pays our money and picks our poison.

[For completeness, I will point out that one month later ("Can I balance my battery while floating?") Andy indicates his Vabs is 3.45vpc and his Vfloat is 3.35vpc. If I am reading correctly Maine Sail used those setpoints for his own bank. Full disclosure: I also use this approach.]

[sparrowhawk1]

Sorry I have to start it out again with LOL. I make coffee by putting a pot with two cups of water and the equivalent coffee grounds into my 3 l instant pot that has about a quarter of an inch or less of water under the rack. Set the time for zero and after it beeps that means it's gone to pressure I let it sit for maybe 10 minutes, pour the coffee through a strainer, best coffee I've ever had in my life. Super easy to clean. As far as buying a charge controller that I can alter, I'm living fine with what I have I'm just trying to tell people that can adjust their controllers what I would do if I had one.

[newhaul]

Originally Posted by sparrowhawk1

Sorry I have to start it out again with LOL. I make coffee by putting a pot with two cups of water and the equivalent coffee grounds into my 3 l instant pot that has about a quarter of an inch or less of water under the rack. Set the time for zero and after it beeps that means it's gone to pressure I let it sit for maybe 10 minutes, pour the coffee through a strainer, best coffee I've ever had in my life. Super easy to clean. As far as buying a charge controller that I can alter, I'm living fine with what I have I'm just trying to tell people that can adjust their controllers what I would do if I had one.

And there is your morning high draw load to kick your charge controller into bulk mode

As I typed this I just went from bulk mode to fully charged . 9 amps to .5 amps in at 1030 local daylight savings time. Or 0930 solar time .

[sparrowhawk1]

Yes I stated earlier I don't have a problem because I normally will put a high draw early in the morning. But if I'm not here to do that my batteries will needlessly deep cycle.

[sparrowhawk1]

Well I guess I should say it's not a big problem because several times around lunch time I went to check to see what my amp hours were and noticed no amperage going into the battery. So I use my hot plate / instant pot / toaster oven and instantly 20 plus amps from solar. Edit I realize that this is not necessarily due to my floating at 13.2:but that my battery was in fact topped off. And I guess for this to make sense I have to say I don't drink coffee everyday

[goboatingnow]

Perhaps we might stop using bulk absorption and float modes terms with lithium to stay with as these are LA charge terms.

[sparrowhawk1]

Originally Posted by goboatingnow

Perhaps we might stop using bulk absorption and float modes terms with lithium to stay with as these are LA charge terms.

I've been trying to say there's no such thing as that with lithium iron phosphate. But the controllers have the options so that's pretty much what we're discussing here yes?
And I didn't mean that to sound snarky I totally agree with you

[newhaul]

Ok just to make sure everyone is on same page here these are the parameters I can manually set on my controller by .1amp on each

[sparrowhawk1]

Well this whole conversation (after 7,000 and something)is why have your float lower than your bulk... You also have your maximum voltage disconnect and reconnect the same so your electronics are going to be constantly be cycling when you hit 14. Also you're disconnecting your charge controller from the battery when you hit 14 if it's set for lower than that no problem but if it's set for 14.2 like mine from what I've read it's a bad thing to disconnect your controller from the batteries with your solar panels still putting out amperage got it edit:I just realized you said controller not BMS and cannot erase the statements but maybe it will help someone with a programmable BMS

[s/v Jedi]

Originally Posted by CatNewBee

13.5V gives you no current in too, but at 95% SOC and powers your loads on board.

I fully agree with CNB here… when your batteries are full, why waste solar production by powering the boat from batteries instead of solar.

For us, half of daily solar production goes into the batteries and the other half is consumed directly during the day.

[newhaul]

Originally Posted by sparrowhawk1

Well this whole conversation (after 7,000 and something)is why have your float lower than your bulk... You also have your maximum voltage disconnect and reconnect the same so your electronics are going to be constantly be cycling when you hit 14. Also you're disconnecting your charge controller from the battery when you hit 14 if it's set for lower than that no problem but if it's set for 14.2 like mine from what I've read it's a bad thing to disconnect your controller from the batteries with your solar panels still putting out amperage got it edit:I just realized you said controller not BMS and cannot erase the statements but maybe it will help someone with a programmable BMS

No the window only shows two digits you have to click and drag left to see the number after the decimal on this controller app screen.
Current my settings are float 13.6v , bulk called boost here is 14.1v , over voltage is 14.7v. ( bms is iirc 15.0v ) and reconnect is 14.5v

Also some controllers are possibly damaged by a bms disconnect hence setting stop lower than bms disconnect voltage.