Testing UV/OV locks

[Dave Festing]

Hi Dacian,

If I ever get a LVD on the main inverter I will shed non-critical loads and transfer to a small inverter.  I have set this up so that it will disabled when UV lock occurs.

Could you suggest how to test this?

Could I raise the UV lock limit above the LVD and then up to just above  the lowest cell voltage?  Or will I have to raise LVD above the lowest cell, generate an LVD and then raise the UV lock up enough that the small inverter shuts-down?

Thanks,

Dave

[Will OBrien]

If you just want to function test, the manual discusses how to set the outputs to verify that your connections are working.

It's really just a simple mode change that's trivial to perform.

On my rig, I came up with a list of tests and worked my way through them, including a discharge/charge test for various states.

[Dacian Todea]

Dave,

All you need to do is set the EXT IOx controlling that inverter to type 0 and the inverter should turn OFF this will show that remote ON/OFF works correctly then if you want the inverter to work up to UV lock or OV lock then set it as type 6 but not sure why you will want that.

There will be probably just a few extra minutes between the normal UV set default at 2.8V and the UV lock set at 2.5V so I do not see what will be gained from this. There is really no energy left between 2.8V (UV) and 2.5V (UV lock)

Maybe there is an extra 2% SOC at best so even with a small inverter and basically no load on that inverter that will not last long.

Best will be to set the large inverter as type 4 and set say a 30% SOC limit and have the small inverter set as type 2 so it will turn OFF at UV that way at UV all loads will be turned OFF and battery can survive until next day when sun can recharge the battery. If you discharge to UV lock 2.5V there is a risk that until charge source is available maybe a few hours the battery will self discharge to much and no longer accept a charge getting damaged.

On Monday, June 7, 2021 at 1:30:57 AM UTC-6 Dave Festing wrote:

[Dave Festing]

Thanks guys for your comments.  I hadn't realised how little difference there was between UV and UV lock.  I was going to change UV up to a higher voltage, but your suggestion of using SOC for the BIG inverter and leaving UV for the small inverter is the way to go.