Looking for advice- help

[DEWGARINC]

I built this system about 4 years ago 4 agm d8 210amh batterys- 3 - 200 watt renogy panels- 3 100 watt panels these are are wired thru a ditribution box in parallel
Mppt controller, and 1500 watt invertor- system is 12 volt off grid at my cabin i have rv 12 volt lights and a 12 volt water system
I have to say the batterys have performed poorly
Trying to decide should I replace the 4 batterys with 12 volt 230 lithium ion or
Switch system over to 48 volt using a conertor for 12 volt and A 48 server rack
Switching panels over to series
And trying to do this without spending a lot of money
Looking for help

 

[sunshine_eggo]

900W solar @ 12V = 75A

Do you have a 80A controller?

840Ah needs 84A to charge properly. 75A is probably close enough, but it may be marginal if you are over-utilizing your available PV.

Given your panel orientation, I suspect you never get close to 75A.

Switch system over to 48 volt using a conertor for 12 volt and A 48 server rack

always a bad idea.

Switching panels over to series

Given your panel orientation, not an option. Panels in a series string must have identical facing.

 

[DEWGARINC]

900W solar @ 12V = 75A

Do you have a 80A controller?

840Ah needs 84A to charge properly. 75A is probably close enough, but it may be marginal if you are over-utilizing your available PV.

Given your panel orientation, I suspect you never get close to 75A.



always a bad idea.



Given your panel orientation, not an option. Panels in a series string must have identical facing.

Would replacing the agm batterys to lithium ion help ?

 

[DIYrich]

Would replacing the agm batterys to lithium ion help ?

When you say "poorly", what is poor about the batteries? What is your load?

 

[Rocketman]

My guess is your biggest issue is not enough solar. (Or too much much demand for the amount of solar that you have).

Good Luck

 

[sunshine_eggo]

Would replacing the agm batterys to lithium ion help ?

Did your batteries achieve 14.4-14.8V (measured at the battery terminals) each and every day for a couple hours?

 

[DEWGARINC]

When you say "poorly", what is poor about the batteries? What is your load?

I am not able to get the batterys above 12.6
With 50amp charger and my generator

 

[DEWGARINC]

My guess is your biggest issue is not enough solar. (Or too much much demand for the amount of solar that you have).

Good Luck

The only load that is constant is starlink and I have turned off the heater cycle
After that a smart TV for a few hours some nights
All interior lights are RV 12 volt LEDs

 

[sunshine_eggo]

The only load that is constant is starlink and I have turned off the heater cycle
After that a smart TV for a few hours some nights
All interior lights are RV 12 volt LEDs

I've found the heater makes little difference in consumption. I have V1, and it's about 60W continuous.

You still haven't answered... what charge controller?

I am not able to get the batterys above 12.6

Full charge is typically 14.4-14.8V for a couple hours.

With 50amp charger and my generator

50A may take 20 hours to charge, and per above, that's too low of a charge current. Have you run the generator for 20 hours to confirm you can't reach higher than 12.6V? If using loads while running the generator, it may take > 24 hours.

Your panel arrangement may help harness more throughout the day, but it will never produce as much as a single array facing south without shading. It's very possible your

This is almost certainly a situation where you just have insufficient charging for your usage. Replacing with lithium may yield the same results.

If the batteries have been abused like this for the last 4 years, they're probably shot, but it's important that you understand what the actual problem is before you start spending money.

 

[DEWGARINC]

I cannot remember what the charge contoller is
I think its an mppt 60, its in the pictures for what thats worth
I have trees all around me, but great sunshine on the top three panels from 10am-3pm and more beyond that

 

[sunshine_eggo]

I cannot remember what the charge contoller is
I think its an mppt 60, its in the pictures for what thats worth

Many models use that or highly similar case. Can't tell. Per above, you need 80A to use the full potential of 900W, but probably not with how your PV is arranged.

I have trees all around me, but great sunshine on the top three panels from 10am-3pm and more beyond that

Given the above, I'm nearly 100% confident that you can't reliably replace what the Starlink and inverter alone use every day.

Your MPPT is too small for your PV, and your PV conditions are bad.

Replacing the batteries will not solve the problem.

And trying to do this without spending a lot of money

Given the above, deploying a bunch of LFP is going to cost you a LOT of money, and not change your situation. PV is notably cheaper than batteries. You should see an improvement and then decide what to do.

You DEFINITELY have a PV problem. You may have a battery problem. Recommend you reconfigure your existing array or add new panels to ensure at least an additional 300-500W of PV is placed in your most optimal PV conditions, i.e., maximum time of exposure and perpendicularity to the sun. A good rule of thumb is due south tilted to your latitude. GIven your 10-3 period, if 180° is due south, you should be at about 195°, i.e., 15° towards the West from due South.

Also, recommend you run your generator for extended periods to try to charge the battery to full. Again, you may need as much as 24 hours of generator run time @ 50A charger output to fully charge a near empty bank.

You probably need 6 hours of generator run time to replace what starlink and other parasitic loads are drawing every 24 hours.

Lastly, based on what I'm seeing, you have both your main terminals connected to the same battery. If that's the case, your main (-) should be moved to the farthest battery as shown:



Please see link #6 in my signature for the proper methods to parallel batteries. I think it starts around page 18.

 

[Rocketman]

I agree with everything Sunshine ego said.

One item that may help you understand what is going on better is a Victron Smartshunt or BMV712. This is a shunt based battery monitor.

The reason it may help is because it has a lot of info in the app, along with some graphs. It can tell you on a daily basis if you are net charging or net discharging.

Also, I just realized…
You have three 200w panels and three 100w panels all wired in parallel. What are the elec specs for the panels:
Voc
Vmp
Imp

As long as the Vmp is close you are probably ok, but if the voltage is very different you may be able to gain some lost solar watts by adding another Solar Charge Controller and splitting the array.

 

[sunshine_eggo]

I agree with everything Sunshine ego said.

One item that may help you understand what is going on better is a Victron Smartshunt or BMV712. This is a shunt based battery monitor.

+1000

Also, I just realized…
You have three 200w panels and three 100w panels all wired in parallel. What are the elec specs for the panels:
Voc
Vmp
Imp

As long as the Vmp is close you are probably ok, but if the voltage is very different you may be able to gain some lost solar watts by adding another Solar Charge Controller and splitting the array.

Very good point. I just assumed they were all "12V" panels, but that's very important to clarify!

 

[DEWGARINC]

They are all 12 volt panels
And yes I already changed the wires at the batterys

 

[sunshine_eggo]

They are all 12 volt panels
And yes I already changed the wires at the batterys

Are all battery interconnects the same length?

 

[Delmar]

I built this system about 4 years ago....1500 watt invertor- system is 12 volt off grid at my cabin i have rv 12 volt lights and a 12 volt water system

If everything is 12V then why the inverter? Could be a drain on the system, standby current 0.8A and 85-90% efficient when operating.

Also do the free stuff first. Rewire the batteries per above and clean clean clean the terminals. Remove the terminal tape: out of sight = out of mind.

 

[sunshine_eggo]

If everything is 12V then why the inverter? Could be a drain on the system, standby current 0.8A and 85-90% efficient when operating.

Also do the free stuff first. Rewire the batteries per above and clean clean clean the terminals. Remove the terminal tape: out of sight = out of mind.

Starlink is not 12V unless you jump through some hoops and use a PoE injector.