PIP 4048, disconect output on low battery

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alex_vd_iest
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PIP 4048, disconect output on low battery

Post by alex_vd_iest »

Hello

First I will introduce myself,
I am Alex, I live in Holland, 28 years.
I have a background in electrical and mechanical engineering ,installs solar-systems with grid-tie inverters,
and I repair Industrial electronics for a living.

But i have a problem whit my own PIP inverter, I can't get this to work.

I have a PIP4048 from MPP solar with a 48V LifePO battery bank and 2.4 kW solarpanels

The problem is that my inverter disconnects everything when the battery is empty.
the output powes is switched off.

What I want, when the battery is “dead” it has to switch back to the grid (bypass mode).
I can't get this to work.

I also noticed that the inverter keeps drawing a small current from the battery when he is on bypass mode, can I do something on that?

i hope you can help me :roll:
thanks,
Alex

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coulomb
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Re: PIP 4048, disconect output on low battery

Post by coulomb »

alex_vd_iest wrote:
Sat, 28 Dec 2019, 03:14
I am Alex, I live in Holland, 28 years.
Welcome to the forum, Alex.
The problem is that my inverter disconnects everything when the battery is empty.
The output power is switched off.
That's pretty strange. Usually it will switch to utility input well before cutting off the output.
What are your settings for Output Source Priority setting (setting 01), setting 29 (low DC cutoff voltage), and back-to-utility voltage (setting 12)?

Or possibly, it's not happy with the AC-in voltage quality. I assume you're using grid power, not a generator?
Your grid voltage is presumably 230 V in Holland, so that should be fine. Is the AC icon (sine wave in a circle, a bit like a tennis ball) on solid, not flashing, not missing?
I also noticed that the inverter keeps drawing a small current from the battery when he is on bypass mode, can I do something on that?
So it sounds like you can get it into bypass mode at least some of the time. Only the very oldest models (circa 2013, maybe 2014) have an AC power supply which can power the electronics when in bypass mode. The power draw is some 35 W (50 W if the inverter is inverting).

If that bothers you, you can set the charger source priority (setting 16) to SNU, and change the maximum utility charge current (setting 11) to 2 A. I suspect that the 2 A setting is provided for this purpose. 2 A will charge at approximately 100 W (depending on the battery voltage), so this will cover the 50 W electronics load (the inverter will then be running, in reverse) and charge the battery at a very modest 50 W or so. It won't overcharge the battery; it respects the bulk/absorb and float voltage settings just like solar charging does. For those times when you need to do "real" utility charging, change setting 11 to a higher value, using either the buttons and LC Display, or using a monitoring program such as WatchPower or ICC.
Nissan Leaf 2012 with new battery May 2019.
5650 W solar, 2xPIP-4048MS inverters, 16 kWh battery.
1.4 kW solar with 1.2 kW Latronics inverter and FIT.
160 W solar, 2.5 kWh 24 V battery for lights.
Patching PIP-4048/5048 inverter-chargers.

alex_vd_iest
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Posts: 3
Joined: Sat, 28 Dec 2019, 02:53
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Re: PIP 4048, disconect output on low battery

Post by alex_vd_iest »

hi,

thats a quick reaction.

this are my setting:

setting (01) : SBU
setting (29) : 42V
setting (12) : 46v

I have a 13S lifePO pack so 54.6V is 100% charge and 41.6V is 0% charge.

what i also thought of, is it a problem that my battery management system (BMS) disconnect the battery at night when the battery comes below the low battery tresurehold of the BMS? you said that the inverter is drawing 35 watt in bypass mode.

my battery pack is quite small at this stage (10Ah), so if i would charge the battery overnight( or when there is no solar power) with 2 amps. it is almost fully loaded after 6 hours.


