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Small Cabin Forum / Off-Grid Living / inverter not reading watts
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bc thunder
# Posted: 25 Nov 2021 13:19

I just hooked up my "good" string.
They were charged at 30a for 6.5hrs
trickle charged for 3hrs
and are currently being charged at 30a while in use.

The second "bad" string are two 6x6=12v
both running off different chargers at 10a

# Posted: 25 Nov 2021 13:32

O you got 50min out of them to get to 50%. How much load?

# Posted: 25 Nov 2021 13:57 - Edited by: gcrank1

If whatever you are running is taking 40a and you are on a charger putting out 30a then you are running on the charger 30 and still drawing 10 out of the bats; that is, they are not charging but continuing to discharge.
More bat calcs:
If those were about 6v 200ish ah bats new after this long cycling abuse w/o being really recharged they may be 80%, so 160ish ah?
In series 6v x 4 = 24v @ 160ah (Both quads in parallel would be 24v @ 320ish ah)
So 50% of a quad would be 80ah usable.
And remember, you have to put back into the bats more ah's than you take out, say 10%)

# Posted: 25 Nov 2021 14:09 - Edited by: gcrank1

Battery chargers....Im confused
Way back, maybe page 1, you said you have an aio with a 40amp charger.
Now we are talking 30amps charging. That for 6.5 hrs then trickled...why the trickled rather than just stay on the 30a? What is this charger?
Neither of those has been specified as to being 24v chargers, or have I missed that?
And now 2 x 10a 12v chargers are mentioned for charging 2 sets of 2x6v series bats for 12v each.
Just 'what' readout is telling you your bats are 'fully charged'? (with only 50% run time it would seen not)
Did you ever tell us what hydrometer readings you got off the 8 batteries when they had been fully charged? They all tested good? No abnormal/bad cell(s) found?

# Posted: 25 Nov 2021 16:15

Theres been way to much info thrown around in this thread.

Maybe it's best to just buy a $20 harbor freight tester so you have a known load. Charge the batteries, load them for a spicing time then check them. At least then you can start with a known AH rating and work with that.

They also sell battery shunt meters that you install on your system and it tells you how much wattage goes in/out. There about $65 on amazon...ops $80 for the 24v version 100a-612v-battery-load-tester-61747.html 1_2_sspa?crid=2S0PM43M5SAHF&keywords=battery+monitor+24v&qid=1637874904&sprefix=Batte ry+monitor%2Caps%2C750&sr=8-2-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyRkFKNFlHRE UxUTcxJmVuY3J5cHRlZElkPUEwMDY1MDU2MUlCUVVXMk5aUkVCUCZlbmNyeXB0ZWRBZElkPUEwNjIzNjQ4MkE 0Q0c1WTg1WkNTUiZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNr PXRydWU=

bc thunder
# Posted: 25 Nov 2021 17:40

BNY i was averaging under 100w on that 55mins.
Just turned the inverter on, the other string lasted about 30mins.
GC My AIO I can change the charge rate. It come default at 60a, but after I read it should be 30a per string, I adjusted it to 30a. So I just put it back to 60a default.
I'm only ever drawing 100watts average.
Your confused lol, my head is swimming right now, but I'm trying to hang on......
I have two chargers in the shed. I used both today. They are both 12v. I put 2 batteries in series to make 12v and hooked to one charger. I did the same with the other two batteries on the other charger. When the charger read full charge, I trickled them. If that's wrong I apologise. I'm doing my best here, and admit I'm in way over my head.
Yes, I told the hydrometer readings, you said bingo, there is your problem.....
Bny I agree there is so very much info here, and once again I feel overwelmed......
I think tomoowro I go back to my plan B. Hook it all up, and drive it in to the dirt, and make a new plan come spring. I don't know what it will be, but it gives me time to think........

