Advice appreciated on re-doing our home system with EG4 products

[seneysolar]

Okay thanks will look into the EG4 PowerPro and Midnight.

Current batteries are Rolls open lead acid (890 ah). I should have clarified - when I said they are going down quick I meant the battery life. When they get a full charge on a fully sunny day, when the PV stops generating for the day the batteries are only about 70% charged. And with lead acid we're only supposed to use to 50% so it's a small window. The capacity has been going down consistently. I think they are sulfated. I have been in lots of communication with the battery manufacturer and controller/inverter manufacturer. It could be a combo of things - we originally ordered the system when we started building the house but things got delayed so batteries sat longer than expected, then got the system set up in middle of winter and got no sun for months so we charged a lot with a generator and the generator we were originally sold with the solar package was undercharging the batteries. Battery manufacturer gave us recommendations to change settings on the controllers/inverter to try to get the battery capacity back up but it didn't work. They say the AIMS equipment consistently undercharges but AIMS warned changing the settings from their default could affect the batteries worse which it seems to have done. So we're chalking it up to a learning experience and switching to lithium.

Summer energy consumption is between 10 to 15 KW per day. We have a 12KW inverter and it generally shows using 3-4% unless something like the well pump or microwave comes on which uses a lot for a short period. In winter we use more - between 15-20kWh.

Id haul these back to civilization and use grid power to do a complete charge, then equalization charge, for hours and hours....

Did the charge controller switch out of "bulk" too soon?

What did they tell you to use for cc settings?

As @Hedges said these are top quality batteries that should last a while. But i fear you are correct that they spent alot of time discharged without getting charged back up to full.

 

[Dooug]

You may want to look into the duty charges getting them north of the border. When I get back to my laptop I'll try and get that information from a conversation I had last year.

 

[Hedges]

Possibly Midnight batteries will skirt that duty. Not sure, cells would be from China.
There is duty-free for Canada made products imported to US, so I would think same going other way.

Are duties paid for China --> US --> Canada higher than China --> Canada ?

 

[OffGridBC]

Thank you all for your replies, much appreciated.

7kW (STC) of PV in summer ought to supply at least the ~ 21kW of PV needed to cover 15kW consumption and 70% round-trip efficiency. Charging takes hours of bulk at 0.12C and a couple hours absorption. If not fully charged, maybe voltage (or current) settings not correct. Or power harvesting way below the expected 5kW +/- from those panels.

We're getting almost full (sometimes it surges over) the rated wattage of panels in full sun so it's not that. We're getting over 30KW per day in summer no problem by the time charge controllers go into float.

Winter you might get only 2 hours effective sun, depending on exposure and angle. I'd think panels sloped to maximize winter is what's needed.

We change angle of panels in winter to maximize. Before we moved here google said this area gets the most days of sun/year in BC so we expected more, but in winter sun is scarce, not much solar generation. We run generator every day in winter.

Possibly cells need equalization. What voltage per cell (or per 6V or whatever is accessible to measure)?
What specific gravity per cell?

(at least some) Rolls batteries are super-premium quality and expensive, could give 20 years service.
Try to fully charge, as a pack or as individual batteries, test specific gravity, equalize as required.

You're from the frozen north. Lead acid works there, so long as not left discharged to freeze. Lithium works (except in extreme cold) but has to be above freezing. Near freezing charge rate can be 0.05C to 0.15C, comfortable temperature can be 0.5C maybe higher.

We have 16 batteries, 6V each, 48V system. I measured voltage and specific gravity a lot throughout last year and especially this past winter when we tried equalizations, subsequent full charges with the generator (we don't have grid access here), and different setting changes recommended by the battery manufacturer but the readings never went up but actually down a bit. After all that I noticed when I top up the distilled water in the batteries that the fluid is brownish in color rather than clear like it used to be. So we may have pushed them too far.

Batteries are indoors in a closed cabinet with 24/7 ventilation. I don't think we got the premium batteries but was definitely expecting them to last longer, though as seems to be the consensus it was probably a combination of different circumstances of them sitting longer than expected at the beginning (we were encouraged to buy them early because it was during covid when things were hard to get but then they arrived quick and we weren't ready for them), not getting fully charged properly through the first winter, and controllers not fully charging either. Our controller default setting for lead acid is 58v bulk and 54 float, cannot set absorption time as it's done automatically. Rolls tech support said they were consistently being undercharged at those settings and that the absorption time it was doing was too short, so I changed it to 60v bulk / 54 float as they recommended but neither the controllers nor inverter would push it that far (quit before it got there). So we pushed it manually with the generator in winter but batteries got worse. So we decided to cut our losses and look for new batteries.

