Ups with large capacity battery?

[OffGridInTheCity]

It's a good question !

I have done it many times before, it has never been an issue . It was an issue with old fashioned chargers, if hooked up to too larger battery, the big battery would demand more than the charger was designed to output , and because the charger has no current limits it would 'overload' and burn out.... It is not an issue with a ups , they will only charge at the rate they are happy with



The only problem is that the slow charge rate is not great for your gel batteries , this will result in reduced lifespan - not a huge concern if you are only cycling 4/5 times a year


This could be solved by an additional small external 12v charger used to supplement up to a suitable charge rate

Agree with @SamG340 - I have several APC 1500(s) and 2 x APC 3000(s) with custom DIY lithium-ion batteries. It's not about 'burning out the charger' but rather that charging is limited and can take time. For example, the APC 1500(s) only charge at ~50w (2-3a) no matter what size 24v / 48v battery I hookup.

Agree also that external / parallel charger can speed things up but APC 1500/3000 case a standard/dumb lithium-ion charger would charge the battery to a higher voltage than the APC likes - which might result in annoying beeping. But there are many chargers out there - some adjustable. Just measure you're UPS battery and see what it likes.

Here's just one example - I use an APC 1500 to power my iCharger X8 for my DIY battery build work and charge the 7s7p 18650 battery as the iCharger depletes it. Been doing this for several years and is why I know about 2-3a charging for APCs.

Note: A sharp eye might catch the ~250mv out of balance - it's because I just turned this back on yesterday after a year of being off and the Chargery is rebalancing the cells.

 

[MTM98290]

So, a separate DC system just to run the internet stuff. Size the battery for however many days you need it to run and use a DC to DC charger from the other system battery to keep the mini system topped off.

Main bank is 48v an auxiliary bank would be 12v or 24v. Can an Orion TR 48-12 be used to charge or will it burn out trying to charge the smaller battery to fast? DC-DC charging would be ideal for efficiency but is much more expensive to attach and setup. I am thinking 12v 100ah with a battery maintainer would be the best balance of cost and backup capacity. That would give us 4+ days of backup capacity.

 

[MTM98290]

Agree with @SamG340 - I have several APC 1500(s) and 2 x APC 3000(s) with custom DIY lithium-ion batteries. It's not about 'burning out the charger' but rather that charging is limited and can take time. For example, the APC 1500(s) only charge at ~50w (2-3a) no matter what size 24v battery I hookup.

I use an APC 1500 to power my iCharger X8 for my DIY battery build work and charge the 7s7p 18650 battery. Been doing this for several years and is why I know about 2-3a charging for APCs.
View attachment 176723
Note: A sharp eye might catch the ~250mv out of balance - it's because I just turned this back on yesterday after a year of being off and the Chargery is rebalancing the cells.

So is it your opinion that using the ups with a larger battery will not have the expected capacity because of idle consumption of the ups when inverting from battery?

Slow charging shouldnt be an issue as it likely it will have plenty of time to charge, although it seems 3a would take over 30 hours to recharge a 12v 100ah battery.

 

[OffGridInTheCity]

So is it your opinion that using the ups with a larger battery

Works like a charm for APC 1500 and 3000s - extends the run time proportional to the capacity.

will not have the expected capacity because of idle consumption of the ups when inverting from battery?

Not sure what you're asking - but let me try to respond.... There's no idle consumption (of battery) when grid is active and/or the unit charges from grid so the battery stay's topped off (e.g. effectively no loss of battery capacity). There is consumption when grid is off and losses in the DC -> AC conversion under load.

An APC 1500 burns 40w-60w with no load based on my measurements when grid is active. I presume it would be at least this much when grid shuts off.

You can use a Killowatt meter to measure for you're UPS.

Slow charging shouldnt be an issue as it likely it will have plenty of time to charge, although it seems 3a would take over 30 hours to recharge a 12v 100ah battery.

The 3a is APC 1500 with 24v battery. You'll need to determine you're specific UPS charging... A 12v UPS might be lower than an APC 1500 24v system but I don't know. Deplete you're battery and see how long it takes to charge up and calculate OR use a clamp meter.

 

[SamDeleted]

which might result in annoying beeping.

A quick twist with a pair of pliers fixes that problem ?

 

[Q-Dog]

Main bank is 48v an auxiliary bank would be 12v or 24v. Can an Orion TR 48-12 be used to charge or will it burn out trying to charge the smaller battery to fast? DC-DC charging would be ideal for efficiency but is much more expensive to attach and setup. I am thinking 12v 100ah with a battery maintainer would be the best balance of cost and backup capacity. That would give us 4+ days of backup capacity.

I'd have to read the manual, I'm not very familiar with it.

 

[SamDeleted]

Can an Orion TR 48-12 be used to charge or will it burn out trying to charge the smaller battery to fast? DC-DC charging would be ideal for efficiency but is much more expensive to attach and setup.

You have to get the smart version that is suitable for battery charging , I think the 'TR' model is correct


I think AC charging off your inverter is by far your cheapest option

 

[SamDeleted]

Orion-Tr Smart DC-DC Charger Isolated - Victron Energy

The Orion-Tr Smart DC-DC charger is a professional DC to DC adaptive 3-stage charger with built-in Bluetooth. For use in dual battery systems in...

www.victronenergy.com

 

[SamDeleted]

@MTM98290


I think victron dont actually make a 48v - 12v Orion in 'smart' (which you need for battery charging)

 

[ZEUS-FL]

My only concern about using a UPS with large capacity batteries is that they are not designed to be use for that long period of time and I believe they will overheat the components. They are made to run full capacity for about 5-6 minutes and not for over 1 hour or so. I am playing with a 350VA UPS right now and a 3S7P 18650 and I found it heats up a lot with a 150W load. For the beeping sound I just remove the internal speaker and I relay only on the blinking LED.

My other concern is the BMS of my setup is a 3S 40A (cheap amazon BMS) that heats up pulling 30A with the setup. Is 40A on papers but... I am running as well an Active 5A BMS to keep the batteries balanced.

the 10W-20W charging should not be a problem. Actually the lower the battery charge, the better for longevity. Is any way to get an 12 or 24V inverter and convert that in UPS? Exist any barebone UPS that we can buy and just add our batteries? Also I am thinking on buy LifePo4 to play with it.

 

[Skid]

This might fit your need. Ecoflow River 2 512W Lifepo4 with EPS of 30MS, refurbished for $219. For your modem any inexpensive UPS would suffice as its battery would only be needed for 1 second.

EcoFlow RIVER 2 Max Power Station 512Wh LFP Generator Certified Refurbished | eBay

Q1: How long can the RIVER 2 Max power my appliances?. 100-120V 50Hz/60Hz, 660W Max. 11-50V, 13A, 220W Max. 12V/24V, 8A, 100W Max. 5/9/12/15/20V, 5A, 100W Max. 12.6V, 10A/3A/3A, 126W Max. 5V, 2.4A, 12W Max.

www.ebay.com

 

[DIYrich]

Tl;Dr

Have the inverter shutdown at 10% soc.
Run internet directly off the 48v battery. Get some step down power to 12v and/or 5v to run your equipment. The remaining 10% should last you a long time.