Floating voltage..

aussie_paul · Guru

Floating voltage..

Joe50 · Guru

Hi Paul, 13.2v seems to be about right - that's the voltage showing on my Victron BMV-702 battery monitor when the charger (Redarc BCDC1240) goes to Float (gets to around 14.4v when in Absorption).

Joe

Jaahn · Guru

Hi Paul smile

What do your batteries require ? They will have a spec for the voltage required. Sounds a bit low to me but if they are not being worked it does not matter much.

Jaahn

macka17 · Guru

It's about right on Solar.
With AC Chargers on float.
Youll be around the 12.5 to 12.8v. They all go UP on charge rate. then down to float.

aussie_paul · Guru

Jaahn wrote:
Hi Paul
What do your batteries require ? They will have a spec for the voltage required. Sounds a bit low to me but if they are not being worked it does not matter much.
Jaahn

Hi Jaahn, just wondering if the controller float is a little low. Trying to find battery specs without taking them out. Info somewhere on a couple of recovered data external HDs!!! Just got to find it. biggrin

Aussie Paul. smile

PeterD · Guru

I would not worry about the float voltage being too low. The main thing is having enough solar power to replenish the battery daily.

AJC · Veteran Member

Hi Paul,

The Prostar manual says 13.7V is the float voltage (all battery types) so yes, you're spot-on, at 13.2V the battery float voltage is too low. (I'm assuming you have enough solar coming in and no big loads connected).

The regulator and battery should be within a metre or so of each other, and have a decent-size cable connecting them. If not, you may be losing voltage along that line. Remedy by thickening up on the cable, or reduce the distance (or both). (the Prostar also has "sense" terminals to overcome this volt-drop, they simply need a thin cable directly onto the battery).

Hope this helps - if not, let's explore further.

Cheers

AJC

aussie_paul · Guru

AJC wrote:
Hi Paul,
The Prostar manual says 13.7V is the float voltage (all battery types) so yes, you're spot-on, at 13.2V the battery float voltage is too low. (I'm assuming you have enough solar coming in and no big loads connected).
The regulator and battery should be within a metre or so of each other, and have a decent-size cable connecting them. If not, you may be losing voltage along that line. Remedy by thickening up on the cable, or reduce the distance (or both). (the Prostar also has "sense" terminals to overcome this volt-drop, they simply need a thin cable directly onto the battery).
Hope this helps - if not, let's explore further.
Cheers
AJC

I have 6B&S cable to the controller, 2.5 meters. The voltage at the battery is the same as at the controller.

Aussie Paul. smile

Jaahn · Guru

aussie_paul wrote:
AJC wrote:
Hi Paul,
The Prostar manual says 13.7V is the float voltage (all battery types) so yes, you're spot-on, at 13.2V the battery float voltage is too low. (I'm assuming you have enough solar coming in and no big loads connected).
The regulator ---the Prostar also has "sense" terminals to overcome this volt-drop, they simply need a thin cable directly onto the battery).
Hope this helps - if not, let's explore further.
Cheers AJC
I have 6B&S cable to the controller, 2.5 meters. The voltage at the battery is the same as at the controller.
Aussie Paul.

Hi Paul smile ,

My suggestion would be this. Do not panic yet hmm Put the unit into use, or into the sun, so the charger does go to full voltage and then drops back to float, while monitoring the voltage regularly. That way you will see exactly what is happening.

There could be a bad connection into the regulator or even a solder joint inside that has become a dry joint if it shows that the float is low. But if the set voltage is OK then only a bit of electronic trouble shooting will say what is wrong.

Sometimes a bad earth somewhere can give silly readings with a multimeter and may fool the regulator too. I have had that problem with my MH and the battery was not fully charging.

Jaahn

-- Edited by Jaahn on Wednesday 25th of October 2017 08:56:59 PM

-- Edited by Jaahn on Wednesday 25th of October 2017 08:59:25 PM

aussie_paul · Guru

Jaahn wrote:
Hi Paul ,
My suggestion would be this. Do not panic yet Put the unit into use, or into the sun, so the charger does go to full voltage and then drops back to float, while monitoring the voltage regularly. That way you will see exactly what is happening.
There could be a bad connection into the regulator or even a solder joint inside that has become a dry joint if it shows that the float is low. But if the set voltage is OK then only a bit of electronic trouble shooting will say what is wrong.
Sometimes a bad earth somewhere can give silly readings with a multimeter and may fool the regulator too. I have had that problem with my MH and the battery was not fully charging.
Jaahn

-- Edited by Jaahn on Wednesday 25th of October 2017 08:56:59 PM

-- Edited by Jaahn on Wednesday 25th of October 2017 08:59:25 PM

Ok Jaahn, thanks. I will connect the AC power and see what the 240v charger does. I don't use the Setec, I have a stand alone 240v charger.

