Hi guys. After a bit of consideration, I've gone ahead and bought 2 Revov 12v drop in replacements for my Mecer 1440w/2.4kva/24v inverter, as replacements for the LA batteries currently in there. Geewiz is selling them as a trolley kit in this exact makeup, so I figured I'd give it a shot. If it doesn't work as I expect it to, I'll have to change the inverter. But if it does, I can use the inverter for as long as it suits the purpose.

I've bought a HB11 battery balancer as well as Geewiz have specified that a battery balancer must be used with these batteries. My batteries are currently in individual plastic battery boxes, with the cabling coming out of each battery box, and then connecting the 2 with an Anderson plug, and then going into the inverter input. 

My question is, can I lengthen the cables from the battery balancer to reach the 2 batteries without any issues ? There are 3 of them, positive (red), negative (black) and the balancing cable (white). I will replace all 3 cables with new ring terminals on the ends to go onto the battery terminals. The other end is a standard green 3 cable plug that goes into the balancer.

I've also read that it's advisable to change the inverter charging setting to 10A instead of 20A for LifePo replacements as it's safer for these batteries. Any input on that? That's the only configurable setting on this inverter, there is no setting to change the battery type or anything else. 

 

Thanks in advance guys. 

Edited December 13, 20222 yr by SudhirM
Adding pic

Update on this, I went ahead and lengthened the cables on the balancer and installed the batteries last week. Working perfectly thus far. 
 

I have dropped the charge setting down to 10A as recommended by Geewiz and the batteries seem to recharge within a few hours between LoadShedding sessions on stage 5/6. 
 

Quite happy thus far. 
 

Next thing I want to possibly look at is an external MPPT Solar charge controller and maybe a panel or 2 to help charge the batteries. Need to do a bit of research into that. If anyone has done this, please advise. 

7 hours ago, SudhirM said:

Update on this, I went ahead and lengthened the cables on the balancer and installed the batteries last week. Working perfectly thus far. 
 

I have dropped the charge setting down to 10A as recommended by Geewiz and the batteries seem to recharge within a few hours between LoadShedding sessions on stage 5/6. 
 

Quite happy thus far. 
 

Next thing I want to possibly look at is an external MPPT Solar charge controller and maybe a panel or 2 to help charge the batteries. Need to do a bit of research into that. If anyone has done this, please advise. 

I have a Epever external MPPT that can charge 12/24V @ 20A and it does have every setting you can wish for but for lithium settings must be done via a PC. Works very well. 

On 2022/12/13 at 5:57 PM, SudhirM said:

10A instead of 20A for LifePo replacements

the Lithiums would be happy with higher charge/discharge currents than is advisable for SLA's or other lead acids. Thus charging at 20A should be more than fine, if they are 100Ah, then probably even charging at 50A should be ok, but check with Revov what they say...

6 hours ago, Kalahari Meerkat said:

the Lithiums would be happy with higher charge/discharge currents than is advisable for SLA's or other lead acids. Thus charging at 20A should be more than fine, if they are 100Ah, then probably even charging at 50A should be ok, but check with Revov what they say...

From what Geewiz said and what I have read elsewhere about the Mecer inverter, they aren’t designed for Lithium batteries and don’t stop charging once the batteries are fully charged. That’s why they recommend changing it to 10A. It’s to protect the inverter not the batteries.  
 

it’s been working fine thus far. 

6 hours ago, Kalahari Meerkat said:

the Lithiums would be happy with higher charge/discharge currents than is advisable for SLA's or other lead acids. Thus charging at 20A should be more than fine, if they are 100Ah, then probably even charging at 50A should be ok, but check with Revov what they say...

 

There is actually a known issue with these Mecer inverters specifically regarding Lithium batteries.

 

 

I'll summarize what I read on the MyBroadband forum:

 

The Mecer inverter often does not switch on its fan when charging a Lithium battery.

On the 10A charge setting, this isn't a big problem since the heat generated inside the inverter is within acceptable bounds.

However, on the 20A charge setting, there is substantially more heat, and if your inverter's fan does not kick in, it is highly probable that your inverter will suffer damage.

 

The common consensus is to leave your Mecer inverter on 10A if you are using a Lithium battery.

Some people have played with the idea of adding a 12V fan to keep their inverter cool when using 20A charging, but I have not seen any success stories/updates from them yet.

 

 

 

 

41 minutes ago, SudhirM said:

From what Geewiz said and what I have read elsewhere about the Mecer inverter, they aren’t designed for Lithium batteries and don’t stop charging once the batteries are fully charged. That’s why they recommend changing it to 10A. It’s to protect the inverter not the batteries.  

The BMS would control on whether the battery would still accept a charge or not, if the cells are not full they would, else they would not, the inverter can't shove current into the battery unless the battery is not yet fully charged, so Geewiz seem to have very little idea about what is going on in this regard. But maybe the inverter is the problem, if you cannot set the Bulk charge Voltage as well as the float Voltage on the inverter, then yes, you probably even at 10A charge you will do damage to the battery, not knowing the inverter I can't say for certain, one thing is certain, a 100Ah Lithium battery can usually be charged at half capacity, 50A, although some will want to limit that to 1/3 or 33A. A SLA or or lead acid types are usually specced at 10% of capacity thus 10A for a 100Ah battery with a maximum of 20A charge current.

You should maybe clarify with Geewiz what the issue is, the lack of Voltage settings on the inverter, in which case a bad inverter to have or is there something else that I am not thinking of?

