Inverter/Charger & Battery Bank question for off grid Cabin with 3000W Generator

[CoachMcG]

I'm considering purchasing a Power Star 24V Inverter/Charger model LW1000. I've been researching various systems and my understanding has significantly improved since i've started but i still have lots to learn. This post is as i currently understand but i may be wrong. That's why i'm turning to you guys/gals that surely have more experience and knowledge!

buy 24 Volt Pure Sine Wave Charging Inverter - 120 Volt AC Output -

Main Features 1. LCD digital display show voltage, load and battery info in real time. 2. Peak power is three times of rated power. 3. Can work with inductive load such as air conditioner, motor door and so on. 4. Pure sine wave output, available for sensitive load. 5. 4-step progressive...

unpluggedpowersystems.ca

Here we go!

1. I believe this model would meet my short term (2-3 years maybe longer) needs. Since i can connect my generator to it, i have no issues running my generator to fire up the keurig machine, hair dryer, tools etc. If i understand correctly, when i start my generator, a transfer switch would disable the battery power and the power running through my inverter would now be supplied by the generator. At the same time, it would now be charging my battery bank. Correct?
2. I have 4*12V Lead Acid AGM Batteries rated at 75Ah. If i want a 24V system, i would connect 2*12V in series and connect those in parallel with a second bank of 2*12V right? This setup would give me a 24V 150Ah=3600W bank... correct? if the inverter is only 1000W, does it matter if my bank is 3600W? I realize i can only use 50% so 1800W.
3. I'm considering a small fridge. I checked and i could get a small bar fridge rated at 115V*1A=115W. Assuming i'm on the right track... 115W running i can multiply by 10 for peak so 1150W for start up. The LW1000 says peak is triple therefore 3000W start up so it could handle the surge of a fridge starting up as long as i'm just running lights... still doing good or am i completely off the rails? LOL
4. Now for the battery bank and Watt hours (Whenever i see these appliance ratings... is it implied that it's Watt/hours? 15W light bulb would use 15W in 1 hour?) My understanding is that 115Wh was if the fridge would be running the full hour so i could divide by 4 assuming the fridge could run 15mins/hour. In other words, the fridge would burn 115watts in 4 hours. 1800/115=15.6 hours? I'm guessing i'm off here because i seem to recall a conversation with someone that a fridge at that rating could run for longer.
5. Last question... for now ;-) How long would it take for the LW1000 to charge my battery bank with my generator. I see that there are various settings in the description (6. Fast and powerful charger with 20A/35A/50A/70A/90A. ) to charge and it says it can charge quickly. How does this work? If my generator outputs 115V and i set it a 20A it would produce 2300Watts in 1 hour and my battery bank would be fully charged?

Thanks again for all the help.... looking forward to stepping out of the Research and development phase. The way i see it, purchasing the LW1000 would give me the ability to power up my cabin through my existing breaker panel immediately and still providing charging capabilities until i get solar panels and a charge controller. Hoping it makes sense!

CoachMcG

 

[SolarRat]

1. Last question... for now ;-) How long would it take for the LW1000 to charge my battery bank with my generator. I see that there are various settings in the description (6. Fast and powerful charger with 20A/35A/50A/70A/90A. ) to charge and it says it can charge quickly. How does this work? If my generator outputs 115V and i set it a 20A it would produce 2300Watts in 1 hour and my battery bank would be fully charged?

A 24v 150ah battery has 3600wh, yes. The max you should charge an AGM battery is about C/10 (10% of the AH rating) or 15 amps. I think you'll be ok with that charger on the lowest 20a setting but don't go any higher. Your charger will be putting out 20 amps @ 24v (not 115v), so 480w. 3600/480=7.5hrs. Lead acids don't charge very efficiently so figure 10hrs if the battery is dead dead...but don't do that. Try to not take the battery below 50% state of charge (~12.15v) or it will reduce it's lifespan (you already knew that I see).

So, your battery has a safe discharge capacity of about 1800w. A 115w fridge with 25% duty cycle (29w per hour not including surge) should run for about 60hrs on that battery, in a perfect world...

 

[CoachMcG]

A 24v 150ah battery has 3600wh, yes. The max you should charge an AGM battery is about C/10 (10% of the AH rating) or 15 amps. I think you'll be ok with that charger on the lowest 20a setting but don't go any higher. Your charger will be putting out 20 amps @ 24v (not 115v), so 480w. 3600/480=7.5hrs. Lead acids don't charge very efficiently so figure 10hrs if the battery is dead dead...but don't do that. Try to not take the battery below 50% state of charge (~12.15v) or it will reduce it's lifespan (you already knew that I see).

So, your battery has a safe discharge capacity of about 1800w. A 115w fridge with 25% duty cycle (29w per hour not including surge) should run for about 60hrs on that battery, in a perfect world...

