battery gurus help reqd

Hi Collyn,

12.08 is across the battery after 5 hrs, now. No change.

It reads the same with my little 12v flouro light running.

the solar connection on the regulator reads 19.30 (connected)

the battery connection on the regulator reads 14.58 (connected)

Just to clarify the 80w panel is connected to the battery via 20 amp regulator

http://www.jaycar.com.au/images_uploaded/slabatts.pdf

Interesting info on SLAs

Notso

at the solar and battery positives I get a reading of 4.61

the battery reading isn't going up at all (over 5 hrs)

I do have a 6 amp charger but first wanted to see the solar at work

I have that site bookmarked but it doesn't address this problem as far as I can see

Yep, it was just some info on how to look after em.

If it's only putting 4.6 amps into the battery it is going to take a while to charge your battery.

One of the things the battery makers recommend is that a charger should supply about 10 to 13% of the batteries Amp Hour Capacity, so for a 100 AH battery a minimum of 10 to 13 Amps would be recommended for Charging.

The only other thing, is there a high resistance somewhere, and it could be internal with sulphation on the plates.

4.6 amps is approx the rated current for 80watt panel. BP 80watt is rated at 4.76A.
If your batt is only half charged (50amp hours) it will take 50 devided by 4.6 hours of charge to bring the battery to full charge. Remember the charge is related to the suns intensity and time of day so you may not be getting the full charge all daylong. If your batt has become stratified (left at a low rate of charge for some time) it will take longer to bring the acid off the bottom. A batt charger will help to do this. You havn't mentioned what rating yor batterys capacity is stated at. For solar applications it is normally the C100 rate. Just remember you can safely charge a lead acid battery only to 10% of the C10 rating. If your 100A/H batt is has the C100 rating that will mean about 8Amps max. If you have a hydrometer check its reading - should be about 1.200-1.300 if fully charged.
Gaz

11 hours????? Not that I'm in any hurry but jeez.....in half an hour it went from 12.08 to 12.48 so I was hoping for better, even bearing in mind the charge slows as it gets near to capacity.

It's a 100ah battery and sealed, so I can't use a hydrometer.

Might pay to invest in one of those megapulse battery restorers with 5 batteries to run.

this 80w panel is certainly enough to keep my fridge running with hardly any loss, conditions permitting.

yep. It's the bloody regulator. I'm new(ish) to this and I've had to bodge up a suitable connector from solar to battery - anyway it's galloping away now 12.22 and climbing.

I might add, in late October I played around with this and wrote on a piece of masking tape a reading of 12.35. So it's been sat in the garage since then and lost .27 down to 12.08. Anyway, I'll see how far that takes it. Probably put it on the charger o/night

12.32...................

12.49......it's either stopped or r-e-a-l-l-y slowed down. Still got full sun on it but the sun is fading/getting weaker.

So, assuming I get 12.49 - 12.50, which is about 90% charged, is it any use me putting it on the charger o/night bearing in mind it's only a 6 amp job and not a fancy 3-stager, or will I be better off leaving it until morning and see if the solar will get it up to 12.60........and ............ if so, do I stop at 12.60 or will it stand a bit more as long I keep my eye on the meter?

You will need to bring it up to something like 13.8 volts, with some batteries it's even more. to get it "Fully Charged"

"So, assuming I get 12.49 - 12.50, which is about 90% charged"

- definitely not. If you are DIScharging a battery, this wmay be true but NOT when charging.

You need to have AT LEAST 13.5 volts at the battery to be at 90% charged.

Mike

Collyn,

I have the Solar panel pos & neg cables going to the relevant points on the regulator and the battery pos & neg is linked by two cables from their relevant points on the regulator. So, solar to regulator (pos & negs) regulator to battery (pos & negs). The regulator has 4 x connection points altogether.

