B2B Chargers - Question for aandncaravanservices

[Brambles]

aandncaravan - 2017-04-22 8:13 PM

 

Then, IMO, you have selected a regulator that doesn't create the most efficient solution.

In Winter you could have a system that is literally 50% worse than the best you could have selected, maybe even worse than that?

 

 

Ooooooooooooo, that is a bit of a sweeping statement without justifying it. Am I missing something as seems adequate to me for a basic setup with added advantage of a controlled output for when battery power is sufficient to enable it. Or, are you referring to when it reaches the cutoff voltage of 14.8 volts it appears to fold back immediately.

[aandncaravan]

Brambles, two things really. If I read it right it isn't like any PWM or MPPT regulator but acting more like a shunt regulator?

 

The second thing is that if it is only a single battery Regulator then the Battery Master is obviously set to remain in situ.

 

As I say above a Battery Master draws power from both batteries and additionally will sap power from the charge it is transferring as I can't see this, like all battery chargers, being more than 80% efficient.

 

I know we are only talking small currents but in Winter the Solar charge will be tiny and will really only be active for about 4 hours a day yet the Battery Master will be sapping power for 20 hours a day from both batteries.

 

 

Quite likely that the power being taken out by the losses of the setup will exceed the power going in.

 

A quality dual battery regulator like the Votronic MPPT 165 at £70 would manage everything automatically with lower losses and lower complexity, as there would be one box and several connections less.

 

Regardless of the Regulator efficiency, leaving the Battery Master in situ to draw off some of what little is being put in seems unusual when there was the opportunity to build a top draw solution when the decision was made to adopt a different regulator.

Such a solution would have also returned full control back to the EBL 29, not short circuiting its functionality.

 

I don't know, but suspect that the Panels, being 3 cascaded 40w units will also be below the best in Winter. A 40w panel tends to have lower 'raw' voltage.

I think, but again guesswork, that the panels are paralleled so '3 lots of 40w' with a lower overall voltage (e.g 3 x 40w of 15veach) than the usual 120w which can be as high as 25v.

 

In Winter when light levels are low, it may be 'normal' to have the panels with 1amp to spare but not a high enough voltage to reach 13v to charge the battery at a decent rate. For example the 'Load circuit' may be able to provide 12v to run some halogen lights at 1 amp, but unless the voltage goes above the battery resting voltage, no charge will take place.

 

 

So unless everything is maximised there might be enough power to 'switch on' the Battery Master but not enough to put back what it is throwing at the Starter battery, which is what we have documented on here before.

 

 

[Brambles]

Arrrrgh, I see now I have missed the whole story. For some reason I thought David's query about voltages was a new query and not a follow on from all the previous history and the Battery Master. No idea how I missed all this.

Certainly agree for winter use wasting power on a B2B charger is not desirable although depends on how much drain there is on the engine battery, I know earlier X250 are a disaster for battery drain but no idea about later produced versions. You , Allen, will have much better practical knowledge of this than me as what Fiat publish and the real world is likely to be is very different in my experience and of course there are extra accessories such as alarms and such.

David, have you got a model number and can you confirm the make of the solar charger, or who supplied it so I can make sure I am looking at the right thing?

 

 

[david lloyd]

Hi Brambles, there doesn't appear to be a model number but it seems to be a generic regulator branded as Solrtronics. I have searched on the web but although I can find very similar ones (with different branding) I cannot find a 30A Solrtronic one.

 

I know winter in England will be a different proposition but this weekend at Peterborough it has kept the habitation batteries fully charged before topping up the engine battery. We don't go overboard with lights etc but at the show do have some led pole lights running, TV for a couple of hours plus all the other background stuff. Yesterday afternoon it showed a reading of 3.2 - 3.4 amps at its best. It does seem to be charging the habitation batteries first before releasing any power to the engine battery as that stayed at 12.7v (on the Hymer panel) until just before lunch when it has gone up to 13.0v.

 

Most people I have asked don't seem to think the Battery Master is a problem and most of our winter touring will be in Spain with a little better light conditions although there will be the Alde heater pump to factor in when it's really cold. So, I still think the new charge controller is an improvement over the Vision Plus one if only because it can tell me what it is doing and I have been able to set the maximum charge level at 14.7v. Allan is absolutely right about a Voltronic MPPT controller and I may do that in the future but just to throw a spanner in the works there is a company here selling a new (to the leisure market) selenium based thin film solar panel that I have just witnessed putting out 5.1A inside his exhibition awning! Throw away the rule book guys - things may be changing.

 

David

[aandncaravan]

David, just had a lot of involvement with a Steca Solar Regulator designed for House Roof Solar Panels that was fitted in a Hymer. That had 'Load Control', so have had to learn more about how the horrible thing works than I wanted to.

 

So learning more about these I wonder if you are confusing the voltages for the Load Control settings with those of the charging side?

 

On some Regulators you can use the 'Load' terminals to power a Beer 'Cool Box', or some kind of 12v appliance. The Solar regulator will then only supply power to this device within certain set voltage thresholds, outside of which power will be cut off.

 

For example, the Solar Regulator 'Load terminals' will power the Beer Cooler when the voltage at the battery reaches 13.5v (because the sun has risen therefore supplying charge to the battery) but this may then be cut if the battery drops below 12.6v, i.e. the Sun has dropped in the sky.

In this example the cutoff voltage would be 12.6v and the 'activate' voltage might be 13.5v.

 

So long as the voltage at the battery was between 12.6v and 13.5v the Beer would keep cool. But bear in mind these are not real 'Battery voltages', but the voltages at the battery terminals which may be significantly higher than the 'real' battery voltage.

 

 

The two regulators of this type we looked at seem to have no 'settable' charge voltages, but fixed and based on Wet Lead Acid batteries only.

 

But that is based on very limited experience with this type of 'load' regulator. One we have actually studied, was not designed for use in Motorhomes. The manual specifically stating it should not be mounted on a flammable surface (it suggests 'Concrete'), see this thread for how bad it was : http://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Sorry-to-go-on-about-dangerous-Solar-Installations-again-/46972/

 

Is it possible to supply a copy of the manual, as I would be interested if it can have the different charging phase voltages programmed into the regulator as that would make it pretty unique?

 

 

 

[david lloyd]

Good morning Allan,

 

This does sound similar to how the 'load' function works on my Solrtronica regulator and it can be set start charging the load or ending it at a certain voltage by scrolling through the menu to the correct place. Here, for instance, you can find 'load on' and 'load off' so it sounds similar.

 

I still haven't found a manual for the Solrtronica device but have downloaded a copy of one for a Solar 30 regulator which appears to be exactly the same but branded differently. I am not sure how to add it here but will email it to you directly.

 

David

[aandncaravan]

Morning David, thank you manual received.

 

It is very confusing, probably due in part to the translation?

It does look very much like the Steca, some of the text for mounting it is very similar.

 

I don't think the regulator is suitable for a Motorhome, pretty sure it will degrade your AGM batteries still more than you old Solar regulator has already?

 

There seems to be one fixed, constant charging voltage which you can set, when the optimum for a modern battery requires at least two voltage levels.

 

To charge a battery quickly, usually requires around 14.4v for Wet batteries and 14.8v for AGM's. This will charge the batteries at the fastest rate without damage. However once the battery is fully charged continuing to apply this voltage will usually result in a damaged battery, which is why good chargers then drop to a lower Float/maintenance/trickle voltage of between 13.2 and 13.8v depending on the battery, length of time idle, etc.

 

You can charge a battery at a compromise constant 13.5v, like some of the Sargent Chargers do, but it will result in slower charging for a Wet Battery and will degrade an AGM. I think you will be lucky to see even 80% capacity once an AGM is a year old if charged permanently at 13.5v.

 

Your Solar charger seems to be a single voltage type where you are able to change the default 13.8v to any voltage you like. Obviously setting it lower to 13.2v will protect the battery in storage but may result in very slow charge. Setting it to 14.7v for your AGM's will give optimum charging.

However, they may then degrade very quickly once fully charged if still given a 14.7v maintenance/float rate.

I suspect the charger is more complex than that, but unable to determine anything from the manual.

 

If it was me, for safety to prevent short term AGM battery deterioration, and the risk of thermal runaway, I would select a 'Cutoff' voltage of 13.6v - 13.8v. Although this will probably result in long term AGM battery deterioration and slower charging, it should avoid the risk of battery explosion?

