Charging batteries AND running the DC fridge on the road: a DC-input battery charger

[tentcamper]

Originally Posted by T and C

Folks,

A question: When you convert your TM bulbs to LED lights, do you have to place an adapter in the socket, or do the LED's just plug into the same sockets?

Tom

I would go to the with ones that fit the sockets. We went to daylight color bulbs. The others are just too blue or dim

It's not that much more in cost to just replace the entire fixture with led fixtures. Some extra work, if you get fixture that cover the old screw holes. The ones that are difficult are the ones in the vents.

[ThePair]

This is the perfect information that I needed! As always, thanks!

As to airflow...I have an SL model so the battery is in the rear compartment. There is a vent on the side, but that gets blocked by the rear shell while driving. I can drill a vent hole through the rear of that compartment, which will then communicate with the opening under the shower (for the bathroom vent/fan). Would this, in your opinion, represent adequate air flow? How about adding a PC fan?

If not, then I’m at something of a loss as to a better location.

[rickst29]

Originally Posted by ThePair

This is the perfect information that I needed! As always, thanks!

As to airflow...I have an SL model so the battery is in the rear compartment. There is a vent on the side, but that gets blocked by the rear shell while driving. I can drill a vent hole through the rear of that compartment, which will then communicate with the opening under the shower (for the bathroom vent/fan). Would this, in your opinion, represent adequate air flow? How about adding a PC fan?

If not, then I’m at something of a loss as to a better location.

Unfortunately, the Renogy is only "up to 90% efficient". At least 10% of input power is wasted as heat, and probably closer to 15% in most circumstances. (In contrast, the Solar Controllers which Klpauba and I use are about 96% efficient and only generate 1/4 to 1/3 as much heat.) Without a fan, the Renogy will tend to heat up the compartment a lot, shortening the lifespan of itself and your batteries.

I don't have a 2720, and can only guess at a "best way" to do this. I'll recommend a large but a slow and quiet 2-watt, 12v 1200 RPM computer case fan, such as this one, will do the job nicely: https://www.ebay.com/itm/NEW-120mm-x.../282462341274/.

There are two other things which you will need to add in. First, a fine-mesh fan screen (screwed in, with stainless steel screws, to cover the hole on the outside of the TM floor. Or, at higher expense but more waterproof, you could use a full "shroud" to cover the fan out-flow hole, just like the one to the one which TM uses to the protect the electric frame connections. (They are: One big wire from the the Power Converter 12V "Ground Bus", and another from the 120V "Green" Bus for Grounded safety wires.) That Shroud is next to the street-side rear "lift", screwed into the outside floor bottom and adjacent to the outside frame edge.

I'd simply use waterproof, non-rusting screen mesh.

The second thing you will need is some flex-duct dryer vent hose inside the Battery Storage area. The fan pushes air out from the bottom, but heat rises towards the top of the compartment. The hose pulls air from the top of the compartment, down and out the fan. (It's just like TM's use of ducting behind the Norcold fridge, except that this one can be much more successful - the Norcold didn't have much room behind it, and the ducting typically needed to be crushed too much.)

Member Klpauba has a lot of heat-generating things in his battery compartment, and has certainly installed a fan. I hope that he lists the parts he used here, in this Thread.

[ThePair]

Originally Posted by rickst29

Unfortunately, the Renogy is only "up to 90% efficient". At least 10% of input power is wasted as heat, and probably closer to 15% in most circumstances. (In contrast, the Solar Controllers which Klpauba and I use are about 96% efficient and only generate 1/4 to 1/3 as much heat.) Without a fan, the Renogy will tend to heat up the compartment a lot, shortening the lifespan of itself and your batteries.

I don't have a 2720, and can only guess at a "best way" to do this. I'll recommend a large but a slow and quiet 2-watt, 12v 1200 RPM computer case fan, such as this one, will do the job nicely: https://www.ebay.com/itm/NEW-120mm-x.../282462341274/.

There are two other things which you will need to add in. First, a fine-mesh fan screen (screwed in, with stainless steel screws, to cover the hole on the outside of the TM floor. Or, at higher expense but more waterproof, you could use a full "shroud" to cover the fan out-flow hole, just like the one to the one which TM uses to the protect the electric frame connections. (They are: One big wire from the the Power Converter 12V "Ground Bus", and another from the 120V "Green" Bus for Grounded safety wires.) That Shroud is next to the street-side rear "lift", screwed into the outside floor bottom and adjacent to the outside frame edge.

I'd simply use waterproof, non-rusting screen mesh.

The second thing you will need is some flex-duct dryer vent hose inside the Battery Storage area. The fan pushes air out from the bottom, but heat rises towards the top of the compartment. The hose pulls air from the top of the compartment, down and out the fan. (It's just like TM's use of ducting behind the Norcold fridge, except that this one can be much more successful - the Norcold didn't have much room behind it, and the ducting typically needed to be crushed too much.)

Member Klpauba has a lot of heat-generating things in his battery compartment, and has certainly installed a fan. I hope that he lists the parts he used here, in this Thread.

I've learned not to underestimate heat generated from devices like this -- the DC fridge mod will not be forgotten!