I have taken the regulator out of the equation since yesterday morning when I was apparently getting no charge to the battery. I have since managed to get a decent charge to the battery (still ongoing) without the regulator and am keeping an eye with frequent readings. btw, when I disconnect the solar from the battery, the reading does drop sharply. As a said earlier, last night I disconnected at 12.50 (it immediately started to drop) and woke up to a 12.35 reading. I'm now up to 12.86, which I presume will drop when I disconnect.

cheers
Steve

thanks for that Collyn.......as I said before I've been running it directly from solar to batt quite successfully all day now. I took up your suggestion and re-arranged the cabling as you instructed only to find the bloody reg has totally died on me. It's going back. It's one of those little black "Super Solar" regulators with gold lettering - I'm sure you've seen them as they seem to be popular. If you have any suggestions regarding an upgrade, I'm all ears. Then I can try the cabling arrangement you suggested. As I have about 5 batteries in use around the place would you recommend one of those Megapulse battery restorers?

I've put the solar/batt back on a direct link. btw, this is a spare batt and not connected to car or caravan.

Question #2397798: If 12.6 is regarded as fully charged what am I doing taking it well beyond that figure, up to 13.8. Is that the difference between the accepted 80% charge and 100% charge?

Steve,
I use an 80wt Solarex solar panel controlled by a Steca solar regulator and can get as high as 14 'plus' volts showing at the battery while the sun is shining when the Steca is in boost mode.

Have just checked the system and it's presently showing 13.2v at the battery on the Steca LCD screen, which is 'normal' when in sun and fridge not running, the panel is putting 2.4 amps back into the batteries, because the fridge is connected and has recently turned off, (cycling, temp showing 0.8 degrees) so the regulator is getting the battery system back to it's 'normal' position, when battery system is low the solar panel will put the full 4.8+ amps, to recharge the batteries.

The figure of 13.2v is the ‘regulated’ voltage being allowed into the battery by the Steca, not the true battery voltage as the Solar panel is putting out close to 20v.

(the Steca solar regulator, unlike the model Collyn refers to, has all six cables, Solar, Fridge and Battery directly connected through it)

Hi Mainey, was hoping you might turn up. As I said before my regulator died on me and I've been charging directly from the panel. Before the sun started to fade I was getting well into the 14.s but I know it's not a true reading and I'm sure I'll wake up to a much reduced reading tomorrow. checked a few minutes ago (after 4 hrs rest) and it's 12.72. Next query is; how far should I take it?

Amazing how just a little shade, only about 20cms into the corner of the panel really reduces the charge. Also, after 5 pm it started going backwards - from what was a false reading - I suppose once it has stopped charging it goes back to a truer reading. This is the first hands on stuff I've done so please make allowances.

cheers
Steve

Steve, what brand of Solar panel is it ??

Kyocera have the shading problem, however their power conversion factor as a % when in full sun is superior to (possibly) all other panels? and if you want a panel that works really efficiently you may as well buy the best available performance, because if your aware that the panel won’t work in the shade you won’t put it there - will you :-)

You ask "how far can you take it" - if it was charging via the (working) solar regulator indefinitely, however in your case now if you monitor the battery often, try for at least a few days and as mentioned above it will take a while to get a true fully charged battery from a 80wt solar panel, your presently adding plenty of 'voltage' but not really deep charging the amperage into the battery, yes the amperage may be going up in number, but not as sufficiently as could be expected from a 10 amp 240v battery charger, however yes in ‘time’ it will be ok.
This would have happened because the battery has been deeply discharged to the point of being ‘flat’ and it takes time to get it back to fully charged with only a 4.8 amp solar panel from this situation. Remembering the 4.8 amp is the maximum amperage and not the realistic average amperage put out by the panel, as for many hours per day it WILL be well below this number.

Remember you are charging 17 or maybe even 20+ Volts, depending on the specifications of the solar panel, into a 12v battery, you really have to expect a problem after a while if charged continuously, maybe it will only be loss of fluid caused by overheating, but it could buckle the plates if it’s a 17 plate crank battery due to excessive heat build-up within the battery and the battery is totally stuffed then, Deep Cycle batteries have fewer but thicker plates, and will often still succumb to heat affected buckling of their plates, rendering them also to the scrap heap.

