Electronics > Projects, Designs, and Technical Stuff

Switch from flat to charged battery while under load

<< < (5/6) > >>

magic:

--- Quote from: gnif on August 11, 2019, 01:15:09 am ---I would like to hot swap between battery banks that are connected to the UPS, the change over will be from the flat solar batteries to the fully charged still unused UPS batteries. The UPS will not be using these batteries at this point as it's AC service will have been restored.

--- End quote ---
That sounds like a fine moment for mains outage :-+

I think the diode solution may be OK. But do check what happens if the UPS tries to charge in the short window when one battery is connected only with diode and the other not connected yet.

capt bullshot:
Back-to-back connected MOSFETS of appropriate rating and control circuitry would be able to switch over from one battery to another within some 10 to 100us. The UPS buffer cap should cover for that. Back-to-back MOSFETS operate like a "real" switch, conducting and isolating in both directions (within their capabilities).
Currently I'm thinking about extending the capacity of my homegrown solar battery system using such a configuration, adding a second battery that would be charged by another source (more solar power):
http://wunderkis.de/pvbat/

ogden:
It is not good idea to modify your "last line of defense" UPS. I would leave it alone. As you consume more than PV can produce - why don't you just install grid-tied inverter w/o batteries. Does "PV license"+ grid tie inverter is more expensive than battery pack for 1KW solar?

gnif:

--- Quote from: ogden on August 11, 2019, 08:45:26 am ---It is not good idea to modify your "last line of defense" UPS. I would leave it alone. As you consume more than PV can produce - why don't you just install grid-tied inverter w/o batteries. Does "PV license"+ grid tie inverter is more expensive than battery pack for 1KW solar?

--- End quote ---

It's not my last line of defence, it's one of two. Grid tied inverters in australia are a joke, we have to have a seperate meter that measures what we generate, and we are reimbursed that amount on our electricity bill, but at the abysmal rate of 6c/kwh. Dave did a video on his grid tie in a little while back that explains all this and how much we get ripped off over here. If I stay within ELV and don't mess with the mains directly there is no issue and instead of getting 6c/kwh saving on my power, I will get 58c/kwh.

ogden:

--- Quote from: gnif on August 11, 2019, 10:58:30 am ---Grid tied inverters in australia are a joke, we have to have a seperate meter that measures what we generate, and we are reimbursed that amount on our electricity bill, but at the abysmal rate of 6c/kwh.

--- End quote ---

Sorry, didn't see video about PV in Australia because honestly don't care. Your grid buys electricity from individuals at 6c/kwh rate, right? This is important for those who during day are able to generate more than they consume, who use grid as a "storage" - sell excess power. This is not your case because your PV generates less than you consume at any time of the day. You may just plug grid-tied inverter into socket and do not tell anyone ;)

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod