Victron mppt 100/ 30 advice please.

[Jimbohorlicks]

I have a victron 100/30 mppt solar controller. With 2 x100 watt roof panels. And an ecotree 100ah bluetooth lifepo4.
When on default lithium settings which is 14.2v absorption and float 13.6v I only have approx 1.75hrs of bulk charge 2 hrs( default) absorption and then it goes into float at a measly <1 amp charge..
I have increased the absorption time to increase the charge rate at a 2 plus amps.
Any ideas how I can increase the bulk charge time please and hopefully the charge current.
The battery is currently at 41% soc with a voltage of 13.27 v on its own app.

 

[Raul]

Bulk time it’s not something you set as it’s not a timed event. Bulk starts the minute you start charging and until the moment you reach absorb setting, in your case 14.2v. This portion of charging time is called bulk, or constant power or constant current. It’s not timed because it depends on charging source rate, and battery emptiness. If is well discharged and the charging rate is low, it will take a long time to hit absorb( constant voltage). If it’s little discharged, and good charging rate, it will take little time to reach absorb voltage.
In your case, if you hit 14.2v you are almost 99% charged, and absorb time will only serve for balancing the cells. Lifepo4 does not need much absorb to fully charge at 14.2v, it’s there to give a chance to the lower cells to catch up. If you set absorb for 2hrs it’s more than enough charge, then drop in float at 13.5v not 13.6v.
I absorb 40 mins at 14v and don’t need the 2hrs, unless the cells are very very imbalanced.

I know it’s hard , but you have to forget the lead acid mindset, Lifepo4 it’s a two stage charging, constant current-constant voltage, no float. lead it’s 3, it includes the float. On Lifepo4, we enter a low float value to eliminate float charging.

 

[Jimbohorlicks]

Hi Raul. Thanks for that. What concerns me is that the battery is only at 41% soc. And once the absorption time has elapsed if i use the 2 hrs default at a rate of around 2.5 amps and then goes to float at less than 1 amp I will never see the battery at 80% plus..
I will need to check my solar panel outputs to see why I am only obtaining 2.5amp max.

 

[Guigsy]

Hi Raul. Thanks for that. What concerns me is that the battery is only at 41% soc. And once the absorption time has elapsed if i use the 2 hrs default at a rate of around 2.5 amps and then goes to float at less than 1 amp I will never see the battery at 80% plus..
I will need to check my solar panel outputs to see why I am only obtaining 2.5amp max.

If the battery is reaching those voltage, it suggests it's nearly charged. It's more likely the BMS is out.

 

[Raul]

Hi Raul. Thanks for that. What concerns me is that the battery is only at 41% soc. And once the absorption time has elapsed if i use the 2 hrs default at a rate of around 2.5 amps and then goes to float at less than 1 amp I will never see the battery at 80% plus..
I will need to check my solar panel outputs to see why I am only obtaining 2.5amp max.

Who/ what is telling you the battery is only at 41% it’s wrong, not accurate.
When it goes to float, you should see 0amps going in the battery, unless you have a load to account for that.
The reason you get 2.5A from 200w solar is the sun, lack of it, and low in the sky.

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[Jimbohorlicks]

If the battery is reaching those voltage, it suggests it's nearly charged. It's more likely the BMS is out.

That's probably why. I will look to recharging the battery with a charger rather than through the victron controller. I will read up on the ecotree bms .

 

[Raul]

That's probably why. I will look to recharging the battery with a charger rather than through the victron controller. I will read up on the ecotree bms .

Invest in a shunt based battery monitor, the bms is pants at measuring small currents.

 

[Guigsy]

With my FogStar battery, through the winter, it doesn't get enough charge from the solar, so it goes for weeks without getting fully charged. The BMS ends up massively out. Although with my FogStar, it thinks it's nearly full, but it is in fact heavily discharged (so inaccurate like yours, but opposite). The only way to solve it is to fully charge it with hookup. Then the BMS recalibrates.

 

[Jimbohorlicks]

Who/ what is telling you the battery is only at 41% it’s wrong, not accurate.
When it goes to float, you should see 0amps going in the battery, unless you have a load to account for that.
The reason you get 2.5A from 200w solar is the sun, lack of it, and low in the sky.

I have an app for the battery which shows state of charge currently at 44% with a voltage of 13.24.v With a multimeter the battery is reading 13.19v
Cells are charging and are 3.310, 3.310, 3.311, and 3.307
On standby they are 3.08, 3.08 , 3.09 3.06.

 

[Guigsy]

Invest in a shunt based battery monitor, the bms is pants at measuring small currents.

Yes. That's what happens to mine. It can't see the small continuous discharges. However, my Victron Shunt can. Its estimate of my battery charge was much more accurate.

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[Raul]

On standby voltage reflects the more real state of charge, so at 12.4v on stand by, you are approximately 20% charged.
On the other hand, at 14.2v, even with only 2amps going in, you are almost full.
The take from this is: stop trying to charge more than the battery can take, maybe you use allot more than you thought, if you reach 12.4v. Maybe you need more capacity.

 

[PeterCarole29]

Yes. That's what happens to mine. It can't see the small continuous discharges. However, my Victron Shunt can. Its estimate of my battery charge was much more accurate.