# Posted: 25 Nov 2021 18:13 - Edited by: gcrank1

Sadly, you are already in the dirt.
100w / 24v = only about 4.2a per hour; not much.
80ah usable out of each quad
1 quad should give you 19hrs. That you are getting out of each quad 1/2hr to less than 1 hr means you are sucking down to 50% with only 2-4amps.
(I do think it is valuable to know how Each Quad Is Working)
This says you have essentially NO charge above 50%!
That is, IF that '50%' IS True by whatever is telling you that.
If by voltmeter alone it will not be a good read unless the load has been disconnected and rested for at least 2 hrs; the thing has to stabilize internally. Even then the v-meter is only a quick & dirty quick check.
Best would be by hydrometer. You Need To Know, for sure and certain.
With a true h-meter read to know what charge level the quad is at you can do a calc of how much ah's you need to put back in to get near full.
With that calc you can set the charger for the optimum charge for the bats and figure how many hours that will take. That 'C rate' is around .13 by Trojan GC2 specs.
Without getting these bats charged above 50% they are dying.

bc thunder
# Posted: 25 Nov 2021 18:40

I replaced one quad today.
They put a multimeter, and load tester on them, and told me they are full.
When I got home, I cheacked with load tester, and they looked fine, but multimeter showed 6.05, and hydormeter read so far downin the red I didn't even check the rest. I think the 4 I took in were better than these. It has been a 7 week ordeal to replace them, and in the end, it was a different store that stepped up to help me out. It's cold, and dark, but I have them on the battery charger in the shed, to try to get them high enough not to freeze. It's -12c now and going down to -18 tonight. I know these temps don't help my situation, but I am stating to feel these batteries may come from a larger bad batch. I will have a better look tommorwow, but really I'm just about fininished now with the whole thing. I can't keep playing catch up, or Mr fix it, wether or not it,s me or the batteries.

# Posted: 25 Nov 2021 19:18 - Edited by: gcrank1

I get it, Ive hit the wall on stuff myself. Can only imagine what you are going through with deep winter coming on
Bat place told (showed?) you they were good to go.
Home tests said no. I would have to be asking about that.....
You did the load test at home before taking the v-meter reading?
I would have checked the v-meter right off and if full charge would have probably not done the load test, it does draw the bat down. Then I would have done the h-meter (number the bats and count cells from + post on each) to document where each battery started out at.
Tests and meters can tell us x,y, z but the proof of performance is, as the old hot-rodders say, where the rubber meets the road.
You got 1/2hr out of one quad, call it an hour out of the other.
Either the bats are no where near what they should be or you have draw way beyond what you think.
Has to be one or the other.
You say an 'av of 100w draw'; are we on the same page in descriptors here? You say 100w, I divide that by your system 24v to get the actual 4.2amps draw. Amps are an 'hour rating', 4.2 is the amps used in an hour to make your 100 Watts.
Are you adding the aio into your draw calcs? It would seem not. Add that to the 100w/4.2a and it ups the amps you are using. And there are 'inefficiencies' in any system; ie, they never are 100% efficient. It would be good to add at least 20% for that, especially in winter.

bc thunder
# Posted: 25 Nov 2021 19:37

No, I did not add that idle draw. So it would be about 80w + 38w =118w/ 24=5amps ??

# Posted: 25 Nov 2021 19:58 - Edited by: gcrank1

Too many pages and numbers to remember anymore.
A bunch of my recent calc's were wrong so I revised the post(s).
You prev said your av was about 100w, that did not include the aio, right? If so, it is 100 + 38 for 138w/24 = 5.75a (I always round up use amps so call it 6a).
Your supposed 80-100 amp hours should still support that for a good long time. It aint happening.
So again, either the bats are not fully charged or your draw is far more than you are calc'ing.
I only count my device draws too, so your numbers are likely right; cant imagine some huge draw you havent been aware of.....
I dont know where to go with this, Im about tapped out too

bc thunder
# Posted: 25 Nov 2021 20:14

The one battery I tested tonite, still in my vehicle, when I got home, with the hydrometer tested at 30%
I'll look at the others tommorow, but if that's where I have been starting from, it's a long steep hill to clime. If I don't like my test results tomorwo, I might slip into town and buy 2 12v marines. If they are a vast inprovement, I'll grab 2 more the next day. It might be worth the piece of mind just to see......