Aussie Paul. smile

Tony Bev · Guru

I am not an Electrician

I have more or less the same concerns, Paul

I have a CTEK 250S Duel DC/DC charger and 2 x 120 AH Bosch AGM batteries

The vehicle sits for weeks at a time with the solar charging the batteries, and nothing apart from a few milliamps running the volt meter

Sometimes I will see the batteries showing 13.2 volts with solar power going into the DC/DC charger, but nothing coming out to the batteries
Many hours later I will see the volt metre once again at about 14.4 volts

My theory is that the batteries are fully charges, and that during the very last stage, the voltage will drop below the normal float value

Hopefully you can see what I mean by looking at the picture at step 5, and seeing the pulse line has dropped below the float line

Hope that makes sense

CTEK charging steps.png

meetoo · Guru

I think some chargers give a pulse (a short bulk charge) every 24 hours or some such, as those ones say that a continual float forever is not great for the batteries. A confirmation or otherwise from an expert on this would be advisable.

Cheers, John.

aussie_paul · Guru

Today I had the house batteries at 11.9v with the Prostar indicating LVD with solar not connected. I connected the solar and set video camera up to record from around 11 am. Overcast for most of the day ending with some full sun late arvo. These are the indications for voltage and solar input each hour.

Not sure if there is any value in these figures

Aussie Paul. smile

Tony Bev · Guru

Hi Paul

As you are aware, I am not an expert

I have no idea what numbers the Prostar is supposed to be showing, as my DC/DC charger/regulator, does not have numbers

I would also like an expert to tell us what the numbers represent

I can only make a wild guess, which could be well off the mark

First picture, 10.5 could be saying that this is the low voltage it will shut down at
Second picture, 12.9 is hopefully what the fully charged battery/s are at rest
Third picture, 18.0 is hopefully what the solar panel is sending to the regulator
Fourth picture, 4.6 ???
Fifth picture 12.9, same as second picture
Sixth picture, 12.7 could mean that something is drawing power from the battery, while the solar is (you mention overcast), putting less in, than what is being used
Seventh picture, 12.6 same as sixth picture
Eight picture, 6.1 ???
Ninth picture, 12.6 same as sixth picture
Tenth picture, 12.5 same as sixth picture
Eleventh picture, 3.0 ???
Twelfth picture, 4.4 ???

aussie_paul · Guru

Thanks Tony, there are two pics for every hour, the battery voltage and the solar input. Also you can see the 3 LEDs on the right under the display showing the stage that the regulator is in.

I left the solar disconnected over night and the battery voltage showed 11.9 just now. There is 0.5 amps being drawn all the time the batteries are connected to the DC system. .06 when not connected.

Reconnecting the solar just now the voltage is showing 12.1, the solar input 2.6 amps and the LEDs showing in the absorption mode. Cloudy day here at the moment.

Aussie Paul. smile

-- Edited by aussie_paul on Tuesday 7th of November 2017 05:54:27 PM

aussie_paul · Guru

My thoughts now are to disconnect the batteries (2) this evening and take note of individual battery voltage. Tomorrow see what the volts are showing.

The second battery was installed a couple of years ago and the one that came to us with the van is possibly the original. Pic attached.

Aussie Paul. smile

aussie_paul · Guru

Just checked the voltage with the same multimeter.

Disconnected battery volts at 10.30 pm.

Old 12.31v

New 12.25v

Aussie Paul. smile

Tony Bev · Guru

I am not a techi, Paul

In layman talk, I would be saying that the batteries, are heading to be toast

I found one way to check deep cycle batteries, was to charge them until they held about 12.8 volts
Then turn something on, where you know what amps are being used, when the batteries drop to about 12.4 volts, calculated the time in hours, to find out how many amps were put out

As an example my original 100 AH GEL battery, was down to 12.4 volts after using 10 amp hours
This meant in my eyes, that 20 amp hours would be more or less, all I could expect, without recharging

After removing this battery and setting it up in the shed, it would hold 12.8 volts just sitting there
As soon as I put a couple of amp load on it, it very quickly ran down

In the RV, the solar was making it look a lot better than it actually was

Looking at your pictures again, after your explanation

Picture 10 showing 12.5 volts, with (as you say only half an amp being drawn)
Something is radically wrong, as the battery/s (one or the other) is/are not holding their charge

Then next morning (after disconnecting everything around 10.30 pm) Old battery 12.3 volt, New 12.25
I would take a guess and say that at least one battery is toast, perhaps pulling the other down to its level

After a charge, I would be disconnecting both batteries from the system, and from each other, then see if at least one battery was salvageable

I successfully ran an old (unknown age/ use or abuse), 100 AH GEL Battery, and also a 55 AH AGM Spiral Bound Battery
I had two x four way switches (same you use to find in 4x4 vehicles)
I would charge the batteries one at a time, by isolating them from the DC/DC charger, through one switch
I would also draw power from one at a time, by isolating them from the house 12 volt circuit, through the second switch

Hopefully a techi will come along and enlighten all of us

aussie_paul · Guru

This mornings resting voltage.