10 minutes ago, Kalahari Meerkat said:

The BMS would control on whether the battery would still accept a charge or not, if the cells are not full they would, else they would not, the inverter can't shove current into the battery unless the battery is not yet fully charged, so Geewiz seem to have very little idea about what is going on in this regard. But maybe the inverter is the problem, if you cannot set the Bulk charge Voltage as well as the float Voltage on the inverter, then yes, you probably even at 10A charge you will do damage to the battery, not knowing the inverter I can't say for certain, one thing is certain, a 100Ah Lithium battery can usually be charged at half capacity, 50A, although some will want to limit that to 1/3 or 33A. A SLA or or lead acid types are usually specced at 10% of capacity thus 10A for a 100Ah battery with a maximum of 20A charge current.

You should maybe clarify with Geewiz what the issue is, the lack of Voltage settings on the inverter, in which case a bad inverter to have or is there something else that I am not thinking of?

The inverter is a very basic inverter. The only thing that’s configurable is the charging current. 10A or 20A - that’s literally all. 
 

 

1 hour ago, Dr V said:

 

There is actually a known issue with these Mecer inverters specifically regarding Lithium batteries.

 

 

I'll summarize what I read on the MyBroadband forum:

 

The Mecer inverter often does not switch on its fan when charging a Lithium battery.

On the 10A charge setting, this isn't a big problem since the heat generated inside the inverter is within acceptable bounds.

However, on the 20A charge setting, there is substantially more heat, and if your inverter's fan does not kick in, it is highly probable that your inverter will suffer damage.

 

The common consensus is to leave your Mecer inverter on 10A if you are using a Lithium battery.

Some people have played with the idea of adding a 12V fan to keep their inverter cool when using 20A charging, but I have not seen any success stories/updates from them yet.

 

 

 

 

Thank you for this explanation. Geewiz was a bit vague. 

3 hours ago, SudhirM said:

From what Geewiz said and what I have read elsewhere about the Mecer inverter, they aren’t designed for Lithium batteries and don’t stop charging once the batteries are fully charged. That’s why they recommend changing it to 10A. It’s to protect the inverter not the batteries.  
 

it’s been working fine thus far. 

As per some other replies when the lithium is full it can't keep on being charged. 

Further AFAIK and seen in specs the lithium has a higher charge voltage for bulk and float than the inverter supplies. This means the lithium might not get to 100% which is also a good thing. Further you still gave the BMS to protect if ever the charge voltage is too high. 

I don't see the problems other members see-at least not yet. 

On 2022/12/13 at 5:57 PM, SudhirM said:

I've gone ahead and bought 2 Revov 12v drop in replacements for my Mecer 1440w/2.4kva/24v inverter

From the datasheet, the Float charge voltage for this inverter is 27.4V +-2%

In the extreme case of +2%

• Float voltage per cell is calculated as 3.493V 
• For LifePo4 this is fine for Bulk or Boost  but definitely too high for Float voltage
• Many recommendations state that float voltage per cell should be +-3.375V or then for 24V system 27V

In the conservative case of -2%

• Float voltage per cell is calculated as 3.357V
• This should be fine

Best will be to measure the charge voltage on the batteries after a full charge to ensure your specific inverter is not float charging at too high voltage. Floating at too high voltage will in the long run shorten the LifePo4 battery life.
If someone has one of these inverters which is out of warranty or willing to sacrifice the warranty, it might be worthwhile to check and see if the there is some way of adjusting the float charge voltage lower in the case where it is too high.
 

There are mecer inverters now with a lithium setting and a small mppt. 

Have you considered selling this inverter and looking at a newer mecer

On 2022/12/24 at 11:48 AM, DeonBez said:

From the datasheet, the Float charge voltage for this inverter is 27.4V +-2%

In the extreme case of +2%

• Float voltage per cell is calculated as 3.493V 
• For LifePo4 this is fine for Bulk or Boost  but definitely too high for Float voltage
• Many recommendations state that float voltage per cell should be +-3.375V or then for 24V system 27V

In the conservative case of -2%

• Float voltage per cell is calculated as 3.357V
• This should be fine

Best will be to measure the charge voltage on the batteries after a full charge to ensure your specific inverter is not float charging at too high voltage. Floating at too high voltage will in the long run shorten the LifePo4 battery life.
If someone has one of these inverters which is out of warranty or willing to sacrifice the warranty, it might be worthwhile to check and see if the there is some way of adjusting the float charge voltage lower in the case where it is too high.
 

What is the point of stating all these settings when the manufacturer provides different settings for charging. 

I'm not saying to use these batteries on a Mecer. Some other members are using some 12V drop inn's on this inverter. 

I have the Mecer 200Ah and Hubble S-100 and they are great. 

1 hour ago, Scorp007 said:

What is the point of stating all these settings when the manufacturer provides different settings for charging

It was stated to point out that although many 12V LifePo4 is marketed as lead acid drop-in replacements, it might actually be damaged in the long run without the user knowing it if the inverter settings are fixed like for some of these small Mecer modified sinewave inverters. 

On inverters where the settings can be adjusted to the values required by the 12V  battery, it will work as expected and last longer if charging is set correctly.

Users would expect a lead acid drop-in replacement battery to be able to charge from 12.5V to 14.8V without sacrificing any lifetime. The internal BMS of the battery should be designed to cater for this. 

2 hours ago, Chris_S said:

There are mecer inverters now with a lithium setting and a small mppt. 

Have you considered selling this inverter and looking at a newer mecer

The batteries have been installed and in use for about 3 weeks now and they seem to be working fine. They’re charging at the 10A rate, and from the Bluetooth monitoring that I can see, are charging to full capacity and then switching off the charger. 
 

For now it seems like they’re working as expected. 

4 minutes ago, SudhirM said:

For now it seems like they’re working as expected. 

Glad for you 😀

As a matter of interest, what is the maximum/minimum cell voltages after charging? 

22 minutes ago, DeonBez said:

Glad for you 😀

As a matter of interest, what is the maximum/minimum cell voltages after charging?