Well I'm off to watch King Richard and relax......

bc thunder
# Posted: 26 Nov 2021 10:27

Hey GC would you check my math here, incase I have this wrong?
Batt cell average 1.245
temp -14c
14+27=41 41/6=7 7x.004=.028
1.217=70% soc

# Posted: 26 Nov 2021 10:44 - Edited by: gcrank1

Math is good.
70%soc is pretty puny.
Where my head started this morning:
Lets say 80ahs usable in a quad at 100% (now old, stressed bats)
You have a 6a load so should be able to go 13+hrs to 50% soc; ya get an hour. Basically you are at 50%soc when you started.
That means you have to stuff 80ahs back into the quad. Just for the calc, a 40a charger should do that in two hours BUT, that isnt how fla bats work. The 'bulk' charging starts out strong then to 'absorb' then tapers down to a 'float/trickle'. So the last part to full charge can take longer than the initial bulk. I typically used to take a deeply discharged 12v marine 100ah grp27 bat home and put on the home 10a charger for overnight, give a check next morning and usually let it run all day. I badly abused some of those bats, regularly discharged below 50%soc, yet 24ish hrs on an old automotive 10a charger and was good to go again.
So for you to do 6.5 hrs on a 30a charger should have put far more ah's back in than 1 hour's worth at 6a load.
Maybe your old bats cannot really take a charge anymore?
Those new ones Need To Be Fully Charged Before Putting Into Service or they too will die. Just the way fla bat are.

bc thunder
# Posted: 26 Nov 2021 11:10

Thanks for the math check.

These are the new batteries, I'm working on.
I got them (some atleast) at 30%
I now have two @ 70%
1 @ 75%
1 @ 80%
they are on the charger now outside, but I'm not sure if the charger will keep putting out, if it thinks they are full???

If I get these to where they should have been, I'll then start a full recovery on the original string.

# Posted: 26 Nov 2021 12:16 - Edited by: gcrank1

Man, that is SAD that they sent you home with bats that were'nt at least 80%! Almost like they figured you for the guy to dump their left-over bats on for the warrantee?
No idea about your charger profile, it could be cutting off or going to low amps float/trickle when they are far from full. If that is your best charger maybe its been doing you in? Is it programmable; ie, can you change the set-point voltages and/or make do only Bulk and Absorb?
My 'old dependable' for when in doubt is like 40yrs old, an old transformer unit that everybody used back in the day. Are your 2 small 12v 10a? chargers old style?
That said, maybe when the big fancy one says Full check what voltage it is reading (rather than just 'full') then check that against your hand-held v-meter. Coming right off the charger they should read somewhat higher than the fully charged 'chart' voltage because they need settle after a few hours and end up at the full charge reading for voltage.
At any point you could verify with the h-meter that All Cells read fully charged or not, it is the gold std test.
If They are Not: put them on the old style chargers to finish charging. Get them to where your hand v-meter and h-meter both agree they are fully charged.
When they finally do, then you would know that when your hand-held v-meter reads what a full charge should be for your bat type it correlates with the h-meter as Fully Charged.
That is the point that you can put them into service and power up a given load, run the load for Y hours while checking every hour how your hand-held reading falls. It should track in a pretty steady way over time to, say, 75%soc. Example: IF you had 100ahs usable (from a 200ah fla bat-bank) that 75%soc would mean you used 25a. At your calc 6ish amp av. load that would be 4 hours.

bc thunder
# Posted: 26 Nov 2021 12:34

One is a small 2/10a charger, the other is a bigger 2/10/40/enginestart. Both are at least 7 years old, and showing it. The 40a is showing full, and the amps have dropped down to under 10, I think.
The smaller one has lit up green indicating charged.
I'll see soon enough.......

# Posted: 26 Nov 2021 12:42

Well, 10a is 10a no matter which charger it is, IF it is really 10.
Just know at the 10 it takes longer to get to top.
Knowing where the 'switching' down takes place will help you calc.

# Posted: 26 Nov 2021 13:16

Quoting: bc thunder
One is a small 2/10a charger, the other is a bigger 2/10/40/enginestart. Both are at least 7 years old,

The 2/10/40/enginestart charger sounds like a twin of a battery charger I have in the garage. IF yours is the same it is NOT a smart charger. The 2/10/40 refers to the maximum output that may be selected; choose one of the three for charging at one of the rates, maximum. The charge rate tapers off as the battery gets full. No bulk/absorb/float like a smart charger such as the family of chargers sold by Iota. The engine start setting allows a brief surge.