 

Given the configuration of your Solar Panels, this regulator and the fitment of a Battery Master, I stand by my initial guess that your Solar setup will be about 50% down on the best it could be.

It will work, as most people will tell you a Battery Master does, but the setup could be twice as good with double the power harvest. Most of the people we see don't know how poor their Solar setup is as 'it works'.

Marshall Kennedy yesterday had his Solar Regulator mounted 40cm from the Solar Panel with a ridiculous 7metre long cable run from the Regulator at the very rear of the vehicle to the battery under the front passenger seat, yet the instructions say to mount the Reg next to the Battery/Power unit. He had been delighted with his setup, but is now a bit disappointed he could have been harvesting twice the power the last 7 years.

 

 

The reasoning behind my conclusion, which may be flawed as the manual is hard to read, goes as follows :

 

There doesn't seem to be any description of the default charging voltages, except in the table at the very end where it states

"float charging voltage (settable) - 13.8v".

There is no mention of configuring the voltages for the usual 2 - 3 phases of charging voltages, just what it describes as the 'Cease charging' voltage. As the 'Cease charging' voltage seems to be the only 'settable' voltage I can only assume this is the Float phase voltage, in reality just a fixed voltage charger?

 

In section 3 it describes how this is changed.

 

"3.10 Review and setting the voltage of ceasing charging

As shown as the right figure, the displaying number is the voltage of ceasing charging. When the

battery voltage reaches up to this voltage, the controller will disconnect the charging loop to

prevent the battery from over charging. After the battery voltage drops, the controller will

reconnect the charging loop."

 

It doesn't state the voltage when charging restarts, just, " After the battery voltage drops, the controller will

reconnect the charging loop".

 

So depending on this exact 'restart' voltage, would significantly affect my argument above.

For example if the charge stops once the voltage at the battery terminals reaches 14.8v and doesn't 'reset' until the voltage at the battery drops to 13v, then the damage done by 'overcharge' would be limited to a degree.

 

 

An important point to remember is that the above is NOT talking about the 'real' battery voltage, but the voltage at the battery terminals. When the Sun comes up the battery might have a real state of charge voltage of 12.4v, but as soon as any charger (including an Alternator) starts putting 14.4v into the battery, that will be the 'voltage at the battery'.

The batteries real voltage for determining it's charge state is still 12.4v, until it starts taking that charge onboard.

 

 

[david lloyd]

Thanks Allan. I have charged the batteries fully the other day using EHU and for the last couple of days been monitoring the battery state of habitation and engine batteries - comparing it to the readout on the regulator and vehicke control panel. It does appear that once the habitation battery reaches 14.7v (set by me as the cutoff voltage) then it does not reduce to a lower voltage but simply cuts off any charge then will restart when the voltage falls below the 14.7v. In practice, this means that the solar panel,is putting in a charge constantly as the voltage does not remain constant at 14.7v although, as the van is parked beneath a carport (with translucent polycarbonate roof, it is not a huge charge. Fir the period between 10.00 and 14.00 it is in the shadow of the neighboroung property too. However, there has been between 5A and 10A going in over the last two days. I have nothing connected to the 'load' terminals and don't intend using that.

 

So far, the batteries have fallen to 13.5v (habitation) and 12.8v (engine) at the terminals without the EHU for the last two days. I think I may just try taking the readings after dark one day to see where they are with no solar charge going in.

 

I think I am marginally better off at the moment in that I can at least use the LCD readout to see what is happening and also set the cutoff voltage for the solar panel charge. However, I am minded to save a few pennies up and fit a good MPPT charger unit. In the near future.

 

David

[aandncaravan]

Well that seems to confirm my analysis.

I therefore think that taking Brambles advice to set the cutoff voltage at the level he suggests will end in disaster.

 

 

 

 

 

[Brambles]

"The Varta recommended Absorption voltage for AGM is 14.8 volts.So this will be your cutoff voltage.

AGM also tend to have higher discharge voltages so where in a flooded 12.1 volts is 50% discharged, it is 12.5 volts for a Varta AGM. "

 

The info I posted still stands assuming the charger cuts back to a safe float charge,

 

[aandncaravan]

It is a single fixed voltage design with temporary 'cutoff', then back to 14.7v.

As David writes, "In practice, this means that the solar panel is putting in a charge constantly...".

