With 1,280 watts of solar I don't worry to much about getting enough solar. This time of the year with the days getting shorter and we're in the national forest boondocking catching light shadows from some pines I would expect some drop off in amps going to the battery (can see it on the display). Yesterday morning while I was walking the dog I was checking the shadowing on the panels from the trees from the hill behind the 5th wheel and noticed that the crank up antenna was casting a good shadow on 2 panels (each in a different series string). This morning at 10am I remebered about the antenna shadow and before cranking it down there was 25-26amp reading, after lowering it down 36-37amp. That's a pretty fair boost just lowering the antenna, during the day seeing we're not watching it anyways. I'll have to pay attention to the tv antenna during the winter so not I'm losing any possible power.;) We know about shadowing on the panels but seeing it yourself is a little eye opener.

Good catch. Just orient the RV different to eliminate the antenna shadow.

I never paid attention to the antenna but will for now on. I've been in this location for 12 days now with the past 3 days having 2.7, 2.8, 2.8kwh harvested. Today with the same conditions as the past days and harvested 3.3 harvested. A .5kwh pick up is nice and certainly helps keeping the batteries charged.

30% drop, and antenna shade probably didn't cover 28-29 sq.ft. (30% of 1,280W). When I posted about this oddity in series panels few years ago, nobody believed me. People were talking about magical powers of bypass diodes, sheesh...

Easy to take out more real estate than actually covered.Certainly did not lose everything.

Itinerant1 wrote:... A .5kwh pick up is nice and certainly helps keeping the batteries charged.... or it helps you staying fit, through cranking exercise :)When batteries are floating and controller goes to rest before sunset, - doesn't matter how much more energy there is in the sky. In your case it sounds like they were not floating yet or some loads were running often.

Solar panel shading | Good Sam Community

35 Replies

Itinerant1
Explorer
Oct 20, 2017
"Adverse conditions" protocol condition to protect the batteries.
Almot
Explorer III
Oct 20, 2017
BMS does control shutdown. This is its main purpose (besides cell balancing). It stops charging when charging voltage is too high, too low, or temperature is too high. BMS can not be (usually) programmed, but controller can be, yes.
Itinerant1
Explorer
Oct 20, 2017
Without a doubt. Yesterday I tested it again by cranking it up and lowering to see the difference and it was the same as the first day. Amps would would lower and rise by just the antenna shadow.
Normal I don't worry about the positioning of the trailer but will think about the antenna now.
CA_Traveler
Explorer III
Oct 20, 2017
Do you now feel that the antenna shadow was the main reason for the reduced charging for the given light conditions?
Itinerant1
Explorer
Oct 20, 2017
Almot wrote:
Itinerant1 wrote:
These are lithium batteries no absorb.

Alright, then you don’t need to push it to 95%. They are happier when staying in 20-80% range.
There is no Absorb or Float in Li battery, but the Float on the controller should be set low enough for BMS to stop charging (in absence of loads). I doubt that your battery BMS will automatically do this at 85%, so you'll have to do it yourself.

RV.net server is finicky today. No service, and then suddenly double and triple post.

Correct the batteries don't need to be in the 95%+ range which after overcast/ snow or just poor solar days and knowing that the weather will be better for replenishing the batteries. The system was installed so I could go 3 days with full convenience without having to hook up the generator for a hold over charge till the sun shines again. The lowest the batteries have been down in the morning while still using the microwave or coffee maker is 24% (120ah).
I know how my setup works after 18 months which is why I was wondering why it wasn't recovering as normal and something so simple as the tv antenna that I never thought about or at least had an impact is it did at this location and time of year.
Without going in to detail with these fully programmable inverter/ charges working in unison of the solar controller the bms is not controlling shut down other than programed
adverse condtions.
Almot
Explorer III
Oct 20, 2017
dp
Almot
Explorer III
Oct 20, 2017
dp
Almot
Explorer III
Oct 20, 2017
Itinerant1 wrote:
These are lithium batteries no absorb.

Alright, then you don’t need to push it to 95%. They are happier when staying in 20-80% range.
There is no Absorb or Float in Li battery, but the Float on the controller should be set low enough for BMS to stop charging (in absence of loads). I doubt that your battery BMS will automatically do this at 85%, so you'll have to do it yourself.

RV.net server is finicky today. No service, and then suddenly double and triple post.
BFL13
Explorer II
Oct 20, 2017
liborko wrote:
Good catch time2roll. I realized that as soon as I posted it.

You are allowed to edit your posts, you know. :(
liborko
Explorer
Oct 20, 2017
Good catch time2roll. I realized that as soon as I posted it.

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Solar panel shading

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