Measurement question ...

[offgriddle]

The Iceman Cometh​

Ok this isn't my Bluetti and it was chosen by and purchased by a neighbor on the homestead. The neighbor has graciously offered to be the iceman, (he runs the freezer that supplies the ice for everyone's coolers).

He has four (4) 160 watt panels that each produce 8.78 Amps at 22.4 VOC currently connected in a series parallel arrangement producing 376 watts.

He also has two (2) 100 watt panels that each produce 5.93 Amps at 21.9 VOC

Considering the cumbersome maximum input limitations of the Bluetti's MPPT being 10 amps, 500 watts at 68 volts, and taking into consideration near and sub zero farenehit wintertime voltage increases, how would you all configure the panels?

IE:
Series Panel String One: 22..4 VOC + 22.4 VOC + 21.9 VOC = 66.7 VOC
Series Panel String Two: 22..4 VOC + 22.4 VOC + 21.9 VOC = 66.7 VOC
Parallel connect strings one and two and hope for the best?!

 

[Fred S]

That configuration limits each string to 5.9a, for a total of 11.8a, but the Bluetti will only take 10a so it's not really an issue. The voltage might end up being a hair too high in cold weather, during times of little to no load. But give it a try.

As mentioned before, with your panels and the Bluetti constraints, all you can do besides that, is to drop back to 45v or so Voc (i.e. two panels in series). Then you end up with only about, realistically, 400w usable because of the 10a limitation.

Another "radical" option would be to determine if a supplemental battery can input to the Bluetti, but not be charged by the Bluetti (i.e. would it be able to act simply as a supplemental power supply to the Bluetti). (Or, confirm that an external battery can be externally charged without harming/interfering with the Bluetti.) If so, you would be adding bulk and complexity, but you could buy an extra battery and a 30a charge controller with an input limit of 100v. Then you'd have more flexibility with your panels. E.g. put the two 100w panels in parallel, then put the pair in series with one 160w panel, to supply the Bluetti at about 300w. Put the other three 160w panels in series (total 67v Voc) to supply 480w to the external controller/battery while it feeds the Bluetti. Then you are not approaching any controller voltage limits, and can utilize just about all of the panels' wattage, and gain some storage capacity.

Maybe others with Bluetti experience can weigh in on the feasibility.

 

[offgriddle]

That configuration limits each string to 5.9a, for a total of 11.8a, but the Bluetti will only take 10a so it's not really an issue. The voltage might end up being a hair too high in cold weather, during times of little to no load. But give it a try.

As mentioned before, with your panels and the Bluetti constraints, all you can do besides that, is to drop back to 45v or so Voc (i.e. two panels in series). Then you end up with only about, realistically, 400w usable because of the 10a limitation.

Another "radical" option would be to determine if a supplemental battery can input to the Bluetti, but not be charged by the Bluetti (i.e. would it be able to act simply as a supplemental power supply to the Bluetti). (Or, confirm that an external battery can be externally charged without harming/interfering with the Bluetti.) If so, you would be adding bulk and complexity, but you could buy an extra battery and a 30a charge controller with an input limit of 100v. Then you'd have more flexibility with your panels. E.g. put the two 100w panels in parallel, then put the pair in series with one 160w panel, to supply the Bluetti at about 300w. Put the other three 160w panels in series (total 67v Voc) to supply 480w to the external controller/battery while it feeds the Bluetti. Then you are not approaching any controller voltage limits, and can utilize just about all of the panels' wattage, and gain some storage capacity.

Maybe others with Bluetti experience can weigh in on the feasibility.

Great input and ideas Fred thank you. The next time me and my homestead neighbor can cobble together a few simultaneous hours to work on his Bluetti maximization project will will discuss your ideas as we have been during the duration of this helpful thread.

Upward and Onward

OG