Upgrade

[Don Keot]

I have at least figured out what I have. 8 batteries in series 6v at 240a each, 11,520w, 6,300 usable, 3.6kw inverter, 80a charge controller and 2520w of solar with an integrated 20k generac generator, on propane. There is also a 240v transformer with the well, 2 ton air conditioner and water heater on it. Generator comes on when they are used. The system was professionally installed in 2008 and was used very little. Looks like I will keep the system, change the batteries for lithium, will double available power and go with small mini splits or inverter window ac. I would like to put in a large water holding tank, fill once a month and maybe get a tankless propane water heater. What do you think?

Bad math, more like 5,500 usable.

 

[rhino]

change the batteries for lithium

Is the cabin always heated in winter? If you are referring to LiFePO4 you can't charge them if they are below freezing. Those AGMs won't have issue with charging below freezing.

 

[Bluedog225]

Sounds like you are on the right track.

Some research on the batteries may save you thousands over what the installer may recommend. E.g. Victron LiFePO4 are crazy expensive. But, in my opinion, you do want LiFeP04, not other lithium types.

DIY batteries may not be a big project you want to take on for a lot of reasons. I don’t. But the 48 volt “server rack“ batteries are worth considering. Check out currentconnected.com. And read some Eg4 threads before deciding whether to buy from signature solar.

I hear nothing but good things about tankless propane water heating. Same for inverter style mini-splits. The garage journal forum has lots of diy mini split install overviews. Mostly Mr. Cool if I recall correctly.

 

[E. Cho]

I despised, hated my propane tankless water heater and 10 year experience and finally ripped it out after going solar.

Reasons are: needs to be vented which created a large 6" hole in my basement wall and cold air in winter was difficult to keep out. Plus the vent required electricity for the fan.

Good high volume units are expensive and are not maintenance free.

Next it required significant gas pressure and water pressure, which I didn't always have, so the igniter very often didn't ignite.

I have hard water and so the heater needed descaling once a year and a PITA without a decent pump = more money.

Propane is expensive and in my rural location required a large $$ minimum order for delivery, plus tank rental fee, etc.

Using 20-30-100 lb tanks filled @ Costco was cheaper but difficult at my age and nearest Costco was 150 miles away and tanks were supposed to be standing during transport or Costco would not fill them. I only had a car.

Water waste, propane waste waiting for water to be delivered to faucet at opposite side of house.

There are more cons. It was an expensive horrible useless experience that wore me out. If you are wealthy and younger and near a propane supplier and near good plumbers then maybe, but not for me.

Not good for cold climates / winter due to venting pipe hole in wall.

An electric water heater works better for me. No poisonous dangerous gas to deal with, breath in or transport, with solar the energy price is fixed vs market driven, if I use my gas or diesel generator if no solar, then I can also do other things like charge batteries, cook, vacuum, shop work vs wasting one dimensional propane. Electric is safer for me, silent as no fan or motor if powered with solar or battery. Not perfect but WAY better and cheaper for my poverty level.

No perfect solution, but I despised the whole house propane tankless heater. My Bosch is for sale BTW. The unit was fine overall but not the execution to run the GD thing.

 

[Bluedog225]

Good to know.

 

[skillet]

Thank you, I have found it is a very good system and will go to lithium to improve usable power.

Are you planning on selling the current batteries ?

 

[schmism]

An electric water heater works better for me Electric is safer for me, silent as no fan or motor if powered with solar or battery. Not perfect but WAY better and cheaper for my poverty level.

I assume you were talking about going to a tanked heat pump version which are very expensive on the front end but likely able to be powered by a modest solar installation. (as opposed to electric tankless that requires a HUGE solar system to support)

 

[Don Keot]

Are you planning on selling the current batteries ?

Yes, if I go lithium.

 

[Don Keot]

Sounds like you are on the right track.

Some research on the batteries may save you thousands over what the installer may recommend. E.g. Victron LiFePO4 are crazy expensive. But, in my opinion, you do want LiFeP04, not other lithium types.

DIY batteries may not be a big project you want to take on for a lot of reasons. I don’t. But the 48 volt “server rack“ batteries are worth considering. Check out currentconnected.com. And read some Eg4 threads before deciding whether to buy from signature solar.

I hear nothing but good things about tankless propane water heating. Same for inverter style mini-splits. The garage journal forum has lots of diy mini split install overviews. Mostly Mr. Cool if I recall correctly.

Thank you for your input, would need to double my solar for 15kw of battery

 

[Bluedog225]

I may be misunderstanding. 48 volt server rack at 100 amp hours is about 5,000 watt hours.

see e.g.: https://www.currentconnected.com/product/sk48v100/

They are stackable to increase amp hours available.