Of course maybe I missed seeing you mention just what you have and maybe what I just wrote is completely wrong. I am just wondering as you seem to be having more than your share of troubles.

bc thunder
# Posted: 26 Nov 2021 13:50 - Edited by: bc thunder

Yes ICC thats the one, and yes amps drop way down at the end. They have been chrging now for thirteen hrs. The little charger has done nothing, it won't charge with the green light on.

The good news is the two on the big charger are coming up, but this will take a long time, if it does work. Then the other two. Then try the other 4 again.

The bad news is I talked to the store, they said I have about the same chance of recovery as I do boiling the acid, because they are 6v

# Posted: 26 Nov 2021 16:55

Dosnt your all in one system have a charger on it? Thses older transformer based chargers leave alot to be desired as you see. Even that 40a one will only do 10a on a dead battery. This could by why it's taking for ever to charge. It's only ever going to do 10a max.

Iota makes RV onboard chargers that can do 3 stage charging or a forced bulk. I paid $100 for a 12v 30a charger. I generaly only use it in forced bulk setting as the solar can do the rest.

bc thunder
# Posted: 26 Nov 2021 17:16

The AIO cc seems to recognize the low capasity as full, thereby not over charging, hence fast to charge, fast to depleat. I'm up at least 80% on all the 4 new batteries, but having a hard time braking thru that barrier. I am switching the chargerbetween the two 12v strings, in one hr intervals, as they are starting to bubble. I might have to stop for the night and let them cool off over night, and blast them again tommorw morning, to see if I can get them over that hump.
I am so sick of this now, if they fry, so be it.
At least I tried.........

# Posted: 28 Nov 2021 14:46 - Edited by: gcrank1

A little bubbling is ok, A Little. If it is vigorous it is too much. If the case is just warmish is Ok, hot is Too Much.
The end grind to full charge can seem glacial, the amps in are soooo slowwww. And if the old batteries had never seen 'full charge' they may never get there now. The new bank should, Better! they are supposed to be new. Btw, it can take a few light cycles of use to get them to optimum.
If you havent seen my thread 'FLA Rescue' you might find my testing process of interest. Even though it is for 12v the process is the same for 24 only with different 'numbers'.

bc thunder
# Posted: 28 Nov 2021 14:56

43.5 hrs on charger, 62 hydrometer tests, -1c to -18c
I took them off at 1pm today, its now or never.
I got 2 uptp 95%, and 2 upto 90%
But couldn't get them to budge past that.
They were bubbling real good at one point, but I started hourly checks, and rotated them on and off the charger, which produce light evervesence like bubbling.
I'm going to try them out. If they work ok, geart. If not, It's been a learning experience..........

# Posted: 28 Nov 2021 17:26 - Edited by: gcrank1

Ok 50/50 within '5%' and wont take no more, Im with you to give a go.
These are the new ones, right?
So, lets say the quad should, at this, make 200ah/24v.
In watts thats 4800/2400 'usable to 50% soc'. I do not like going that deep at all, my target is 70-75%soc, that equals 25% to 30%dod(depth of discharge) Farrr easier on fla bats.
So you have, say 1200 (@25%dod) to 1440w(@30%dod) to not abuse the bats.
You aio uses 38w, per hour, x 24hrs, = 912w !
Sadly, your aio uses a good % of your bat bank just running itself.
Your prev mentioned 100w usage would use up the 25% in about 12 hrs, 30% in 14'ish, 50% in 24, really more like 20-22?) depending upon the Real Avail watt hrs.
So, dont draw the single quad down Too Far! or you will be hours upon hours at your charge rate trying to fill em back up (again). Shallow discharge/min use of the aio, will be your friend, even after you get both quads paralleled back together. By all means min the use of power for now!
I suggest running your calculated 100w load for 2 - 4 hours. That should pull 200w - 400w off, an easy calc from YOUR est available watts.
Then check your soc to verify the calc.
If that works out you will have verified some of the power profile of this quad (it wont apply to any other).
Pls try to keep no more than 25%dod (that means try, in my real world it turns into 30%, lol).

