Inverter Battery Advice

[Defib]

Greetings folks

I have an Ellies 720w power trolley and it has served me well.

With the abuse Eskom has been throwing at it, the deep cycle OEM battery is now wanting to retire.

I have been told, and my limited knowledge, says a lithium battery is much "better" at the end of the day.

Now, I have read on this forum that it may destroy the inverter. Does anyone have advice or input on this.

After sales support from Ellies is a swear word, and I can assure you, if I walk into Ellies, person A will say it's perfect and person B will say no, so dilemma.

I would appreciate assistance please, thanks.

 

[leon.davibe]

I look at it like this regular battery changes or one inverter change

Though an inverter change isn't needed normally(only edge cases ie with broken fan logic can be remedied with additional fan)

Lifep04 charges at the same voltages as lead acids
So no problem

Not going lifep04 is the real crime imo

 

[AlphaJohn]

I look at it like this regular battery changes or one inverter change

Though an inverter change isn't needed normally(only edge cases ie with broken fan logic can be remedied with additional fan)

Lifep04 charges at the same voltages as lead acids
So no problem

Not going lifep04 is the real crime imo

That is why soo many inverters die cause people belive and spread this lie.

They are similar not the same.


Also, LFP has a higher absorption rate than LA.

If your inverter has adequate cooling you might get away with using an LFP, if it does not have the option to change V settings.

 

[leon.davibe]

That is why soo many inverters die cause people belive and spread this lie.

They are similar not the same.
View attachment 1517789

Also, LFP has a higher absorption rate than LA.

If your inverter has adequate cooling you might get away with using an LFP, if it does not have the option to change V settings.

Yes and that graph only shows half the picture

Sure a lead acid is full at12.8 v but to maintain it for natural losses it is being floated at 13.6v which is nowhere to be seen on the chart

Soc resting and cycle use ain't the same thing

 

[leon.davibe]

And charged at 14.4 v also not on the graph

by that logic of the chart all the devices that currently have lead acid in isn't suitable for lead acid but indeed suitable for lifep04

 

[AlphaJohn]

And charged at 14.4 v also not on the charge by that logic of the chart all the devices that currently have lead acid in isn't suitable for lead acid but indeed suitable for lifep04

That is why I mention the abortion rate, as well.

For example, my Mecer 24V 1440W can park at 28.9V for 6 hours easily (That is 14.45V X 2 for well over 4 hours after my LFP BMS turned of charging.)

Sure way to kill an LFP is to keep charging above 100%. Good BMS will prevent this but it's part of the dangers of using an Inverter not made for the battery.

 

[wingnut771]

Just add a fan and it will be fine.

 

[leon.davibe]

That is why I mention the abortion rate, as well.

For example, my Mecer 24V 1440W can park at 28.9V for 6 hours easily (That is 14.45V X 2 for well over 4 hours after my LFP BMS turned of charging.)

Sure way to kill an LFP is to keep charging above 100%. Good BMS will prevent this but it's part of the dangers of using an Inverter not made for the battery.

The voltage is perfectly in spec ie LFP cell spec sheets recomend charge to 3.65 per cell that is 14.6
and max 3.75v (15v)

But yea agreed it doesn't need to stay at that voltage once full it is nice if the cells can rest and settle at 3.4 (13.6) float

As far as i have it it won't accept charge once full the higher voltage ie above 3.75 can cause damage to cell though

But when the voltage goes over the protection voltage the cells don't see that voltage

ie have done this experiment with a crappy daly bms

Cranking the volts up to over 16v and the cells get disconnected and only the hot side of bms and charger form a loop ie if you measure the voltage on terminals it reads 16v

But the cells go and rest at 13.6v waiting for high voltage recovery voltage to be hit to reconnect the cells to the charging circuit

Edit : yes if the bms ever fails you want the voltage to be in the safe range of the cells

If cells are out of balance that won't save you either the high cells will get damaged

 

[fromyorkshire]

That is why soo many inverters die cause people belive and spread this lie.

They are similar not the same.
View attachment 1517789

Also, LFP has a higher absorption rate than LA.

