Battery question

[dhaas]

Ive been reading a lot about solar, generators, converters ad inverters and its making my head hurt. We are leaving for a dry camp trip next week. I had my 2 batteries tested for my TT, and both tested good. I purchased a single portable solar panel from costco with a presumably lousy converter. I also have a 3000 generator, but dont really want to listen to it if I can avoid.

My main question is this. My small TV pulls 28 watts, and the dvd player supposedly less than that. I used a small 300 watt inverter I have, and it powered the TV and dvd player fine, but took my batteries from 12.7 to 12.3 volts in about 10 minutes, with the solar panel wired up. Now its foggy today, but the panel was charging the batts before I turned the tv on.

Are the batteries bad? Shouldnt I be able to run the TV for a bit as it doesnt pull much power? Thanks

[dhaas]

genny is fairly quiet. Its the champion 3000 dual fuel. Just didnt want to be running it at night when folks are trying to relax.

I can run an extension cord, and mount the inverter out with batteries, was just hoping to keep it easier. There is a 12 volt plug beneath the TV so i made a male plug set up with 16g wire and used that to the small inverter I have. Was hoping the minimal draw wouldnt be too much through likely smaller wiring from plug to converter or where ever it terminates/originates.

I have the wfco converter most everyone does. Was considering swapping out the charger portion to the PD 4655 but may trade up campers soon.

The batteries should have been around 12.6 when i started. Not full I know but that is as much as my battery charger at home will charge them to. I was just surporised they drew down that fast. Is that normal?

[time2roll]

I would run the the battery lower than 12.3 if needed and see how it goes. 12.7 very likely was not fully charged. You need 14.4 volts for 4 hours minimum to call full charge(or fairly close). Your generator will run a lot if your converter does not put the battery up to 14.2+ volts.

[KD4UPL]

Moving the slide takes a tremendous amount of current and would temporarily lower the battery voltage quite a bit.
12.3v under load isn't that bad depending on the size of the load. Battery voltage is a terrible way to judge the charge level of a battery unless the battery is completely disconnected from charging or discharging for several hours.
As noted, if you have long thin wires from the battery to the inverter you can lose a lot of voltage there. As an example, TV and DVD pulling about 50 watts, inverter 80% efficient, you're drawing about 5 amps at 12.3 volts.
If you ran 10' of #14 wire for positive and negative you would be loosing about .3 volts in the wiring.

[Lwiddis]

Generally you’ll need one solar watt for each battery amp hour to recharge your batteries. In some parts of NoCal 1.5 watts per amp hour may be necessary. Solar is wonderful but only with adequate batteries, panels and controller, so surfing in to Costco or wherever and buying one panel and a questionable controller won’t cut it.

Since you haven’t told us your daily total energy use (via an energy survey) there is no way to determine what you need in solar equipment...panels, controller and batteries.

Portable panels have their place but I will bet you my roof mounted panels were producing power before you put your panel out. And mine weren’t subject to theft or needed to be put away when you went out to dinner or at sundown. Sure you can point yours at the sun. I’ll just buy an extra panel. 100 watt panel is only a 100 bucks.

[BFL13]

SidecarFlip wrote:
With flooded cell batteries, 12.3 volts unloaded is just about dead. Dead with a 12 volt flooded cell is 12 volts.

Take your genny and deal with the noise. My genny is quiet, guess yours isn't.

Not correct at all! 12.3 resting is about 65% SOC, far from dead. 12.0v is maybe 40%, still far from dead. Trojan uses 12.1v as 50%. SOC.

Don't confuse new members with such wrong notions. 😞

[RJsfishin]

Check the voltage at the batteries, it may look a bit higher.
But just moving that slide would burn a couple hours tv time

[SidecarFlip]

With flooded cell batteries, 12.3 volts unloaded is just about dead. Dead with a 12 volt flooded cell is 12 volts.

Take your genny and deal with the noise. My genny is quiet, guess yours isn't.

[BFL13]

You also get low voltage when the TV is on if the DC input wires from the inverter to the battery bank are long and thin. You can run the tv/dvd much longer before the inverter "sees" low voltage and alarms or shuts down if the inverter is closer with short fat wires.

This is hard to do with a TT, where the batteries are out on the tongue and the inverter is inside.

One way if you can keep the inverter out of the rain with a cover, is put it out there with the batts, plug the shore power cable into it with a 30/15 adapter, turn off your converter (somehow), put the fridge and water heater on gas only, and don't use the receptacles for anything else (no microwave or whatever) just the TV/DVD.

That also puts the inverter's noisy fan outside too 🙂

[dhaas]

It was just after I moved the slide out and in, with TV still on. The inverter went into low voltage mode and shut down.

Im just surprised the TV took so much voltage. My interweb reading led me to believe it was a low power consumption deal. I was hoping to be able to run the TV at night so my boys could watch a movie before bed, but it appears it may pull too power?

[2112]

Is that 12.3V while everything is working or after everything is turned off and the batteries rested for awhile? If while everything is working, your batteries are fine. The voltage will drop while under a load. The higher the load the more they will drop. Remove the load and see if the voltage increases.