Reference small discharge . would a battery master count as a small discharge not reconised by the BMS (asking as i will have one)

 

[Guigsy]

I've got quite a few parasitic loads in my van. The Victron shunt can see 0.2 amps being pulled even with everything off. The FogStar BMS just reads zero. That adds up over the weeks.

 

[Jimbohorlicks]

On standby voltage reflects the more real state of charge, so at 12.4v on stand by, you are approximately 20% charged.
On the other hand, at 14.2v, even with only 2amps going in, you are almost full.
The take from this is: stop trying to charge more than the battery can take, maybe you use allot more than you thought, if you reach 12.4v. Maybe you need more capacity.

Yes I probably do. I have just purchased 2 x 100ah ecoworthy lithium without blue tooth so will need to invest in a shunt based monitor
I did have a look at this one.

DC 0-200V Voltage Current Battery Tester, Specification: PZEM-015 With

1. Mainly used to test various battery voltage, discharge current, discharge power, discharge impedance, internal resistance, capacity, discharge energy, power consumption and running time, and display the measurement data through the LCD screen.2. Voltage:- Measuring range: 0-200V. (When the...

buy2fix.co.uk

Any comments? They do need to be calibrated . Do the victron smart shunts need calibrating or are they just fit and go?

 

[Raul]

Yes I probably do. I have just purchased 2 x 100ah ecoworthy lithium without blue tooth so will need to invest in a shunt based monitor
I did have a look at this one.

DC 0-200V Voltage Current Battery Tester, Specification: PZEM-015 With

1. Mainly used to test various battery voltage, discharge current, discharge power, discharge impedance, internal resistance, capacity, discharge energy, power consumption and running time, and display the measurement data through the LCD screen.2. Voltage:- Measuring range: 0-200V. (When the...

buy2fix.co.uk

Any comments? They do need to be calibrated . Do the victron smart shunts need calibrating or are they just fit and go?

On Victron shunt you need to set few parameters to suit your system. One switch to Lifepo4 preset values, then enter your battery capacity. After that you can tweak the values by small increments to make it more accurate. The voltage can not be calibrated, but it has a low tolerance, so pretty accurate. The current can be calibrated, you can fit it to the battery, without any loads or charging, then you can calibrate current to 0, as nothing goes in or out. It’s pretty good out the box, I never needed to calibrate the current. Also the power lead if it comes with a 100ma fuse, change that for a 1A, the lower resistance of the 1A fuse, greatly increases the voltage accuracy, it’s even recommended by Victron. Maybe newer models already come with the 1A fuse.

As for the above linked item, you are wasting your money, not very accurate at all.

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[EuroTrotters]

With my FogStar battery, through the winter, it doesn't get enough charge from the solar, so it goes for weeks without getting fully charged. The BMS ends up massively out. Although with my FogStar, it thinks it's nearly full, but it is in fact heavily discharged (so inaccurate like yours, but opposite). The only way to solve it is to fully charge it with hookup. Then the BMS recalibrates.

Would more solar help that ?

 

[Guigsy]

Would more solar help that ?

My van is parked on my drive in a courtyard of townhouses and flats that means it gets almost no sun. Literally no direct sun at all through the winter until a couple of weeks ago. But the battery is 280Ah. So it means I need to plug it in a couple of times over the winter period to keep it charged. If I doubled up the 175w solar, I think discharge would still be greater than winter charge.

If I ever get around to fitting the B2B I've already bought, then the occasional run it gets would probably be enough...

 

[EuroTrotters]

My van is parked on my drive in a courtyard of townhouses and flats that means it gets almost no sun. Literally no direct sun at all through the winter until a couple of weeks ago. But the battery is 280Ah. So it means I need to plug it in a couple of times over the winter period to keep it charged. If I doubled up the 175w solar, I think discharge would still be greater than winter charge.

If I ever get around to fitting the B2B I've already bought, then the occasional run it gets would probably be enough...

Thanks , good to know

 

[Jimbohorlicks]

On Victron shunt you need to set few parameters to suit your system. One switch to Lifepo4 preset values, then enter your battery capacity. After that you can tweak the values by small increments to make it more accurate. The voltage can not be calibrated, but it has a low tolerance, so pretty accurate. The current can be calibrated, you can fit it to the battery, without any loads or charging, then you can calibrate current to 0, as nothing goes in or out. It’s pretty good out the box, I never needed to calibrate the current. Also the power lead if it comes with a 100ma fuse, change that for a 1A, the lower resistance of the 1A fuse, greatly increases the voltage accuracy, it’s even recommended by Victron. Maybe newer models already come with the 1A fuse.

As for the above linked item, you are wasting your money, not very accurate at all.

Not really concerned about accuracy as long as its near enough..
But I understand that the victron shunt will look at another seperate battery as well.is this the case?

 

[Raul]

Not really concerned about accuracy as long as its near enough..
But I understand that the victron shunt will look at another seperate battery as well.is this the case?

Depending on the model, the bmv 702 and 712 can monitor the voltage of a second battery, or, a temp sensor. The port can be used for one purpose at a time. But only voltage monitoring for the second battery, the primary battery has the rest of the data.