Unique "UPS" scenario

[JAS]

Hey all,

Summary: Are there any solar generators that run loads from the Inverter all the time even when being charged via AC?

Details:

So I have an issue that I run into at our off-grid cabin. (It's a 1st world problem, I know)

I have my cabin wired to run off a 1200W inverter running through a transfer switch that lets me run a generator when needed. Inside, I have a TV, DVD Player, and XBox 360. The problem arises when the transfer switch switches from Inverter/Generator. The transfer is not fast enough and the electronic devices all shut off. And then I hear the complaining from all the kids

Short of replacing the transfer switch with something much faster and more expensive (which would probably be way overkill for our cabin). I'm thinking I could get a small solar generator (something in the range of 300-400 watt inverter) to act as a UPS between the electronics and the power source. I could also use this solar generator to carry back and forth from home to the cabin and for other uses around home when necessary.

So I would not be using this solely as a UPS, just something that would keep the electronics running for the 1-2 seconds between Inverter/Generator transfer. I was originally looking at the new Bluetti EB3A since they advertise it as a "UPS". However, after contacting them, they said it is a 20ms transfer time. I don't trust this to be fast enough to keep the devices from shutting off.

So my question is: how do other solar generators handle "pass-through" charging? I guess I'm actually looking for a unit that will run from the inverter all the time even when being charged via AC. Any suggestions on a small unit that can do this?

Thanks,

Jeff

 

[Aly_Oops]

Most devices i use would just reboot if switching is too slow. Check my other post on sone of the test i am doing on the Eb3a unit. No issue with my internet modem, router, ikea homekit and apple speaker.

 

[Aly_Oops]

Regarding Solar Cable for EB3A: I received this reply from Bluetti....
Thanks for your email and sorry for the late reply.

1：The solar charging cable
The solar charging cable will be shipping out separately.
due to the cable need to wait for shipment. It will be shipped within three weeks.
We use the Canada UPS delivery. When it could be shipped, we will send you an email about the tracking number.

 

[Aly_Oops]

Regarding UPS setup, I received this info from Bluetti.

3:UPS

After the machine needs access to the AC input source (AC charging cable must be used, DC port does not apply),
turn on the AC switch of the machine.
The load attached to the AC outlet of the machine is powered by a bypass.
The bypass will not work without the AC switch, that is, the UPS feature is not turned on

FYI:
I do some more testing, I get the impression the unit will charge/fan up while in UPS mode. Too me, that not kosher. My other UPS don't operate that way. Completely quiet until power failure.

 

[Aly_Oops]

When does the fan come on conditions. Here is the parameters from Bluetti.

2：When the fan is running, it has the usual fan noise
FYI: (Their answer to my squeal/buzzing sound of fan - Not an answer, I accept the fan noise, not the buzz andvsqueal noise. Has not stop yet.

PV and Grid Charging Power Strategy:
PV Temperature and Inversion Temperature Limit Conditions:

1. Silent Mode: Power Grid Charging Power Initial 100 W
The temperature of LLC radiator is greater than 70 ° C, and the maximum charging power of the grid is limited to 60W%.
The temperature of LLC radiator is less than 65 ° C and the charging power of the grid is returned to the initial 100W.

2.PV maximum charging power is 200W:
PV heat sink temperature greater than 85 ° C temperature per 1 ° C increase, PV maximum power drop 20W;
Until 105 ° C, the PV charge drops to 0W.

The above strategy is a combination of noise and heat dissipation.
FYI: (Noise fan okay, why the buzz/squeal?)

FYI: Nice to get a reply and some details, but they don't say if the buzz/squeal is normal or not?

 

[A.Justice]

You can get used computer UPS's on eBay for dirt cheap without a battery. A lot of government buildings and offices upgrade their systems every few years, so there's quite a bit of relatively new, high quality equipment available used. I know it's not exactly what you are looking for, but it's probably the cheapest and easiest option.

