Small offgrid inverter recommendations.

[ranger#1]

Building a small system to run a mini split for my bedroom. Just want to play around and see how much pannel I will need to charge during the day and if the 8ds will sustain overnight.

Looking for 2‐3kw inverter suggestions.



Batteries, 4 8D's in series

Solar, 6-800w 200voc

Load,

1, 900w running minisplit.
2, phone chargers.

 

[sunshine_eggo]

IMHO, 8D is not a great choice unless they're free, and you have an endless supply as they fail.

Ask @HighTechLab about his 8D experience.

Assuming 300Ah, the batteries can only run the unit for maybe 7 hours and stay above 50%. You'll need at least 2000W of solar to guarantee you can run those 7 hours every 24 hours.

Now if the mini-split operates at reduced power simply maintaining a temp, then you'll get more run time, but that depends on your insulation.

 

[ranger#1]

IMHO, 8D is not a great choice unless they're free, and you have an endless supply as they fail.

Ask @HighTechLab about his 8D experience.

Assuming 300Ah, the batteries can only run the unit for maybe 7 hours and stay above 50%. You'll need at least 2000W of solar to guarantee you can run those 7 hours every 24 hours.

Now if the mini-split operates at reduced power simply maintaining a temp, then you'll get more run time, but that depends on your insulation.

They are free. They are 210ah on the name plate at like 1/20 c rate iirc.

I've done some testing on them to see what I can get with a realistic c rate but can't remember the outcome.

Realistically I should only need 4-5hrs of combined on time from the minisplit.

 

[HighTechLab]

Yeah, my experience was more of my energy was going to heating the batteries due to them failing than our actual loads. Went lithium about 4-5 years ago and will never touch lead acid again (except starting battery in my dually).

 

[Mahendra Gomanie]

Yeah, my experience was more of my energy was going to heating the batteries due to them failing than our actual loads. Went lithium about 4-5 years ago and will never touch lead acid again (except starting battery in my dually).

Same here ,but there are lithium starting battery .
Check out Antigravity starting batteries this is one such brands.

LITHIUM BATTERIES, MICRO-STARTS

Smallest, Lightest, Most Powerful Lithium Motorsports Batteries - the First with Built-In Jump-Starting! Top Rated MICRO-START Jump-Starter Power Supplies

antigravitybatteries.com

I know I have one in my car since 2021 .
When it goes dead it act as a just start with the press of a button.

 

[SoggyShoes]

I have an Antigravity battery in my motorcycle. It is awesome! It is so light that i thought it was fake, but it fires up my big v-twin much berrer that the lead acid OEM. I have gone 9 months without starting the bike or charging battery and it fires right up. And has the built in "jump start" where the BMS shuts off at 20% unless you push the "jump start" button (haven't been on a situation where I was able to test that yet).

The only problem I had with it was that it was so much shorter than the lead acid battery that the cables didn't reach without putting some plastic blocks under it to lift it up.

@Mahendra Gomanie , I didn't think you could use lithium batteries in a car. Won't that kill the alternator?

 

[Mahendra Gomanie]

I have an Antigravity battery in my motorcycle. It is awesome! It is so light that i thought it was fake, but it fires up my big v-twin much berrer that the lead acid OEM. I have gone 9 months without starting the bike or charging battery and it fires right up. And has the built in "jump start" where the BMS shuts off at 20% unless you push the "jump start" button (haven't been on a situation where I was able to test that yet).

The only problem I had with it was that it was so much shorter than the lead acid battery that the cables didn't reach without putting some plastic blocks under it to lift it up.

@Mahendra Gomanie , I didn't think you could use lithium batteries in a car. Won't that kill the alternator?

I have been using it for three years didn’t had to replace the alternator,
Theses are designed to be replacement for lead acid drop in
A number of guys that are into car audio are using them as well with the stock alternator and with out the separate audio batter

 

[Mahendra Gomanie]

Most modern alternators don’t go beyond 14.4v if it does then that’s a problem.

 

[Mahendra Gomanie]

Check those out . Don’t know what type bms is in there but I guess that’s why they have those prices.
But I have no regrets with the purchase so far .

 

[SoggyShoes]

Check those out . Don’t know what type bms is in there but I guess that’s why they have those prices.
But I have no regrets with the purchase so far .

I will! The one in my motorcycle is amazing.

 

[Mahendra Gomanie]

I will! The one in my motorcycle is amazing.

Same here