UPS as invertor PowerMust edition

cmg_george

cmg_george

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Oct 24, 2017
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Hi,
I'm planning to play with my very old PowerMust 1060 UPS as invertor.
I already remove the old batteries and and made some tests with it and looks very promising:
- it is a 24v model (it had 2 in paralel bat)
- it starts without main plugged in
- shutdown when batteries is around 21V
- looks to charge the battery to 27.8V
- looks not to have any problems with 29V
- annoying bip bip bip can be disable by software (using administration software)... however this settings is not keep by ups after restart
- power is arround 900W
- does not shutdowns after x hours on battery (i had it today running for 4h)... however the administration software at each start sets a local shutdown after 30minutes on battery

I don't know how to manage battery (the 18560 pack that i will build for it) charging.... i should add an external charger?
Lets assume that i will used it for the moment only as UPS with a brand new (almost) 18650 home made pack... should i use the UPS changer? From my tests it's not stopping charging...(this i test using my DC Power Supply which by luck i discover that when i pluged in the UPS to main it start showing me the voltage outputed by UPS to the "battery") i would really appreciate some ideas on this part. I also don't know charging current... how can i measure before putting the 18650 pack on it?
Thank you!
 
cmg_george said:
- it is a 24v model (it had 2 in paralel bat)
- annoying bip bip bip can be disable by software (using administration software)... however this settings is not keep by ups after restart

I don't know how to manage battery (the 18560 pack that i will build for it) charging.... i should add an external charger?
Lets assume that i will used it for the moment only as UPS with a brand new (almost) 18650 home made pack... should i use the UPS changer?
Click to expand...

* 24V would be 2 in series, not parallel. However, it's probably 2s2p. So 1 'pack' would be 2s (2 in series), and then the two packs are connected in parallel. This is kind of backwards to how APC does their battery packs. They have 2 in parallel for a pack, then the 2 packs are connected in series. Saves on wiring and potential cross wiring.
* If the setting for turning off the buzzer doesn't stick when the UPS cycles, it's possible that it has to be set via the terminal, not through the software. This can be difficult to do as the commands are hard to find sometimes depending on the manufacturer.

Yes, you would charge the batteries with an external charger. However, you could use a small BMS that goes between the UPS and the batteries and it handles the charging and discharging aspect of things.
I wouldn't worry too much about the charging current that it puts out. Especially if you decide to go with an external charger. But if you want to test the charging current you need to either use a shunt and measure the voltage drop across it, or you need to put a Multi-Meter in series with the Pos side of the wiring.
 
Any recomandation on that BMS?
Why not to worry about charging current outputed by the UPS? This part is not very clear for me...i'm afraid that the charging current will be outputed all the time and it will damage the batteries.
 
Charging output is only needed when the batteries are low. Software you can change the float voltage so it won't keep trying to keep the batteries topped off. And if you use a BMS, it won't charge the batteries until they drop to a cut-in point anyways.
If you take a closer look at one of the battery packs, you'll notice they it is probably two sandwiched together in one wrapper. At least that's the way APC batteries and done.
You might be able to use this BMS or one like it that was discussed in this thread:
http://secondlifestorage.com/t-My-Build?pid=16747#pid16747
 
In my PowerMust i could not find any settings for charging batteries.
I will come back with pictures on UPS, software and old batteries.
 
Like I said earlier, you might have to go in through a terminal program and manually adjust the settings. The Home based APC UPS's are like that. That software (both home and server) doesn't give you access to those settings. But using terminal to do the communications, you use the direct commands to change the settings.
I've never dealt with PowerMust, so I don't know if those options are available to you.
 
Well, thats definitely what I was referring to. I didn't see anything in there either for changing the charge/float voltage, either. Maybe someone else can look at it and see something I didn't. Some of the lingo is a little over my head. Plus, I just woke up and still a lil groggy ;)
You might be able to see if you can flash the firmware with a newer version, or a custom version. Look for other types of Megatech protocols and see what you come up with. You are definitely in the right direction though :)
 
UPS will switch to grid when grid is connected and then start to charge. Dont add grid and it wont charge. Add grid and it will switch to grid and start charging :)
 
@daromer i hope i will make this UPS better then that. I would like it to switch to grid when battery voltage goes low.
Is it possible that the charging current to be only 30mA? I put my multimeter in serie with the power supply and this was the reading on multimeter... for me looks strange.

EDIT: actually maybe my power supply only draws 30mA?
 
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