Hi, 

I have a 1000w ellies trolley inverter (24v) with 2 x 105Ah lead acid batteries (2.5 kWh). I'm finding that the battery is only lasting 1.5 hrs during load shedding with a load of 440w. 

I was expecting the batteries to last at least 4 hrs at this load.

I have a meter on my DB which shows a voltage around 200v and current of less than 2 amps, hence my 440w load estimate.

I assumed the batteries were end of life, but had them tested at a Battery centre and they reported 100% health and 100% charge. 

1) Is it possible that the battery centre test is not good enough? 

2) Any other test I could run on the batteries? 

Thanks

 

 

 

 

 

Are you sure it's your batteries and not a cut off voltage setting within the UPS ?
Perhaps the default cut off is set at a voltage that forces the shutdown?

Maybe check the Battery voltage at the time it shuts down

Edited July 2, 20223 yr by zsde

Thanks I will check that.

Here is a table that gives you a good comparison of SOC vs Voltage.

 

2 hours ago, Aveer said:

Hi, 

I have a 1000w ellies trolley inverter (24v) with 2 x 105Ah lead acid batteries (2.5 kWh). I'm finding that the battery is only lasting 1.5 hrs during load shedding with a load of 440w. 

I was expecting the batteries to last at least 4 hrs at this load.

I have a meter on my DB which shows a voltage around 200v and current of less than 2 amps, hence my 440w load estimate.

I assumed the batteries were end of life, but had them tested at a Battery centre and they reported 100% health and 100% charge. 

1) Is it possible that the battery centre test is not good enough? 

2) Any other test I could run on the batteries? 

Thanks

 

 

 

 

 

The Battery Centre just checks for the current the battery can provide for a short period. Connect a car headlamp bulb to 1 disconnected battery and see if it can produce close to 100Ah. The bulb is normally 55W drawing about 4.8A. This is the standard C/20 test for a lead acid. Again a 100Ah is normally used at about 10A=120W(C/10) to get a good life out of it. Currently your 440W is double the above per battery.

Based on the number of hours of this test you know what capacity the battery might have to use for further calculations.

Edited July 2, 20223 yr by Scorp007

A lead acid battery of 105Ah should not be used to provide more current than 21A, unless its a starter type battery... also, if you are expecting to have a 440W load on a pair of these, you would have, after one hour, discharged the batteries by app. 20% and a wee bit, I'd imagine, this is what I would call your discharge limit, if you expect more than 2 or 3 years out of these, so after 1.5hours you'd have a SOC of less than 70%, which I'd consider low with lead acid type batteries...

 

@zsde I have tested and it seems one battery is bad, as it registered 10.8 V. Thus it seems the battery centre test isnt reliable. Thanks. 

Edited July 4, 20223 yr by Aveer
error in click

On 2022/07/02 at 9:22 PM, Kalahari Meerkat said:

A lead acid battery of 105Ah should not be used to provide more current than 21A, unless its a starter type battery... also, if you are expecting to have a 440W load on a pair of these, you would have, after one hour, discharged the batteries by app. 20% and a wee bit, I'd imagine, this is what I would call your discharge limit, if you expect more than 2 or 3 years out of these, so after 1.5hours you'd have a SOC of less than 70%, which I'd consider low with lead acid type batteries...

 

@Kalahari Meerkat thanks for this info. What do you advise as the maximum load for 2.5 hrs runtime and 4.5 hrs runtime. It does seem like the attached Ellies manual is over-stating what the unit can do, or perhaps not stating that you will kill the batteries if you run it at high load. 

Quick-Reference-Chart-Guide-Ellies-Trolley-Inverters.pdf

With leadacid you should aim to not use more than 25% of the amps if you intend for the batteries to last a long time, and even then the actual loads you put on them should ideally be within the 0.2c range.

Those figure they give on their brochure is actually quite misleading for unsuspecting consumers.
You can run those sorts of loads but the battery gonna get fried in months not years.

7 hours ago, Aveer said:

@Kalahari Meerkat thanks for this info. What do you advise as the maximum load for 2.5 hrs runtime and 4.5 hrs runtime. It does seem like the attached Ellies manual is over-stating what the unit can do, or perhaps not stating that you will kill the batteries if you run it at high load. 

Quick-Reference-Chart-Guide-Ellies-Trolley-Inverters.pdf 845.92 kB · 1 download

The reference guide is correct until battery is totally discharge. Thus their 9hrs for a 100Ah is right.

Yes these times will be up to the point that the inverter cuts out. Consumers demand long run time and it is up to us to know only to discharge to 50%. Around 12V for a single battery.

It is just like lithium that we must find out if a battery is rated 0.5C or 1C.

Good day, 

I have an issue with a 720w UPS trolley system. It's only a month and a half old but already failing to last even an hour during loadshedding. My mistake was plugging a desktop on it. For 2 weeks it worked perfectly but from yesterday it kept on beeping continously within +/- 40 minutes into loadshedding, and reflecting error 4 fault. I charged it overnight to cover 13 hours charging time recommended but plugging it again did the same thing even when the desktop was not on. What could be the problem as I even switched the fuses with the hope it's maybe them? Please help. Thank you... 

Read the thread you just posted in. It’s likely the batteries are kaput

Seems about right:

 

See here: https://erikthiart.com/tools/calculate-battery-runtime-using-watts.php

A good estimate for a lead acid of 100Ah 12V is around 15A=180W. Double for 24V with 2x100Ah batteries. Battery must be recharged after being discharged to 50%(12V) and it can take a good 8hrs or more. This is what we don't have between LS cycles of perhaps 6hrs. The next cycle will be shorter to reach 12V. After a few LS cycles you get say 15min. This is when the battery commits suicide and should be charged to full and a smart charger is needed to get to about 14.4-14.7V. Depending on the type of lead acid. Now it's ready for discharge. 

Just my own estimated figures. 

16 hours ago, Lepulana said:

Good day, 

I have an issue with a 720w UPS trolley system. It's only a month and a half old but already failing to last even an hour during loadshedding. My mistake was plugging a desktop on it. For 2 weeks it worked perfectly but from yesterday it kept on beeping continously within +/- 40 minutes into loadshedding, and reflecting error 4 fault. I charged it overnight to cover 13 hours charging time recommended but plugging it again did the same thing even when the desktop was not on. What could be the problem as I even switched the fuses with the hope it's maybe them? Please help. Thank you... 

Sounds as if the batteries are shot, lead acid batteries are not forgiving and are not designed for big loads.

If you need to run big loads or discharge a battery more, or just want a battery that will last you longer then Lithium is the way to go. Gotta fork out some extra money for the lithium batteries.

 

These trolley inverters do not take into consideration that a lead acid should not be discharged below 50%

The other question is whether the battery was brand new or not? How long was it lasting when you first got it 2 weeks ago?