bc thunder
# Posted: 28 Nov 2021 18:42 - Edited by: bc thunder

Sadly I'm at 70% right now........
It is very underwelming......
Turned on around 3pm, with some sun (100-200w) till about 4pm, turned it off and on a few times trying to get to 7pm, when I would turn on the generator.
Even with turning on and off, and with some sun, I might not make 7pm
Voltmeter agrees.......
The cold will steal some power (only -3c), and i'm starting from 90%, but this just feels wrong. Right from the day I first hooked up, back in Aug, something just feels wrong.
Maybe my first hunch was right, the AIO is sifing off power. I don't know. The dealer has stopped returning my calls, the battery guy won't return my calls.
I just don"t know anymore...........

# Posted: 28 Nov 2021 18:44

Re. charging:
Remember that for every hour you run a given load, in your case '100w', you have to re-charge a min. 10% more back in.
We hope that our chargers pump in what they are set for. The only way to tell will be to know what soc you begin charging at and time how long it takes to get back to where you started.
From what you have experienced the fancy meters that read actual amps or watts in and out may simplify this. I dont have one....yet.

# Posted: 28 Nov 2021 18:56 - Edited by: gcrank1

Get the charger going on those bats asap.
This is with the new bat bank charged to 90-95% verified via v-meter and h-meter?
And only mere hours to 70% (which by my calc of your 100w load should go 12hrs to 75%soc)
As said before,
1) you either have a BAD bat-bank (not likely with the old and new acting pretty much the same)
2) Or, the load is FAR more than you have calculated.
Your other stuff you run is all off the aio?
I would want to get/run a stand-alone psw inverter; I am not confident in the aio.

bc thunder
# Posted: 28 Nov 2021 19:30

I'm running off the generator now.
Tommorrow I'll charge again in the morning, and at first light use the hydrom.
This is the new 90% bat bank. I haven't started the old string recovery, don't know yet if I'll bother.
My entire cabin load:
Internet: 75w/80w can be 150w at start-up for 30 sec or so.
Tv: 30w
Laptop charger:30w
led bulb: 5w/7w
I don't use the tv, and the laptop charger at the sametime. Turn one on, the other off, then reverse....
The AIO: I was told 38w
Call it 200w tottal just to be safe (but it never is), I don"t think I could get 6hrs to 50% soc
Tomorrow is suposed to be cloudy, I'll unhook the array and see how far I get on battery alone........
If I replace the AIO, I need a complete new system, from top to bottom. I don't want to spend another dime on solar till I know what the problem is for sure.
Some say buy new batts, some say buy new system, some say more array. I'm not rich, and even if I was, I'm gunshy for sure.......
Just don't know whats next

# Posted: 28 Nov 2021 20:32 - Edited by: gcrank1

Id be running the charger off the gen When Ever the gen is running, it is the smart thing to do , a wise use of energy. Charge 'something', no downside.
With a cloudy 'low-solar' day I wouldnt discon the array, not much if anything incoming, extra work, why bother, wont prove anything.
You dont need a 'whole new system'.
You have chargers that run off the gen
You have array
You have batteries
(What voltage ac are the things you are running?)
Get just an inverter (not an aio) that you hook to the bat bank, that is one set of wires from quad to inv, its easy. Get it in a 'size', amps output that exceeds your highest surge load but not so large that it far exceeds your loads (costs power doing nothing). LOTS of info online on 'how to choose an inv'.
The output from the inv is easy too. The better, and more expensive ones hardwire into your service box. Do you have one?
Or, the simple ones you 'plug into' (mine).
Fwiw, on my 12v bat-bank (2 x 100ah/ 100 usable to 50%soc) I have a 300w psw inv hooked up all the time. Overnight, with it on but nothing running, the next morning I cant measure the bat charge diff in voltage. It is nothing fancy or expensive, bought it off Amazon, but it is 12v, not 24v (bet 24v is more expensive?)
I have run a 10a load without issues, it should run 15a no problem (havent tried).
It has a usb port and a 'std' duplex outlet on the face. I plug into it, run the cord to a multi-outlet strip; I keep my led light cicuit plugged in and what ever else I want to run I plug in as needed (that keeps things in order).
Basic, simple, works great.

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