Old 12.23

New 12.29

I will charge them to float all day and disconnect and seperate the batteries tonight. I will find some globes to attach to each individual battery tomorrow to measure as you said Tony.

Ok, lots of dribble from me!!! biggrin Am I likely to get to the bottom of our energy situation with what I am doing? Or, can someone give me a step by step set of instructions to me get to the bottom of and UNDERSTAND our energy situation?

Aussie Paul. smile

T1 Terry · Guru

Hi Paul, the load test is the only way to actually know if the batteries are still functioning or just lead weights. A 60w globe on a 100Ah battery will give a C20 load and this it the load just about all AGM, GEL and flooded cell deep cycle batteries are rated at, 5 amps for 20 hrs until flat or 5 amps for 10 hrs till they drop to 12v while the light is still connected. That 12v under load is the 50% State of Charge indicator, 5 amps @ 12v = 60w, 5 amps x 10 hrs = 50Ah. If you get 5 hrs before the battery drops to 12v or less then the battery has lost half its useable capacity and sort of borderline as to whether the battery will do the job you have in mind.

First step though, charge the batteries to 14.8v and keep it there for at least 4 hrs, then down to 14v and keep it there for at least 12 hrs. These batteries are flat or have no remaining capacity due to either old age or sulphation. The high charge rate will clean the plates a bit, if old age is the problem there is no material left so cleaning them will result in them collapsing, but they were dead anyway so you just verified it. If they are just sulphated and still have good material under the coating they will come good.

T1 Terry

Jaahn · Guru

Hi Paul, smile

I agree with other posters that your batteries are not looking good. Lead acid batteries do not like being at the low voltages you are showing. If they are not 'toast' now they certainly will be unless you get them fully charged regularly.

So as Terry said charge them fully, for some time to get them as good as they can be. I would not go to 14.8 for long, as they are gell but to 14.2/14.4 V. However you are limited to what the charger will do anyway. Do one at a time by disconnecting the other one.

Then put the headlight globe on one and see how long it takes to get down to 12V. Then do the other one. Then report back. confuse Do not forget to recharge them after the test.

Jaahn

PS What is drawing the 0.5/0.6 amps all the time ? That is about 12Ahr going out every day. No wonder the batteries are down. A couple of days of that and they will be flat without constant charging.

-- Edited by Jaahn on Wednesday 8th of November 2017 08:25:13 PM

-- Edited by Jaahn on Wednesday 8th of November 2017 08:25:55 PM

aussie_paul · Guru

Thanks guys. Jaahn, the .5 amp seems to happen as a result of the Setec charger. The solar is charging during the day as the van is in the open. I no longer use it as a charger so I guess it is the DC distibutor, and I really haven't looked at what sections of it are used and what might be drawing current for no reason.

After removing a globe from the Pajero I now have the oldest battery disconected, voltage measured, and running the globe using 4.16 amps. I have my phone alarm set for an hour, and volts being monitored with multimeter. Second battery now done.

Today's van battery testing

Old battery disconnected 13.19. 1 hour drawing 4 amps. 12.71 loaded and 12.84 disconnected

Newer " " 12.84. 1 hour drawing 4 amps. 12.53 " " 12.77 "

Aussie Paul. smile

-- Edited by aussie_paul on Thursday 9th of November 2017 03:21:41 PM

-- Edited by aussie_paul on Thursday 9th of November 2017 03:22:50 PM

-- Edited by aussie_paul on Thursday 9th of November 2017 03:26:14 PM

aussie_paul · Guru

After re reading the instructions I am currently running down the older battery from float.

After 3 hours with light globe load, voltage is 12.40v.

After 4 hours with light globe load, voltage is 12.31v.

After 5 hours with light globe load, voltage is 12.22v.

Aussie Paul. smile

-- Edited by aussie_paul on Thursday 9th of November 2017 09:23:22 PM

-- Edited by aussie_paul on Thursday 9th of November 2017 10:05:24 PM

-- Edited by aussie_paul on Thursday 9th of November 2017 11:08:09 PM

aussie_paul · Guru

Baby sitting these two beauties today so their folks can get some uninterupted landscaping done.

