System can't keep up after upgrades and reconfiguration

[dixonge]

Don't combine them on the roof. For the two portable panels 10-12AWG leads and hook them into the circuit at or near the SCC. If you need to, put a small bus bar or terminal for all the solar and then run one set of wires to your SCC.

Everything on the roof is combined w/ MC4 branches. I could add some MC4 and combine w/ portable panels in the battery compartment just before the SCC. I already have the parts, would just need the extra cable length for the portable panels.

 

[Wellbuilt]

The water dosent really matter short term , the acid get stronger and can cause problems over time , but your acid in the cells have low sg so it dosent matter The battery could heat up more but you don’t really have enough power so no issue there .

Running the number dosent help you .
having 10% rate of charge at peak noon ?‍ Is not enough , you need hours of good charge not a peak .
You can only get 80% of your watts in and that is in good sun with the panels pointed at the sky
With out reaching full charge you battery’s sg drifted apart your one battery is dead now , you need to bring that battery up to match the other .
You need to charge them to full as you can get then eq .
My buddy stands up 3 big 295 watt panels in his bath room shower area .
800 watts may be enough in Arizona if you can point them at the sun .
You can’t really add panels to a mppt charger if they are not pointed in the same direction The mppt won’t work .
You mite need to add a controller for a new bank .
The RV guy use a external plugs for the panels .

 

[Wellbuilt]

You could just use a Anderson plug for a second bank , that’s what I use on my sail boat .

 

[dixonge]

With out reaching full charge you battery’s sg drifted apart your one battery is dead now , you need to bring that battery up to match the other .

You say one battery...but all cells in two of the batteries are low at 1.150

You need to charge them to full as you can get then eq .

I separated them this morning. Original two batteries are now charging, RV operating on house batteries so no load at all on solar battery bank.

800 watts may be enough in Arizona if you can point them at the sun .

I have used two different formulas to estimate solar panel needs:
1. Ah/10*12 - in my case 460Ah/10=46amps *12 = 552 watts of panel. Like you said, this is an *ideal* number and only sufficient in Arizona in the summer.
2. Usable Ah * 3 - in my case 230Ah * 3 = 690 - I'd round that up to 800 to keep it simple and give extra. But according to you this isn't sufficient on a flat roof in the winter.

So what formula are you using and what is the 'magic number' I should be shooting for, assuming I keep my existing batteries?

You can’t really add panels to a mppt charger if they are not pointed in the same direction The mppt won’t work .

OK, so since my roof panels face in different orientations it wouldn't help to tilt two of them...or to tilt two new panels on the ground if the roof panels are still flat? Dang.

You mite need to add a controller for a new bank .

Let's say I use my old PWM as one of the controllers. Is this a problem? Which set would benefit most from mppt - flat on the roof or tilted on the ground?

 

[Wellbuilt]

At the end of the day , your watts don’t really matter its just not practical to run a system with out a way to charge
your bank when the battery’s need juice .
The best way to do this is with a good Quality inverter / charger and small generator .
My system uses 10% of my battery over night and I can replace that power in 1 hour
but if I discharge 20% of the bank I need to charge 3 hours to replace the power
if I dis charge 40% I need 4.5 hours and that just gets me to 90% I would need a long absorb to get to full .
Your battery are down below 30% every day and never get that long absorb charge the Duracell GC battery need .
I dont want to be a downer but it is what it is , using solar in Arazona is like being on the sun compared to my area .
I charge 4 of your banks at my place with the panels at 42o I use 4500 watts and at this point in time I’m not getting thru my 2 hour absorb and will raise my voltage and absorb time to compensate

 

[dixonge]

At the end of the day , your watts don’t really matter its just not practical to run a system with out a way to charge
your bank when the battery’s need juice .

Are you really saying that no amount of solar panel watts are enough to charge a battery bank in an RV??? You just basically ruled out 90% of the RV solar installs currently in use. People are running Air Conditioning, washer/dryer units, microwaves, full-sized residential fridges, etc. Yes, they have massive panel watts and LifePo4 battery banks. But what they are *not* doing is running their generator all the time. Without their examples, and dozens of others, we would have never expected to do the same.

Your battery are down below 30% every day and never get that long absorb charge the Duracell GC battery need .

