Where to start?

General Talk

Moderators: OutBack Moderator Team, OutBack

raysun
Forum Emperor
Posts: 3029
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
Suniva 330 watt panels (12 - 6 strings of 2 in series)
Hyundai 355 watt panels (6 - 3 strings of 2 in series)
Honda EU7000is gas fuel generator

Re: Where to start?

Post by raysun » Fri Jul 10, 2020 4:27 pm

fcwlp wrote:
Fri Jul 10, 2020 4:22 pm
You have a big battery bank. With five parallel strings of the Rolls S-460 (C100 of 460AH and C20 of 350AH) you have 1,750AH @ 24V. Most of us recommend no more than two parallel strings of batteries and a few will go to three. I will typically go with one string in my designs. With parallel strings the string with the lowest resistance gets the most current on charging (i.e., gets hotter than other strings) and most current drawn from when the inverter is inverting.

Can you read the date code on the batteries?

You have 12 solar panels. Given the vintage of equipment they could be anywhere from 100W to 200W panels. So if 150W you have a max of 1,800W or ~64A at 24V using 85% efficiency. Which would be consistent with the MX60 CC which outputs 60A. A Rolls FLA battery is normally charged at 10-13% of the C20 rate or 175A to 228A. So at best you are able to supply only 60A or 3.4% of the C20 rate.

Bottom line the current battery bank is way too large for the amount of PV that is available. If the batteries are still good, this is ok for a weekend cabin as they will have plenty of time to recharge while you are not there. As a retirement location you will have to optimize the battery and the PV supply.

The batteries will definitely need to be equalized. Get some DI water and make sure the plates are covered prior to initiating the equalization with your tech. Do not fill the cells before equalization as they will boil over.

You picked a good weekend to get out of PHX. We will probably just break 100 in Young. For those of you not in AZ, temps are supposed to hit 117 in Phoenix this weekend.
@fcwlp do you recommend trying an EQ charge with the battery in a fully discharged state, or should a normal charge cycle be executed first?

fcwlp
Forum Czar
Posts: 544
Joined: Wed Jan 22, 2020 9:40 am
My RE system: GS8048A, FM80 w/3,600 W PV Fixed, FM80 w/2,700W on Zomeworks tracker, Mate3, 24 Trojan 2V L16 1100AH @ C20, Grid-Tied with Kohler 14RESA LPG Generator and MEP-803 Diesel if needed
I also install and maintain grid-tied and off-grid systems, details will be given for these system if required
Location: 80 miles NE of Phoenix at 5500'

Re: Where to start?

Post by fcwlp » Fri Jul 10, 2020 4:33 pm

Good clarification. An equalization charge should only be done after completing a bulk and absorb cycle.

My guess is the OP will need to do a couple of equalization cycles, monitoring the S.G. during each one. At that point he will likely find some bad batteries and should follow raysun's advice and pick the best batteries and make a smaller bank.

raysun
Forum Emperor
Posts: 3029
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
Suniva 330 watt panels (12 - 6 strings of 2 in series)
Hyundai 355 watt panels (6 - 3 strings of 2 in series)
Honda EU7000is gas fuel generator

Re: Where to start?

Post by raysun » Fri Jul 10, 2020 7:14 pm

fcwlp wrote:
Fri Jul 10, 2020 4:33 pm
Good clarification. An equalization charge should only be done after completing a bulk and absorb cycle.

My guess is the OP will need to do a couple of equalization cycles, monitoring the S.G. during each one. At that point he will likely find some bad batteries and should follow raysun's advice and pick the best batteries and make a smaller bank.
Thinking about this a bit more, I might disconnect each of the 5 strings from each other, and attempt charging one string at a time using the generator and the Inverter charger. That is, if any of the strings have enough residual voltage to even start the inverter (or the MX60 charge controller for that matter.)

Considering that the battery may be well and truly depleted, it may take an external charger to get enough juice into any of the monoblocks sufficiently to bring the system to life. That's why I thought breaking the battery down to 12V pairs and using a standard automotive charger would be a cheap and effective method to rejuvenate them enough to get a sense of whether those particular monoblocks should be put back into service or set aside. A 12V 25A to 40A charger that has a "charge a dead battery" feature would do the trick.

Once at least 4 monoblocks have taken and hold enough charge to power the Inverter, then use the Inverter charger (powered by the generator) to put an actual charge into them at 24V, followed by an EQ.

Tedious process doing 4 monoblocks at a time through EQ, but it will reduce the number of cells being maintained at once, lowering the chance that a shorted or otherwise dead cell keeps the rest of the battery from charging properly.

Also, I see the DC side has a PV (solar panel) disconnect. It should be opened (the panels disconnected from the charge controller) until such time as the system battery starts up the MX60. In fact, there's a charge controller disconnect that should be opened too, until a functioning battery is in the system.

The reason for disconnecting the PV panels is the charge controller can be damaged if the panels are supplying power, but there's no battery to sent it to.

Always connect battery to charge controller, then PV panels.