Running the newer, bought in 2014, battery down today.

Unloaded voltage 12.90. Added 4 amp load.

2 hours 12.44v

4 hours 12.35v

5 hours 12.29v

6 hours 12.23v

7 hours 12.18v

8 hours 12.12v

9 hours 12.06v

9.5 hours 12.03v

10 hours 11.99v so disconnected battery.

Aussie Paul. smile

-- Edited by aussie_paul on Friday 10th of November 2017 05:16:36 PM

-- Edited by aussie_paul on Friday 10th of November 2017 05:17:50 PM

-- Edited by aussie_paul on Friday 10th of November 2017 07:13:25 PM

aussie_paul · Guru

Anyone have any idea what could be causing the .5 amp discharge when I connect the battery bank to the Setec charger?

Aussis Paul. smile

Jaahn · Guru

Hi Paul smile

I looks like those batteries may be down to about half capacity, probably as expected. Not "toast" yet.They might get you by for a while yet if you sort out some good charging and find the current drain. LA batteries need to be bought up to full charge every day to last well.

I have no idea what is inside a Setec unit, but if the mains are disconnected then you should be able to feel what ever is hot to touch dissipating that sort of power in there.

Good Luck Jaahn

aussie_paul · Guru

Jaahn wrote:
Hi Paul
I looks like those batteries may be down to about half capacity, probably as expected. Not "toast" yet.They might get you by for a while yet if you sort out some good charging and find the current drain. LA batteries need to be bought up to full charge every day to last well.
I have no idea what is inside a Setec unit, but if the mains are disconnected then you should be able to feel what ever is hot to touch dissipating that sort of power in there.
Good Luck Jaahn

Thanks Jaahn, the van sits outside in the sun with nothing being used except for that unknown current drain. I would have thought that the Prostar controller would have them up to full charge every day.

I realise that when away using the van the batteries have to run own our needs AND charge the batteries.

I guess not knowing enough in the early days I have mistreated these batteries while I was learning and adding solar panels(now 320watts) dc/dc charger, and the dedicated 40 amp 240v charger.

Should I run the batteries down and then hit them with 40, 50, or 60 amps up to 14.8? If so would I do this to each battery separately?

My job for the day to track down the Setec current drain.

Aussie Paul. smile

aussie_paul · Guru

I have been a bit more exhausted lately so not much progress made. I have had the Setec apart and disconnected the charging side of things. I disconnected each circuit from the Setec and tested to document what they run and the current draw. I have some sort of "short" happening on two of the circuits where the lights dim and the self resetting overload protection kick in. It wasn't doing this before so possibly me mucking with and moving wiring has made it worse. One short is on the TV and the other is on one of the light circuits.

I have always wondered why there was more voltage drop to the TV than I would have thought, but because the wiring behind the Winegaurd booster is very difficult to get at and the tv power probably goes across in the roof cavity to the TV it has been in the too hard basket!!

Aussie Paul. smile

p.s. I have now found that the .5 amp drain is in the TV circuit. I am at least narrowing it down!!

-- Edited by aussie_paul on Tuesday 14th of November 2017 03:11:58 PM

meetoo · Guru

aussie_paul wrote:
I have been a bit more exhausted lately so not much progress made. I have had the Setec apart and disconnected the charging side of things. I disconnected each circuit from the Setec and tested to document what they run and the current draw. I have some sort of "short" happening on two of the circuits where the lights dim and the self resetting overload protection kick in. It wasn't doing this before so possibly me mucking with and moving wiring has made it worse. One short is on the TV and the other is on one of the light circuits.
I have always wondered why there was more voltage drop to the TV than I would have thought, but because the wiring behind the Winegaurd booster is very difficult to get at and the tv power probably goes across in the roof cavity to the TV it has been in the too hard basket!!
Aussie Paul.
p.s. I have now found that the .5 amp drain is in the TV circuit. I am at least narrowing it down!!

-- Edited by aussie_paul on Tuesday 14th of November 2017 03:11:58 PM

Love your tenacity Paul. smile

Cheers, John.

Tony Bev · Guru

Do not wish to put you on the wrong path, Paul

My TV amplifier uses about half an amp, but it also has a small red LED light showing when it is switched on, with a push type on/off button

I would assume that one day the LED light may fail, and the amplifier is still switched on, thus draining the battery at about half an amp

The easy way to check, is to check at the end of the antenna lead, there will be 12 volt (or so) running up the lead to the part on the aerial, when the amplifier is switched on

Hope that this info is useful