Either add a lead acid yourself, or with some slight modifications, a lithium battery can be attached.

 

[JAS]

You can get used computer UPS's on eBay for dirt cheap without a battery. A lot of government buildings and offices upgrade their systems every few years, so there's quite a bit of relatively new, high quality equipment available used. I know it's not exactly what you are looking for, but it's probably the cheapest and easiest option.

Either add a lead acid yourself, or with some slight modifications, a lithium battery can be attached.

Yes, I've decided to give the UPS route a try. I have a spare UPS at work that I can take to the cabin with me and see how it works out. It would be nice if I could leave it there. But, with most inexpensive AGM models, they don't like to sit uncharged for months on end.. So, I'll have to cart it back and forth.

 

[A.Justice]

Yes, I've decided to give the UPS route a try. I have a spare UPS at work that I can take to the cabin with me and see how it works out. It would be nice if I could leave it there. But, with most inexpensive AGM models, they don't like to sit uncharged for months on end.. So, I'll have to cart it back and forth.

I modified one of mine to have an external battery that hooks up with XT60 connectors, it might be easier to just bring the small lead acid battery with you, rather than the whole unit.

 

[Hedges]

Battery charger.
If generator recharges battery, that makes an on-line UPS with no glitch.

There are inverter/chargers which transfer with little or no glitch. These are the ones that synchronize to grid and carry part of the load themselves, typically UL-1741 listed. More expensive and more efficient than battery charger.

 

[Aly_Oops]

I got this unit to use ice fishing, as I have lot of electronic. Last winter when the unit batteries ran out, I just hook it up to my 100amp lithium battery. Work great. Occasionally I have a need for UPS for some devices that I do not have a backup, other essential device have it. I do have some remote security camera that I will use occasionally too.

I am checking for myself how good will it work as UPS and sharing my results in event other have an interest.

At this time, the unit is nice, the normal fan noise is not a problem for me. I think there is a problem with my unit. The fan bearing or something is not right. I found other on utube that noted the same issue.

It seem bluetti is not willing to admit to the issue in the same manner that they did not want to admit to hot neutral on the AC200MAX (my unit is due to arrive here Friday). They have sent me an email, that the problem is fix on the unit I am getting. If the unit arrives not fix, it will be returned real fast. I be using it as a 30amp supply to my RV trailer. Code does not permit hot neutrals.

DYI for ice fishing is not convenient or practical, as for the my RV trailer it can be feasible if i can get 800 to 1200 watt solar setup permently mounted. Up north over panelling is a requirement. Ground setup is not desirable for me, nor will it be efficient. That why I still use the Honda Generator and lithium battery bank. With the AC200MAX, I expecting the use of Honda Generator will be less frequent on longer trips.

We are in research mode for panel purchases for next year project. We have no plans for Solar at the house.

 

[Aly_Oops]

Yes, I've decided to give the UPS route a try. I have a spare UPS at work that I can take to the cabin with me and see how it works out. It would be nice if I could leave it there. But, with most inexpensive AGM models, they don't like to sit uncharged for months on end.. So, I'll have to cart it back and forth.

LIFEPO4 can sit a long time, very low monthly loss. 6 month to a year is safe with Lithium Lifepo4 batteries. I have a bunch of different types and I use my reminder apps to charge for each specific types.

 

[JAS]

LIFEPO4 can sit a long time, very low monthly loss. 6 month to a year is safe with Lithium Lifepo4 batteries. I have a bunch of different types and I use my reminder apps to charge for each specific types.

Yep, I'd love to find a true UPS that uses LFP and doesn't cost $$$

 

[Aly_Oops]

New reality, price go up fast, may go down slowly and service goes down real fast. Lot of things we buy, we can do without. It the only way to force prices down. eh?

 

[Hedges]

We are in a minority, so prices will stay up. Gotta pay it if you still want to be in the game.
Or, buy at liquidation sales.
At least then we can afford comfortable living.

The one thing we can do different is pay a premium for the good stuff.