xp 2 questions

[e67]

2 different questions,6000xp
1-If some people have blown up units due to start up rush...can you add the additional step of a manual pre charge resistor like I have,(100W20(resistor)J
and do it manually before you do the normal start up? If so ,is this resistor a good one for the purpose????A blown up inverter would be a catastrophe for me...

2-The pv instructions on the XP say that you "should/must" use 2 strings that have the same number of panels. My strings are certainly the exact same panels but 1 string is 5 panels and the other 7 panels. Is that really an issue???

thanks

 

[MaikaiLife]

Hi @e67

1: Can you manually charge up the capacitors in the inverter with a pre-charge resistor? YES, and many rack mount batteries already have this such as EG4, where every battery they make has a pre-charge resistor. If you're not using EG4 batteries with the 6000xp and they don't have a pre-charge resistor built-in, you can use a resistor like the one you've stated to slowly charge up the inverter before you connect the inverter to the batteries directly.

Here is a link to a video that might help you better understand this process.


2: PV instructions for the 6000xp. The page you're referring to is at the top of page 13, what they're saying is that for "each" MPPT you should use all the same brand and model of panels. They're also saying if you had two strings you combined in parallel that they must be the exact same string size.

Here is an example of a configuration that is acceptable.

MPPT1

3x 30V, 3A panels in a series string would create 90V at 3 amps. 3x 30V, 3A panels in a series string would create 90V at 3 amps.

Each of these is a series string, if I combined these two series strings in parallel I would get 90V at 6A. If I combined this series strings in series, I would get 180V at 3A.


Here is an example of a configuration that is non-desirable .

MPPT1

3x 30V, 3A panels in a series string would create 90V at 3 amps. 2X 30V, 3A panels in series string would create 60V at 3 amps.

If I combined these in parallel, because the voltages of each series string do not match, this will reduce the output and may cause panel damage.

Watch this video for a better understanding:

However, if I combined this in a large series string of 5x 30V, 3A panels, that would give me 150V at 3 amps, which is fine so long as the panels brand type, and output are all the same.

So I believe that EG4 is simply saying don't mess around with mismatched stuff and simply use the same type, brand, and output panels together to avoid any potential issues.

 

[e67]

I thought someone had blown up the inverter with a LifePower4 but I might be wrong. I am using LifePower4.
Another thing.. Start up procedure seems to vary based on the model. For the 6000XP it says everything off and then turn on the battery breaker on the 6000XP. Then turn on the battery one by one. Then turn on the inverter if no problems. Is that correct? The manual says this...

 

[marionw]

It's oftentimes in the startup sequence. For EG4 Batteries; The Inverter must be off. All batteries must be off and battery breakers (on the battery) open. Any breakers or disconnects between the inverter and batteries must be closed. If the inverter has a battery breaker it must be closed. Close the breaker on one battery which will start up the BMS and insert the built in pre-charge resistor into the battery output.