Hi everybody,
I've been looking for information about my project and I found a lot of contradictions on forums, website, etc.
I am thinking about sharing with you the setup I have in my head (which is likely to regroup most of the issues/questions people seem to have) in order to regroup major information on one post only that I am going to update.
To organize it, I am going to use numeric list to make it clearer and easier to answer as there are a lot of questions, when answering please provide the numbering (ie. 2.1.).
Diagrams are attached, they contain the piece of information needed, here are full explanation :
I will edit this post adding
when a question has been answered and I'll summarize the answers here :
Answers
I've been looking for information about my project and I found a lot of contradictions on forums, website, etc.
I am thinking about sharing with you the setup I have in my head (which is likely to regroup most of the issues/questions people seem to have) in order to regroup major information on one post only that I am going to update.
To organize it, I am going to use numeric list to make it clearer and easier to answer as there are a lot of questions, when answering please provide the numbering (ie. 2.1.).
Diagrams are attached, they contain the piece of information needed, here are full explanation :
- 2 x LifePo Batteries 48V - 100Ah - 1 C - Short circuit 200A
- Growatt inverter - SPF5000ES or SPF5000TL-HVM : the only difference that I found are the MPPT specs :
- Max PV Array Open Circuit Voltage : 450Vdc vs 145Vdc
- PV Array MPPT Voltage Range : 120~430Vdc vs 60~115Vdc
- Solar panel : RS7E-210M - 210W - Voc=23,95V - Isc=11.07A
- 12V to 220V pure sine wave inverter to charge the battery through the main inverter using the alternator (it appears to me that it is the cheapest way to charge via the alternator using only one charge controller, the goal is to not kill the alternator, I don't know it's power but lest's assume 180A, so max draw 80A)
- Batteries
Battery cut at 200A, on the Growatt manual it is recommended to use 2AWG cables, even if the batteries are connected in parallel, I want to be able to use only one of them (if one breaks or whatever) so that is why I set the same wire gauge before and after the bus bar.- 2AWG seems really thin : it seems that to withstand 200A it needs to be 4/0 AWG : is it right? should I size the cable for 5kW out of the inverter or 10kW peak?
- Is this ok to have the same wire gauge before and after the bus bar ?
- Should the negative be grounded to the chassis (knowing that sometimes it can be power to shore, so if so, does it need a disconnect when connected to shore power?)?
- Main Inverter
- Are they any noticeable differences that I missed between those two inverters?
- The minimum MPPT Voltage for the SPF5000ES is 120Vdc, my array Voc=119.75V : should I then use the SPF5000TL-HVM in order to benefit from the MPPT? (if I understood well the Voc will actually be higher with lower irradiance so the first inverter should do the job, isn't it ?)
- Grounded to chassis ? Is there a protective device to install between the inverter and shore power to prevent ground fault or other unwanted voltage?
- Secondary Inverter
Inverter of 2000W (4000W peak) used to power the main inverter to charge the batteries. As I was thinking of not drawing more than 80A on the alternator (providing 14V), assuming that the inverter has an efficiency of 80% I came to 80*.80*14=896W output to charge the battery (2kW inverter to run smooth).- Is the inverter good enough for the intended output?
- Is the wire gauge good according to the 150A fuse?
- I know that MCB have trip point at 3x the current (for Cs ones) so if I set a limit of 4A of charging from shore on the main inverter (4*220=880W) if something goes wrong and 7A is drawn (7*220=1540W so 1540/.8/14=137,5A on the wires and on the alternator without the MCB tripping because it is not even twice its rating. What kind of device could be used in this situation in order to limit the current on the secondary inverter in order to not have to oversize the 12V cables and for the 12 V fuse not to blown all the time ?
- Secondary inverter ans shore power breaker
- Is the MTS MCB a good option in order to choose th AC input from shore power or secondary inverter without having the possibility to set both of them ON at the same time ?
- Do I need to make two grounded circuit : one for the chassis, one for the shore power, that I could choose when plugged to shore?
- Solar Array - Configuration 1
- I've been seeing junction boxes that include an additional fuse before connecting to the MCB : is it useful? why? isn't the MCB enough?
- There is also SPD (Surge Protection Devices) but to me it need a true ground in order to works : is it true? will it work if it chassis grounded? if no, should I implement one when connected to shore ?
- Solar Array - Configuration A and B
In order to have more solar power, I am thinking of putting several panels solar, under the fixed array, that I could expand like a drawer, here is the setup that comes to my mind to add those panels in series
- Is the configuration A ok? should I insert an additional component where I put a "?" ?
- Solar Array - Configuration C
If i go with the SPF5000TL-HVM, I will overreach the maximum MPPT voltage in config A and B so I will have to set the 2nd array in parallel and then build 2 equals arrays
- Is The schematic correct ? Blocking diodes prevent flow from one array to another isn't it ? should I plug them before or after the MCB ?
- Is the wire gauge correct ?
I will edit this post adding
when a question has been answered and I'll summarize the answers here :Answers
