Batteries losing power at 6:00 PM

offpower108

Live in Southern Oregon and have 8 - 6 volt Batteries with solar system.  Sun is out 0800 till 2000 these days.  Never have problem with losing power in the summer.  Now, power goes off around 6:00 Pm and generator kicks on.  Never did this.  Will test cells tomorrow and voltage.  Have noticed lots of build up on cables to batteries .  Sound familiar?  Really want to go with lithium batteries next.  

Thx 
steve

Photowhit

How old are the batteries and what is your system voltage 12, 24, 48?

Sounds like the battery bank has just lost capacity, 4-5 years is about right for inexpensive golf cart batteries. Might get 7 out of Trojan or Crown.

If wired in 4 parallel strings for 12 volt, check your connections and the voltage or better yet the specific gravity of each cell. Oxidation on your connections will likely lead to poor connections. but multiple strings usually works out poorly afte 2-3 years as the batteries don't evenly share the charging or loads.

softdown

90% of my power consumption is from fridges and freezers. So summer is not a solar delight here.

Lithium batteries, in my opinion, are ~ three times better and three times more expensive. Fine if you know you will own for 15 years.

Just replaced a couple cobbled together cables and that seemed to help a bit. Running four freezers and two fridges, my system needs all it can get. Here in the desert it is raining almost every day. Very weird.

offpower108

I have 8 , 6 volt Trojan L16H-AC batteries, I checked all cells this morning and all cells were good except one, it was not reading anything on hydrometer.  Which is red, rechargeable.

I have them is series, and have noticed lots of buildup on cables, cleaned all yesterday.   In afternoon showing 60 V and only 4 amps on Magna Sine, Outback showing in 93.6 V, out 56 V.

Always could watch TV until 730 PM with no problem , fridge on all night.  Now every night for past three days power kicks off kicks off and IM down to 49 V on Magna Sine, generac kicks in.

I want to replace the one battery, eventually go to one 48V lithium battery.  Instead of 8 in series.  (Does one battery last ass long as 8 6 volt in series?  Hard to find Solar people where I live in southern oregon, City of Bly.

thanks for all feedback , I built bridges for the railroad , electrical is not my strong point .

I think the batteries were purchased latest 2018-2019.  Called store tomorrow.

Again Thanks

Photowhit

Trojan L16's should last more than 4 years, have you been maintaining them? Equalizing each month, keeping the electrolyte topped off?

When you say -

offpower108 said:

I have 8 , 6 volt Trojan L16H-AC batteries, I checked all cells this morning and all cells were good except one, it was not reading anything on hydrometer.  Which is red, rechargeable.

Why do you say rechargeable, is this a simple floating balls type hydrometer, or a glass (or plastic) read out type?

Might look to replace the single battery with a dead cell, but I'd be worried the whole battery bank has issues. Before you do, you might want to get a hydrometer that you can check the actual SG readings. It's actually odd for a cell to just die, took most of 10 years for my forklift battery cell to die, even though I know it had been contaminated.

As to lithium batteries, you currently have 370amps(?) at 48 volts or about 17,760 watt hours of storage. Lithium would allow a bit more usable capacity, but the largish LiFePo4 batteries are around 5 kWhs, i would want 3 of them to replace that battery bank. Do your batteries live inside? Lithium batteries don't like temps at or below freezing.

NANOcontrol

My refrigerator runs on a microprocessor.  I wrote into the program a voltage slump test as the fridge is a pretty reliable 120A stress test on the batteries each time it starts. It has been handy pointing out poor connections before they become a problem.   Even those cheap $10 load meters capture minimum voltage, I only connect up the voltage.

offpower108

Hi Photowhit, I check batteries cells and fill with distilled water, I used plastic hydrometer and checked that one cell twice, reading was at lowest red, really no reading. I don’t equalize, are you talking about when the batteries were first purchased and running cables all positive and negative across batteries?  My batteries are in their own three separate boxes, with holes to tie into each other.

Can I just purchase one lithium 48 volt battery, are you saying three 48 volt?  Going to solar store in bend Oregon Thursday, hopefully see what they have and ask further about the cell in battery . My batteries are inside, in three enclosed boxes with air hoses on top of box to vent to outside.  I have had lots of build up on cables this year , never had that before to this level.  Might be issue, cleaned up.

I really need tech or somebody to look at what I have , test entire system.  

Thx

Photowhit

offpower108 said:

Hi Photowhit, I check batteries cells and fill with distilled water, I used plastic hydrometer and checked that one cell twice, reading was at lowest red, really no reading. I don’t equalize, are you talking about when the batteries were first purchased and running cables all positive and negative across batteries?  My batteries are in their own three separate boxes, with holes to tie into each other.

Equalizing is a slight overcharging of the battery bank, It allows low specific Gravity cells to catch up with the fully charged cells as well as keeping the electrolyte from stratifying.

Trojan Tips 5 - Equalization is Key to Extending Battery Life and Performance - YouTube

offpower108 said:

 My batteries are in their own three separate boxes, with holes to tie into each other.

