Brain melted. Need fresh pair of eyes to find problem

[zzerg85]

hello and thanks for having a look and maybe able to help to explain this.

I have 3x330w solar on my campervan in series
Mppt is a 100A 150voc epever
250A Daly bms
304ah 12v eve lifepo4

Settings are on the screenshots.
I used another users lifepo4 settings after extensive research and YouTube videos.

I know the volt on the mppt is higher than battery because it measures open circuit voltage. When everything is off mppt and Daly bms readings on battery voltage are the same.

But my battery is on float charge and I don’t get why. I don’t think it’s full. I think the bulk reconnect should kick in but it does not

My brain is melted and I can’t think anymore from all the information. If you could give me a fresh pair of eyes on what I am Missing let me know

Thanks

 

[MurphyGuy]

Bulk Recovery Charge = 13.2 volts. If the bat is at 13.3 volts then it needs to fall 0.1 volts before bulk charging starts again??

I'm not real familiar with Daly settings but that's my guess.

 

[zzerg85]

Bulk Recovery Charge = 13.2 volts. If the bat is at 13.3 volts then it needs to fall 0.1 volts before bulk charging starts again??

I'm not real familiar with Daly settings but that's my guess.

Maybe I switched up bulk and float charging parameters? Should it be the other way around?

 

[zzerg85]

It sits at 13.2V that’s not full how do I charge it to full ??

 

[MisterSandals]

It sits at 13.2V that’s not full how do I charge it to full ??

It probably is at 13.2xxx and needs to drop to 13.2000 to start bulk charging again.

Try13.3V bulk as MurphyGuy suggests.

 

[Rocketman]

In an RV I really recommend using a shunt based battery monitor- I use a Victron Smartshunt. I work’s really great. The monitors in the bms’s sometimes are accurate and sometimes not.

For example on the 1st screen (very bottom) it says you battery SOC is 97% and on the 3rd screen top is says 54% - (???).

On battery settings- You want rebulk just below float- that way as long as the battery are just floating along with the solar providing all the power that’s needed the batteries are full. But when they drop then you get rebulked.

I think your settings are off a little - but only on the high cut-off stuff.

I use 14.25 for absorbing charge (bulk) and 13.5 for float. - not that much different.

What does the owners manual say for “Bulk Charging recovery”? What does this setting do? It may be this is not a “rebulk” setting- but something else…

 

[mikefitz]

Bulk Recovery Charge = 13.2 volts. If the bat is at 13.3 volts then it needs to fall 0.1 volts before bulk charging starts again??

I'm not real familiar with Daly settings but that's my guess

Bulk recovery is the setting in the Epever charge controller not the BMS.

I know the volt on the mppt is higher than battery because it measures open circuit voltage.

When charging the MPPT volts will be slightly higher than battery volts due to cable and connection drops. But with correctly sized cable and a short cable run these should be minimal. With the very low charge current shown there should be no significant drop.
13.33 at the charger and 13.263 at the battery seems OK to me.

I think the bulk reconnect should kick in but it does not

Bulk reconnect will not occur until battery volts is lower than 13.20 volts. Apply a load on the battery to pull down the volts

When the battery is under charge the voltage should reach boost volts, 14.2 and hold this for boost duration, ( set to at least 30 minutes), does this happen?

Mike

 

[zzerg85]

Bulk recovery is the setting in the Epever charge controller not the BMS.


When charging the MPPT volts will be slightly higher than battery volts due to cable and connection drops. But with correctly sized cable and a short cable run these should be minimal. With the very low charge current shown there should be no significant drop.
13.33 at the charger and 13.263 at the battery seems OK to me.


Bulk reconnect will not occur until battery volts is lower than 13.20 volts. Apply a load on the battery to pull down the volts

When the battery is under charge the voltage should reach boost volts, 14.2 and hold this for boost duration, ( set to at least 30 minutes), does this happen?

Mike

I’m in the Uk and all we have is very rainy days. Total cloud all day. So I haven’t even been able to see what my panels are pulling. 6amps was the max I have seen when it was charging. Panels have been on my roof for a year and very dirty. I cleaned them the other day. I know partially shade on one panel can fuck the whole string.
I think the bulking with 1amp for short time makes fuck all difference.
The battery was at 50% according to bms when I set it up. I payed top dollar for amy to get best matched cells. So that make sense. In 3 days of working on the van it only went up 4.2% according to bms. Which I believe as it wasn’t charging anything basically.
Can I not float charge? Only bulk until it’s done and than nothing until rebulk kicks in?

 

[Rocketman]

If float is 13.4v - have rebulk at 13.3v.

 

[zzerg85]

First morning sunshine with no clouds at 9am
Bulking.
Is this what 1000watt supposed to pull?

 

[mikefitz]

Your battery is near full at the voltage of 14.38. It's not accepting high current ( because its near to fully charged) , thus the solar yield is lower than expected .
If you want to see the solar yield load the battery.

