Cannot charge after Smartlithium battery got deeply discharged

Q&A and troubleshooting
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1

I use a MultiPlus Compact with a 330ah smart lithium battery in a camper van. The battery got deeply discharged recently. The low voltage warning popped up, and the Victron Connect app shows that discharge has been disabled.

So I plugged in shore power. But the battery doesn’t start charging. However, when I connect a blue smart charger directly to the battery. The charger shows that it is charging. This seems to indicate that the battery itself is functioning.

I would like to know why charging didn’t start with the MuiltiPlus when I plug in to AC power source after a “deep” discharge.

Thank you.

2

Do you have fuses between the inverter and battery?

Is this the inverter itself? Or the battery? Is it a victron battery? What is controlling the inverter - (BMS to inverter connection?)

3

Do you have fuses between the inverter and battery?

There is one. I confirmed that the fuse is intact.

Is this the inverter itself? Or the battery? Is it a victron battery?

It is a Victron Smart Lithium battery. The low voltage warning is from the battery. It also says “discharging disabled” on Victron Connect app.

I have a network cable between BMS and the inverter. So I think that the inverter is controlled by BMS.

4

What bms do you have exactly on the battery? Victron have a few options

5

What BMS.
Do you have the “mains detector” fitted to the multi compact?

6

I have VE.Bus BMS V2.

7

I don’t know what “mains detector” is. But if this is a separate piece of device, I doubt that I have it.

8

I also want to add that this system has been working as expected prior to the battery deep discharge.

9

Yes. We understand that.
Basically the system ended up in a locked out condition.

It is off. There is no way for it to know you switched on mains power.

You need the mains detector as mentioned by water_rat

A mains detector and a short RJ45 UTP cable ship together with the VE.Bus BMS V2. These are needed for mains detection once the inverter/charger has been turned off by the BMS.

10

The mains detector is required if you have a metal cased multi compact.

If you have the newer multi compact apparently the mains detector is not required.

11

From the BMS V2 manual. This happened with my test bench system.
“Q2: The batteries are empty, and the inverter/charger will not start to charge; how to get the system up and running again?
Connect a small battery charger, for example, a 5A charger, and wait for the battery voltage to get back up to 12, 24 or 48V (depending on the system voltage).”

1 Like
12

My guess would be that the BMS went into protection mode.
This disconnects the battery cells from the terminals (via the BMS board), so that the cells can’t discharge any further, but it keeps the BMS powered.
Once the BMS sees a charging voltage (for a 48v LiFePO4, that would be about 53v) it will come out of protection mode and start charging, but won’t allow discharging. Once it gets up to about 10% or so depending on the parameters set in the BMS, the discharge FETs will come on and both charging and discharging are allowed.

My guess on the MP would be that it didn’t think a battery was present.
The smart chargers, and the MPPT controllers, don’t wait to confirm there is a battery present, so they are the perfect tool to bring a battery out of protection mode.

AIO units like the Growatt have particular problems coming out of protection mode - they won’t charge a battery in LI mode (ie a battery with a comms interface) until comms comes up, but comms wont come up until the battery sees a charging voltage, so you are in a pickle. In that case, you change setting #5 to US2 (the mode for dumb LiFePO4) and usually the growatt will pulse the battery to ‘test’ for the presence of a battery, eventually bringing it out of protection mode.

If you have some software or app to talk to the battery via cable or bluetooth, you will be able to see if this was the case - it would have logged the alarm state, hopefully with an accurate timestamp.

RP>

13

RP. The above reply addresses this issue for most lithium batteries but is not correct for Victron Smart Lithium as they have a very different set up to normal batteries, i.e. no on board BMS. You need to know these batteries and which BMS is connected to them to trouble shoot.

14

Thank you, guys. As a few have pointed out:

  1. I should have installed main detector to prevent situation like this.
  2. Without main detector, using a separate method to charge the battery will get out of this state.
15

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