Renogy Batteries got too low now will not charge

[Gravity2424]

I’ve been living in the van for about a year very few solar troubles and I’ve never had issues with power reserve even when it’s rainy or cloudy for several days straight. Recently I had been parking in the shade for a few days using the inverter way too much to charge devices and ran into low voltage and my controller shut off the system. Now I can’t get the battery to charge up above 40%. I’ve been turning the load off on my controller so there’s not even ambient charge getting wasted to try and get my batteries up to 100% because obviously I don’t want them just sitting at such a low percentage to avoid further damage. That was my plan the last two days but it just doesn’t seem like it’s charging at all despite the controller telling me it is receiving from the PV. Is this what happens when batteries are too badly damaged that it just won’t charge above 40% or is there something wrong with the connection between the solar panels and my battery/ controller? Here are the readings from my controller. It’s not super sunny at the time of this post and when the pictures were taken so the charging current does reach higher but I’m not too proud to admit that I have no idea what’s going on.

 

[Bob B]

I have seen a few posts lately about this type of problem with a Renogy system .... Do you have Renogy batteries as well? I don't have Renogy stuff so am not very knowledgeable about them.

Once the Renogy batteries get low they need some sort of jump start to get them operating again.

.... Maybe us the search feature on the forum to search for Renogy batteries not charging and edit the title of your thread to indicate Renogy battery charge problems to attract people knowledgeable about your specific system.

 

[mikefitz]

Details needed.
Panels, power, how connected, how many?
Batteries, type , amp hours, battery volts?
What loads?
How in the solar controler configured?
How are you measuring SOC?
Take some voltage measurements to help diagnose , example , measure volts at controller output terminals and at battery terminals when under charge.

 

[Gravity2424]

Edit: Meant to post this as a reply

 

[Gravity2424]

I have seen a few posts lately about this type of problem with a Renogy system .... Do you have Renogy batteries as well? I don't have Renogy stuff so am not very knowledgeable about them.

Once the Renogy batteries get low they need some sort of jump start to get them operating again.

.... Maybe us the search feature on the forum to search for Renogy batteries not charging and edit the title of your thread to indicate Renogy battery charge problems to attract people knowledgeable about your specific system.

Yes they are renogy batteries I will look through some other forums thank you.

 

[Gravity2424]

Could this all be as simple as buying a battery charger and hooking it up to my battery? Any safety precautions if this is the route? How long would I expect to leave it on?

 

[Gravity2424]

430 watts of panels, 3 panels, connected to the controller
2 200 AH 12v batteries in parallel
I don’t know what how the controller is configured means
The SOC is shown on my controller monitor as well and reads 44%
I have a multimeter but not sure where to measure what you’re talking about. Sorry I’m not much of a help

 

[12vDC]

Could this all be as simple as buying a battery charger and hooking it up to my battery? Any safety precautions if this is the route? How long would I expect to leave it on?

That will work. I believe either a DC-DC charger or a robust AC-DC charger will provide the necessary voltage to wake up the battery BMS.
I tried a couple times using one of those little lithium capable chargers with no luck however, my onboard inverter/charger would always work plugged into shorepower.

The duration would depend on the amount of current being fed to your batteries, 100A would mathematically take 4hours to charge your system when fully discharged. My inverter is capable of over 100A charging but I would only do 75A on my 200Ah bank.

 

[Gravity2424]

That will work. I believe either a DC-DC charger or a robust AC-DC charger will provide the necessary voltage to wake up the battery BMS.
I tried a couple times using one of those little lithium capable chargers with no luck however, my onboard inverter/charger would always work plugged into shorepower.

The duration would depend on the amount of current being fed to your batteries, 100A would mathematically take 4hours to charge your system when fully discharged. My inverter is capable of over 100A charging but I would only do 75A on my 200Ah bank.

So should I leave the inverter and controller all still connected to the battery while I do this or should I detach everything to charge and reattach after? I’m also not sure if being plugged into shore power charges my batteries or not. Everything works in the van the controller just shuts itself off from low voltage if I try to run anything after a few hours.

 

[Supervstech]

Ok my math saus 400Ah is 5120Wh.
At 430W array, figure this time of year, you are only getting 210W from it, and only around 3 hours a day...
So it will take 8 days with zero loads for the solar to recover the energy lost.
If you can get a 1000W battery charger, you could shorten that to 5 hours... give or take.

 

[Gravity2424]

Ok my math saus 400Ah is 5120Wh.
At 430W array, figure this time of year, you are only getting 210W from it, and only around 3 hours a day...
So it will take 8 days with zero loads for the solar to recover the energy lost.
If you can get a 1000W battery charger, you could shorten that to 5 hours... give or take.

 

[Rocketman]

After you get the issue resolved consider adding a Dc-Dc charger to your system- (research item: make sure it can/will wake up an a sleepy battery). Then to wake up in the future you just start the van for a few minutes.

Good Luck with the problem

 

[12vDC]

So should I leave the inverter and controller all still connected to the battery while I do this or should I detach everything to charge and reattach after? I’m also not sure if being plugged into shore power charges my batteries or not. Everything works in the van the controller just shuts itself off from low voltage if I try to run anything after a few hours.

In my case, my inverter is also a DC charger. Im thinking yours is not.

To charge from an AC-DC charger you need only make a connection to your battery bank. No need to disconnect anything in a properly wired system.

As stated above, your power use seems to be exceeding the current available means to sufficiently recharge the bank.

You should not rely soley on the SOC readout. It is highly possible for the status to stray farther and farther than actual if/when not achieving a full charge. And also with a paralleled battery bank there are opportunities for the system to underperform.

 

[Rocketman]

If you don’t have a shunt based battery monitor get one - like Victron Smartshunt or BMV712. They are much more accurate than the battery based ones.