You cannot force high current into the near full battery. What is the SOC reading?

Is this what 1000watt supposed to pull?

There is not much point in charging higher than 14.2 volts .

Mike

 

[zzerg85]

These are my panels. Bit dirty and the back is getting a bit of shade from the apple tree

Your battery is near full at the voltage of 14.38. It's not accepting current ( because its fully charged) , thus the solar yield is lower than expected .
If you want to see the solar yield load the battery.

You cannot force current into the full battery. What is the SOC reading?


Mike

battery voltage right now on the mppt app is 13.43 on the BMS app it’s only 13.3

SOC is 100% on the mppt and 57.3% on the bms

I really can’t wrap my head around the concept of float / bulk and bulk reconnect. If the bulk kicks in it should go and charge all the way and once it’s done it should float until de bulk reconnect kicks in. Right?

 

[littleharbor2]

I’m in the Uk and all we have is very rainy days. Total cloud all day. So I haven’t even been able to see what my panels are pulling. 6amps was the max I have seen when it was charging. Panels have been on my roof for a year and very dirty. I cleaned them the other day. I know partially shade on one panel can fuck the whole string.

I'm confused. How can it rain every day and your panels be dirty?

 

[mikefitz]

There is something not quite right on the system, the volts should be almost the same.
Don't worry about charge volts at the moment, concentrate on resolving the voltage discrepency.
Measure with a meter and confirm.
Ignore the SOC on the Epever, it is incorrect.
With the shadow ( and dirt/ moss) on the panels you won't get much output.
What components are connected between charger and battery?

More details of your system are needed, diagram and photo.
Are the panels in series or parallel?
Is the instalation new?
Is it a diy battery?
Have the cells been top balanced?
Has the battery been successfully charged with a AC charger?

 

[zzerg85]

I'm confused. How can it rain every day and your panels be dirty?

Panels flat mounted so rain is pooling slightly at one of the sides. Van isn’t in level. I should have installed them in 5%-10% angle to provide proper drainage. Puddles collect dust and when it’s dry the dust remains concentrated on that spot.

 

[zzerg85]

There is something not quite right on the system, the volts should be almost the same.
Don't worry about charge volts at the moment, concentrate on resolving the voltage discrepency.
Measure with a meter and confirm.
Ignore the SOC on the Epever, it is incorrect.
With the shadow ( and dirt/ moss) on the panels you won't get much output.
What components are connected between charger and battery?

More details of your system are needed, diagram and photo.
Are the panels in series or parallel?
Is the instalation new?
Is it a diy battery?
Have the cells been top balanced?
Has the battery been successfully charged with a AC charger?

I agree epever SOC is incorrect.
I was under the impression voltage is higher read on mppt because it’s charging.

When I disconnect solar and loads(there aren’t any) mppt voltage read drops to same value as the BMS and I also manually measured. They all agree.

 

[littleharbor2]

Panels flat mounted so rain is pooling slightly at one of the sides. Van isn’t in level. I should have installed them in 5%-10% angle to provide proper drainage. Puddles collect dust and when it’s dry the dust remains concentrated on that spot.

Got it. You will soon be dealing with hard deposits on the glass that won't just wash off.

 

[mikefitz]

With the new information of voltage difference between charger and battery my comments regarding a near full battery are not correct.
From the condition of the panels, near horizontal instalation, early morning, considerable shadow, series connection, the output seems about right.

The MPPT will read slightly higher , but not that high. The screen shot indicated 14.38 at the MPPT output. You then typed 13.38, which is correct?


With a volt meter, measure the voltage at each connection point between MPPT terminal and battery.

 

[zzerg85]

With the new information of voltage difference between charger and battery my comments regarding a near full battery are not correct.
From the condition of the panels, near horizontal instalation, early morning, considerable shadow, series connection, the output seems about right.

The MPPT will read slightly higher , but not that high. The screen shot indicated 14.38 at the MPPT output. You then typed 13.38, which is correct?


With a volt meter, measure the voltage at each connection point between MPPT terminal and battery.

Thanks for reply

14.38V was in the morning when I messed with bulk reconnect to see what it pulls. After moved it a bit it kicked in(stopped since) it was the charging voltage in bulk mode

Right now it’s 13.44V and float

 

[mikefitz]

Can you confirm that when it was in bulk mode the MPPT reading was 14.38 volts and the BMS reading was 13.3 volts ?

If this is the case AND it can be confirmed with a meter, you have a problem.

The MPPT will stop charging in boost volts and drop to float when the charger ' thinks' the voltage has reached boost volts .

Your problem is either with the Epever or there are volt drops between the charger and battery. This drop could be in either the positive or negative path. Test with a voltmeter.

It seems you have alternative charging, dc to dc and shore power, haveyou tried these methods of charging the battery?

Has the battery , with bms, ever been successfully charged and tested before installing?