Solar panel and IBS battery monitor query

[wuntenn]

I have an IBS battery monitor setup on the two batteries in my Land Rover. It works very well. I am intending fitting a solar panel and the 'normal' way to do this as far as I can see is via a dual battery charge controller of which there are various types.

However the IBS unit has a wiring diagram on its website here which shows the use of a single battery charge controller connected to the aux battery, and my assumption is that in that setup the IBS unit monitors charge on the aux battery and then switches charge to the main battery.

I've queried this directly with IBS directly and got the following response, which kind-of confirms that (apart from the last sentence):

"you need with the panel and a solar regulator what is charging into Aux battery. If enough charge is available it also links in the Starter battery.
IBS is not regulating any charge."

So (being now slightly confused), do I just use a single battery charge controller and wire it in as in the IBS diagram, or forget about the presence of the IBS and wire up both batteries via a dual battery charge controller?

I'm assuming that their use of the word 'regulating' is intended to imply that current may be supplied but it's not being 'monitored' as would be done by a proper solar charge controller.

Any obvious pitfalls with either method? (I have to add that I am no electrical wizard).

 

[unseenone]

I'm working on the same project, drop me a PM if you'd like to talk, I'll send you my e-mail and phone. Read through this thread as well. http://www.expeditionportal.com/forum/threads/125344-Is-my-battery-really-draining-and-how

When a charge is applied to the Aux battery, the voltage will go up, and the batteries will link, and charge both. Some variables, depending on what kind of battery your Aux is.

 

[takesiteasy]

I'm also interested in this topic. My main battery is used for starting the truck. The auxiliary supplies the camper load. The IBS manages the charging and disconnect process and works well to charge both while driving. Often while camped, the truck battery is only slightly discharged while the auxiliary battery is quite discharged. I have noticed that when I connect my charger to the aux. battery, the IBS links the two batteries together. In theory, this is good to charge both batteries. In reality, the charger times out before it gets to the float level and neither battery gets a full charge. I have never seen the IBS disconnect the batteries while the charger is hooked up. For my simple-minded solution, I installed a switch to disconnect the IBS so that I can charge the auxiliary battery by itself. When it gets charged, I reconnect both for maintenance.

I suspect a solar charger would have the same problem. Connecting a dual charging controller directly to the individual batteries would seem to solve this problem but you still might need to disconnect the IBS. Not sure of that. Hopefully someone with more knowledge will weigh in. Thanks for posting the topic.

 

[wuntenn]

Thanks both of you, and for the thread link unseenone - that was worth a read. I may ping you - thanks for the offer. I have a campervan-construction pal who is a good electrician and I'm going to speak to him in a few days and see what he says.

 

[unseenone]

I would think the reason for the timeout before it is charged are the charge controller. The other possibility might be too little solar panel wattage. I haven't explored that aspect yet for the mobile, except to say from the Specifications the Morningstar would be a good place to look. If you have a voltage and temperature sensor, it stands to reason it can tell if it is charged or not. If the voltage is still low, it can restart the cycle.

 

[wuntenn]

Thread update - ok it seems that the solar panel needs to be run through a single battery charge controller, rather than a dual controller model, and connected to the aux battery. The IBS unit (apparently) handles the charge to the aux and when it detects a full charge state hands over the charge to the main battery. This is apparently also done when the vehicle is stationery - the IBS literature states that this is happens when the ignition is switched on, but I'm reliably informed that this function is ignition-independent and will do so when switched off also.

I just managed to pick up a less-than 1/2 price new Morningstar charge controller & built in monitor - a PS30 - the unit is a tad over specced for my needs in terms of its load handling - but it was cheaper than many of the cheapcheap ones so seemed a good deal.

Any cable experts out there suggest what gauge wire I need to run the full length of a 110 roof, then back to the front seats and down into the battery box - I estimate around 17 feet maybe 18 feet max. Because my roof lifts and the panel will be at the rear (which is the 'top' when lifted) I need to run the cable form the back to the front for entry to the vehicle.

Panel is 100w and specs are:

Max System Voltage(V) : 1000
Vm(V) : 18
Im(A) : 5.56
Voc(V) : 21.24
Isc(A) : 5.89

I'm guessing 6mm2 would be ok?

 

[takesiteasy]

snip...The IBS unit (apparently) handles the charge to the aux and when it detects a full charge state hands over the charge to the main battery. This is apparently also done when the vehicle is stationery - the IBS literature states that this is happens when the ignition is switched on, but I'm reliably informed that this function is ignition-independent and will do so when switched off also. snip...

I'm curious where you got this information. I would like to think this is the way it would work but I have not observed it to be the case in my set-up. It appears to me that the IBS links the batteries as soon as it detects a charge current flowing to the auxiliary battery, regardless of the charge state of the auxiliary battery.

