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Little Help Required


Richyv
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Morning Guys.

 

iv had my UPS System installed for about 15 months now and this morning we woke up with no power. apparently the power went off around 2am and by 6 we were offline.

my system consists of 1x 5k axpert inverter with 8x royal 1150 batteries in 2x 48v strings. I started investigating and checked the voltage on each battery first. the 1st string was all good at around 12.7/12.8 on each battery. the issue lies with the second string 3 of the 4 batteries were 13.2 and the other was at 10v. They were all purchased at the same time. iv bypassed the second string now and taken the 10v battery out and charging with another charger.

what should i do from here? is it just a matter of them not being balanced correctly?

your input would be appreciated 

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Obviously one battery has failed. Depending on how often you have dipped into your battery bank you may be nearing  the batteries EOL (end of life). All batteries have small variations in them due to the manufacturing process. These variations become bigger over time and lead ultimately to premature failure of one or more batteries. Vented LA (lead acid) batteries have an advantage in that a short period of overcharge (equalisation) reduces this variation and prolongs battery life. This come at the cost of some electrolyte which is easy to top up and is in fact part of regular battery maintenance.  VRLA (valve regulated lead acid) batteries have no way of being topped up and equalisation should be used sparingly. 

A method of prolonging VRLA batteries life is to keep them in balance using either a battery balancer or a device like a Zener balancer.

Here is a video that an Aussie mate made for me a while ago as I as starting my solar journey so I could understand the issues involved.

If you evaluate you other batteries and they seem OK I would buy one replacement

 

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It bothers me a little that the second string has open circuit voltages of 13.2V compared to the first string's 12.8V.

The trouble with parallel strings is always that current takes the shortest path. So one string is always overcharged slightly while the other might not get sufficient charge. And this always ages both strings and there is always one battery that checks out first.

But in a UPS, where the batteries are usually floated most of the time and kept well charged, it's usually not so bad.

Also, without an idea of the loads we don't know if this is normal. It might be completely normal for the whole bank to run out after 4 hours, and despite those other batteries measuring so handsomely, they might be very close to empty too.

So truth is I'm not really sure where you are. Maybe you're okay and recharging that battery will put some life back into it. That's the first thing to do I think, since it costs the least.

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21 minutes ago, Chris Hobson said:

Obviously one battery has failed. Depending on how often you have dipped into your battery bank you may be nearing  the batteries EOL (end of life). All batteries have small variations in them due to the manufacturing process. These variations become bigger over time and lead ultimately to premature failure of one or more batteries. Vented LA (lead acid) batteries have an advantage in that a short period of overcharge (equalisation) reduces this variation and prolongs battery life. This come at the cost of some electrolyte which is easy to top up and is in fact part of regular battery maintenance.  VRLA (valve regulated lead acid) batteries have no way of being topped up and equalisation should be used sparingly. 

A method of prolonging VRLA batteries life is to keep them in balance using either a battery balancer or a device like a Zener balancer.

Here is a video that an Aussie mate made for me a while ago as I as starting my solar journey so I could understand the issues involved.

If you evaluate you other batteries and they seem OK I would buy one replacement

 

Have used the System maybe 20 times for short periods maybe an hour or 2. the normal load is around 300 watt max so the batteries shouldnt be dead just yet

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7 minutes ago, DeepBass9 said:

If you have links between the strings at each battery, and a balancer, then you shouldn't get that problem, as per the HA02 diagram :

HA-02 e.JPG

I dont have any balancer or anything like that. what would i need and where can i get it?

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Hi Richyv just something very simple . Is the battery banks  correctly connected . Did help a friend with the same setup where the wrong wire size ( 6 mm ) and different wire lengths on battery banks was used . The battery's will never balance or last . Good example of connectsion on Power Forum of battery bank section .

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23 minutes ago, Chris Louw said:

Hi Richyv just something very simple . Is the battery banks  correctly connected . Did help a friend with the same setup where the wrong wire size ( 6 mm ) and different wire lengths on battery banks was used . The battery's will never balance or last . Good example of connectsion on Power Forum of battery bank section .

all interconnects in strings are same length using 35mm cable. is that cable ok?

