37v solar panel for 12v off grid system need help

[paguliukas]

Hello guys i have im my shed 12v off grid system with mppt solar charger and 370ah lead battery bank.
and i have two solar panels of 37v at the moment i have connected only one with 350w and i have same one just 250w but all characteristics is the same.
but with one solar panel i never fully charge my battery bank i only use for light few hours and 12v car radio thats all for few ours a day but my baterry bank voltage slowly drops down so want to connect second panel as winter coming aswell less sun
and im not sure if my mpt charge will hold the amperage but trick is the sola panels are damaged cracked glass so they dont work 100%l et say 70% percent
any ideas how to connect them and do i need diodes aswell
any help apreciate as im not electrician
i ad pic of my mppt 30AMP
and solar panel

[Logan5]

Stop with the inadequate solar charging. Get a grid powered or generator powered charger on those batteries ASAP! To have 370 AH 12v battery is obviously paralleled and is killing it's self. Add your inadequate solar charging to that and your batteries are already damaged. are you using 6 volt or 12 volt batteries? what's with only having 500 watts to charger a 370 AH battery? I hope you have fuses on this.

[paguliukas]

Its 3bateries each 90ah size conected in paralel i can make smaller bank because i just need for 2 hours of light two lights 50w and car radio so i think im not using a lot of power
No fuses at all

[inetdog]

The part of the CC specifications you list does not mention the input voltage range. A true MPPT CC will list the range of usable DC input voltage from the panels.
For a 12V CC that should be at least 40V if it has a true MPPT input. The maximum safe panel voltage (Voc, not Vmp) should be even higher.
Have you measured to confirm that the output current is greater than the input current from the panel when the battery is accepting full charge?
If you have a fake MPPT CC you are losing almost 2/3 of the potential panel power.

[paguliukas]

This way u can check if its is real mppt il try to check tomorow thanks

[Logan5]

You need fuses, unfortunately the only good way to wire 3 X 12 volt batteries, is in series giving you 36 volts. 36 volts is not a standard battery bank size. 12v, 24v and 48v. You also do not have enough array to charge your 370 AH battery and because you parallel wired them they have become unbalanced by the slow and intermittent, inadequate solar charging. W/o fuses, if you accidentally make a small mistake you could get burned people have lost a finger due to their wedding ring, or worse start an electrical fire. Again get a charger on your batteries before they are boat anchors. I would tell you to do your research before you spend your money on solar and batteries, but you are already past that.

[paguliukas]

Can u explain how to ad fuses the diagram would help
I made my solar system with what i scavenge from people

[littleharbor]

That $12.99 ebay controller isn't mppt regardless what it has printed on it. Broken panels, cut wires???? What do you have invested in this system? How ever much, you have already wasted your money. You get what you pay for and you've payed for a junk controller and broken panels.

[paguliukas]

So far im invested 30pounds my plan to get cheap solar system for my garage lights.those panels are made for 48v system but i connect one panel so i get 37v to my solar charger if is real mppt it should convert extra voltage to amp and send it to 12v battery . My 3 batery bank is balanced because i keep eye on it.it has 0.2v diference
Plus my batery bank never gets fully charged so i dont need to wory about overcharge because of batery imbalance

[Logan5]

batteries that never get fully charged do not last very long.

[paguliukas]

When i have small power bank it vas fine it got fully charged but with 370ah its too much for broken solar panel of 300w to charge whats your advice maybe try to make 90ah power bank?

[paguliukas]

I know guys you think my solar system suck thats true but so far its does the job it provides me with light and music and like this is 1year already.but biggest worry its batteries i want to keep them in good condition

[Mike90250]

A PV with cracked glass, is broken and will only last a few months before it fails. (maybe in a dry desert it would last longer)

[paguliukas]

Still working 1year after and its rainy a lot in uk
Okay can you guys advice on cheap but good mppt charger ? I vas thinking about blue solar ? Because i want to connect 2 panels for my battery bank

[paguliukas]

That ebay crap is crap not mppt for sure

[paguliukas]

What about bluesolar 75/15 mppt

[SunEagle]

What about bluesolar 75/15 mppt

I believe the Victron Bluesolar 75/15 is a true MPPT charge controller.