Scrap the Converter that came with the Travel Trailer?

[Grininmonkey]

I was originally thinking that I would need to scrap the built-in "Converter" which currently is the DC Load and Charging source when AC is supplied to the trailer.

I am investigating all the equipment I need and my end goal is to increase the trailers battery bank and add PV Panels. So now I want to look for the most efficient setup which would supply AC and DC load from Shore or Gen when connected and when PV Panels are below minimum output use the (Shore/Gen) DC supply to continue / start charging.

Question is, can I supply an MPPT controller DC from Converter in place of PV source and it do so only when PV is down and Converter output is available?
I want to have one device that is in control of bank charging and that device have optional DC sources, and control which source is supplying that device.

Is it efficient to keep the Converter and disable its charging (which mine has no parameter control but is a 3 stage) and have a setup which would only utilize an "Inverter" when (Shore/Gen) is unavailable, however the Converter would be used and Inverter off when (Shore/Gen) is available.

I am worried about having true control of the bank's charging, I don't want to have to keep up with and match multiple chargers based on my current DC source.

Another DC Source is the Vehicle when connected and traveling, which is then tying in the trailer bank to the vehicle's alternator, Would this connecting need to be modified to route thru new setup as well?

[Clarification]
I understand having more than one source or input to one MPPT controller is going to cause the MPPT to freak out when trying to calculate Pmax=Imp*Vmp. I am suggesting having an automated/Manual input control where "only" one source is supplying the controller.

I guess I could break out my old Parallax Basic Stamps and control some relays myself?

[Sunking]

Question is, can I supply an MPPT controller DC from Converter in place of PV source and it do so only when PV is down and Converter output is available?

No nor would you want to. Shore power is a stiff source.

In a properly setup RV you will have three sources of power.

Alternator through Battery Isolator
Shore Power
PV

Anytime the engine is running the alternator will be the main charge source. When connected to Shore Power it will be the main source. PV is for show and tell. It i snot something you have to worry or fuss about, the batteries will draw power from the highest level source, just like the Inverter wil take power from the highest source. Neither care where its power is coming from.

[Grininmonkey]

There is a lot of information on proper battery charging and service to get the optimal life etc.. and that's where my concern is coming from, especially in the RV scenario where there is not a consistent routine which could always be applied. Traveling, Dry Camp, Shore, Sun - No Sun, etc...

Perhaps I am just reading to much and just need to move on to the "get it done" phase. But the common thread or train of thought I see is, to discharge to an optimal DOD and then charge at specific parameters for your bank. Charging one minute then not, and have multiple charging sources with different behaviors switching from one to another would seem to create a likely multiple DOD and Charge situation which everything I have read said is bad on your bank?

[crotalus]

You do not want to scrap your converter. In your travel trailer you could have three sources to charge your batteries, shore power/generator(converter), tow vehicle, and your solar controller. Each one of the sources will have their own charge controller and supply current when needed by each device.

If you are going to add more batteries the concern might be the size of your converter. Does it have the capacity to charge the extra batteries? If you replace the charging unit of the converter the probability is that you might have to increase the size of the AC wires to the converter. An example would be to go to a 50 amp converter from a 30 amp converter.

Your solar charger must be large enough to handle any power supplied by the solar panels.

The alternator on your tow vehicle should be able to handle the demand also. If you have a truck the alternator is 95 amp or greater.

I have a small travel trailer with an attached 100 watt panel and a Trojan group 27 115 Ah @ 20 Hr rate. I also have an additional 50 watt portable that I can plug in if need be. In 5 years I have not any problems except when dry camping for days without any sunshine.

One thing that you need to do, if you have not done so yet is to replace your light bulbs with LED bulbs. That is a huge difference. Also if you have a television in the trailer be careful of the LED bulbs you buy as a lot of them do not have EMI shielding. When you turn on the lights you could see your television go black.

It is nice to be able to dry camp with solar and keep your battery charged for extended periods. I find that the limiting factor is the water supply.

Enjoy!

[Sunking]

You want as many Charge Sources as you can get your hands on. The two best sources are Shore Power, and the vehicle Alternator via a Electronic Battery Isolator. You do not want to eliminate your best source.