Don't really understand the 3 separate boxes... or perhaps 4? Might as well put them in one box, the hydrogen will pass through most boxes, A hydrometer can be many types, but a simple glass hydrometer is hard to beat, Auto hydrometers with floating balls or leaver are okay for quick looks but hard to record the levels. Hydrovolt is a nice compromise.

Glass hydrometers are available at auto parts store for around $10-15;



Hydrovolt;

offpower108 said:

Can I just purchase one lithium 48 volt battery, are you saying three 48 volt? 

I'm just doing math...

I think the largest commonly available LiFePo4 batteries are 5 kWh capacity, Your current system has 370ah x 48 volt (8 6 volt in series) for 17760 watts or 17.76 kWhs of storage, of which 80% is usable if needed (this is normally very rare and it appears you have a generator kicking on at some point)

I DO NOT KNOW YOUR ENERGY USE!!! you may find 1 or 2 - 5 kWh lithium batteries to work out fine. I don't use a generator, so I would want 3 - 5 kWh Lithium batteries to replace that size lead acid battery bank.

For daily use, I would recommend using LiFePo4 batteries, Yes I guess you could buy and all-in-one power wall type battery-inverter that use lithium ion batteries, and perhaps there at LiFePo4 versions.

Link to one that use to say UL1741, now says uses UL listed cells;

EG4-LL Lithium Battery | 48V 100AH | 5.12kWh Solar Battery (signaturesolar.com)

offpower108

Thanks for info, 

littleharbor2

I built my 11.5 kw LiFePo4 battery from 16 cells including a BMS and active balancer for right around $2,000. As you can see it can be much cheaper to DIY from scratch although that price on the link Photowhit posted does seem pretty good.

offpower108

Checked all battery voltage on the 8 - 6volt batteries , this was at 11:15 Pacific, had 58 .3 for volts on Magna Sine, all battery’s were in green OK except one with bad cell checked by hydrometer beginning of the week. That was in yellow, Weak.  

Should I check at night.  Early evenings when we eat low battery hit.

Was looking at Homegrid Stacked series, lithium batteries, 

offpower108

Will the EG4-LL lithium work with Magna Sine inverter\ Charger

offpower108

Thanks for info, 

offpower108

I have Solarex VLX solar panels, only rated 80 Watts, have twelve of them , solar store suggested some with more watts?  

KenMorgan

i have a home built DIY system that consists of two magnsine Magnum MS 4448 PAE's.  it is powered by a homebuilt lithium (LiFePo4) battery pack.  (chemistries are important here.)   so to clear the air:
4448 PAE x 2
200 watt panel x 56 with 12 left over for later projects
4 BMS's one per 16 cells  (initially I was running 1 bms for 32 cells)
4 tristar SCC to the battery banks.

basically I initially ran 32 cells in a 2P16S configuration or 2 parallel 16 series.  so two cells connected together in parallel (x16) and then those cells connected in series to achieve 48 volts (54.4) without running AC they were more than enough. 

However I  wanted to run AC 24/7 during the rainy months to keep the house dry, so I ordered 32 more and continued to march.  with 64 cells (640 amp hours or about 35Kwh of cells I can currently run up to 7-10 days with no solar and zero issues.  YMMV  

i power one 6' fridge, one 5' freezer, the split pack (mitsubishi) an airpump for the septic system that runs 24/7 and all the lights are LED.  laptop with a 40" screen for movies what not and cell phone charging.  I also power my 1500' shop via the same pack.  it has all LED lighting and only the welder, compressor, and car lift are powered by a 10kw genset (denyo)  it also acts as backup if solar fails vi a magnum generator controller.   

during the winter I only had the initial 32 cells or about 17.5 Kwh of power available (about 320 Ah @48 volts) I had no issues but when I started using the A/C 24/7 in the spring I noticed that power was dropping lower then I wanted for long cell life so i ordered 16 more.  hooked them up had various failures of BMS and inverter due to a lightening strike and ordered 16 more cells along with new BMS's (damaged in lightening strike).  end result is a 1P16S x 4 pack with four individual BMS's going into a busbar that feeds the inverter and receives charge from the solar controller(s) .

currently I use about 160 amp hours or 9Kwh ish per day when i am not there running the a/c constantly and the two fridge/freezer units as well as septic pump.  when we are there nd wasting power we manage to use about 200 amp hours or 10-11 kwh per day.  my system is usually fully charged by 1100 and after that into float with the panels powering everything.

I  could get by with only 1/4 of the batteries but would not have the defense in depth I want for my system.  I have gone 5 days during a typhoon with only two for the battery packs online before the cells dropped to the 30% level.  with four packs i expect to extend that to 7-10 days while I am there.

I can now lose two packs and still be good for 4-5 days with normal use or 7-10 days with all packs.  redundancy  is the key for true offgrid living if your spouse and children are not in lockstep with you.  I personally could live in my camper with 500 watts and 400 amp hours at 12 volts, but my family cannot.  

ITS ALL ABOUT EXPECTATIONS.