Renogy system fail? is it the battery?

[Samu]

Hi,

I currently have a Renogy system in my campervan. It is a:

- 200ah Lifepo4 12v Renogy battery
- A Renogy 30A DCDC/MPPT combo
- A Renogy 2000W inverter/charger

and 200 watts of solar on the roof.

Up until now everything worked fine. I had my settings to 'lithium' and the battery charged trough solar, driving and sometimes the inverter/charger.

At the moment the battery only charges several amps (1 or 2 amps if I'm lucky) from solar and/or driving. A trip of 500 miles in nice weather didn't charge the battery. Instead the battery drained from the trip (because of the fridge running). When I plug in the charger/inverter nothing works.

Is there something wrong with the battery? Seems impossible that the charger/inverter and MPPT/DCDC broke at the same time.

The cells of the battery are slightly imbalanced at 3,2 - 3,3 - 3,3 - 3,2 volts.

What is the problem here?

 

[BentleyJ]

What is the battery voltage with all charging sources turned off? With only 2 significant figures reported for individual cell voltages its impossible to determine if the imbalance is 50mV or 150mV. That said, its possible the BMS has shut down on HVCO.

 

[fratermus]

At the moment the battery only charges several amps (1 or 2 amps if I'm lucky) from solar and/or driving

It would look like this if the BMS turned off charging and the charging sources were powering small loads.

 

[Samu]

What is the battery voltage with all charging sources turned off? With only 2 significant figures reported for individual cell voltages its impossible to determine if the imbalance is 50mV or 150mV. That said, its possible the BMS has shut down on HVCO.

12.9 volts. What is HVCO?

 

[BentleyJ]

12.9 volts. What is HVCO?

High voltage cut out

 

[Samu]

Does anyone know what might be wrong?

 

[Sojourner1]

Have you checked ALL connections? Checked ALL fuses and if you have trip breakers be sure they're fully on, trip them off then on. Look at wiring to be sure nothing has rubbed through with traveling.

I would figure out why the inverter/ charger isn't working and go from there. At anytime prior you had no shutdowns, accidental overloads or any other hickups in the system you're not mentioning or remembering?

 

[justinm001]

Does anyone know what might be wrong?

What's wrong, you bought renogy and are relying on them. Pick up a SOK battery from CC and you'll be a lot happier.

200w of solar is only 8a max so the couple amps charging sounds about right after loads. Does your controller show how many watts its making? Do you have a shunt that's showing if the batteries are getting/pulling loads?

Pickup a cheap 120v to 12v charger with lfp profile and keep it as a backup. Use this to charge the batteries and see if it'll work.

My bet is your inverter isn't setup properly and not charging.

If youre dead set on not buying anything disconnect all loads plug one battery into the inverter and other into the mppt see what happens. Now you have 2 isolated systems with 2 separate charging devices so if 1 charges and other doesn't then swap the batteries and see if you get the same result. This way you can't test each device separately and find the device or devices that are having issues.

 

[HarryN]

If the battery is reading 12.9 volts, then there is a good chance that the BMS has tripped and what you are reading is actually just leakage.

The most likely cause of the trip is that a battery like that is not capable of delivering enough current to run the inverter at the load that was on it. If you are going over 100 amps discharge for very long this is very possible.

Anyway, on battle borns, you can re-set the built in BMS by disconnecting the battery from ALL other sources of power. I am not sure if that works for renogy or not but it is a common way to do a BMS reset.

For this reason, I put a breaker on each parallel battery string ( in your case one battery ) so that it can be isolated from the rest of the power system and re-set easily.

There is one other aspect that is possible - those units have fairly high standby power - but I would work on the BMS aspect first.

 

[mikefitz]

anyone know what might be wrong?

Renogy products?

You say you up till now, if it worked OK before what has changed?

Some Renogy batteries are being shipped with out of balance cells. This causes the BMS to shutdown the charge path. Renogy batteries will also 'go to sleep' if they see no current flow in/out. The Renogy battery may simply be faulty.

Try lowering your charge voltages, down to 13.8 if necessary.

However your comment that it has worked well up to now suggests a failure, or changes to the system.

Mike

 

[Tomthumb62]

I have the Renogy Rover 30A charge controller. Similar to yours without the DCDC charger.

I believe it’s got a design problem. The default setting for High Voltage Cutoff is 17.0V. This will trigger (hopefully) the BMS to cut off charging.

See my post here for more details:

Post in thread 'Renogy 40a mppt Li settings'
https://diysolarforum.com/threads/renogy-40a-mppt-li-settings.46856/post-856546

EDIT: note that the BMS should be a last ditch effort to protect the battery cells. And hammering a BMS with over voltage can cause the charging fets to get stuck open or closed, destroying their ability to protect anymore. Which at that point, you’ll need to tear the battery apart and replace the BMS. Some batteries are designed to easily replace the BMS but most are not.

 

[Sojourner1]

Maybe the OP will come back and update us.?