SandyP
Forum Guru
Posts: 423
Joined: Tue Jun 21, 2011 4:44 am
My RE system: 8 x 190W 24V Suntech panels (4 strings of 2) July 2011
4 x 325W 24V Suntech panels (2 strings of 2) added Sept2018
Mate2
Outback FM60 MPPT (max output lowered to 55amps)
12 x 2V Hoppecke GEL 660 Ah C100 - 24V System
Outback VFX3024 Inverter/Charger
Victron BMV-602s
Honda 5.5kW Genset
Location: Victoria, Australia

Re: Where to start?

Post by SandyP » Fri Jul 10, 2020 7:50 pm

raysun wrote:
Fri Jul 10, 2020 7:14 pm
../..
Considering that the battery may be well and truly depleted, ../..
Yep, I expect they are beyond useful recovery as the plates will be well and truly sulphated (hardened as well).

Time to start planning to get a new battery bank, but to size the battery bank properly you need to know what your expected power usage is going to be. So look at what lights/electrical appliances etc are in the house and get an understanding of their power consumption and how much you will use them each day.

As has been mentioned, parallel battery banks are best avoided, so if the budget allows go for a single string of batteries (ideally 12 x 2V cells for your 24V system).

raysun
Forum Emperor
Posts: 3029
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
Suniva 330 watt panels (12 - 6 strings of 2 in series)
Hyundai 355 watt panels (6 - 3 strings of 2 in series)
Honda EU7000is gas fuel generator

Re: Where to start?

Post by raysun » Fri Jul 10, 2020 9:03 pm

SandyP wrote:
Fri Jul 10, 2020 7:50 pm
raysun wrote:
Fri Jul 10, 2020 7:14 pm
../..
Considering that the battery may be well and truly depleted, ../..
Yep, I expect they are beyond useful recovery as the plates will be well and truly sulphated (hardened as well).

Time to start planning to get a new battery bank, but to size the battery bank properly you need to know what your expected power usage is going to be. So look at what lights/electrical appliances etc are in the house and get an understanding of their power consumption and how much you will use them each day.

As has been mentioned, parallel battery banks are best avoided, so if the budget allows go for a single string of batteries (ideally 12 x 2V cells for your 24V system).
If you need to start (relatively) cheap to get the system up and running, you can put in 4 GC2 (Golf Cart 2) sized battery blocks. They are 6V around 200AH for about $200 each. They would give about 2.5kWH of usable power - enough to keep the lights on and the refrigerator running. They will last about 2 years. (Actually they will last as long as the full replacement warranty minus 1 month, which is when you turn them in, get new free replacements, and then the new ones will last a year or so after that.)

There is a cynical truism in off-grid power: "One will destroy one's first battery." It might as well be a cheap one.

Seriously, the time spent getting used to the system and off-grid living will be a good investment. As @SandyP mentioned, you will need to figure out your power demands before specifying your battery, so buying time to figure that out will be to your advantage. Especially if you step up to the very pricey Lithium Ferrophosphate battery technology we're trending toward. $15k for a 20 year battery is something one wants to get right.

What you have right now in the battery, IMO, is a classic object lesson in going too big because homework wasn't done, and it sounded good to get a big bucket of electrons. The falsehood in that notion is getting a too big battery means you need to invest in maintaining a too big battery, and all that excess is needlessly expensive.

My philosophy is to size the battery for the maximum you will consume in one day, and charge daily. The sun comes up every day, so a daily cycle is there anyway. If its clouds and stormy weather, then that's what the backup generator is for, and if the battery isn't too awfully big, the generator runtime is relatively short - like 4 hours (for my off-grid house that consumes 12kWH/day.)

Last but certainly not least, give yourself a retirement present - hawk the gold watch the company gave you and buy a Honda EU7000is generator. Trust me on this. 😉

guardm16
Forum Member
Posts: 11
Joined: Tue Jul 07, 2020 3:32 am
My RE system: I really dont know what I have

Re: Where to start?

Post by guardm16 » Mon Jul 13, 2020 4:33 am

Thank you everyone. I certainly do have much to learn and consider. As soon as the solar guy looks at the system this week I should know more. I will probably take Rayson's advice and pair up the batteries and use a car charger to see what if any will take and hold a charge. Then cut back to 8 batteries in 2 strings of 4. If that will run things I will consider myself lucky. If I have to go and get some GC2 batteries to get the system up and running then that will be the next step.

Eventually I would like to go with Lithium but only once I feel I have learned enough not to kill them. :grin: :lol:

Does the old MX60 have the ability handle Lithium?

Thanks everyone.

guardm16
Forum Member
Posts: 11
Joined: Tue Jul 07, 2020 3:32 am
My RE system: I really dont know what I have

Re: Where to start?

