Truck remote start and TC battery charging

[bkenobi]

When I got my TC, I had the dealership install the wiring for TC hookup under the bed. I added remote start as a feature to the truck when I bought it specifically so I could charge the batteries without having to go outside or leave my key in while idling.

I found out after using this setup for a while that the truck only provides 12v under remote start though. After speaking to the service guys who installed the wiring, it sounds like the reason is based on how they determine when to allow higher current draw. They trigger the key in ignition as the test to determine if the TC should get higher current.

Does anyone have their truck setup for charging with remote srart? I'm wondering what you trigger off of. I think the dealership will fix it for me if I explain what I need. Also, any downsides to setting it up this way I nay not be considering?

Fwiw, I have a 2016 Ram Cummins.

[Kayteg1]

Voltage Regulators don't monitor battery stage.
They will keep preset voltage and the alternator will deliver amps to match.
That with computerized VR follows the idea of battery maintainers who float the amps to keep 13.5V.
My understanding is that older system could deliver 14.5V and charge the batteries with hundreds of amps, what is not good for them.
Than again, with TC charging it is long #10 wire that makes the restrictions.
On one side it limits the charging, but on other side it prevents the 260 amp to reach camper batteries.

[Bedlam]

Different battery capacities and aging plus line loss prevent both truck and camper batteries getting an equal charge. If it were that simple, there would not be a recommendation to replace both batteries in a parallel or serial multi-battery system when one fails.

[mkirsch]

If the computerized regulator system in the truck just "replaces what was used in starting" then it's pretty stupid.

Any regulator system worth its salt should be charging based on the state and condition of the battery!

When a depleted house battery is connected to the truck, it is essentially connected in parallel to the truck's starting battery. Together they should read as a partially depleted battery and the truck's charging system should begin charging to bring the battery up to full charge.

When the truck's charging system does not do that and instead stops charging because it put so many Amp-hours based on how much it thinks it takes to start the truck, there is a problem.

[Bedlam]

There are ways to make this work but will require the extra cost of a DC to DC converter/charger (solar charge controller can be used). You could also invert the DC truck output to AC power and run the onboard TC charge controller/rectifier.

[Kayteg1]

Grit dog wrote:

sch911 wrote:
The Ram factory remote start system only runs for 15 minutes. How is that expected to charge the batteries?

Not discounting the other 4 pages of discussion, the second post in the thread here sums it up. How much battery charge would you expect to get in that short term anyway?
As well, unless you ran a dedicated heavier gauge charging circuit to the camper batteries, you can’t pull a lot of amps.

Enough for the propane detector to stay quiet for next 2-3 hr till the morning.
You could always push remote button 2nd time.
All that whining and nobody actually come with idea how to hack the truck system to make it working????

[Grit_dog]

sch911 wrote:
The Ram factory remote start system only runs for 15 minutes. How is that expected to charge the batteries?

Not discounting the other 4 pages of discussion, the second post in the thread here sums it up. How much battery charge would you expect to get in that short term anyway?
As well, unless you ran a dedicated heavier gauge charging circuit to the camper batteries, you can’t pull a lot of amps.

[Kayteg1]

theoldwizard1 wrote:

Kayteg1 wrote:
Even with my mechanical education I know that when alternator will put 14V into trailer wire, you will have full 14V on other end unless you start putting load on it.
When I drive for several hr with fridge on propane, my TC batteries will show 14.2V.

What is the make, model and year of your truck ?

I was an automotive engineer for 31 years. Cars and light trucks built since about 2000 (?) simply do NOT put out that much voltage for more than a minute or two after start up. Shortly after startup, they may put out that much voltage, but only at high idle (2000 RPM).

If an alternator put out 14.2 volts constantly, your battery would boil dry.