[Grininmonkey]

I hear what everyone is saying and I completely agree, but I am referring to control of the voltage and current which is applied to charge and when it is applied. This might all be a fruitless train of thought, but....

Most Youtubes, forums, etc are explaining what to do and not to do in terms of Discharge/Charge behavior in static scenarios, but it seems to me that the same would apply in a mobile situation?

Most folks say, that the optimal use on your bank should be to Discharge and continue to do so even when power is available to charge to an optimal DOD (30,50 or 80)% and then charge (but when demand stops, no matter the DOD, go to charge), where the bulk charge is at a specific voltage that is optimal for your bank. The long and short of it is, if I understand correctly, is a consistent shallow DOD and charging behavior at various voltage/current rates (Meaning different charge sources that might not allow for settings) will reduce the battery life and the best thing for your battery is to be in Bulk more often than Float, with a deep DOD Cycle performed every so often and flirt with the slightly overcharge more frequently than under.

So at the heart of my question is.. do I indeed gain something by controlling a specific DOD and charging characteristic, meaning an extra year or whatever out of my battery investment?

If there really is something gained, then I would need to have something in place that would only charge, and use whatever source is available, using one set of charging parameters?

[Grininmonkey]

One thing that you need to do, if you have not done so yet is to replace your light bulbs with LED bulbs. That is a huge difference. Also if you have a television in the trailer be careful of the LED bulbs you buy as a lot of them do not have EMI shielding. When you turn on the lights you could see your television go black.
Enjoy!

I have all but the outside lamps using LED. Coffee Maker is now a 12VDC Model and will hopefully be replacing Fridge/Freezer with one of these: http://www.thetford.com/product/de-0061ev-0061/ which only consumes 3.x Amps of DC (no LP). I need my Coffee, Cold Sweet Tea and Fridge for Dry Camping, so I'm working on making those possible off of DC alone

Water goes by by, so quick, mostly due to my Sweet Tea requirement (2 gallons a day), lol

[Willy T]

How I'd control it is dependent on the Inverter selection and how it's wired and the equipment you choose. If your going to have a Inverter / Charger with automatic change over from shore ( pass through ) and Transfer to Invert you wouldn't need the converter at all. If you plan on just a plain Inverter ( with on / off switch ) then you'll need it and it would have a switch or a relay to turn it on / off. Once you disconnected from shore power the converter would be shut off. If you have a generator is it going to use the same power cord, makes a big difference.

Automatic always costs more and is prone to difficulties.

As far as the PV producing power and the converter that you could control with a axillary output signal or some kind of VCS ( Voltage Controlled Switch ).



It's hard to get a exact visual of what your trying to do.

[Grininmonkey]

It's hard to get a exact visual of what your trying to do.

MultiSourceChargeControll.png


I was originally thinking about NO and NC relays controlled by a 5VDC IC to perform some sort of logic, such as (If PS (C) which could be PV array has power, then use the free source) otherwise connect to PS(A) which could be (Shore/Gen) unless PS(B) has current which could be (tow vehicle).

But again, this was just coming from the mindset of using one "Charger" with one set of "Charging Parameters" with one expected charging behavior. Something like an Xantrex TRUECharger2 which has conditioning and Equalization Mode available.

PV source I believe is what throws the concept into chaos because the most efficient way to pass energy from PV to Battery is using an MPPT direct to the Batteries as it calculates using the battery direct connection.

[Willy T]

[ATTACH=CONFIG]7029[/ATTACH]


I was originally thinking about NO and NC relays controlled by a 5VDC IC to perform some sort of logic, such as (If PS (C) which could be PV array has power, then use the free source) otherwise connect to PS(A) which could be (Shore/Gen) unless PS(B) has current which could be (tow vehicle).

But again, this was just coming from the mindset of using one "Charger" with one set of "Charging Parameters" with one expected charging behavior. Something like an Xantrex TRUECharger2 which has conditioning and Equalization Mode available.

PV source I believe is what throws the concept into chaos because the most efficient way to pass energy from PV to Battery is using an MPPT direct to the Batteries as it calculates using the battery direct connection.