Post by guardm16 » Mon Jul 13, 2020 4:48 am

Nope, I just found my answer in a paper called:

Deploying OutBack Equipment
with Lithium-ion Batteries

Equipment Compatibility
Inverters
SkyBox: All versions compatible
Radian 8048A/4048A: All versions compatible
Radian 7048E/3048E: Firmware versions 001.005.003 and higher are compatible
Radian 8048/4048: Not compatible
FXR series: All versions compatible
GTFX/GVFX/GFX series: Not compatible
M-series: Not compatible
Charge Controllers
FM Series: All versions compatible
MX Series: Not compatible

SandyP
Forum Guru
Posts: 423
Joined: Tue Jun 21, 2011 4:44 am
My RE system: 8 x 190W 24V Suntech panels (4 strings of 2) July 2011
4 x 325W 24V Suntech panels (2 strings of 2) added Sept2018
Mate2
Outback FM60 MPPT (max output lowered to 55amps)
12 x 2V Hoppecke GEL 660 Ah C100 - 24V System
Outback VFX3024 Inverter/Charger
Victron BMV-602s
Honda 5.5kW Genset
Location: Victoria, Australia

Re: Where to start?

Post by SandyP » Mon Jul 13, 2020 7:40 am

raysun wrote:
Fri Jul 10, 2020 9:03 pm
../..
My philosophy is to size the battery for the maximum you will consume in one day, and charge daily. The sun comes up every day, so a daily cycle is there anyway. ./..
Given that it is to start as a weekender I would go for a battery bank that allows you to use 50% of the Ah capacity over the weekend - so total battery capacity = 4 times your expected daily Ah consumption. It then has 5 days to fully recharge if the weather is poor/cloudy etc.
guardm16 wrote:
Mon Jul 13, 2020 4:33 am
Does the old MX60 have the ability handle Lithium?
You may be lucky and have a FM60 as they look the same as a MX60 :smile:

guardm16
Forum Member
Posts: 11
Joined: Tue Jul 07, 2020 3:32 am
My RE system: I really dont know what I have

Re: Where to start?

Post by guardm16 » Sat Jul 25, 2020 6:47 am

Well after careful work all attempts to resuscitate the old batteries were unsuccessful, the entire bank was DRT. (Dead Right There)

We installed two strings of less expensive batteries (taking the advise from Raysun and others) Should we learn that we need more/better we can go that route, but in the time being if we kill these we will learn something in the process. Thank you everyone.
Attachments
Crown.jpg
bank.jpg

SandyP
Forum Guru
Posts: 423
Joined: Tue Jun 21, 2011 4:44 am
My RE system: 8 x 190W 24V Suntech panels (4 strings of 2) July 2011
4 x 325W 24V Suntech panels (2 strings of 2) added Sept2018
Mate2
Outback FM60 MPPT (max output lowered to 55amps)
12 x 2V Hoppecke GEL 660 Ah C100 - 24V System
Outback VFX3024 Inverter/Charger
Victron BMV-602s
Honda 5.5kW Genset
Location: Victoria, Australia

Re: Where to start?

Post by SandyP » Sat Jul 25, 2020 7:41 am

guardm16 wrote:
Sat Jul 25, 2020 6:47 am
../.. if we kill these we will learn something in the process. Thank you everyone.
Two points to consider (to defer battery death)
1) Do you have an Outback battery temperature sensor?
2) For regular use of the house you will need to double your solar array (and another charge controller) as it is currently insufficient to ensure the battery bank gets fully recharged - unless you are happy using the generator.

raysun
Forum Emperor
Posts: 3029
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
Suniva 330 watt panels (12 - 6 strings of 2 in series)
Hyundai 355 watt panels (6 - 3 strings of 2 in series)
Honda EU7000is gas fuel generator

Re: Where to start?

Post by raysun » Sat Jul 25, 2020 11:03 am

guardm16 wrote:
Sat Jul 25, 2020 6:47 am
Well after careful work all attempts to resuscitate the old batteries were unsuccessful, the entire bank was DRT. (Dead Right There)

We installed two strings of less expensive batteries (taking the advise from Raysun and others) Should we learn that we need more/better we can go that route, but in the time being if we kill these we will learn something in the process. Thank you everyone.
That's a good-sized battery, configured as a sensible two strings. I couldn't get specs from the manufacturer, but assuming a charge rate at 10% of the C20 rating, about 85A will be a practical target. As @SandyP mentioned, more PV infrastructure is in the cards.

In the interim, pay close attention to specific gravity. A good, easy-to-use hydrometer like the Hydrovolt may be helpful.

If the battery is fairly lightly used, and subsequently lightly charged, the electrolyte will tend to stratify. Check the manufacturer's specification on frequency and duration of Equalization charge. As a rule of thumb, if any cell varies by 0.030 or more from the others, an EQ charge is called for.

Keep in touch. Let us know if you have any questions.

EvaaWilli2
Forum Junior Member
Posts: 1
Joined: Wed Jul 29, 2020 3:44 am
Location: Houston
Contact:

Re: Where to start?

Post by EvaaWilli2 » Wed Jul 29, 2020 5:02 am

Thanks for all answers, your advice helped me too

Post Reply