Hmm. I'm wondering if maybe it would make more sense to mount this thing in the space behind the battery, where the plumbing is for the tub. There's already a hole/mesh screen in the floor. I'm going to see how much space is back there -- it would then be separated from the battery compartment, so heat wouldn't affect the battery. Low enough position should allow for passive ventilation through the floor duct, and I could in concept leave the bathroom exhaust fan (which blows air into this compartment) on while traveling, which would then draw in fresh air from the bathroom/interior. The diagram only calls for passive ventilation, so the one fan may be enough?

[klpauba]

Originally Posted by rickst29

...
Member Klpauba has a lot of heat-generating things in his battery compartment, and has certainly installed a fan. I hope that he lists the parts he used here, in this Thread.

You give me more credit than I deserve, Rick, as I have no fan installed. I have the MPPT controller and batteries in the compartment that are active while traveling. I've only used the 1000W inverter a few times while parked and open up the door while in use. Our microwave trips the inverter so we rarely use the inverter, actually. The only other active device I can think of back there, the victron battery protect, is mounted in the rear bumper and suspect it gets lots of air and doesn't draw much power.

Should I be concerned?

[rickst29]

Originally Posted by klpauba

You give me more credit than I deserve, Rick, as I have no fan installed. I have the MPPT controller and batteries in the compartment that are active while traveling. I've only used the 1000W inverter a few times while parked and open up the door while in use. Our microwave trips the inverter so we rarely use the inverter, actually. The only other active device I can think of back there, the victron battery protect, is mounted in the rear bumper and suspect it gets lots of air and doesn't draw much power.

Should I be concerned?

No worries for you, even though I thought that you used the Inverter more often. The Victron doesn't generate any heat at all, and the EP-Solar "BN" Controllers (which we both use) generate about 1/3 as much heat as the less efficient Renogy device. A lot of our "waste heat" comes from the voltage booster, under the hood of the Tow Vehicle (where it is pretty much harmless.)

The Renogy has to do both jobs, voltage boost and solar Controller, within one box, and the solar controller is a less efficient PWM device. In a small space with inadequate airflow, it might create a problem,

[rickst29]

Originally Posted by ThePair

.... I'm wondering if maybe it would make more sense to mount this thing in the space behind the battery, where the plumbing is for the tub. There's already a hole/mesh screen in the floor. I'm going to see how much space is back there -- it would then be separated from the battery compartment, so heat wouldn't affect the battery. Low enough position should allow for passive ventilation through the floor duct, and I could in concept leave the bathroom exhaust fan (which blows air into this compartment) on while traveling, which would then draw in fresh air from the bathroom/interior. The diagram only calls for passive ventilation, so the one fan may be enough?

Yes, that might be adequate. I'd give it a try in that location first.

[ShrimpBurrito]

Originally Posted by rickst29

If you plug in the Power Converter as a "Renogy input", it will monitor the Bargeman Cable as a battery.

Yes, but it will only do that when the TM pigtail, supplying power to the converter, and the Bargeman cable from the TV are connected. That is not likely to be something that happens very often, if ever.

Originally Posted by rickst29

Without a battery (or other charge system) providing 10-15V at the Distribution Panel, most Power Converters won't even turn on. (You can plug in the 120V cord, but they won't turn on without a battery present.) The entire controller, on the circuit board, needs that power source in order to run.

I can't speak with converters other than mine, but my OEM converter, which arguably is not nearly as elegant as newer models, does not exhibit this behavior. I have specifically found that the converter provides DC power to the TM when a battery is not installed. IIRC, the only difference is that, since the battery acts as a noise filter between the converter and the TM when installed, the fluorescent light flickers. The LED lights may be a bit dimmer, I can't remember, but everything works. And obviously, this noise issue would not be a problem under normal circumstances, since there would be a battery installed. And newer converters may have this filter built in.

Originally Posted by rickst29

These need to remain as independent chargers. Renogy "+12V" into a battery terminal, and Power Converter "+12V" into the Power Distribution Board, which reaches the battery through a separate fused wire.

That may be true, I don't know, but I've not yet heard or thought of a reason to be convinced that is the case. But I haven't thought it through exhaustively though; I would certainly call the manufacturer to get their input, though I wouldn't be surprised if they would just tell you as a matter of course that they don't recommend it simply because it's outside of their tested scenarios.

Of course, upgrading the converter obviates the need to answer this question, and so if he already has an upgraded converter, there would be no reason to do that (though I presume this is not the case, hence his question).

Dave

[ShrimpBurrito]

Originally Posted by rickst29

Without a fan, the Renogy will tend to heat up the compartment a lot, shortening the lifespan of itself and your batteries.

I of course do not have the Renogy, but with my similar device installed without a fan in the compartment, I have not noticed a shortened battery lifespan. I also have never noticed a significant build-up in heat in that compartment upon getting to a campsite and opening the door. I've felt the device though at that point, and it does indeed get warm, but not to the extent of my thinking I needed to install something between it and the wall to protect the wall from heat damage. I think I would be worried about that before excessive heat in the compartment.

FWIW. My advice is free, and you get what you pay for.

Dave

[rickst29]

Now that you have pointed out the behavior you get: IIRC, my original Converter did run 12v lighting (and etc.) when my 'battery disconnect' circuit breaker was not yet flipped "on". But my new PD seems to want at least some DC Voltage present on the output (the +12V DC Distribution board), before it will raise output Voltage at all.