Charging tv battery with td converter/charger

[dh]

I got to thinking today, lets just say I get in late to the campground, back it in to a spot and go to bed, planning on setting up everything in the morning. Get up in the morning, unhitch and go to pull the TV away and find I left the lights on all night, with a dead battery (and discruntled neighbors who had my headlights shining in thier camp all night). Could I plug the TD up to 110V and then plug in the 7pin to the TV and let the power center charge the TV battery?

Just to clarify, my chargewire from the TV goes dead when the ignition switch is turned off, so TD battery would still be fully charged.

[wannabefree]

The short answer is no. Converters of any type have circuitry in them to prevent current from flowing in the wrong direction.

The long answer is too long. I suppose it's possible to build a converter that will charge your TV if you really wanted one, but I have never seen one.

[Shadow Catcher]

I quite frankly have never checked, and the simple answer is use jumper cables. If I remember correctly the wires to charge the battery come directly off of the TV battery through a fuse, so a charge current would back feed the TV battery. It would be easy enough to check, use your VOM to check the current at the TV battery at rest and then with the converter on.

[eamarquardt]

I think it depends upon how your tv is wired. If there is a relay that needs to be activated from the tv to charge the trailer battery, and if the tv battery is dead the relay's not gonna get activated, and you're not gonna "backfeed". If it is a mechanical switch though, you might be able to backfeed and get enough into your tv battery to start. Best bet is to disconnect your tv battery, turn on your ignition, and see what happens. You won't be able to start but your ignition may come on which would suggest you can backfeed the tv battery from the trailer.

Jumper cables and/or turning off your lights will always work and you neighbors won't be unhappy with you.

Once had a fishing boat pull into an anchorage at 0200 and run his radio loud as they worked. Very rude.

Cheers,

Gus

[8ball_99]

Your battery would have to be very dead to not be able to kick the relay for the charge wire.. My guess is if you turned the key off for a few mins you would have enough charge to kick the relay.. Once you did your truck would have plenty of power to keep it connected because it would be pulling from your trailer battery/converter.. Leave it sitting with the key on and it should charge the Truck up..

[dh]

Thanks for the replies, I have a lot of time to think about things like this while babysitting a Bridgeport in auto pilot making 16" passes.

[bdosborn]

I think the key off bit is what would prevent you from charging from the trailer. The charge line on my truck is always hot and I charge from the trailer whenever I plug in to shore power and don't disconnect the trailer. Or I can charge from the solar panels. I added this dodad to automatically disconnect the truck from the trailer when dry camping so I don't drain the truck battery accidentally.



Yandina Battery Combiner Clicky

The combiner automatically disconnects the truck and trailer when the voltage falls below 13.3V. It also automatically connects the truck and trailer when it sees a voltage of 13.3V or higher. So I can charge the truck from the PV panels and/or battery charger without worrying about draining the truck battery. I can set it to off if I want to charge just the trailer battery. It also combines when I start the truck to charge the trailer battery. I wouldn't need it if I didn't keep forgetting to unplug the trailer from the truck when we stop.

You have to be careful about voltage drop with the Yandina. I was dropping below 13.3 v whenever I ran the fridge on 12v. The 10 amp draw through the factory wiring ( a #16!) dropped the voltage below 13.3 v and the combiner was dropping out. I ended up running a #6 wire back to the RV plug on the truck to fix that problem.

You don't really need to get this fancy with a combiner to charge the TV from the trailer, but you will need a charge line that is hot with the key off. That could be as simple as running a new fused wire from the battery to your trailer plug.

Bruce

[terryjones1]

In my van conversions, I installed a Surepower Battery Separator Model 1315-200.
I directly connected the primary & secondary batteries pos outputs to the Separator through circuit breakers.
The separator is then connected to the converter pos output.
The priorities are to assist in engine starting, if required, and to protect the charging system from excessive power drain.

[bdosborn]

In my van conversions, I installed a Surepower Battery Separator Model 1315-200.

The Yandina replaced a Surepower 1314. I found that it was closing in when I was on battery power (12.7 V), which its not supposed to do. I could tell it was closed because the relay draws 1 amp when closed (!!) so the amp reading on the Trimetric meter was higher than normal. Score one for the Trimetric.

When I talked to them on the phone the FIRST thing they told me was it was installed incorrectly as it was in the trailer and not "close" to the TV battery. I told them that conflicted with their literature that shows the device installed in a trailer but they didn't care. I also argued that being close to the battery didn't have anything to do with the unit closing in at 12.7 V because its never supposed to do that. They agreed to look at it if I sent it in but their general attitude was that I was an idiot and they'd humor me.

Strike 1

It took 6 weeks, 26 emails (I'm not kidding, I saved all the emails) and 4 phone calls to get them to send it back. They lost it for awhile, then it sat on somebodies desk for awhile, then they forgot to ship it. They said they tested it and it was fine. I don't think I ever would have gotten it back if I hadn't kept nagging them for it.

Strike 2

I reinstalled it it and it promptly closed in at 12.7 V.

Strike 3

I replaced it with a Yandina and have lived happily ever after. The Yandina only uses 150MA when closed so I like it better, overlooking the fact that it works like it should in the first place.

I have a $75 Surepower 1314 POS in the garage that anyone can have if they want it. Surepower is on my never-getting-another-cent-from-me list.

Bruce

P.S. That reminds me, I need to post this to the Surepower review I did awhile back....