Hello All,It has been a while since I have been here. I need to come back more often. I have a 2016 fuzion 345. Love the tech but man does it eat power. I did put 6 6 volt batteries and that will get me through a weekend, not much more. I have an onboard gen but I get away for peice and quiet.Because I use power I have bought 2 - 280 panels and all the trimmings. Last item I need to know. Which is better parallel or series. I know that pannenels in parallel is more volts, series is more amps. I just don’t know which set up I should do. Which is better for battery health? Which is better for quicker recharge. I will be adding an inverter later.I would like your thoughts.

Actually, in parallel you add the amps, and in series you add the volts.The big factor there is the Voc limit of the solar controller which will fry if you go over the Voc limit at all, no second chances.Unless there is much shading in your situation, there is no advantage in amps to the battery either way. If there is some shading, parallel is better for daily AH haul.

Those are likely 60 cell modules with a Vmp or around 30 volts. You will need an MPPT controller to allow them to charge your 12v battery bank without wasting most of the power. An MPPT controller will have a maximum Voc. Your panels are likely around 37 Voc at 25 degrees Celsius. When it gets really cold that will likely increase to around 45 Voc. If you put them in series make sure your controller can handle the 90v input or you will fry it.Volts add in series, amps add in parallel.

BFL13 wrote:Actually, in parallel you add the amps, and in series you add the volts.The big factor there is the Voc limit of the solar controller which will fry if you go over the Voc limit at all, no second chances.Unless there is much shading in your situation, there is no advantage in amps to the battery either way. If there is some shading, parallel is better for daily AH haul.You are right. I did get it backwards. I was going off this site.http://solarloco.com/blog/diy-solar-panels/the-difference-between-series-and-parallel-circuits/I have a 40 amp controller. It can handle 1560w/12v. 72 cell Voc < 46v.

I was thinking more amps would charge quicker. Much like more amps on small electronics. There just not much information to read about benifets to more volts vs amps.

y22man wrote:I was thinking more amps would charge quicker. Much like more amps on small electronics. There just not much information to read about benifets to more volts vs amps.It does not work that way. Total power to the batteries is governed by the MPPT and series or parallel will not significantly matter when it comes to total power. One advantage to series is that the wire gage between the solar panels and controller does not have to be as large for series wired panels.

Solar panels in series or parallel? | Good Sam Community

CA_Traveler
Explorer III
Jul 30, 2018
I've posted this before and the graph clearly shows the advantage of series panels with bypass diodes. Virtually all 60+ cell panels have bypass diodes because they protect the panels in the larger series/parallel arrays found on houses, buildings, off grid arrays, etc.

This graph shows the positive effect of bypass diodes with clouds and leafy shade. There are 3 30V (about) serial panels with 3 bypass diodes each which results in each bypass diode controlling about 10V of panel output.

The morning starts with overcast clouds and full solar panel array voltage output (about 90V) in the limited light.

At 8:37 the clouds departed leaving leafy shade covering the panels resulting in 6 bypass diodes conducting and 3 of the panel sections producing power at 30V. As the shade changes on the panels the panel voltage increases to 40, 50, 60 and 70V.

At 9:27 all of the shade is off of the panels and the panel voltage is 90V. The MPPT controller continues to optimize the panel output as the sun continues to rise.

The panels are flat mounted and the sun is rising.

Note: Bypass Diodes have the effect of 9 independent serial panel sections. When there is a shadow on one section that section is bypassed – ie the effect is like a short for that section and it bypasses the amps of the other sections. One bypassed section results in 8/9 of the voltage, two sections in 7/9 of the voltage, etc, however the panel amps are not effected. I’ve seen charging with only 2 sections or 20V. Bypassed sections do not have to be in the same physical panel.
Almot
Explorer III
Jul 30, 2018
Almost full at 13.7V - maybe.
Could've been almost full before the sunrise already.
Could've been just approaching the Absorb - most likely, considering his "20-30 minutes". Hence, "floating" they are likely not, after 30 minutes of charging.
He said was "40 amp controller". Would've been easier to tell more if the current was known.
Too much data missing. I am out.
Boon_Docker
Explorer III
Jul 30, 2018
beemerphile1 wrote:
y22man wrote:

...One question I have, what is the load terminals used for....

A load such as a light or radio or whatever can be powered directly from the solar power rather than the battery if you wish.

Not quite.
The load terminal does use battery power when the sun isn't shining. It is a terminal that you can set a time for on and off. It also has a low voltage cutoff so the battery does not drain too low.
BFL13
Explorer II
Jul 30, 2018
12.4 is say 75% SOC of 6-sixes at 225 a pair so bank is 675AH so was down by 169AH going in. Allow 35 amps for likely charging rate based on OP info.

35 amps is a 5% charging rate so would reach say 95% before Absorption starts and then if it is a Tracer it will hold at 14.6ish for two hours more before dropping to 13.6v

The Bulk is to do 169-34 = 135AH at 35 amps = almost four hours, then another two before dropping to 13.6v = almost six hours.

OP says he was at 13.7v after half an hour. So only another five and a half hours to go before it drops to Float. That would not signal the batts are truly full of course, but almost full.
red31
Explorer
Jul 29, 2018
load terminals, on at dusk off at dawn or other timed night events, ignore.
Almot
Explorer III
Jul 29, 2018
y22man wrote:

It took the pannels about 20 - 30 minutes to take the bank from 12.4 volts to float at 13.7 volts.

One question I have, what is the load terminals used for? Is that for the inverter?

1) 13.7 in itself doesn't tell much. Could be early stage of charging before Absorb, or the ending stage after. What controller and what the Absorb voltage is set to?

2) Ignore load terminals. No, they are not for inverter.
beemerphile1
Explorer
Jul 29, 2018
y22man wrote:

...One question I have, what is the load terminals used for....

A load such as a light or radio or whatever can be powered directly from the solar power rather than the battery if you wish.
y22man
Explorer
Jul 29, 2018
Update:

This weekend I installed the system.

2 - 280 panels
40 amp charge controller

This is all connected to:

6 - 6v battery bank

It took the pannels about 20 - 30 minutes to take the bank from 12.4 volts to float at 13.7 volts.

One question I have, what is the load terminals used for? Is that for the inverter? I can not find a good answer.

Now for an inverter and how to connect it into my system.

Thanks to all for the input.

Jay
lawrosa
Explorer
May 06, 2018
I have 2 - 280 watt panels. 36 v each. I get 70v say in full sun. 8 amps or so panels but with mppt say 40 amps.

OK. I can stand in front of 1 panel and lose nothing really but maybe a few volts.

I charge the same or similar....

Yes thes residentials have 4 bypass diodes in them from what I know...
time2roll
Nomad
May 05, 2018
y22man wrote:
Not sure how this post got so hostile.
Don't let it ruffle you up. Fairly normal for the internet. Hard to make soft points with short little messages. Most comes off as pointed and harsh but that is not the intention.