 

Be interesting to see just how big and messy the battery explosion turns out to be after Thermal Runaway takes control?

 

 

[Brambles]

In tests reported on 22nd April it was reported the voltage cut back to 13.2 volts and remained on float charge until the voltage dropped when a load is applied.

 

Now we have a test which shows the solar charger stopped charging but as soon as voltage dropped below 14.7 volts started again. Confusing!

 

So I a wondering if the various voltage settings have been altered deliberately or by accident. It just does not make sense for the solar charger to stop charging when reaching 14.7 but to immediately start again when it falls from 14.7. If that is the case and can not be altered then I totally agree - rapid failure of the battery, and the charger is not fit for purpose in a motorhome or a building installation.

 

Just my pennies worth for what it is and back over to you Allan as you seem to be on top of this one,

 

 

[aandncaravan]

A house Solar Power Installation is used very differently to one in a Motorhome.

In a House Solar solution the key design criteria is to extract as much power as possible for the maximum amount of time and feed it to the grid so you never actually want the 'charger' to do anything but work flat out all the time.

 

That is quite different to a Motorhome where much of the time the batteries won't be very discharged as the Motorhome will be out of use a lot of the time. Even when being used, the battery will have often got back up to 80% by early afternoon.

 

So whereas a House Solar Reg will often be designed to run flat out, a Motorhome regulator needs to be very focused on long term 'storage' maintenance/float charging with the ability to rapid charge when required.

A house Solar reg with dual battery output, once again works on the premise that both batteries will be heavily discharged, whereas a Motorhome Starter battery will almost always be full.

 

Only a few of the reasons why we think the likes of the Steca are not suitable for Motorhome use and only Motorhome specific regulators should be used.

 

We still rate the Schaudt compatible Votronic as one of the best around for all Motorhome makes. Several people have now reported a trouble free purchase from the Australian supplier we list on our Solar web page. I don't know how he does the Votronic MPPT 165 dual battery regulator at £69, including postage from Aus. But it is the cheapest supplier we have found with a high customer satisfaction rating.

 

Swapping from a pre 2016 made single battery Solar Reg to the MPPT 165 can usually result in a useful increase in charging potential as well as longer battery life, especially Starter battery life as these often get an 'overcharge' on the none Motorhome specific regulators.

 

 

[david lloyd]

Brambles - 2017-05-04 4:53 PM

 

In tests reported on 22nd April it was reported the voltage cut back to 13.2 volts and remained on float charge until the voltage dropped when a load is applied.

 

Now we have a test which shows the solar charger stopped charging but as soon as voltage dropped below 14.7 volts started again. Confusing!

 

So I a wondering if the various voltage settings have been altered deliberately or by accident. It just does not make sense for the solar charger to stop charging when reaching 14.7 but to immediately start again when it falls from 14.7. If that is the case and can not be altered then I totally agree - rapid failure of the battery, and the charger is not fit for purpose in a motorhome or a building installation.

 

Just my pennies worth for what it is and back over to you Allan as you seem to be on top of this one,

 

 

Hi brambles, sorry for any confusion caused.

 

The figures shown on my post of 22nd April were new to me as I had just installed the charge controller at Peterborough so it was running just on solar charge.

 

The second last figure of 13.2v I quoted was not the float charge but the actual voltage the batteries were at - at that moment. The graphic indicator showed that charge was still flowing into the batteries but there is nowhere that indicates at what voltage. My assumption is simply that the charge controller never drops below trying to charge at 14.7v (which is the cutoff charge I have set it at) but as we were using power it never climbed back to that voltage at the batteries.

The charge controller screen can be scrolled through and gives the following information at present (20.25 this evening:

pv 12.8 (this is the present voltage at the batteries)

24c (this appears to be the ambient temperature)

pv 0.0A (this usually indicates the amps going in - nine st this time)

Load 0.0A ( the unit has a set of terminals for an extra 'load' to be wired in - not used)

pv 1241 AH (this is the cumulative number of amps going through the unit)

Load 0AH (possibly the number of amps being used by the load)

Load Off 10.7v (the voltage at which the additional 'load' will be turned off)

Load On 12.6v (the voltage at which the additional 'load' can be used)

pv off 14.7v (the voltage at which the unit stops charging the battery)

Load on 24h (this is the only time reference and seems to be how long the load is available for use)

 