There may also be sulphation on the battery plates which will not be removed by a 80wt solar panel and that's where the Megapulse Series III, (not I or II, as ‘III’ can be used with multiple batteries, you say you have 5, at the same time) would be beneficial to your battery system, it will do the batteries no harm at all. I have a 'III' connected 24/7 to my two Deep Cycle batteries, so maybe that’s why they are approaching five years old now and still holding charge :-)

Obtain a "quality" solar regulator if you are going to be using the solar system in a camping situation often, a major benefit is a large LCD screen, so you can see when the panel is working at it’s very peak output, particularly when aiming for the optimum sun position, it saves guessing and fiddling with extra gauges and gives better performance in quicker time. I use a Steca ($225), the Plasmatronics ($310) are also very good, stay clear of the elcrapo end of the market as you have a problem now and may just repeat it.

Mainey, First of all, is 12.70 100% charged? This is where I get a bit lost because I thought 12.6 or more was fully charged. So, when you say "yes it in time it will be ok" (end of 2nd para) do you mean I'll get it to say, 13.8 and if so, can you explain how, if it is already "fully charged"?

The solar panel is a Photowatt PWX 80 from Solar Sales, Welshpool, W.A.

Yes, technically, the open Circuit Voltage, the voltage of a battery when it is not delivering or receiving power, is 2.11 volts for each fully charged battery cell, which equates to 12.66 for a fully charged 12 volt battery, therefore ~12.7v is fully charged, when written as only one decimal point L0L, however on different testers it may read as 12.6v or 12.8v, reason being it reverts to the nearest number, eg, if the battery was actually 12.64v it would read 12.6v or if it was 12.66v it would read 12.7v.
A test meter has only to be out a few % to get an untrue number, however if you use the same meter all the time and the fully charged reading is always 12.8v then one day it goes up to and stays at 12.9v you have a difference somewhere, which does not mean it’s good or bad, however it’s a difference and maybe should be looked at.

'Fully charged' can only be tested accurately when the battery has 'rested' for some time, hence a battery showing 12.4v could actually still be fully charged -> IF it was tested shortly after powering a fridge or lights etc, and the electrochemical reactions within the battery had not settled down, if the same test was done a few hours later the ‘rested’ voltage would definitely be much higher!

"yes it in time it will be ok" (end of 2nd para) do you mean I'll get it to say, 13.8 and if so, can you explain how, if it is already "fully charged"?
Steve, what you are actually seeing when testing at the 12v battery, and assuming the 12v battery is still connected to the solar panel, the solar panel is in the sun and is actually producing power, (any power at all) is the voltage with-in the battery, and this includes the solar panel input at the time.
Tis exactly the same to use the car alternator as an analogy.
The car alternator charges the 12v battery at about 14v or 15v, if you put a multimeter on the battery when the engine is running it will read between 14v and 15v and when you turn the engine off the battery voltage will reduce to the power available only in the battery, eventually reducing to it's a fully charged state.

haaa, now then, first of all apologies for the "12.7". I was being lazy. it actually read 12.70. My meter is actually a little belter - I didn't get it from Go-Lo y'know - Supercheap or nothing for me. If it ends with a "0" I leave it out. Sloppy, I know. Never mind, so, back to the "fully charged"; after it's had a nice little rest (overnight) and it reads 12.70, (that's better) I presume it's not gonna get any higher, because that is as full as it will ever get. I think I got a bit carried away (duh) when somebody mentioned getting it up to 13.80. They obviously meant whilst on charge and I was getting giddy thinking my battery was going to give me a final reading of 13.80 LOL I wish.
Anyway, 12.70 it is, which is a lot better than the 12.08 I started with and thought it was a dicky battery. Dicky regulator more like.

The voltage on a fully charged (well-rested) battery varies with a lot of factors - temperature, battery-chemistry.

My 80aHr AGM measures 13.0 volts many days after being disconnected from the charger.

Battery voltage will only ever give a rough indication of state of charge.

Mike

many thanks Collyn. I'll look into that regulator. I should be Ok, with all batteries topped up and ready to go now. I'm hoping it'll hold at about 12.70, which was my last reading.

cheers
Steve

Thanks Collyn. I'm getting there.

btw, I'd be interested to see how you go with the Megapulse.

cheers

interesting regulator experience. Think I'll get myself a good un.

