Paneling for a 2400KW PIP

[Mac6792]

I've been going around in circles trying to determine the best way to panel this 24 volt MPP 2400kw All in one. It's a max 2000Watts solar input, Max 145VDC input., Max 80Amps in. My goal is to get the max wattage I can given the space and input limitations. I'm less concerned about additional cost of wiring

I have space for a 8 panels pretty much any sized. While my roof is southern facing I do have some shading at different times of day. With the shading and VDC limitations doing all serial seems to be a non-starter. Would you choose say 4 large 360 watt panels with 42.7 voc and connect them in parallel? (1440 watts) Perhaps 6 200 watt panels with 24.335 voc, connect 3 pairs in serial? This would give me 146.1 Vdc (1200 watts) is that ok to go a little over? Perhaps 2 pairs in serial and then 2 pairs in parallel for a total of 1800 Watts? and 146.1 voc and 57 Amps.

Other points - I've read that temperature can affect Voc so I'm not clear that its a good idea to be anywhere near max.
- Using the large panels solely in parallel I'd need at least 24Volts active on that panel to begin charging (56%) Is that a reasonable expectation given that I expect some shading?
- Using the smaller 200 Watt panels in Parallel - I'd only have just 24 volts Voc so would that mean I'd need 100% of the panel active for it to begin charging the batteries?
- It's unclear to me whether I should be calculating total Voc using the Voc specs of the panel or the Vmp number


Feel free to tell me I'm doing this all wrong

Any help is appreciated

 

[Watts247 - Ian Roux]

Hello.

Panel voltage over 115Vdc will lead to NO CHARGE-ing, as the spec says that the voltage needs to be within 30 to 115V (Vmp ) for the 24V battery system 60V is the min for 48V systems
(over 145VDC - Voc causes damage)

3 to 4 panels in series would be perfect, and add parallel strings from there, if you go over the rated panel wattage, have no fear, the MPPT charge controller can only harvest the max of 2kW, anything extra will just mean that it can harvest the max for longer .

From me , it sounds like you have the rest all under control

best
Ian

 

[gdpetti]

So, 'NO CHARGE-ing' but no damage to the MPPT solar charge controller unless it goes over the 145VDC? I'm looking at the same issue, how to max the panels on the van for most usage situations that will most likely be under the limit of the MPPT voltage range 30-115VDC.

So no damage, just no charging when or if the panels produce over 115Vdc? Charging will stop and restart when it goes over that 115limit? Do I understand this correctly? Just make sure they don't go over the 145 limit, right? That is when damage occurs?

The panels I'm looking at are 24V with Voc of 40V, so they aren't likely to go much over 130-140, in the best conditions, right. So, they should be ok, 3 of them in series?

 

[John Frum]

I've been going around in circles trying to determine the best way to panel this 24 volt MPP 2400kw All in one.

Respect ?

 

[Mac6792]

Interesting point - The Q-Cells I use are rated at about 40 VOC- also in the spec sheet it shows they are 33-34 volts at the MPP- That has been my experience. I have 2 panels in series and see between mid-fifties to high sixties for voltage at each inverter. I kept my 8 panels in series pairs to offset any shading losses although I could have gone to 3 per string. That said you may be just fine with 3 in series

 

[gdpetti]

That was my understanding from Ian's post above.... as long as the Voc stays under the 145Voc limit, it is ok. If it goes over the MPPT range of 115Vdc, then the controller will simply shut down until the Voltage dips back down into the range. I just wanted that confirmed... I don't want to damage the unit.

 

[godawgs]

Hello.

Panel voltage over 115Vdc will lead to NO CHARGE-ing, as the spec says that the voltage needs to be within 30 to 115V (Vmp ) for the 24V battery system 60V is the min for 48V systems
(over 145VDC - Voc causes damage)

3 to 4 panels in series would be perfect, and add parallel strings from there, if you go over the rated panel wattage, have no fear, the MPPT charge controller can only harvest the max of 2kW, anything extra will just mean that it can harvest the max for longer .

From me , it sounds like you have the rest all under control

best
Ian

Hey Ian: I have a few questions on the LV2424 - paralleled for split-phase 240V NA.
- Do I understand correctly that I can oversize the arrays above 2kW without damage to the LV2424? If so, is there a max. oversize? I'm planning on 2475W on at least one unit.
- Can I run different DC loads to each LV2424 and still have proper unit operation? For example, I can fit just 15 more panels in my space. If I have 9 on 1 LV2424 and 6 on the other, will the units still function correctly? I understand the wattage/amperage will be different, but it shouldn't be a problem with my utility company.
- Have you heard of anyone running just a single side of the split-phase (e.g. just L1 @ 120V)?

Thanks,

Chris

 

[Watts247 - Ian Roux]

Hey Ian: I have a few questions on the LV2424 - paralleled for split-phase 240V NA.
- Do I understand correctly that I can oversize the arrays above 2kW without damage to the LV2424? If so, is there a max. oversize? I'm planning on 2475W on at least one unit.
- Can I run different DC loads to each LV2424 and still have proper unit operation? For example, I can fit just 15 more panels in my space. If I have 9 on 1 LV2424 and 6 on the other, will the units still function correctly? I understand the wattage/amperage will be different, but it shouldn't be a problem with my utility company.
- Have you heard of anyone running just a single side of the split-phase (e.g. just L1 @ 120V)?

Thanks,

Chris

Chris, so sorry, I harld log on here. yes you can mismatch your panels on each inverter, 2.4kw of panels should be just fine, as its a rare day that your panels will ever put out 100%