I am monitoring it daily at the moment at roughly the same time after fully charging the batteries on EHU have seen the following:

 

After charging hab batts 14.6v - regulator indicates 14.6v - panel indicates +13.5v - engine 14.3v

After 24 hrs - hab batts 14.0v - regulator indicates 14.1v - panel indicates 12.5v - engine 13.1v

After 48 hrs - hab batts 13.6v - regulator indicates 13.5v - panel indicates +13.5v - engine 12.8v

After 72 hrs - hab batts 14.5v - regulator indicates 14.6v - panel indicates + 13.5v - engine 13.6v

After 78 hrs - hab batts 12.8v - regulator indicates 12.8v - panel indicates 13.0v - engine 12.7v

 

The last figure is one I have just taken and the others are around 2pm to 4pm obviously showing some charging taking place to top up the batteries. This is confirmed by the figure that shows amps flowing in as that figure went from 1215AH after the EHU charging up to 1241 this evening showing increases of 6A on day one, 10A on day two and 10A today even though the motorhome is parked beneath a translucent polycarbonate carport and in the shadow of a neighbouring building from around 11.00 to 14.00 hours.

 

I don't know what all that means but these early figures don't seem to indicate that the unit is charging at 14.7v constantly although the sun isn't on the panel constantly. Having said that, the batteries did get up to full charge by 2pm today and was charging the engine battery which had gone up from 12.8v the day before to 13.6v and has now fallen back to 12.7v.

 

Are we more confused? I am.

 

David

 

[aandncaravan]

David, the figures are a bit confusing?

As this is about assessing the Solar Regulators performance, the figures you should be taking are when the Panel is in the maximum sun. I.e. only after 14:00 when the shadow of the house moves off the panel. Same time and same conditions.

The figures are meaningless otherwise.

 

 

One thing of concern is the voltage taken tonight of 12.8v?

If no power is being used in the Motorhome, good AGM batteries should be showing 13.0v or slightly more.

If you look at the attached chart, in the VRLA column, 12.8v reflects a 25% discharged battery?

 

To drop to that level after being charged fully on mains only a few days ago, and again today by Solar, suggests the AGM batteries are not as good as you might expect?

 

I suggest you disconnect all charging, including Solar, leave the batteries to stabilise for 5 days and take another voltage reading.

Any further discharge would indicate poor batteries.

 

If they are very poor then that might skew the results of any Regulator assessment as the batteries could be discharging almost as fast as they are being charged so suggest you establish the battery condition before going any further?

 

 

 

 

 

 

 

[aandncaravan]

Brambles, I have added the Regulator manual to the bottom of our AGM battery webpage, maybe you might be so kind as to see if you can fathom it out?

http://www.aandncaravanservices.co.uk/agm-batteries.php

 

It is too big to load on the Forum.

[Brambles]

Thanks, shall take a look.

 

Edit -- had to laugh at very 1st sentence in manual ... This controller is a kind of intelligent .........

[Brambles]

Well that was interesting and see what you mean now Allan. It clearly is 'intelligent of sorts, but for all intents and purposes appears to be a single stage charger. (which I think you have already said).

 

It looks like the only safe thing you can do to continue using is to set the end of charge voltage to 13.2 volts.

This will at least charge the batteries but not as fast or as fully as desirable, and look for a better charge controller which includes 3 stage charging or similar as Allan has suggested.

Arrrrrrrgh, going to look at this again in the morning.

[aandncaravan]

Brambles, that same sentence made me chuckle. Even more so when I read it again after reading the full manual.

 

The Load control is quite sophisticated and the information it gathers about everything, both long term Harvest and short term information, is excellent.

 

Shame the actual battery charging side isn't.

I am sure it works, but my old teacher might have written :

 

"Six out of ten, could do better."

 

 

[Brambles]

Had another look.

Yes, its basically a float charger and a load controller. Primary use would be solar panel system in a home without power to provide lighting.

There are plenty of other versions available in this range of controllers and I eventually came across one which includes what they call boost voltage for two hours and then falls back to the float voltage.

Its on this page somewhere... http://www.chinasolarregulator.com/solar-controller-c-series.html.

 

[aandncaravan]

Arthur, may I come back to your original post on B2B's and charging voltages because there has been, what I think is an interesting development?

