Mecer ME 2000VU issue, what is the your "feeling"

Thought I ask, maybe someone else has seen this.

I had this issue with the Mecer UPS, where it would drop the output volts after getting into a frenzy, relays clickity clack like mad, till it starts recharging the batteries, and the problem goes away.

The issue: Incoming volt is a steady 242v, then UPS clicks, and the output drops to 208v, then back to 242, then 210v, back to 241v etc. Goes into UPS mode, as there is a 10% drop, but on the output, not input.

Swapped the AC source from another UPS (my bad) to direct off the Critical loads. It worked perfectly for a day or three, then it started again getting progressively worse, the same as before.

Now, when it starts dropping the volts, I unplug the AC source for a few seconds, and put it back, the problem goes away whilst recharging is triggered. And once batteries are recharged, it runs for a while again with no issues.

3 other UPS, none of this that I’m aware of.

The question, speculation, is it:

  1. Because of being fed by an inverter, the Critical loads DB, stable at 242v.
  2. The new batteries, 2 x 7ah, worked in other UPS. It “feels like/reminds me” of when a BMS would cut out, forced discharge, and the system goes back to being stable.
  3. Inverter faulty, a dormant issue that progressively “builds up” to an issue as described.

Has anyone seen this anywhere before?

Sounds like either dying batteries or a bad connection/relay… Since you have a history with relays, that’s where I’m placing my bet :stuck_out_tongue_winking_eye:

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My money’s on the inverter going bad.

How old is the UPS?

Still newish, still actively sold.

I would guess 1-3 years, as I removed the OEM batteries. People should not buy these UPS’es for LS.

As a matter of fact, got this one R2k+, a Mecer ME 1000VU (±R1.6k), and an APC Pro-900 (±R5k) all for free, all because of batteries being dead.

If you want Yuasa NPW45-12 batteries, it’s cheaper to buy a complete UPS. The cheap alarm batteries most people replace them with are not made for UPS duty, and weigh about half as much…

Not a chance. I take the cheapest 7ah I can find, just want UPS to beep, and sometimes carry the load for a minute or less.

Absolutely more for the protection they have built-in than anything else.

For the one 700va APC, I put together a DIY 24v Lifepo4 bank. Was the same price as 4 x 12v 7ah batts at the time, been running for a few years now, and I hear it at times, as Eskom does “things”.

And I must be careful ito the cheap 12v batts too … at one point it becomes silly.

Then I don’t know. Just recently had a chat with someone about electronics obviously not lasting forever, so after a couple of years something might go wrong. Thought this might have been an old UPS in service for years.

Oh 100%.
I had the same discussion with a friend over the weekend. They didn’t renew their office lease and everyone is now remote working and got the UPS’ that was at their desk to take home “for loadshedding”. Barely lasted a couple of weeks into this year’s loadshedding. Tried explaining that these UPS’ are made to keep the load (laptop & monitor) running for a minute or two while the backup kicks in. “Think big office, automated generator kicking in or your case you running out and starting your gennie.”.

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Yup. I’ve seen 500W UPSes with a 12V 7Ah battery in. Granted, they ship with a decent 7Ah battery that can hold up for some minutes, but still, even 100W is like a 1C discharge. No way can you do that for more than a few minutes.

The UPS itself usually has a cost-saving transformer in that’s not exactly optimised for low current draw, so the self-consumption of these units are on the high side.

And then on top of all that, they have insufficient cooling, they actually rely on the battery running out before the unit overheats.

UPSes are not meant for load-shedding. And people who sell them like that, including the heros at Takealot, are not doing us any favours.

Well… maybe they are… because they create more business for those who make real inverters :slight_smile:

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Way back when we had first received loadshedding (must be around 2009/2010) I used a 500W UPS I had laying around to run my ADSL router during loadshedding. With only 12W usage it lasted much longer than a 2hour LS event. But you can’t do anything more than that with these UPS for long hours.
They are primary there make sure your PC can do a controlled shutdown.

PS. I did have to mod the UPS. That beeping for 2 hours would drive anyone crazy. So my UPS received some prestic “damping” meterial inside the buzzer.


I used to use pliers on some wires and the noise goes away BUT not anymore. I now want the hear the blips and bleeps, should be absolutely minimal.

Just to confirm, I use these UPS’es as protection, against myself first, secondly Eskom, and not as LS devices. That is what the Victron is for. Victron is the “big battery”.

BUT, Victron is pass-thru, so all Eskom has to offer, passes-thru, unless it is LS, then it is “pure” i.e. battery and/or solar power.

Don’t think everyone is as aware of that as I am, me having UPS beep and blip infrequently during the daytime, more when Eskom starts taking strain or comes back on. Also often very late at night, when they pick up something un-towards from Eskom.

I mean, come on, the relays that start to go on Victron, because of Eskom LS. Victron is robust, most stuff protected by these little UPS’es, are not.

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Same here! I have a little 600VA UPS on my Home Assistant PC and I hear it beep and buzz often during the day.


Your own little R2D2 :smiley:

Connected the UPS direct to Eskom, no load, and waited. After a few hours, the relay started its “dance”.

So I’m going with the bad history with relays.

Will recycle it, and get another free one.

It hit me this morning, this is now the 3rd device with a relay in our house that has developed an issue.

This little unit, a 2.4kva APC Double Conversion UPS, and the MPII.

Have an itch to maybe consider the idea of giving some thought to that maybe relays can be finicky.

Relays are not all made the same. The metal that is used for the contacts is important for how long the relay contacts will last. Cheap stuff use the cheapest components and then they get you to buy a new unit. Why sell 1 unit when you can sell 2?

You can always upgrade your relay to a better model. They are not expesive, but you will need to solder.

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Yes, I’m aware. Got a UPS repair guy I like. Will send the units to him, maybe they can be salvaged.

I don’t like to just chuck things if they can be repaired better than before.
New stuff, costs a hell of a lot lately, and I know they are not built to last.