RCT MP-T2000S battery dropping under load

[tristan135]

I bought a RCT MP-T2000S inverter and all of a sudden after a few months of ownership its acting a little strange. While under battery operation and under no load or a small load the battery shows a high percentage, between 90% and 100%. However, when under a regular load of around 300w it nearly instantly drops to between 15% and 25%. I remove the load and it goes back up to 90/100%. It's obviously been heavy load shedding at the moment, perhaps the battery is just flat but incorrectly shows its full under no load? Maybe a loose battery connection? I'm really not sure what's going on.

Any ideas? Thanks

 

[chrisc]

What type and size of battery please?

 

[Rickster]

You let the batteries go too low in the past, they are cooked...

 

[leon.davibe]

Yea lead acid isn't up to the abuse of shedding, especially how some inverters do the shutdown

None of the cheap inverters do a shutdown on a voltage that would be regarded as 50% soc/dod which is what you should do if you want to get any meaningfull life out of lead acid

The problem is that battery capacity is according to quickmath right for load of about 250w for 4hrs shedding

But in reality not

As peukert loss makes it even less, so using that amount of load almost certainly means discharging more than 50% in 4hrs shedding

And then going under 50% just makes the down hill steeper

ie capacity drops off as it ages and now you have less capacity and 50% of that is even less. Meaning as its aging you are discharging deeper and deeper

Until the batteries are shot

And have very little usable capacity left hence why it dips so quick and then recharges that quick

ie if you have very little usable capacity left it will drain quick and recharge quick

Unforuntaly lead acid isn't meant for load shedding only for seldom used and not that long a stint

imo small lead acid banks is meant for keeping servers up while you start the generator

If you want to use lead acid as a backup you would need a big bank multiple batteries and since you are going into lithium price range it simply makes no sense to buy lead acid

Buying lead acid is throwing money in the water

A person has to go lithium period

The problem with this statement is the budget ,it is what it is such is life

My 2c