 

[E. Cho]

I assume you were talking about going to a tanked heat pump version which are very expensive on the front end but likely able to be powered by a modest solar installation. (as opposed to electric tankless that requires a HUGE solar system to support)

Yes to electric tank water heater but no to a heat pump version, which I simply cannot afford. I could barely afford the basic 12 US Gallon standard water heater tank. If I had the money I might also have considered the really small point of use electric tanks, which I've read very good reviews of as being very well insulated to hold heat for long periods, and I don't often need to heat all 12 gallons, vs 1-6. So for small quantities I use my 1600 watt electric kettle when the sun is shining or my wood stove if it is heating and it always has a large pot of water on it.

 

[Don Keot]

I assume you were talking about going to a tanked heat pump version which are very expensive on the front end but likely able to be powered by a modest solar installation. (as opposed to electric tankless that requires a HUGE solar system to support)

Might look into solar hot water, was very popular in Colorado when I was in the Boulder area.

 

[Don Keot]

I may be misunderstanding. 48 volt server rack at 100 amp hours is about 5,000 watt hours.

see e.g.: https://www.currentconnected.com/product/sk48v100/

They are stackable to increase amp hours available.

I’m thinking of three 48v 5 kw batteries

 

[Don Keot]

Yes to electric tank water heater but no to a heat pump version, which I simply cannot afford. I could barely afford the basic 12 US Gallon standard water heater tank. If I had the money I might also have considered the really small point of use electric tanks, which I've read very good reviews of as being very well insulated to hold heat for long periods, and I don't often need to heat all 12 gallons, vs 1-6. So for small quantities I use my 1600 watt electric kettle when the sun is shining or my wood stove if it is heating and it always has a large pot of water on it.

The hot water tank in our trailer works pretty well, I may look at it further.

 

[Bluedog225]

Got it. Would love to see those.

 

[BobR]

We just bought a cabin that is totally off grid and has an early Outback 48 volt system with 10/220v panels, 8 new 6v agm batteries and I think is the 3kw version. I think rather than upgrade the Outback system, I would rather get the Signature Solar system. I’m asking would the new 12kw inverter package be the best for my needs or two of the 6.5kw inverters be more desirable? I will need 240 for the well and water heater and will replace the 2 ton conventional air conditioner with mini splits. I would stay with a 48v system, are there any suggestions and what might the number of pv panels and 5kw batteries be? Thanks for your suggestions, I’m just trying to get it right the first time.

I'm no expert 'but'; I would put the brakes on any upgrades.

The first thing I would do is get your system working properly.

The next thing would be to work on reducing your consumption; Air cond. (I like inverter mini splits), appliances, etc.

Those new batteries will have a long life if treated properly.

Find out how much storage you need for your 'actual' use.

 

[BobR]

Yes, if I go lithium.

I may get stoned for saying this; but I don't believe Lifepo4 are the best choice for every system.

There are pros and cons for every battery chemistry; storage state of charge, temp., c-rate,etc..

 

[Don Keot]

I'm no expert 'but'; I would put the brakes on any upgrades.

The first thing I would do is get your system working properly.

The next thing would be to work on reducing your consumption; Air cond. (I like inverter mini splits), appliances, etc.

Those new batteries will have a long life if treated properly.

Find out how much storage you need for your 'actual' use.

Yes, that is what I’m going to do. Got some well and water leak problems I’m working on currently, solar is standing by, batteries fully charged and I am using some electricity but not living conditions. Not spending the night yet.

 

[Don Keot]

Here it is, a year later, I did get the existing solar system working properly and did not change anything. I now have a 5k btu inverter window ac in a bedroom and 12k btu Mr cool mini split in the living/kitchen area. I can run both ac’s all day without using any battery drain and turn off Mr cool at night. System working great in Texas summer. Wood stove keeps us warm in the winter but sometimes the generator comes on because of lack of good sun. The 250 gallon propane tank has lasted all year and still has some left. I ended up happy without spending a lot of money. The ac’s were $2k total. Thanks for the suggestions, summer, no problem, winter takes close watching.

 

[wdwtx2.0]

Here it is, a year later, I did get the existing solar system working properly and did not change anything. I now have a 5k btu inverter window ac in a bedroom and 12k btu Mr cool mini split in the living/kitchen area. I can run both ac’s all day without using any battery drain and turn off Mr cool at night. System working great in Texas summer. Wood stove keeps us warm in the winter but sometimes the generator comes on because of lack of good sun. The 250 gallon propane tank has lasted all year and still has some left. I ended up happy without spending a lot of money. The ac’s were $2k total. Thanks for the suggestions, summer, no problem, winter takes close watching.

Glad it is working out.