It is 2017 Ford.
The 14.2V was taken from TC factory display that I did not calibrate, so there is margin for error.
I observe voltage on modern vehicles and Ford in the past was famous for putting 14.5V in the system, what was cutting batteries life.
Other brand we use- Mercedes has voltage regulators set to not go above 14V and we had their batteries lasting 13 years.
New Ford seem to have it fixed, but too early to tell for sure.

[theoldwizard1]

Bedlam wrote:
I don't look at the truck as the primary charging source for house batteries, but it will maintain them and keep them from draining to an unsafe level under load. To get a full charge on the battery, you need a smarter charger that is sensing parameters closer to the battery. Depending on the battery chemistry, 80 percent charge may be good enough as long as you do not discharge bellow the battery threshold.

This one of the most truthful statements made in this thread !

[theoldwizard1]

Kayteg1 wrote:
Even with my mechanical education I know that when alternator will put 14V into trailer wire, you will have full 14V on other end unless you start putting load on it.
When I drive for several hr with fridge on propane, my TC batteries will show 14.2V.

What is the make, model and year of your truck ?

I was an automotive engineer for 31 years. Cars and light trucks built since about 2000 (?) simply do NOT put out that much voltage for more than a minute or two after start up. Shortly after startup, they may put out that much voltage, but only at high idle (2000 RPM).

If an alternator put out 14.2 volts constantly, your battery would boil dry.

[bkenobi]

Fwiw, I don't expect any significant in 15-30min of remote start. I only intend it to keep draining low batteries in the evening or to stop the CO alarm for a few hours. Charging for me is ground power at home or driving a few hours.

[Bedlam]

I don't look at the truck as the primary charging source for house batteries, but it will maintain them and keep them from draining to an unsafe level under load. To get a full charge on the battery, you need a smarter charger that is sensing parameters closer to the battery. Depending on the battery chemistry, 80 percent charge may be good enough as long as you do not discharge bellow the battery threshold.

[Sam_Spade]

theoldwizard1 wrote:

A car/truck alternator is the WRONG TOOL to recharge house batteries, especially deep discharge batteries.. PERIOD !!!

BUT.....it is better than nothing.
13.2 is enough to put SOME charge back.
If you are driving for 8 hours, it might put back a significant amount.

Reading these threads is dangerous.
Now I need to pay closer attention to my alternator charging voltage......because after I got the "battery solenoid" replaced it now appears to stay above 14 all the time.

[Kayteg1]

Even with my mechanical education I know that when alternator will put 14V into trailer wire, you will have full 14V on other end unless you start putting load on it.
When I drive for several hr with fridge on propane, my TC batteries will show 14.2V.
So what is all that whining about?

[theoldwizard1]

Z-Peller wrote:

Not entirely true. On my GM trucks back to 2009, the owners manual says driving in towhaul or turning on headlights will send full charge to trailer plug regardless of truck battery fully charged regulator issue.

What it says on page 4-82 is

If charging a remote (non-vehicle) battery, press the tow/haul mode button located at the end of the shift lever. This will boost the vehicle system voltage and properly charge the battery. If the trailer is too light for tow/haul mode, turn on the headlamps as a second way to boost the vehicle system and charge the battery (in the trailer).

But, previously on page 3-21 it says

The vehicle has Electric Power Management (EPM) that estimates the battery’s temperature and state of charge. It then adjusts the voltage for best performance and extended life of the battery.

When the battery’s state of charge is low, the voltage is raised slightly to quickly bring the charge back up. When the state of charge is high, the voltage is lowered slightly to prevent overcharging. If the vehicle has a voltmeter gauge or a voltage display on the Driver Information Center (DIC), you may see the voltage move up or down. This is normal.

I simply do not believe the statement on 4-82 as it contradicts the statement "When the state of charge is high, the voltage is lowered slightly to prevent overcharging". Or maybe I should says, I don't believe that the proper voltage will be delivered to a trailer battery to recharge it 100%. It might keep it from being further depleted by loads in the trailer, but it will not be recharged.