 

[Herbie]

I'm curious where you got this information. I would like to think this is the way it would work but I have not observed it to be the case in my set-up. It appears to me that the IBS links the batteries as soon as it detects a charge current flowing to the auxiliary battery, regardless of the charge state of the auxiliary battery.

The IBS is like most of the other systems out there (including my T-Max), it can't sense "charge flowing", it only monitors the terminal voltage of each battery. As it happens, when something is trying to charge the battery, the terminal voltage will naturally rise, so these systems can sort of see when charge is happening, but it has no direct concept of current flow with respect to either battery.

These things are pretty simple - if the voltage on either battery terminal rises above what it considers a likely charging voltage, it will close the relay and connect the batteries. If the voltage on either terminal falls below that it considers a significant "load" or idle voltage, it will isolate the batteries. Applied to all of this is usually a small delay. So after starting the vehicle, the alternator is putting a high enough voltage onto the starting battery that the device will close the solenoid after a short delay. When the engine is shut off, the voltage of each battery will fall back to its resting value appropriate for its state of charge, which is low enough to isolate the batteries again. The same exact thing happens with a voltage applied to the house/aux battery via a solar charge controller or other battery charger (like a mains-powered charger). When the aux terminal voltage crosses the threshold, the batteries are connected. When charging stops, they are separated.

When my solar panel is connected and goes into a mode where it's outputting a float-level charge (as opposed to bulk or absorption charging), it's right around the threshold voltage, so I can hear the relay opening and closing periodically throughout the day.

 

[unseenone]

I am going to try and address several of the last comments here.

I got my information directly from Traxide, granted it is a different unit than you are using, and I posted his suggestions. According to him, I could also plug in and charge from my 40amp Anderson plugs already fitted in the rear of the vehicle. This is done very regularly in Australia where that unit is made, as folks have caravans, 3 batteries and many odd configurations we wouldn't necessarily see here very often.

On the wire to the battery -- the wire from your battery will go to your controller, not to your solar panels. You should use the standard solar panel power cables, which should be fitted with standard ends. You might also be able to run the cable outside or through the vehicle, in a more direct route?

What kinda deal did you get on the Morningstar, was it a private sale, or is there somewhere we should be looking?

What solar panel do you have..

Here are standard solar power wires; http://www.solar-electric.com/incaforsoelp.html

I might suggest a prefabricated custom cable, which comes nicely crimped, sealed, and shrink wrapped. http://www.powerwerx.com/adapter-cables/design-build-your-own-custom-cable.asp

You probably should over spec it, to avoid voltage drop, and plan on adding that voltage sensor line if it supports it. You can go 22.3 feet at the rated 30amps with AWG 2 cable. This would be fitted with 175amp Anderson disconnect for convenience near the battery. That is a LOT more than you are going to carry if you are only using 1 100 panel. You could use AWG 6 and go 17.7 feet, that's rated for 15 amps, half of your solar controller. The output of your solar panel at 100w is probably going to be in the order of 6-10 amps max.

The minimum supported wire size is AWG 14 and Maximum is AWG 2 on the Morningstar.

It seems like you should be able to use a multimeter and confirm the behavior of the IBS.

Here is a nifty looking wire sizing chart, courtesy bluesea.com

 

[wuntenn]

Thanks for coming back in folks.

I got the info from several threads on the IBS - one an Australian forum where the (long time) user stated this, and another UK forum where the poster (whose advice has been very accurate in the past on various technical/mechanical/electrical subjects) and who uses the IBS, stated the same thing. The above text of mine is my interpretation of their comments. I think this confirms what the owner of IBS said when he replied in somewhat less than perfect english:


"you need with the panel and a solar regulator what is charging into Aux battery. If enough charge is available it also links in the Starter battery.
IBS is not regulating any charge."

I did understand that the IBS does not 'regulate' but does monitor voltage and does whats necessary to maintain a charge in each battery and disconnect/connect as appropriate. I also understand the wiring setup battery>controller>panel. But I am happy to be wrong in stating that it hands over charge once the aux battery is charged - it may simply link both as you suggest. I need to investigate this a bit more!

My main concern really was about whether the IBS worked when the ignition was not switched on and it seems this is the case - is this your experience?

Morningstar 30 I'd seen at UK£140 up to £190 then found a place selling it at £99, and today did an Ebay UK purchase for £50 from here: and the vendor said he'd just put some more up as he had a number of them to sell (he was anxious that I didn't assume he was selling the same one over and over and doing a swindle). Good price I think (certainly in the UK).

The panel I am looking at is this - currently on sale. Not bought it yet - have an option on one in the next two days even if the sale is finished - as I contacted them during the sale they are happy to honour the price. Any thoughts? Bearing in mind I am a novice at electrical and ignorant (and learning fast) about solar!