Yes, it recently did this. But until recently it was at 100% every day.

 

[Wellbuilt]

im not sure if you are better off using mppt flat or pointed at the son .
I think flat because that will give more power when the other banks is not plugged in .
the good news is those battery’s are hard to kill , and they are not Very old so I think the will come back .
( Warning ) get the voltage very close between the cells before you re cancer them .
You don’t want a bunch of power rush from a high battery to low battery you could warp the plats
don’t ask how I know ?

 

[Wellbuilt]

life po is diffrent they don’t need to be full charged the can sit at 50% with no damage .
Those battery charge in less time , you can dump power into them .
This is just math , you get the full charge or you don’t , every time you don’t reach full charge you’ll lose a little power
if you get a good charge every week power comes back, if you go for a month The battery sulfates and won’t come back .
Question ? Did you charge the batteries to full charge before you combined them in the coach ?
The the voltage really needs to match went you start using them .
If your Battery voltage is 10 % diffrent you charge controler will see a average voltage between the to sooooo the battery in the group that has higher voltage is just getting under charged 5% and the lower battery gets over charged 5% what happens is all you battery get dragged down .
The battery monitors don’t really work very good , my monitor resets every day when I get to full charge
over a few weeks of low charge my% number drifts .
It works good if every thing is working but in the winter or if your don’t get good power it give you a fails reading .
I go by watts in , resting voltage , and sg with your sg off so far you cant get to a true 100%
for your sister you really need to keep the battery’s sg at 1. 265 to consider it full at the end of the days charge .
1.265 is about 90% or a little more , I have not been really doing any Math here , I have years of experience off grid on land and in the water .
I’m no expert electrision , I have jut been using the Duracell battery since they started carrying them in 04 I think .
As a side note ,
If you have one battery that looks worse then the others you could go to sams club and fish around in there recycle pile , guy are trading in banks of battery’s that won’t give good power but there are allways good battery’s in the bunch
You can swap them they don’t charge you for that

 

[dixonge]

Question ? Did you charge the batteries to full charge before you combined them in the coach ?
The the voltage really needs to match went you start using them .

No

If your Battery voltage is 10 % diffrent you charge controler will see a average voltage between the to sooooo the battery in the group that has higher voltage is just getting under charged 5% and the lower battery gets over charged 5% what happens is all you battery get dragged down .

SG for all cells was showing fully charged as recently as 2-3 months ago, so I don't think they were too far apart when installed in February

 

[Wellbuilt]

You where seeing 1.280 2 months ago hmmmmm sounds funny .
At the rate you are charging I wouldn’t think your water could even be that low .
7 months on low charge you should not be out of water.
My battery’s where low last week and I added 2.25 gallons of water in 4 months so about 1/2 a gallon for 4 battery .
New battery’s don’t really use much water .
In my area GC battery’s in February in sams club have been sitting since the summer.
We try to only buy in April/may and I allways get the battery’s the come in fresh , have the same lot numbers
and I look for battery’s with the same voltage .
Allways get to full charge then combine the bank , then give it a good eq .
hey the good news is if they don’t come back. YOU CAN JUST RETURN THEM FOR REPLACE MENT AND START OVER WITH FRESH ONES .?

 

[dixonge]

You where seeing 1.280 2 months ago hmmmmm sounds funny .

It could have been May when I checked it - started noting problems staying at full charge in mid-July (according to my notes)

In my area GC battery’s in February in sams club have been sitting since the summer.
We try to only buy in April/may and I allways get the battery’s the come in fresh , have the same lot numbers
and I look for battery’s with the same voltage .

Bought first batteries in July 2020, date code from March 2020
Bought second set in February 2021, date code from Oct. 2020

Didn't test voltage at all other than what the monitor showed after hooking them up.

Allways get to full charge then combine the bank , then give it a good eq .
hey the good news is if they don’t come back. YOU CAN JUST RETURN THEM FOR REPLACE MENT AND START OVER WITH FRESH ONES .?

Well I guess that's true for the 2nd set, but the first is out of the 1-year warranty...

