First kick at the Cat after Energy Audit

[West Coast Canuck]

My first post was on Dec 20/2020 and I see now I had no idea, Thanks to Mr. Sandels and six weeks of reading posts, energy audit, purchase of a current meter I feel I have a small grip on things

Please see system size calculations below

My system will consist of:

- 60 amp Critical electrical Panel with 18 single 15 amp fuses (Completed)

- 16s2p Lishen 272 amp cell configuration, for (272a X 3.2v X 16pc) =13,926ah X 2 banks =27,858ah Storage.

- 2pc MMP Solar 6548, 6500watt all in one inverter. 6500w X 2 =13,000w with 6000w X 2 = 12,000w surge.

-Positive 2/0 wire from cells, - T type fuse 250 amp, - emergency 300 amp shut off switch, to Positive copper Bus Bar, same configuration for each for the 2 Parallel 16s cell banks.

-Negative 2/0 wire from cells, - BMS 200amp, - Shunt 200amp, Negative Bus Bar, same configuration for each for the 2 Parallel 16s cell banks.

-Positive and Negative 2/0 wire from Bus Bar to each MMP Solar 6548, 6500watt

Solar, 5.92 kw total, 16 panels Mono Cell, 370w Open circuit VOC 47.8v, Power VMP 38.9v, Short circuit 9.88A, Power current 9.52A, much more work to be done on calculations, string orientation, roof drawings, engineering to come.

If I could get some INPUT and CRITICISM on my Cell packs, fuse size and type, BMS size, wire size I would be more than HAPPY

 

[svetz]

Some thoughts:

• Make sure the two inverters can work in parallel; sometimes to get them to do so you need to order a special cable.
• The 2/0 wire max ampacity is normally around 150 amps, since your max draw is 250 amps make sure there's no single path (e.g. to the BMS) that might exceed 150 amps with 2/0.
• Check the inverter instructions, you may find there are special rules to follow when operating in pairs regarding matching your solar string inputs.
• Since you live somewhere its been known to get cold occasionally, you'll want to check the temperature correction factors, see Figuring out how many panels in series and parallel based on your MPPT for an example if you're not sure.
• The MMPs aren't considered top-shelf and I've seen posts regarding problems with tech support. If you haven't looked into them, the Sol-Arc 12k might be a good fit. I haven't seen anyone say anything bad about their quality and their tech-support sounds top notch.

 

[West Coast Canuck]

Thank you for your review it is much appreciated, do you think a fuse and BMS on each battery pack of 16 cells is the way to go and are they sized right, thanks

 

[MisterSandals]

- 16s2p Lishen 272 amp cell configuration, for (272a X 3.2v X 16pc) =13,926ah X 2 banks =27,858ah Storage.

The 13,926 should be watt hours.
Putting 16x cells in series to make a 48v (51.2v nominal) battery is 272ah.

 

[West Coast Canuck]

Thank you I finally have the concept of Amp hours but just slow to react If you have a chance I am trying to calculate my main wire and fuse, BMS sizes, from my energy audit my continuous current from Battery is 156.9 and my mpp solar 6548 has a maximum current draw of 6500/48v = 135.42 amps I had thought welding wire at 2/0 is 235 amps and would use this on both of my 16 cell 272ah packs, type T fuse at 156.9 X 1.25 =196.125so 200amp fuse, BMS 156.9 X 1.25 = 196.125 (200 amp BBS) do you think I am getting close

 

[FilterGuy]

Sol-Arc 12k might be a good fit. I haven't seen anyone say anything bad about their quality and their tech-support sounds top notch.

I have not worked with one but I have heard a lot of good about them as well. I recently had a need to help someone using a Sol-arc with some advice on their system so I downloaded and read the manual. First.... that unit is about as full-featured as it can be. If the manual is to be believed (and I have no reason not to believe it), that unit can be used in about any situation you can imagine. My one 'complaint' is that the documentation style is confusing to me. Their documentation lists what to do but do not give a lot about the why. I need to know the why before I am comfortable with doing it. However, SolArc is not unique in having less-than-clear documentation and theirs is better than a lot of others I have seen. I am even considering SolArc 12K for a project I am thinking about doing next year.

 

[West Coast Canuck]

As I will start with one LV6548 I have changed my Energy Audit slightly to work better. Solar panels will stay the same but not until spring
set up as i figure it:
-Positive 2/0 wire from cells, this is the manual recommendation - T type fuse 200 amp, again manual- emergency 300 amp shut off switch, to Positive copper Bus Bar, same configuration for each for the 1- 16s 48v cell bank.

-Negative 2/0 wire from cells, - BMS 200amp, or (250amp) - Shunt 200amp, Negative Bus Bar, same configuration for each for the 2 Parallel 16s cell bank when added in future

-Positive and Negative 2/0 wire from Bus Bar to each MMP Solar 6548, 6500watt max current 153.8amps.

First 16 cells top balancing and started charging with the only charger i have 3.6 v 10 amps (will be a while)

ANY comments or direction appreciated

 

[West Coast Canuck]

Second Kick at at the cat, Please Review

Attachments as above.
Expected current on welding wire as per LV6548 = 154amps
Type T fuse =154*1.25 = 192amps, use 200 amp fuse

Welding wire size = 200 amp fuse x 1.25 = 250amps, use 2/0 welding wire

BMS continuous current as per LV6548=154amps x 1.25 =192 amps, use 200 amp BMS

Please review and see how to refine these numbers if needed, THANK YOU