As a for a direct route for cables on the roof.....hmm.....the logical place is at the rear as there's a perfect sized gap there, and when the roof is lifted I can fab a way to angle the panel up left or right according to sun direction. But having said that if putting it at the front and shortening the cable by 9' makes life easier it might make sense to do that instead.

 

[unseenone]

OK, I didn't realize your in the UK, once converted, the price is slightly more here than there, but not a deal killer. Folks here are making plenty of margin on them I'm sure.

As I read what he said, it agrees with what I'm saying... Charge at the 2nd battery, it will relink when the voltage comes up, and charge both, at the most simple level. This can be confirmed with a multimeter on the batteries to check links/voltages, etc.

You may be able to get away with mounting it stationary, flat if you do not want to fuss. Most of the ones folks posted on this thread are flat mounted. You just want to avoid shadows on it.

I would mount it where you want it, and work the sizing from there, rather than be less than happy with your installation. The wire lengths for the feed cables (2) from the solar panel is a non-issue, you could run 50 ft if that's what you want. If you note, the image of the solar panels you are looking at (not bad actually) you will see the connectors, that use standard MC4 cables, any length you need will be fine... that connects to the charge controller. The charging wires go from the charge controller to your battery (fused) of course.

I would read through the manual for the controller as well. That will need to be mounted inside the truck, it is not rated for outside.

Check out this thread for some mounting ideas. http://www.expeditionportal.com/for...one-have-pix-of-how-they-mounted-solar-panels

 

[wuntenn]

Aye in the UK - where we pay through the nose for a lot of things!

Anyway - thanks a bunch for your insight - really appreciate it. And thanks for the panel appraisal - it looked a pretty good deal compared to a lot of what I've looked at I have to say. And yes once I get in about the electrics I'll get the meter on it and actually watch whats going on.

I'm taking my van out of my friend's workshop tomorrow as they're starting their summer work and need the space, and the weather is good enough for me to get back on the job on my driveway.

 

[unseenone]

Just for a reference point for you, I'm posting a picture. Pictured some L16 6 volt 400amp hr batteries, AWG 2 Cable (charging), AWG 2/0 Cable (battery interconnect) 175 Amp Anderson connectors, MC4 Solar cable. Keep in mind this is larger stuff than you need, but it will give you some idea of the various bits we've talked about.

Bear in mind, I used AWG sizes, rather than the easier metric used there, I apologize for that.

http://disco3.co.uk/gallery/thumbnails.php?album=35750

Here's a link to a neat setup from an Australian I know (he's a member here as well). This is one 250w house panel. Great guy, interesting setup and web site. http://www.goingbush.com/iveco.html

 

[takesiteasy]

snip...These things are pretty simple - if the voltage on either battery terminal rises above what it considers a likely charging voltage, it will close the relay and connect the batteries. If the voltage on either terminal falls below that it considers a significant "load" or idle voltage, it will isolate the batteries. Applied to all of this is usually a small delay. So after starting the vehicle, the alternator is putting a high enough voltage onto the starting battery that the device will close the solenoid after a short delay. When the engine is shut off, the voltage of each battery will fall back to its resting value appropriate for its state of charge, which is low enough to isolate the batteries again. The same exact thing happens with a voltage applied to the house/aux battery via a solar charge controller or other battery charger (like a mains-powered charger). When the aux terminal voltage crosses the threshold, the batteries are connected. When charging stops, they are separated.

When my solar panel is connected and goes into a mode where it's outputting a float-level charge (as opposed to bulk or absorption charging), it's right around the threshold voltage, so I can hear the relay opening and closing periodically throughout the day.

This explanation is clear and fits with what I observe happening in my system. Thanks!

 

[wuntenn]

Just for a reference point for you, I'm posting a picture. Pictured some L16 6 volt 400amp hr batteries, AWG 2 Cable (charging), AWG 2/0 Cable (battery interconnect) 175 Amp Anderson connectors, MC4 Solar cable. Keep in mind this is larger stuff than you need, but it will give you some idea of the various bits we've talked about.

Bear in mind, I used AWG sizes, rather than the easier metric used there, I apologize for that.

http://disco3.co.uk/gallery/thumbnails.php?album=35750

Here's a link to a neat setup from an Australian I know (he's a member here as well). This is one 250w house panel. Great guy, interesting setup and web site. http://www.goingbush.com/iveco.html

Aye that's meaty cables indeed! Thanks for that.

The Iveco link is excellent - they're pretty formidable trucks, I've seen a few UK reg ones and several French and Swiss/German ones running about. Very capable by all accounts and a sensible alternative to a Unimog.

Thanks again for your assistance. It's appreciated.