 

[Wellbuilt]

Hey , if you added water then charged the battery’s and then hit them with low watts your acid is not mixed .
You should not add water be for you check .
You’re procedure should be to just add enough water to cover the plates in side , then charge to FULL
then EQ like crazy and then check the sg , you don’t really have enough power to get the electrolytes
moving , soooooooo it mite not be as bad as it looks , I was thinking your inverter should not work with the battery’s so low .
What dose the voltage look like when the system is off not charging .
I allways squeeze the bulb on my Hydrometer three times to move the acid around then ( look in side )
check for floating white stuff ? Make sure the fluid is not discolored ? Then check the acid
I ride around camp could help mix the electrolytes ?

 

[Wellbuilt]

That is the Beauty of 6v battery’s you can check them individually 6.4 is full resting voltage .
Well you have till February to fix the battery’s or get 2 new ones .
There is a learning curve to all this , money well spent .

 

[Wellbuilt]

If you have your receipt Sams will start the warranty from February .

 

[dixonge]

Hey , if you added water then charged the battery’s and then hit them with low watts your acid is not mixed .
You should not add water be for you check .
You’re procedure should be to just add enough water to cover the plates in side , then charge to FULL
then EQ like crazy and then check the sg , you don’t really have enough power to get the electrolytes
moving , soooooooo it mite not be as bad as it looks , I was thinking your inverter should not work with the battery’s so low .

I added water, charged, EQ'd, then checked SG. But while the SG is low, I haven't noticed any problem w/ inverter. Wife ran 900W blender a couple of days ago, no problem. Main symptom is the slow recharging.

What dose the voltage look like when the system is off not charging .

Just checked the two newer batteries. They were connected overnight, but disconnected this A.M. before any charging took place. Both are showing at approximately 6.3-4V

I allways squeeze the bulb on my Hydrometer three times to move the acid around then ( look in side )

Good idea!

check for floating white stuff ? Make sure the fluid is not discolored ? Then check the acid
I ride around camp could help mix the electrolytes ?

We drive over rough dirt roads to the dump station every week. 60-mile round trip from this location.

 

[dixonge]

If you have your receipt Sams will start the warranty from February .

Right, I do have it. But that won't help for the first two purchased in July of LAST YEAR.

 

[Wellbuilt]

Hmmm 6.3v is not bad at all . 12 volt battery charging chart

 

[Wellbuilt]

6.3 is not bad for over nite 90% keep hitting them with power.
You mite be ok I bet your real low sg was a bad reading .
hydrometer suck also I use 2 different ones morning star makes a good on that is Automatically temperature , and a diffrent model ?
I like the second one because it gives good readings ? the morning star not so much
all of this is not a exact science it’s more of a feeling , there is no perfect charge , its like Balancing on a razors edge
I change my setting weekly to match usage , power used every day and power in Rain time of year and weather forecast .
My controller in the pic is first thing in the morning 800 am I’m charging at 43 amps for my 430 ah battery I’m in bulk charge .
I’ve brought in 0.9 KWH so far .
The sun only hit the panels 30 mins ago
my controler will max out at 3700watts in settings I have the system set to a 50 amp max in put .
The thing is I’ll never see full out put power , I’m at 93% now , and in a hour or so I’ll go into absorb and then the controller
will start to limit power .
My 0.9 kwh will clime to 3.5 kWH then the absorb will limit power for the rest of the day buy the end of the day
my kwh will top at 5.2 +- this gives me the power used all day and a little extra over charge .
when the battery’s adsorb down to 500watts coming in I am charged . But I go a little lower some times then I hit foat
54v for 48 volt system This float voltage still adds power to the battery but I just leave it , my system is turned off when I leave so it dosent sit in float for day on end.

 

[Sgt Raven]

You could just use a Anderson plug for a second bank , that’s what I use on my sail boat .

Exactly. MC-4 connectors are not designed to be taken apart regularly. Anderson plugs are designed to be self cleaning as they're connected/disconnected. Some of the Solar Generator manufactures have decided they make the best choice for their portable panels, too.

 

[dixonge]

Hmmm 6.3v is not bad at all . 12 volt battery charging chart

On the two newer batteries - went through bulk, absorption and float, then manually equalized (one hour) - moved connections over to older batteries for more charging and let the two newer ones rest for a couple of hours.

6.7v on each battery
Tested SG on each cell, even trying your trick to stir up the water. All cells were basically 1.210 or just below that.

So now what? Add acid?