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MPP solar PIP-1012LV batteries disconnected may damage the unit

Bud Martin

Solar Wizard
Joined
Aug 27, 2020
Messages
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I am ready to buy one this small unit but something does not make sense to me about do not connect the solar panel first then the batteries (I am doing off grid setup) because it can damage the unit. I contact MPP Solar and they says the same thing. The thing is, you are supposed to install a fuse or breaker or disconnector between the batteries and the unit for protection, that means while the unit is running but the fuse/circuit breaker for the batteries is tripped it will then cause damage to the unit. So what is the use of having fuse/breaker/disconnector for the batteries, or Low batteries disconnect (done by the unit ) if it will damage the unit.
Can some one with the same unit please tell me if t hat is ture or not?
I watched Will's video (
) about this unit, the link to his website also shows the fuse for the batteries.

Thanks!
.
 
You connect the battery first to turn it on.
Disconnecting the battery with panels attached will not damage it.
 
Thanks for the reply.
Peggy form MPP Solar replies me this:

PIP1012LV-MS is not a battery less model. therefore, battery will be a mandatory , must connect with inverter while inverter is operating .
Yes, it can damage the inverter if the solar still keeps input power and there is no battery.

I'm not sure now If I can trust MPP Solar.
I wonder if the unit will keep the inverter running if the batteries are disconnected and the inverter will run off the solar panel. My load is only 200W, I will have two 200 Watts panels.
 
This point comes up often.
There are many different variables so MppSolar are probably playing safe and states the safest option.
A switch and fuse at the battery are there to protect the system and user as well as to meet possible regulations. Not necessarily there to protect the inverter!
In reality it is only the short length of cable between the battery and inverter that can be assured of being protected by any switch or fuse in that location.
Connect and disconnect in the correct order and it is up to you to put in a switch or fuse.
 
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The primary reason, for any SCC, to connect the battery first is so that the device can configure itself to the battery system voltage. The other reason, specifically for the MPP all-in-one units is that it is powered from the battery (it cannot be powered from PV) so without first connecting the battery, it won't switch on!

After the SCC has determined the battery system voltage it is generally considered safe to disconnect the battery even with a live solar input but, if MPP are telling you not to do this then their products probably don't have the same levels of input protection higher spec units have. There has been an ongoing debate on here about BMS's disconnecting batteries whilst PV remains attached and the general wisdom is that this does not harm the SCC. Search for 'Can't break my SCC' for a thread all about this.

I would follow manufacturer's guidelines (if you want to ever claim on a warranty).
 
Thanks for the reply.
Peggy form MPP Solar replies me this:

PIP1012LV-MS is not a battery less model. therefore, battery will be a mandatory , must connect with inverter while inverter is operating .
Yes, it can damage the inverter if the solar still keeps input power and there is no battery.

I'm not sure now If I can trust MPP Solar.
I wonder if the unit will keep the inverter running if the batteries are disconnected and the inverter will run off the solar panel. My load is only 200W, I will have two 200 Watts panels.
If you disconnect the battery the inverter and SCC will turn off.

The inverter is turned on and off by a switch.
The SCC is on when the battery is connected and there is sun on connected panels.
Now I have to call Ian to check if disconnecting the battery with panels attached will damage the unit.
I don't believe it will but Peggy seems to be saying it will.
 
If you disconnect the battery the inverter and SCC will turn off.

The inverter is turned on and off by a switch.
The SCC is on when the battery is connected and there is sun on connected panels.
Now I have to call Ian to check if disconnecting the battery with panels attached will damage the unit.
I don't believe it will but Peggy seems to be saying it will.
I am connecting my battery to my MPP Solar PIP1012LV-MS. I connected both terminals on the battery, then the negative to the inverter. As I touched the positive to the inverter, I got a spark. The inverter was not powered on. I checked the positive and negatives cables to verify I did not mix them up and it is correct. Any concern with the spark?
 
As I touched the positive to the inverter, I got a spark.

This is typical if the first time you connect an inverter after sitting disconnected for some time. There are internal capacitors that are charged when you connect the battery supply. This is why you will see Will using a large resistor to slow the inrush current down upon first connection.

As for concern, yes and no. Depending on the quality of equipment, this inrush current has been known to fry components. If yours is working, congrats you didnt fry anything.
 
I am connecting my battery to my MPP Solar PIP1012LV-MS. I connected both terminals on the battery, then the negative to the inverter. As I touched the positive to the inverter, I got a spark. The inverter was not powered on. I checked the positive and negatives cables to verify I did not mix them up and it is correct. Any concern with the spark?
The spark is the inverter capacitors charging.
I use an old style lol incandescent light bulb to precharge with no spark.
Hold the contact on the base of the bulb against the battery terminal.
Then touch the cable against the threaded side of the bulbs base for a minute which will charge the capacitors.
No spark.
My bulbs do not light up.
 
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