If your inverter has adequate cooling you might get away with using an LFP, if it does not have the option to change V settings.

Hi thanks for this. I have two Mecer inverters, the 720w and 1440w. I have one of each. I am having issues with two 'new' 12v 100ah gel batteries that I bought (cheaply, big mistake, but I have them now) and how long they are lasting. I am running a very low load and even with just my laptop on screen they are lasting less than 90 minutes. If I add any further load then less than an hour. I have tried these batteries in both 12v parallel and 24v series set up and stand alone. Same issue, the alarm on both inverters soon goes off. I have used the same set up with some much older (1 year) standard lead acids and now another new gel (all the same spec) and they work fine in both inverters. I bought a decent charger, charged them, no impact. I finally removed the batteries and 2 hours later they are still discharging 12.7v. Help?!

 

[wingnut771]

Hi thanks for this. I have two Mecer inverters, the 720w and 1440w. I have one of each. I am having issues with two 'new' 12v 100ah gel batteries that I bought (cheaply, big mistake, but I have them now) and how long they are lasting. I am running a very low load and even with just my laptop on screen they are lasting less than 90 minutes. If I add any further load then less than an hour. I have tried these batteries in both 12v parallel and 24v series set up and stand alone. Same issue, the alarm on both inverters soon goes off. I have used the same set up with some much older (1 year) standard lead acids and now another new gel (all the same spec) and they work fine in both inverters. I bought a decent charger, charged them, no impact. I finally removed the batteries and 2 hours later they are still discharging 12.7v. Help?!

LA (gel/flooded/agm) are like a box of chocolates. You don't know what you get until....

Rule of thumb is to make sure when you receive LA battery that is at 80-100% SOC by measuring with multimeter before accepting delivery. There is a very high chance of DOA with LA because if they sit on shelf for long time below 100% SOC, they get destroyed.

If they are DOA, swap them out for another set pronto...

 

[fromyorkshire]

LA (gel/flooded/agm) are like a box of chocolates. You don't know what you get until....

Rule of thumb is to make sure when you receive LA battery that is at 80-100% SOC by measuring with multimeter before accepting delivery. There is a very high chance of DOA with LA because if they sit on shelf for long time below 100% SOC, they get destroyed.

If they are DOA, swap them out for another set pronto...

Thanks - please see my other reply to your reply - I think I am getting that level of SOC

 

[leon.davibe]

Hi thanks for this. I have two Mecer inverters, the 720w and 1440w. I have one of each. I am having issues with two 'new' 12v 100ah gel batteries that I bought (cheaply, big mistake, but I have them now) and how long they are lasting. I am running a very low load and even with just my laptop on screen they are lasting less than 90 minutes. If I add any further load then less than an hour. I have tried these batteries in both 12v parallel and 24v series set up and stand alone. Same issue, the alarm on both inverters soon goes off. I have used the same set up with some much older (1 year) standard lead acids and now another new gel (all the same spec) and they work fine in both inverters. I bought a decent charger, charged them, no impact. I finally removed the batteries and 2 hours later they are still discharging 12.7v. Help?!

1lead acid is 12.8v if full

13.6v is just what the charger floats them at to compensate for natural self discharge

ie if the voltage drops from 13.6 down to 12.8 they aren't discharging they are simply coming down to resting voltage
And if the battery hasn't fully absorbed it may go lower than 12.8 to indicate the actual SOC

Now naturally if you leave them overnight and come back to lower voltage ie if it never comes to a resting voltage or 10v you have dead cells then yes they are discharging because of dead cell

If the voltage is 13.? While charging

Doesn't mean they are full ie if the charger trying tho charge the battery the voltage is always a bit higher than the batteries actual voltage to create a potential difference so that the power will flow into the battery

That is why the charger pushes past that voltage ie to 14.? To make sure it absorbed power until it is full and then settles to the float to sustain/prevent natural losses ie to have battery allways full

Now yes you could have gotten a dud like wingnut says if that is the case it is better to return asap otherwise they claim you damaged the battery via misuse

Though lately many sellers make it clear lead acid carries no warrantee (loadshedding not being lead acid friendly)