The only thing you want going through your mppt charge controller is your PV, all the rest are paralleled on to the batteries. The connection to your vehicle produces no power when the Engine is off and has a isolator on it. The Battery charger / converter has no power unless it has 120v going to it and has diodes to prevent backfeeding.

The question is when you have shore power what do you want to come on. When you un-plug from shore power what do you no longer need. If you have a generator, what do you want to power when it's running. If you have a Inverter, what do you want it to power ?

[Sunking]

You do not have to worry or control anything. The highest source wins.

• If it is the panels, the controller controls voltage and current.
• If shore power the Inverter/Charger controls the voltage and current
• If alternator the Electronic Battery Isolator controls the vlotage and current.
• If all three are available hardest source wins.

You don't have to worry about it.

[Grininmonkey]

I think I am back to the conclusion of not using the built-in Converter to Charge. Considering that PV is only going to be a possible source for a limited period of the time, using a better for my battery charger such as the Xantrex charger when AC is available either via Post or Gen could be my main concern in terms of how a charger is charging the bank. Something with corrected temp compensation etc.

Travel time is more limited than PV, so the alternator connection is essentially keeping absorption at best and float typical.

So I am leaning towards the attached image?

BankChargingSetup.png

I understand hardest source wins, but I do want to have an ability to allow DOD if (Post/Gen) is connected potentially in order to perform a real cycle from time to time and avoid to many shallow cycles. The Charger I am looking at also allows for Flooded service to equalize and condition if/when I would need to do-so.

[Willy T]

I think I am back to the conclusion of not using the built-in Converter to Charge. Considering that PV is only going to be a possible source for a limited period of the time, using a better for my battery charger such as the Xantrex charger when AC is available either via Post or Gen could be my main concern in terms of how a charger is charging the bank. Something with corrected temp compensation etc.

Travel time is more limited than PV, so the alternator connection is essentially keeping absorption at best and float typical.

So I am leaning towards the attached image?

[ATTACH=CONFIG]7032[/ATTACH]

I understand hardest source wins, but I do want to have an ability to allow DOD if (Post/Gen) is connected potentially in order to perform a real cycle from time to time and avoid to many shallow cycles. The Charger I am looking at also allows for Flooded service to equalize and condition if/when I would need to do-so.

Your drawing looks good. I have never used the Xantrex tru charge 2 , but I am sure it's good and yes it is temperature compensated.

You are going to have to have a lock out breaker or shore power switch to connect the Inverter/ Shore Power cord to the distribution panel so only one can be connected at a time. Otherwise you'll be backfeeding to the one not being used.

Here is a lock out breaker setup.

ScreenHunter_116.jpg

[pfaber]

I think I am back to the conclusion of not using the built-in Converter to Charge. Considering that PV is only going to be a possible source for a limited period of the time, using a better for my battery charger such as the Xantrex charger when AC is available either via Post or Gen could be my main concern in terms of how a charger is charging the bank. Something with corrected temp compensation etc.

Travel time is more limited than PV, so the alternator connection is essentially keeping absorption at best and float typical.

So I am leaning towards the attached image?

[ATTACH=CONFIG]7032[/ATTACH]

I understand hardest source wins, but I do want to have an ability to allow DOD if (Post/Gen) is connected potentially in order to perform a real cycle from time to time and avoid to many shallow cycles. The Charger I am looking at also allows for Flooded service to equalize and condition if/when I would need to do-so.

I am of the same mind after investing in a new battery bank (batteries aren't that affordable in Canada). I look forward to hearing how your project turns out as I'm looking at the same scenario with my rig.

[Shadow Catcher]

Play well together

We have a large teardrop trailer (I know kind of an oxymoron). that is set up for serious boondocking. We have a 185W high voltage solar panel that feeds into a Morningstar MPPT controller and 150AH Lifeline AGM. The converter is a Progressive Dynamics 45A power center and then the TV is hooked in through the 7 prong. It all plays well together. I have called Lifeline and talked with one of their engineers and they blessed the Progressive Dynamics converter and Morningstar controller and Morningstar Suresine inverter. I do not believe in integrated electrical/electronics, you do have failures and when that happens the invertercharger is either replaced or repaired.