Victron smart shunt vs lifepo4 battery question?

[jaycocreek]

I got my smart shunt and hooked it up,then waited 24hr to fully charge my battery with my Noco genius charger on the lithium setting watching the numbers closely(boring) until the charger stopped charging supposedly when full on lithium...

Today I started to draw the battery down from 100%..The starting voltage was 13.59V according to the Victron..Then this..

Does this seem normal for just running the 12V TV/DVD player through a 300 watt PSW and the TV on 12V?..It seems it drew down the battery in voltage more than I would have guessed as the history shows..

[jaycocreek]

StirCrazy wrote:
what charger are you using?

Steve

Noco Genius 10 amp.

[StirCrazy]

what charger are you using?

Steve

[BFL13]

20 amps is a low charge rate for the LFP, so on generator you could use way more charging amps to reduce gen time. RV converter plus solar plus 20 amper plus 10 amper. To get the right profile using the new 20 amper, you could use just it for the last bit so it would stop at the right time and the shunt would sync right.

[jaycocreek]

I did see the charging voltage climb into the 14's then drop back down into the 13's a couple times and I tried to lookup the reason and didn't come up with anything definitely except cell balancing as the cause..No clue if that's right or not but it finally went into the 14's and stayed there for a short while before the charger stopped and shut off..

I believe my Lifepo4 Expert power 20 amp charger will be here Thursday and I'll use that exclusively on the lifepo4 battery..It charges at 14.4 volts with the lithium profile..I want a quicker charge for boondocking if I need to use a generator and my solar panels can't keep up...

[BFL13]

With the smart shunt do you see the BMS balancing act before you sync as though "full" ? I think I saw where you do the balancing act and then wait about 20 minutes at Vabs and then declare you are full ? Might not have that right.

If you told the shunt by syncing it a bit lower than full, that might explain why it thinks you have 110AH instead of 120?

[jaycocreek]

My battery is rated for 120ah..When I first got the shunt I estimated the SOC because I didn't want to fully charge it after what the battery Bluetooth did..I think I guessed 90% SOC prior to charging to finish the Victron setup...After it was setup,I decided to finally charge the battery with the Noco charger and I could watch voltage off the shunt to make sure the charger was charging correctly,and it did..

Then when it was full or close to,I synced the battery to 100% in the Victron settings..It was today I thought I should take it down from 100% because I'm not completely sure when I can take off fishing..

I started today with a resting 13.59 volts from the day before and ended with 13.28 after it set for 1 hour while I ate lunch..So I used.31 volts for the short time I used it then I had honey do's to do and couldn't finish draining it..

I am just curious if that's in the ballpark of what it should do,after the Bluetooth battery failure, I'm cautiously optimist if the battery is fine...Seeing and following the Noco charger with the Victron,it did nothing out of the ordinary watching every number for two hours..lol

[BFL13]

jaycocreek wrote:

2oldman wrote:
I see nothing wrong with those numbers, but I am kinda surprised to see a 'resting' 12v battery above 13v. Is it still being charged?

24 hours to fully charge? Must be a small charger. Very small.

Sorry,I should have added Lifepo4 as being the battery..The charger is a Noco Genius 10 amp smart charger with a lithium setting..I have a Lifepo4 charger on the way that charges to 14.4 volts instead of 14.6..

With the Noco Genius 10 and the LFP battery at 13.1 volts,it took about two hours to charge to 14.4 volts,at the start,it was taking the whole 10 amps then down and down to under an amp before it finished and turned off..I sat and watched it the whole time thinking maybe the charger is messing up after the weird bluetooth numbers from the battery bluetooth.

So if the LFP stayed in Bulk to 97% at 10 amps, and then amps tapered then we need to know when amps tapered to know the SOC when you started

If it did one hour at 10 amps and then tapered, that means you started the recharge at 87% SOC. However starting at 13.1 resting is 40% SOC according to BB.

Not enough info! OTOH, I can see why you suspect the numbers don't line up right. Not a clue, sorry.

[pianotuna]

20ldman,

In your shoes, I would once every 30 days do a full recharge so that the BMS is allowed to fully charge all cells.

[pianotuna]

.

[3_tons]

So you are powering an inverter, TV, DVD player, and probably a few parasitical devices such as LPG and Co detectors (lights, etc??)...Try as I might I don’t see a problem...

3 tons

[BFL13]

It appears the shunt thinks the battery has 110AH.

Time remaining after an hour at about 2.5 amps is 43 hrs it says. (24 +19) and it already used 2.5AH, so 43 x 2.5 =107.5 + 2.5 = 110AH.

Can't remember what your LFP is rated at in AH.

[2oldman]

I understood it was Li. You should be able to charge it in under 2 hours with a 'standard' charger. 24 hours is way too long. I never bother charging mine to 100% (float) as they really don't need it, and besides, my inverter will conk out with an 'overvoltage' error if I do.

[jaycocreek]

2oldman wrote:
I see nothing wrong with those numbers, but I am kinda surprised to see a 'resting' 12v battery above 13v. Is it still being charged?

24 hours to fully charge? Must be a small charger. Very small.

Sorry,I should have added Lifepo4 as being the battery..The charger is a Noco Genius 10 amp smart charger with a lithium setting..I have a Lifepo4 charger on the way that charges to 14.4 volts instead of 14.6..

With the Noco Genius 10 and the LFP battery at 13.1 volts,it took about two hours to charge to 14.4 volts,at the start,it was taking the whole 10 amps then down and down to under an amp before it finished and turned off..I sat and watched it the whole time thinking maybe the charger is messing up after the weird bluetooth numbers from the battery bluetooth.

[FWC]

That looks right. The 'resting' voltage for a LiFePO4 is around 13.2 - 13.3 for SOC between 98 and 10%. 13.19V under a small load seems to be right on the money.