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8 hours ago, Richyv said:

... the issue lies with the second string 3 of the 4 batteries were 13.2 and the other was at 10v ...

Order the balancers so long. Good investment.

I would load test each battery. That one battery at 10v is deader than dead, done, dusted and it could be causing problems for the rest.

It could also be shorting internally.

How to find that: When under load, go and touch the poles and see if that battery, and the others, are getting hot. Go on, you know you want to.

If they are hot, STOP and remove that battery immediately. It can explode if it gets too hot.

Surest and safest way is to load test each battery. Royals are Leisure batteries, 105ah each. Load test each one individually @ 300amps draw for between 5-15 seconds.

See if they stay in the green. If they drop down into the red, sell if for the going lead price.
If they stay in the high green, you are ok.
Borderline on red/green ... the end is near. :-)

 

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I love the idea of placing a cheap digital volt meter on each battery permanently

I call it a early warning system

you can soon see  a problem battery  

quick  question    does your positive to the inverter come from the top string and your negative from the bottom string

cheers

 

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On 2018/08/07 at 6:26 PM, The Terrible Triplett said:

Order the balancers so long. Good investment.

I would load test each battery. That one battery at 10v is deader than dead, done, dusted and it could be causing problems for the rest.

It could also be shorting internally.

How to find that: When under load, go and touch the poles and see if that battery, and the others, are getting hot. Go on, you know you want to.

If they are hot, STOP and remove that battery immediately. It can explode if it gets too hot.

Surest and safest way is to load test each battery. Royals are Leisure batteries, 105ah each. Load test each one individually @ 300amps draw for between 5-15 seconds.

See if they stay in the green. If they drop down into the red, sell if for the going lead price.
If they stay in the high green, you are ok.
Borderline on red/green ... the end is near. :-)

 

That battery is definitely dead as it wont charge over 11.5 volt. id like to test the other 3 in the string ,How would i load test them @ 300 amps? 

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On 2018/08/07 at 11:15 PM, maxomill said:

I love the idea of placing a cheap digital volt meter on each battery permanently

I call it a early warning system

you can soon see  a problem battery  

quick  question    does your positive to the inverter come from the top string and your negative from the bottom string

cheers

 

NO, the positive and negative from inverter run to the first string and then a loop to the second.

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28 minutes ago, Richyv said:

How would i load test them @ 300 amps? 

Take them to a car battery shop, they have the testers. Or ask them if you can borrow one.

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  • 5 months later...

So i have decided to replace the batteries. i had them tested and 4 failed. the 4 im currenly using are not giving me enough to last thru load shedding. im looking at 2 options- 1. nerada LFeLI-4 8100C 2. 2X pylontech US2000b. does anyone have any experience with these units?

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11 minutes ago, Richyv said:

nerada LFeLI-4 8100C 2. 2X pylontech US2000b

Go for Pylontech ... Narada's are very good UPS batteries, not as good as Pylontech for solar.

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38 minutes ago, Richyv said:

nerada LFeLI-4 8100C

This one? Just checking... normally "Narada" means sealed lead acid UPS... also assuming you made a spelling mistake of course, in which case TTT is right... apples and oranges, go for the Pylons. But if it is a Leoch..., well then the call isn't that easy.

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55 minutes ago, plonkster said:

This one? Just checking... normally "Narada" means sealed lead acid UPS... also assuming you made a spelling mistake of course, in which case TTT is right... apples and oranges, go for the Pylons. But if it is a Leoch..., well then the call isn't that easy.

No this one https://batterydistributors.co.za/product/narada-48npfc100-23/ 

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And reconsider the way in which the batteries are connected to the inverter. Have a look at this write up about ensuring the cable distances are precisely the same length always.  The same reference is found in the download section on this forum I think or in one of the threads dealing with the basics of power and electricity.

http://www.smartgauge.co.uk/batt_con.html

Or, scan this forum for more about battery balancing. There is plenty of information and advice about adding strings in parallel, all with one common theme throughout and that is cable lengths, quality terminations and proper connections.

 

Edited by Geoff.D
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