Stuart
I did a series of extensive tests on the Megapulse for a CMCA technical note about three years ago.

It certainly reversed sulphation on the ten deep cycle batteries on which I tried it (proven by before and after -discharge/time testing. My 48-volt unit is also demonstrably working on my big (24 by 2-volt cells) home battery bank. The unit was less successful on deeply sulphated starter batteries. With these the deposits tend to build up on the bottom of the cells - and eventually partially short out the plates - if that happens the Megapulse is not effective.

I feel the main application is for deep-cycle batteries that are not optimally charged or used. (A correctly charged and used deep-cycle battery does not seriously sulphate - hence less need for this form of protection.

The most thorough independent testing by an authoritative German institute showed that it was successful more than 80% of the time.

Do bear in mind that pulsing is now a recognised technique that is being routinely included in many recently introduced up-market chargers.

It is not as new as many think- my TWC smart alternator regulator (designed by the Australian marine electrical engineer John Payne and marketed for a time by Hella)) used it in the 1980s. I stil have one on my OKA.
Collyn Rivers

Yep.
I've had outstanding results using a Megapulse. We have one which is moved from vehicle to vehicle to caravan etc, and while fitted it sits on charge so works 24/7.

We restored a defunct battery in my son's old Corolla. It sat on charge for three days when he bought the car and wouldn't crank the engine at all. Three or four weeks on the Megapulse, and it's been running his car for a year now, still going.

Collyn,

do you think the Basic model will do the job?

I have two cranking batteries, an AGM (aux on 4x4) a deep cycle (caravan) and an SLA that I recently acquired for zilch that I was playing with at the weekend.

cheers
Steve

Collyn,

I was referring to the Megapulse in the follow-up to which it was attached. I thought there were different models/levels of the megapulse battery restorer? Perhaps not. The one I've seen was about $120 from memory.

One other query. As I have a bit of an assortment of batteries, (a 100a/h SLA, a 100 a/h AGM and a 75 a/h deep cycle) would it not be advantagous/possible for me to link two of them together in series? Or due to their differences, is that not possible/advisable. My 100 a/h is my aux. under the bonnet and the deep cycle came with the caravan. I have the SLA sitting around spare. I've been swotting up in your Caravan edition today ready for my big try-out. Oh, I have one 80w solar panel.

....I intend adding another panel at some future date when the cook isn't paying attention;>)

"would it not be advantagous/possible for me to link two of them together in series?"
- only if you want lights to be VERY bright - for a very short time - you would have 24 volts !.

To retain 12 volts you need to connect all batteries in parallel. As long as the batteries are similar chemistries they can be charged and discharged in parallel. Maintenance-free batteries are calcium-Calcium and need higher charging voltages so it would not be a good idea to connect them to conventional batteries.

Mike

so, does that mean an SLA battery can be linked with an AGM?

In general, SLA and AGM have similar charging characteristics - checking with the manufacturer for similar Float and Cyclic voltages is always a good idea.

I assumed that you would only be slowly charging batteries that you have paralleled. If you plan to fast charge them you have to be careful - even if they are discharged while in parallel, one could hog all the charge current under some conditions.

For long battery life you should limit the initial (Stage 1) current into a battery, but keep in mind that even the most modern car Alternator does not limit battery current. Dual Battery installations using the most expensive battery isolator system do NOT sense charge current and therefore do not limit Stage 1 charge current either.

Mike

we've already been thru a lot of this stuff Mike. I'm not "fast charging". I'm using an 80w solar panel with a regulator.

What I want to do is link the SLA with the AGM in series and have my 80w solar panel charging them both so that there's little (collective) discharge. Eventually I'll lash out on another panel and all my dreams will come true.

Steve

You are confusing series with parallel connections.

Two series connected 12-volt batteries (ie, positive of Bat 1 to negative of Bat 2) will result in 24-volts not twelve.

The connection you are after is parallel (positives connected together and negatives connected together).

I would personally be wary of parallel connecting batteries that have substantially different charge/discharge needs or characteristics.

I would not (for example) personally do or recommend parallel charging an AGM and a deep-cycle battery - nor any other type of battery with a calcium/calcium battery.
Collyn Rivers