Thanks a lot! I guess I wasn't 100% but your clarifications make total sense! Also, looks like i understood the concept but my math was off for the fridge part... my bad ;-)

 

[mtt04]

Coach the only I would mention is the All-in-one units like MppSolars can use a generator and they are very reasonaly priced and are all in one units.
Go to the all in one section here and also look up Will's videos. E erything is one small box. Charger, inverter, etc
I'm converting all my woods forestry cabins to them. Slick as heck.

No more 5 foot wallboards of various parts.
One box sitting on a wall.
I use the AC IN port for my generators
Works great
Before you pull the trigger check them out

 

[CoachMcG]

Coach the only I would mention is the All-in-one units like MppSolars can use a generator and they are very reasonaly priced and are all in one units.
Go to the all in one section here and also look up Will's videos. E erything is one small box. Charger, inverter, etc
I'm converting all my woods forestry cabins to them. Slick as heck.

No more 5 foot wallboards of various parts.
One box sitting on a wall.
I use the AC IN port for my generators
Works great
Before you pull the trigger check them out

I appreciate your input, i looked at them before but will have a second look! Thanks!

 

[Refinished]

From what I have been able to find in the docs, the MPP Solar AIOs can only take sine wave input, perhaps limiting generator input to inverter generators like the Honda EUs. Is this what you use?

 

[CoachMcG]

I have a Firman 3000 inverter generator. Not sure if it's pure sine or not.

 

[Patrick Guitard]

I'm considering purchasing a Power Star 24V Inverter/Charger model LW1000. I've been researching various systems and my understanding has significantly improved since i've started but i still have lots to learn. This post is as i currently understand but i may be wrong. That's why i'm turning to you guys/gals that surely have more experience and knowledge!

buy 24 Volt Pure Sine Wave Charging Inverter - 120 Volt AC Output -

Main Features 1. LCD digital display show voltage, load and battery info in real time. 2. Peak power is three times of rated power. 3. Can work with inductive load such as air conditioner, motor door and so on. 4. Pure sine wave output, available for sensitive load. 5. 4-step progressive...

unpluggedpowersystems.ca

Here we go!

1. I believe this model would meet my short term (2-3 years maybe longer) needs. Since i can connect my generator to it, i have no issues running my generator to fire up the keurig machine, hair dryer, tools etc. If i understand correctly, when i start my generator, a transfer switch would disable the battery power and the power running through my inverter would now be supplied by the generator. At the same time, it would now be charging my battery bank. Correct?
2. I have 4*12V Lead Acid AGM Batteries rated at 75Ah. If i want a 24V system, i would connect 2*12V in series and connect those in parallel with a second bank of 2*12V right? This setup would give me a 24V 150Ah=3600W bank... correct? if the inverter is only 1000W, does it matter if my bank is 3600W? I realize i can only use 50% so 1800W.
3. I'm considering a small fridge. I checked and i could get a small bar fridge rated at 115V*1A=115W. Assuming i'm on the right track... 115W running i can multiply by 10 for peak so 1150W for start up. The LW1000 says peak is triple therefore 3000W start up so it could handle the surge of a fridge starting up as long as i'm just running lights... still doing good or am i completely off the rails? LOL
4. Now for the battery bank and Watt hours (Whenever i see these appliance ratings... is it implied that it's Watt/hours? 15W light bulb would use 15W in 1 hour?) My understanding is that 115Wh was if the fridge would be running the full hour so i could divide by 4 assuming the fridge could run 15mins/hour. In other words, the fridge would burn 115watts in 4 hours. 1800/115=15.6 hours? I'm guessing i'm off here because i seem to recall a conversation with someone that a fridge at that rating could run for longer.
5. Last question... for now ;-) How long would it take for the LW1000 to charge my battery bank with my generator. I see that there are various settings in the description (6. Fast and powerful charger with 20A/35A/50A/70A/90A. ) to charge and it says it can charge quickly. How does this work? If my generator outputs 115V and i set it a 20A it would produce 2300Watts in 1 hour and my battery bank would be fully charged?

Thanks again for all the help.... looking forward to stepping out of the Research and development phase. The way i see it, purchasing the LW1000 would give me the ability to power up my cabin through my existing breaker panel immediately and still providing charging capabilities until i get solar panels and a charge controller. Hoping it makes sense!

CoachMcG

I am wondering if there a way to get the generator to start automatic when the PV’s are not charging the batteries cause the sun is down or when the batteries have reached there min voltage?

 

[CoachMcG]

I am wondering if there a way to get the generator to start automatic when the PV’s are not charging the batteries cause the sun is down or when the batteries have reached there min voltage?

I just purchased a SAMLEX EVO 2224. I saw there's a space to connect a device if your generator has a remote. From what i understand it could start your generator remotely when your batteries get low... better put some research cause i might be wrong. In my case, my Firman 3083 has a remote but the battery shuts down after so many hours. The battery is needed to electronically choke the generator for startup... not sure if this would work for my setup. Would be worth looking into!