 

If you have been reading our Battery to Battery charger webpage as indicated by your post, you are probably also aware of the pages on AGM batteries?

 

In the last few days I have been updating the AGM battery page because it was reported to us that Powerframe technology (the EFB version) has been given full Stop/Start status. Previously the exclusive domain of AGM batteries.

One BMW Dealer has reportedly found these Powerframe batteries more reliable than the short life AGM's and is fitting Varta Wet Acid EFB Silver Powerframes to replace failed AGM's.

 

Two things have occurred to me tonight :

1. That the Varta EFB substitutes will be charged at AGM voltages.

2. That the already fast charging Silver Powerframes will become Turbo'charged' at 14.8v, getting up to full power really, really quickly.

 

Silver technology batteries have very good higher voltage tolerance, one of the reasons Ford insisted on Silver technology batteries when they introduced the 'intelligent' Alternator (pre Stop/Start) into the likes of the 2005 Mondeo/Focus where the Alternator would charge at voltages around 16v.

 

Conventional batteries used to substitute a Silver battery in a Ford have been shown to have very short lives, showing the Silver technology works.

 

 

Powerframe has been shown to have very good high temperature tolerance which induces the same battery degrading corrosion as higher voltage charging does. Suggesting that the combination of Silver and Powerframe would yield a greater benefit than Silver alone.

 

So putting together the proven track record of Silver technology and the recent official endorsement of EFB Silver Powerframe as 14.8v capable, suggests very strongly that the slightly lesser Varta LFD90/Bosch L5 should tolerate a B2B's 14.6v charge voltages better than any other battery by quite a margin? Probably very fast charge rates, that outperform all other batteries in the same price band right to the batteries End Of Life.

 

Even if the Powerframe LFD90's are degraded by the higher voltages, they must surely degrade far less than any other technology?

 

If you have Varta LFD's, you might be playing it too conservatively?.

 

 

More on this on the AGM Battery page : http://www.aandncaravanservices.co.uk/agm-batteries.php

 

 

 

[arthur49]

aandncaravan - 2017-05-05 10:05 PM

 

 

If you have Varta LFD's, you might be playing it too conservatively?.

 

 

 

Yes I've been (trying to?) follow this in recent posts. Interesting. Very interesting. I don't have Varta LFDs at the moment and my two leisure batteries, though cheapos, survived a drop test at service, and APPEAR fine.

When I do replace the batteries I've already decided on Varta LFDs. If I change the van I will reconsider my B2B ............. and as I've said before, maybe a wee trip to N Wales :-D

 

Added in Edit: Allan, meant to say its not the initial charging voltage of my B2B that concerns me - its 14.4v. Its the capability of shoving up to 45A into my leisure batteries that concerns me, but as I've said before I've never drained my batteries such that they need anywhere near 45A .... in any event I use a remote control to turn B2B off if I think thats enough

[aandncaravan]

Higher charge currents are also handled better by the Powerframe Varta LFD90's.

If you look at the Victron Energy charts on the AGM page, you will see that the critical issue with higher charge currents is how they raise the battery Plate temperature.

 

It is the Plate temperature which has such a drastic effect on battery life, which according to the Victron charts, can drop a batteries 10 year life to 2 years.

 

Powerframe batteries were tested in desert temperatures and outperformed conventional batteries by better than 2 : 1, lasting nearly 96,000 miles versus a conventional batteries 42,000 miles. See chart below.

 

 

 

[arthur49]

Looks good Allan. I do believe that my current charging solution of B2B used with care, is a good one given the EC155 is basic.

[david lloyd]

Allan (aandncaravanservices) could I just confirm something with you. As you know from previous posts my EBL29 charges two Varta LA90 AGM batteries which also have a 120w solar panel wired directly to them via the basic Solrtronica charge controller. There is a Battery Master wired directly into the rear ports of the EBL where the battery cables exit.

 

At the moment (and until I replace the basic solar controller with one suited to the Schaudt EBL) I am frequently using EHU either at home or on sites to charge the batteries. If the EBL29 charges both habitation and engine batteries from EHU is there any need for the Battery Master? If I remove it will the new arrangement of either a LRM1218 of the Votronic Duo MPPT solar controllers wired directly into the EBL29 still charge both habitation and engine batteries or does the engine battery have to have a separate supply from the solar charge controller?

 

David