I am using Watchpower for the settings, i can make som screenshots. and somehow post it here on the forum, as it helps?


thanks!
Alex

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coulomb
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Re: PIP 4048, disconect output on low battery

Post by coulomb »

alex_vd_iest wrote:
Sat, 28 Dec 2019, 18:05
setting (01) : SBU
setting (29) : 42V
setting (12) : 46v
Those all seem good.
I have a 13S lifePO pack so 54.6V is 100% charge ...
I guess you mean LiPo (Lithium polymer, no Fe = iron) or one of the other non-LFP lithium chemistries. It's considered normal to use 14S for those.
what i also thought of, is it a problem that my battery management system (BMS) disconnect the battery at night when the battery comes below the low battery tresurehold of the BMS? you said that the inverter is drawing 35 watt in bypass mode.
In that case, the screen would go completely dead. That would explain no output. Is that what's happening?
my battery pack is quite small at this stage (10Ah),
That's way too small for a 5 kVA inverter. What might be happening is that when you get a minor surge in power (e.g. a fridge starts up), and the battery is somewhat depleted and therefore high in internal resistance, the instantaneous battery voltage drops very low and the inverter goes into a weird shutdown mode. 100 Ah is considered the minimum for a 5 kVA inverter.

Perhaps it will come good as your battery grows in size.

I don't think that WatchPower screenshots will help at this stage.
Nissan Leaf 2012 with new battery May 2019.
5650 W solar, 2xPIP-4048MS inverters, 16 kWh battery.
1.4 kW solar with 1.2 kW Latronics inverter and FIT.
160 W solar, 2.5 kWh 24 V battery for lights.
Patching PIP-4048/5048 inverter-chargers.

alex_vd_iest
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Posts: 3
Joined: Sat, 28 Dec 2019, 02:53
Real Name: alex

Re: PIP 4048, disconect output on low battery

Post by alex_vd_iest »

hi
In that case, the screen would go completely dead. That would explain no output. Is that what's happening?
No when the BMS turns off the screen is still lit, it displays the grid icon. it only shuts down when i turn the input power off (230Vac from the grid)
I guess you mean LiPo
sorry lipo indeed my error, mixing things up.


but still, that my inverter disconnects everything when the battery is empty and not going into bypass mode.
is this due to a to small battery pack?
my feeling is that is not the size off the pack,

i am planning on a big battery pack, if things are working out for me with this inverter.

Also because of the minimum load the inverter has connected on the output, approximately 50 watt. (for testing)

the AC grid voltage is between 229 at night and 244 during daytime, there are a lot of grid tie solar system in the neighborhood.



thanks!
Alex

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coulomb
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Re: PIP 4048, disconect output on low battery

Post by coulomb »

alex_vd_iest wrote:
Sat, 28 Dec 2019, 21:44
No when the BMS turns off the screen is still lit, it displays the grid icon. it only shuts down when i turn the input power off (230Vac from the grid)
Ah. That sounds like the BMS is literally disconnecting the battery, and the inverter's screen is still running because yours is an older model that still has the AC power supply.

If so, the problem is the BMS disconnecting. This model of inverter is not designed to run without a battery present (or disconnected by the BMS). I suspect that's why the inverter doesn't go into bypass mode.

However, I'd expect to see fault code 56 ("Battery connection is open") if this was the case. You have not mentioned any error, so I assume it's not happening.

To find out if the BMS really is disconnecting the battery, can you check the voltage at the battery terminals of the inverter with a multimeter, when it's not supplying the loads? If it's zero or way less than 48 V (could be some leakage through either the BMS or the inverter), then I believe that's the source of your problem.
but still, that my inverter disconnects everything when the battery is empty and not going into bypass mode.
is this due to a to small battery pack?
If I'm right, it's because the BMS is disconnecting the battery from the inverter-charger. This should not happen except in dire emergency, and when it does, you can't expect the inverter-charger to power the loads, even from the grid. At least by my understanding.
i am planning on a big battery pack, if things are working out for me with this inverter.
Hopefully with a larger pack, the battery voltage won''t get so low that the BMS disconnects it.

It might also be possible to adjust the threshold on the BMS so the batter doesn't disconnect so soon.

Regardless of that, you would want to get setting 12 to put the inverter-charger into bypass mode before the battery voltage gets so low that the BMS disconnects. So even with this tiny battery test set-up, it seems like you just need to juggle setting 12 and the BMS threshold (if that's possible) to achieve this. It might be that you won't get realistic energy out of the battery, but hopefully with more battery capacity, things will get more realistic.
Nissan Leaf 2012 with new battery May 2019.
5650 W solar, 2xPIP-4048MS inverters, 16 kWh battery.
1.4 kW solar with 1.2 kW Latronics inverter and FIT.
160 W solar, 2.5 kWh 24 V battery for lights.
Patching PIP-4048/5048 inverter-chargers.

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