Id haul these back to civilization and use grid power to do a complete charge, then equalization charge, for hours and hours....

Did the charge controller switch out of "bulk" too soon?

What did they tell you to use for cc settings?

As @Hedges said these are top quality batteries that should last a while. But i fear you are correct that they spent alot of time discharged without getting charged back up to full.

Don't have access to grid power at current location, would have to haul them somewhere. See above for explanation.

 

[OffGridBC]

Possibly Midnight batteries will skirt that duty. Not sure, cells would be from China.
There is duty-free for Canada made products imported to US, so I would think same going other way.

Are duties paid for China --> US --> Canada higher than China --> Canada ?

You may want to look into the duty charges getting them north of the border. When I get back to my laptop I'll try and get that information from a conversation I had last year.

Good suggestion. We are only an hour from Montana and go to pick up things fairly often (once a month). There is no duty on items made in the US or Mexico but for products or components made in China or elsewhere they charge duty. Depends on the mood of border agents too. I was planning to order to have shipped to Montana and pick up there because still typically cheaper than getting it here.

 

[seneysolar]

If kept warm, going lithium will be a great improvement.
You have another learning curve ahead of you with different charge profile and settings for lithium, but you sound like you are willing and eager to learn.
Being completely off grid i recommend to familiarize yourself with the low and high voltage protection features of the specific battery you choose and have a process to recover it if it happens.
I carry an Iota DLS-54-13 power supply on my service truck for this reason. Some charge controllers/batteries need to be woke up after a bms shut down.

 

[OffGridBC]

If kept warm, going lithium will be a great improvement.
You have another learning curve ahead of you with different charge profile and settings for lithium, but you sound like you are willing and eager to learn.
Being completely off grid i recommend to familiarize yourself with the low and high voltage protection features of the specific battery you choose and have a process to recover it if it happens.
I carry an Iota DLS-54-13 power supply on my service truck for this reason. Some charge controllers/batteries need to be woke up after a bms shut down.

Oh man, thanks for the heads up. I was hoping (maybe naively) that lithium batteries were easier - connect and all would run smoothly. We've had our share of issues with our current system. I do want to learn so I understand how it works. If the controller/inverter are set to make sure the batteries don't get below or above the low/high voltage, the batteries or controller can still shut down? I don't want to go through buying new batteries to have them fail in a short time again like our current batteries, so any advice is appreciated on a good battery management system. And recommended equipment such as batteries/controllers that are good quality & work well together, as I don't have any experience/knowledge of lithium. A few people mentioned Midnite coming out with new batteries so I contacted them and they said mid-august. I will look into the battery charger you mentioned. Thanks again.

 

[seneysolar]

Oh man, thanks for the heads up. I was hoping (maybe naively) that lithium batteries were easier - connect and all would run smoothly. We've had our share of issues with our current system. I do want to learn so I understand how it works. If the controller/inverter are set to make sure the batteries don't get below or above the low/high voltage, the batteries or controller can still shut down?

For the most part, everything will probably run smoothly. You may have to tweak settings by .1 or .2 from mfg settings not a big deal.
Sometimes high use systems that do repetitive short generator charging, like in the winter, get cells out of balance. Lithium charges quickly (a couple hours) but every once in while, if not getting much sunlight, id do a longer charge to give the cells time to balance.

An example is this post going on right now-

EG4 imbalance

You just need to understand whats hapens and how to correct it if 1 cell bumps into that high/low limit. It may happen a few times as you get started, but once you get everything set, you're good!

I don't want to go through buying new batteries to have them fail in a short time again like our current batteries, so any advice is appreciated on a good battery management system. And recommended equipment such as batteries/controllers that are good quality & work well together, as I don't have any experience/knowledge of lithium. A few people mentioned Midnite coming out with new batteries so I contacted them and they said mid-august. I will look into the battery charger you mentioned. Thanks again.

Definitely worth seeing what midnite has to offer come fall. Dont be surprised if its delayed, but it will be a quality product.
EG4 batteries are pretty good, might be the best value in a server rack battery.
Also look at SOK for comparison.
Personally id stay away from battle born, just not worth the money.

 

[Quattrohead]

The EG4 indoor Power pro batteries are going to be your best bang for your buck. Couple them with an EG418K PV or pair of 6000XP inverters and you will have the most sturdy power supply you need for your new home.
They have high voltage PV inputs so you can string 10 panels in series easy enough.