![]() and I didn't know any better and it looked like what others were doing. I chose this because its cheap to buy un-insulated twisted copper. My packs have up to 60cells so that's 1.68a per cell. However, this could just be my ignorance and 10awg IS OK as they told him.īattery wise I use twisted copper 6AWG with chassis amps of 101. I have trouble believing it and in fact did the same mod to my ProTran as he did. Pro Tran told him that 10awg is perfectly 'in spec' for 50amps at chassis distance (few inches). Reading and learning.Īt 1:47 'ish into it. The expertise here is very much appreciated. How do you guys figure that out? It doesn't look like ampacity increases linearly with cross section according to the chart linked by OffGridInTheCity. So if I went with MPP Solar's recommendation of 1/0 cable and a 220A breaker for the battery, that means my busbars will require the same ampacity. Definitely won't have the battery capacity to deal with that anytime soon, but I'd still like to wire / fuse sufficiently & safely to handle brief inductive loads (e.g., well pump) without going overboard on the cable. Understood about the per cell draw at that level of sustained load. Then the builder connects those same packs to the inverter with 1/0 welding cable!? Maybe I'm missing something there too. So, 4 strands of twisted 12 AWG configured in a closed loop (doubled) would total 26.48 mm2 or about the same cross section as 3 AWG cable (but even less ampacity apparently). Where individual packs are bussed with 3 or 4 twisted strands of 12 to 14 gauge copper wire. Yes, this is something else that has confused me in studying some of the powerwall builds seen here and elsewhere. For typical cells of say 2,500mAhr, that's only 2.5hrs run time from 100% full to 0% (in theory). Some simple numbers Eg, 125 cells 1A each =125A. If you're planning for sustained draw of 125A, you'll need a large battery pack to supply those Ahrs & to keep the per cell current reasonable. Ie the inverter &/or the breaker should shutdown/trip before Note this discussion also applies all the wiring inside the pack as well.Īnd think about the combined amp rating of each individual cell fuse in each parallel "P" block section in the battery bank too. The impedance & voltage drop are both less with bigger cable sizes & this helps the inverter's input capacitors cope with the loads as well. The less voltage drop you have, the less your efficiency losses for the system are. Other factors to think about are voltage drop & impedance. ![]() It's only partly about the safe rating of the cable (you should still make sure this is OK) ![]() The surge time rating of the inverter & breaker should both (separately) be less than the surge time rating of the cable.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |