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Battery and charging Q's


Pete and Tracey

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Hi Bryan and Erna. Could you tell me how old your batterys are and any thoughts on why they have karked it. Reading this thread, i can see where we have gone wrong in the past in taking the batterys to too low a voltage in the past.

Den and Col

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Hi Everyone,

We are camped at Haslam in SA at the moment and are having some fun with our batteries/solar controller.

Before we left Perth, we had our controller upgraded from a PL40 to a PL60 (4 panels and 3 batteries) as we have had some funny experiences with our power over the past 12 months.

Our batteries were load tested and confirmed ok.

As an example, this morning our PLM showed SOC at 73% but the DATV was 10.8 volts.

At 9.00 am the load in and out was balanced at approx. 4 amps (bearing mind the comments on the accuracy noted above) but the DATV varied wildy by up to 2 volts and still 'flashed' when showing 12.2 volts.

Our van is 3.5 years old and has been performing well in the past.

Not being an electrician, the information posted above will be of great assistance once we get back to Perth, but if anyone has some thoughts on whats going on, we would appreciate your comments.

Ian & Jill

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Hi Ian and Jill,

What I would do is read the voltage of the batteries according to the display on the Solar Regulator. This will be accurate, regardless of what the SOC and DATV say. Once you know the Battery Voltage according to the Solar Regulator, compare it to the list I published earlier in this thread. This will give you a reasonable idea of what the SOC is.

If your entire DC system is wired correctly then the SOC you are reading is quite possibly accurate. The Voltage you are reading at the DATV would then represent the amount after the Volt-drop is deducted from the battery Voltage as indicated by the Solar Regulator.

So, if we think that your SOC is accurate, then I'm guessing that the Voltage of your batteries is near enough 12.35 Volts. So 12.35 volts - 10.8 Volts at the DATV = 1.55 Volts dropped. If this is true, then the cabling to the DATV is too small in cross-sectional area, and/or too long, or has a high resistance joint in it somewhere. I think that this is also born out by the figures that you are getting once the batteries are on float. At Float, the batteries will be between 13.6 Volts and 13.8 Volts, depending on how your PL60 was programmed. So, 13.8 V at the batteries, - 12.2 V at the DATV = 1.6 Volts dropped. It adds up. The cable to the DATV has an issue.

If you have one, measure the Volts at the DATV and batteries with a Voltmeter. If you don't have one, they are so cheap these days that I'd get one if I were you.

Cheers

Russ

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:helpsmilie: Hi Grahame,

A quick question, at this moment i to am having battery problems 3x120 ah.

At sundown the batteries show 13 volts capacity and to all acounts are fully charged as they will only accept 1.4amps when i have started the generator.

At about 3am the remote regulator in the van is flashing showing the battery voltage at 10.8volts, and the compressa 230litre fridge is trying to cut in but can't. I turn the fridge off and the batteries go back to 12.5 volts, if i turn the fridge back on the batteries go back to 10.8volts and the fridge cuts in and out continusly.

When i read the max volts it shows 13.8v, and minum 10.8v, and battery percentage of charge around 90% with 34amps used.

I removed the three batteries when fully charged an let them sit for 4 days, they all remained at 13volts, i took them to not one but 4 battery places and they tested them with their equipment, an all said the batteries are good.

I have since connected a 40 litre engle fridge to each of the batteries in turn and after about 4hrs they all fell to 11.8volts and after another hour the battery fell to 10.8volts and was still runing the fridge.

The 3 batteries are 28 months old and to me they are throw away, but can you tell me =

How come the batteries take and hold charge?

When in line in the van they drop so low in say 7hrs to a point where they won't start the 230litre fridge?

And when tested Three battery places say they are O.K?.

Any help would be appreciated to stop me going around the bend.

Cheers

32 Kev

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Ian and Jill,

We drove into Haslam mid Jan 2011 and liked the spot, although we did not stay as we had sights set on Ceduna.

Reading your comments I am not sure if the "funny experiences" have started occurring since the PL40 was upgraded to the PL60. The PL40 has quite a low max load capability of only 7Amps although it will charge at 40A. The PL60 max load is 30A and charge at 60A.

Has the PL60 been set up correctly? If you follow your little booklet that came with the PL60 and enter the SET Menu you are able to set the Time, Voltage, Program number and battery capacity. For smooth operation you need these basic settings right.

Time is set in tenths of an hour, so 8.5 is 08;30am and 14.2 equates to 14:12pm in the afternoon. The Time setting will drift a little and needs to be adjusted about every six months. If you have the Time badly wrong then the FTIM function may not work. FTIM happens once in every 30 control periods i.e.days and drives the batteries hard for a period by staying in Boost phase to stop them sulphating. You need FTIM happening about midday when the sun is overhead on the solar panels. If the Time setting has drifted badly then your regulator may be trying to boost the batteries at 11:00pm at night - not much of a solar performance at that hour.

Your system voltage is 12V of course (these regulators will handle up to 48V so it needs to be set)

Program No 1 is for sealed or gel lead acid batteries, (although No 0 will work for you)

Batt Capacity is settable between 20Ah and 20,000Ah, pick a setting at, or just above your battery capacity. This setting tells the regulator when to start switching down on charge current. I have seen one installation (not a caravan) where the Batt cap had been set at 1/10 the correct setting and the batteries were consistently going flat.

Now your comment about measuring DATV voltage at 10.8V. The factory settings for all pre set Programs 0 thru to 3 is called LOFF(V) and is set at 11.3V. Thus the regulator should be switching off all loads fed from its load terminal when batteries reach 11.3V. Russ's suggestion that something may be amiss with wiring to the DATV could be a place to start looking.

Hope I am not trying to tell Grandma how to suck eggs!

Grahame

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Thanks Grahame, :thumbsup:

Put3 new batteries in all working fine, just wanted to check before throwing other batteries away.

Thanks for your time

32 Kev

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Hi Everyone,

I am thinking about relocating my batteries from the front boot to under the bed in our 18' TE (to be nearer to the vans suspension and hence further away from the tow ball}.

My thoughts are that this should have a significant effect on my tow ball weight that is approx. 380 kg's without the outboard loaded.

Has anyone any thoughts on this, positive or negative?

Regards,

Ian

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Hi Ian,

This would be relatively easy to check. You could simply take the batteries out and put them in the future location without making any connections or changing any wiring. Put the van over a weighbridge and check to see if it has made a significant difference and if it has, proceed with the wiring changes. I have found that is much easier to dismount the batteries by taking the boot doors right off (pretty easy process.)

Points to remember (if moving the batteries is worthwhile doing):

You will need to extend the cables back into the van with some fairly large diameter cables to reduce losses (volt-drop).

If you run an inverter, you may have to locate it under the bed as well, so as to reduce cable distance. This may introduce some ventilation issues. (For cooling) Better to run a 240V cord back to the boot than 12 Volt DC cables from the boot.

Be sure to have good mechanical protection of the cables to prevent accidental crushing or piercing by objects stored under the bed. Keep DC and AC cables separate.

Ian, I would be very interested in hearing how much difference this makes as I, too, have an issue with ball-weight.

Cheers

Russ

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Hi Ian,

When moving or altering the weight distribution in a radical way as to reduce the ball weight, I would take it on a long tow test (at speed) and see what the difference it makes.

I have heard of people doing this exact thing, only to find the van tows like a dog (due to insufficient ball weight) and are now madly trying to extend A frames to put large storage boxes to distribute some weight back on the ball.

I am sure there will be those that disagree and say that a light ball weight is a good thing, but in my opinion 10% of total van weight on the ball, is recommended for a reason.

Maybe check with Kedron before you progress any further.

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I'd do a trial tow first with just sitting the batteries under the bed but moving batteries can become a expensive job with all the wiring changes etc.

What else can be removed from the front eg jerry can holder, outboard motoe, moving a water tank to the back etc as I assume you are trying to get the ball weight below 350kg.

Cheers

Darryl

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Hi all

I have been watching this thread for some time as I have had problems with the power to the 150 lt Coolmatic compressor fridge from 3 deep cycle batteries when the batteries get to 12.6v when not on 240 volts providing power via a 12v charger. We have a 2002 21ft XC and have had 2 sets of batteries since 2004.

Our problem is that when the batteries get to 12.6, the fridge cuts in and out, runs for 5 seconds then stops, and tries to start again in 3 minutes, right through the night if the batteries were low enough to start with.

Last week I watched a DVD called "Gray Nomads 101" , where it was pointed out in one of the segments that 12v power to the fridge could be lessened by the "feed" supplying power to the fridge, lights, radio and any other 12v appliance. It was also appropriate that his van was a Kedron.

In simple terms the author of the DVD (Syd) said that the "feed" (wiring) was inadequate for its purpose and should have been a much heavier "feed" when the van was built.

With the comments of this thread, and the DVD info, I went to our local auto elec (he has 12v experience) and he tells me it is a common problem with vans that wiring is inadequate.

So I bit the bullet and had him do a direct "feed" from the batteries to the fridge this past week, complete with a trip?. We will be taking a few days down at Binnalong Bay (thats in Tassie) free camping next week to see how it all goes before we head of to WA at the end of May.

While the car and van were at the auto elecs, I had him do an extention to the mudflaps of my 03 Patrol 4.8. You have seen the brush/broom that trucks use around the wheel arches. This is what I had fitted front and rear and also had built a full length unit hanging under the tow bar for more protection for the van, held on by 2 bolts to a vertical section welded to the tow bar. Makes it easy to remove.

I am pleased with the end results and will come back later next week about the fridge.

Cheers Rod (we live in Tassie)

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  • 3 weeks later...

Hi all

I have been watching this thread for some time as I have had problems with the power to the 150 lt Coolmatic compressor fridge from 3 deep cycle batteries when the batteries get to 12.6v when not on 240 volts providing power via a 12v charger. We have a 2002 21ft XC and have had 2 sets of batteries since 2004.

Our problem is that when the batteries get to 12.6, the fridge cuts in and out, runs for 5 seconds then stops, and tries to start again in 3 minutes, right through the night if the batteries were low enough to start with.

Last week I watched a DVD called "Gray Nomads 101" , where it was pointed out in one of the segments that 12v power to the fridge could be lessened by the "feed" supplying power to the fridge, lights, radio and any other 12v appliance. It was also appropriate that his van was a Kedron.

In simple terms the author of the DVD (Syd) said that the "feed" (wiring) was inadequate for its purpose and should have been a much heavier "feed" when the van was built.

With the comments of this thread, and the DVD info, I went to our local auto elec (he has 12v experience) and he tells me it is a common problem with vans that wiring is inadequate.

So I bit the bullet and had him do a direct "feed" from the batteries to the fridge this past week, complete with a trip?. We will be taking a few days down at Binnalong Bay (thats in Tassie) free camping next week to see how it all goes before we head of to WA at the end of May.

While the car and van were at the auto elecs, I had him do an extention to the mudflaps of my 03 Patrol 4.8. You have seen the brush/broom that trucks use around the wheel arches. This is what I had fitted front and rear and also had built a full length unit hanging under the tow bar for more protection for the van, held on by 2 bolts to a vertical section welded to the tow bar. Makes it easy to remove.

I am pleased with the end results and will come back later next week about the fridge.

Cheers Rod (we live in Tassie)

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Hi all

We had our few days down at Binalong Bay (in Tassie) and the modifications to the wiring from the battery to the fridge worked. We had 3 days where we free camped and did not use 240v. The vans batteries got down to 12.3 on the 3rd day after a lot of cloud on the 2nd day but the fridge kept on, no cutting in or out and everything else worked also. We are now confident that we will be ok. Looking forward to getting on the Sprit on Sunday for 4 months in getting to WA and back again via the roads less travelled. Cheers Rod (our van has "tassie devils" front and back.

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  • 1 month later...

Hi guys and gals,

Great thread eh?

So.........I have been watching the SOC like a good little boy and have been observing that the SOC has increased to 130%. This is of corse due to the fact that the inverter is not connected to the PLM via a shunt and it does not know of the current draw of the inverter when we use it.

Question is, how do I install a shunt into the system and is it a do I yourself type job? I have a technical background. is it a hard job?

Advice would be appreciated from the learned.

Cheers,

Pete

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G'day Pete,

Installing a Shunt isn't difficult. I'm assuming a Plasmatronics regulator is installed. First, when you buy a Shunt you will get the Shunt itself, an interface device and a cable that connects the Shunt to the Regulator. If you are running an Inverter you will need to divide the number of Watts it is rated at by 240 (to give you the Amps it supplies) and then multiply that figure by 20 (to convert it to the amount of DC current it will draw.)

With this figure, add a fiddle factor of about 10% to account for losses in the inverter and be wary that some inverter loads can cause momentary surge currents well in excess of the rated current of the inverter. Armed with this info, you can then buy a Shunt that is rated to carry the current that you calculated. The Shunt also has a calibration value. For example, if you buy the 100 Amp Shunt it could have a value of 50 mV per 100 Amps or 100 mV per 100 Amps. All this means is that in the case of, for instance, the 100 mV/100A Shunt, it will drop 100 millivolts across it if 100 Amps of current are flowing through it. You need this info because the interface device has specific connection points according to the calibration of the Shunt.

Right! Armed with this info, it is a simple matter of cutting into the positive or negative cable that connects to the inverter (it doesn't matter which) and inserting the Shunt in series. Then connect two thin wires from the small screws on the Shunt to the "common" terminal and the terminal that matches the calibration of your shunt, in the interface device. Use the cable supplied (looks like a telephone cable) to connect the interface device to the Plasmatronics regulator.

Turn all other 12 Volt appliances off and ensure that there is no current flowing in any circuits. If your "out" reading on the PL unit has a reading, use the trimmer on the interface device to "zero" the Shunt. Then turn the inverter on. If you read an "out" current, you have the Shunt wired correctly. If you see an "in" current instead, reverse the connection of the two thin wires that connect the Shunt to the interface unit.

That's it - job done! For more info, read this http://www.plasmatronics.com.au/downloads/PLS2MANv2.1.pdf

Cheers

Russ

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  • 9 months later...

G'day Russ

Your wiring diagram is really good. Thanks for that.

We have a 2009 TopEnder which gives us some issues with Solar Charging. Not all camp sites are ideal for solar charging with fixed panels on the roof.

I noticed when we were camped in Leeuwin Naturaliste National Park, where we had total shade on 2 of our 3 solar panels with the 3rd in full sunlight all day & we were only getting 2 - 3 amps with nothing running, not even the fridge. Therefore we run our batteries down & had to charge from the car.

I spoke to Tom at Kedron & he informed me that the sloar panels in Kedron vans which were built longer than 12 months ago, the panels are wired in parallel & therefore will only propuce the power of the weakest panel. I may have this the wrong way around, he may have said in series but the result is the same.

He told me that vans built within the last 12 months the solar panels are wired in the other way around ie individually, & therefore if only one is in sun it will produce 7.5 amps or thereabouts.

He told me rewiring of this isn't possible in our van.

A guy at the 12V Shop asked why they would be wired that way, as it doesn't make sense. I couldn't answer his question.

Does the above make sense to you & which way around is it? Does series or parallel gives the charge of the weakest panel?

Do you know a solution to this issue if it's actually right?

Cheers

Alan

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hi Alan & jane

Out ATV2 is 4yrs. old and 2 panels in shade and 1 in sun still gives us just over 7 amps.per hr.I have no idea how they are wired. If in doubt ring Tom again and reconfirm the wiring system.He has always been very helpful to us. :)

Cheers

Rick

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G'day Russ

I spoke to Tom at Kedron & he informed me that the sloar panels in Kedron vans which were built longer than 12 months ago, the panels are wired in parallel & therefore will only propuce the power of the weakest panel. I may have this the wrong way around, he may have said in series but the result is the same.

He told me that vans built within the last 12 months the solar panels are wired in the other way around ie individually, & therefore if only one is in sun it will produce 7.5 amps or thereabouts.

He told me rewiring of this isn't possible in our van.

A guy at the 12V Shop asked why they would be wired that way, as it doesn't make sense. I couldn't answer his question.

Does the above make sense to you & which way around is it? Does series or parallel gives the charge of the weakest panel?

Do you know a solution to this issue if it's actually right?

Cheers

Alan

G'day Alan

I'm thinking that Tom may be confusing himself with his reply. If you connect panels in series, then the output voltage is a multiple of 12 Volts times the number of panels that you have installed. In your case it would be 36 Volts and that is just not what Kedron do. As your system is a twelve Volt system, it MUST be wired in parallel. Perhaps Tom means that the connections to the panels are all commoned together at the roof, with a single positive and a single negative lead coming down to the boot, as opposed to three positives and three negatives (one for each panel) going down into the boot? Either way, the panels are paralleled but the latter method would have less Volt-drop between the panels and the regulator (given that the same sized cable were used in either scenario.) To answer your question, a series connection is the one where the whole system is brought down by the weakest link in the chain as opposed to a parallel system where individual panels can be out of service without totally losing current to your regulator. It is irrelevant in your case because I can guarantee you that your system will be wired in parallel (one way or the other.)

When it comes to panels, if one panel is in full Sun, and the Sun is directly overhead, then in an ideal World it should be possible to see about 10 Amps being delivered to the regulator. In the real world you should see at least seven Amps. What may be happening is that the Regulator thinks that the batteries are fully charged and is limiting the charge, or the panel that is in full Sun is not delivering as much current as it should be. If it is the latter I would start looking for a blob of bird poo on the panel, a build-up of dust or something similar.

You may need to see an Auto Electrician and have a few things tested. I would start with the batteries, followed by checking the configuration of the solar regulator, followed by open circuit voltage tests of each panel, followed by current measurements of each panel under ideal charging conditions (best done by connecting to a battery that is already somewhat discharged and will draw full current when connected).

If you were seeing three Amps of charge current, no discharge current and your batteries still went flat, it would seem that the batteries are U/S. This can happen for a variety of reasons including: Discharging too deeply too often; Not charging the batteries at all when the van is in storage (causes sulphation): Individual dropped cells within batteries and so on. Individual cells can fail by going short circuit, or by going open circuit. In the latter case it results in the battery being completely dead and in the former case the battery thinks it is now a 10 Volt battery, not a 12 Volt battery (which is very bad because the regulator still thinks it is 12 Volts and the end result is that the five remaining cells in the battery have their voltages raised well above tolerable levels.)

You scenario doesn't sound good but I can't be of much more help without getting my hands on your van, or some readouts being made available, sorry. Who knows, it might be something as simple as a bit of bird poo?

Cheers

Russ.

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G'day Russ

Thanks for a brilliant answer.

You cleared up the wiring arrangement for me, Tom was right, it was just my understanding of what he said was wrong. You clarified this for me explaining that the panels are in parallel & then commoned together on the roof with one with a single +ve & -ve lead runiing down from the roof.

Now that this has been cleared, Tom definately indicated that with our wiring if two of the three panels were in shade, we would only get the charge off the weakest, whereas you're saying different?

When we were getting 3A with only 1 panel in sun, I got up on the roof & cleaned the panels, so no bird poop or dust, they were squeaky clean. They weren't really dirty anyhow. Tom asked the same. The only other explaination is that the aircon on the roof was throwing a bit of shade onto the panel in the sun for a lot of the time, due to the position of the sun. I guess 90% of the panel was in full sun all the time.

It sounds like I will have to get an Auto Elect to have a look at it. The batteries & panels work great when all 3 are in full sun. Yesterday we topped up to 14.2V & 99.9% SOC in full sun all day & after watching a movie last night etc, they are still at 12.8V & SOC 81% this morning.

One question, is the Xantrex C-series Multifunctional DC Controller the Solar Regulator, or is this something else?

Thanks again for your help.

Cheers

Alan

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