A dissapointing tailgate

[vjgkam]

After a lot of research and help from a number of forums such as this one, I decided to set up a satellite dish at a tailgate last wekend for the Penn Stare game.

I have a deep cycle marine battery for power, and a 400 watt Black and Decker power invertor.

I used my RCA DirecTv 40gb Tivo, and a small 13" television that pulls 58 watts of power.

The system ran GREAT, and finding the dish was super easy (again, all as result of help from forums like this one).

The problem was, the invertor gave the low power signal after 3 hours of watching, and the whole system went dead 5 minutes later.

Id this typical?? I expected a longer life from the battery based on the low wattage being used.

Any thoughts??

 

[papalittle]

your power inverter will shut down if the input power from your battery gets down under a certain voltage. next time connect battery to a car via jumper cables and charge the battery every hour or so for a few minutes.

 

[vjgkam]

thanks

papalittle,
I'm thinking of buying another battery and using two at future tailgates.
How long (using jumper cables from a car) would you expect it to take to fully re-charge the battery if it drained all the way down??

 

[csschrot]

If you plan on doing long tailgates and make it a common thing I would suggest on of these. http://www.hondapowerequipment.com/gensup.asp We use the 3000 for the tailgate I help with. I'm thinking if you are just doing a couple of small things the 1000 would be fine. They are fairly quite and I don't think they use that much fuel at all.

Shawn

 

[papalittle]

papalittle,
I'm thinking of buying another battery and using two at future tailgates.
How long (using jumper cables from a car) would you expect it to take to fully re-charge the battery if it drained all the way down??

I battery fully drained could take a very long time to recharge using a car and jumper cables, best thing is to use a battery charger and do a deep cycle charge.

 

[lakebum431]

I just let the truck run the whole time. Last year I used to just start it every hour or so, but then it has to cycle through the finding satellite screens and it is easier for me to just let it run. Might cost a few extra bucks, but at that point who cares.

 

[dfergie]

A Generator is your best bet for long duration...

 

[GrumpyGuy]

3 hrs. sounds about right. Inverters are not the most efficient devices. I would not be surprised if the inverter is eating up as much of your battery capacity as the TV itself is.

Fullyrecharge after draining all the way down? - 8-12 hrs is my guess. But do not attempt to fully charge the battery using the jumper cables - this is very rough on a battery, and could even be dangerous to bystanders should the battery overheat.

You should be able to regain some significant percentage of a fully charged condition after 10 minutes or less. Don't expect the battery to last another 3 hrs after a quick topping up.

When recharging first begins the rate of charge will be at its highest. The charging current will taper off rapidly in the first few minutes, then continue to decrease at a more gradual pace. When this current reaches a low steady level the battery can be considered fully charged.

When you return home after a game be sure to place your battery on a proper regulated deep cycle battery charger. The worst thing one can do to a battery is leave it sitting for an extended period of time with anything less than a full charge.

 

[vjgkam]

drats

I had guys telling me they were getting 7-8 hours off one battery.
maybe the thing to do is buy two....let one drain and hook up the other. That will give me 6 hours. Then, put the first on the jumper cables for 15 - 20 minutes and hopefully get another 1-2 out it.
We normally tailgate for 4 - 5 hours. But, for games like Michigan which starts at 8PM this year, we'll be tailgating from 11AM - 7PM, so I'll need at least two batteries.
The generators are just way to far out of my league right now in terms of price....
One last question: Is a charger for a deep cycle battery any different from a charger for a regular car battery??

 

[GrumpyGuy]

There are small inexpensive chargers designed specifically for the characteristics of deep cycle batteries. Some have a "float" feature which kicks in once the battery reaches a fully charged state. This allows you to leave the charger connected and charging the battery 24/7/365. In float mode the battery is fed a minute amount of current - as low as a few milliamps. This is the ideal way to store a deep cycle battery. Deep cycles maintained in this manner, and used in stand-by applications where they only see occasional use such as during power outages, have been known to give good service for 20 years or more.

I paid about 20 bucks for the charger I use for my astronomical observatory's backup power system.

But, if you don't care to get fancy, you can use a standard automotive battery charger. Just charge it overnight after each use, and perhaps once a month during storage periods.

 

[bhelms]

There are a number of chargers out there that have a deep cycle charge profile in addition to the "standard" rates. I got one at Sears some years back. These are in the higher-price category, but offer quicker charge rates and battery boost for quick starts.

Echo GrumpyGuy on keeping a standby battery constantly charging at a very low rate, but I'd use a separate trickle charger for that, a $20 buck unit like he mentioned. One of those will take longer to restore the initial charge, but it frees-up your other charger for more serious use, and uses considerably less energy so in time it might even pay for itself, YMMV...

 

[directvfreak]

Tailgate= RV!