Killed my battery

tylersdad · 09-08-2015, 08:16 AM

I didn't realize that the various monitoring systems in the RV would kill the battery over the course of a week and my battery is now reading only 6.5V...so, pretty much dead.

Is it worth getting a battery charger and trying to revive it or should I just go buy a new battery? If a battery charger will work, any recommendations? The Schumacher chargers on Amazon get varying reviews for charging deep cycle batteries.

bedrck46 · 09-08-2015, 08:21 AM

I would suggest that you get a battery charger and charge the battery Having one in your tool collection is always a good item to have. I have two a 10 amp unit and a 2 amp unit. Also get into the habit of disconnecting the battery power when the camper isn't being used and then you won't have the problem of a dead battery unless the battery is bad. If the battery is new as the TT is I would at least get it charged.

hboy · 09-08-2015, 08:38 AM

I also use a battery disconnect. This is the only way to kill all draw on the battery.

Then check amazon or something to find a trickle charger/battery maintainer. Something to hook up to when not being used for an extended time.

tylersdad · 09-08-2015, 08:41 AM

Thanks, folks.

I added a battery disconnect switch yesterday. Would've done it earlier if I would've known that the various monitoring systems drew so much power.

tylersdad · 09-08-2015, 09:37 AM

Another question. If I plug in to shore power, will the onboard charger bring the battery back to life? I'm trying to avoid spending the money right now.

bedrck46 · 09-08-2015, 10:01 AM

It should What you need to do after you connect to shore power is to check the voltage at the battery you should then show 12 + Volts which would show it is charging Don't just go by the monitor panel Test at the battery

**Mustang65** · 09-08-2015, 10:17 AM

Quote:

Originally Posted by tylersdad

I didn't realize that the various monitoring systems in the RV would kill the battery over the course of a week and my battery is now reading only 6.5V...so, pretty much dead.

Is it worth getting a battery charger and trying to revive it or should I just go buy a new battery? If a battery charger will work, any recommendations? The Schumacher chargers on Amazon get varying reviews for charging deep cycle batteries.

It may or it may not be able to charge your battery. That is the best answer I can give.

Most controllers have a low voltage point in the charge controller that when reached will automatically stop trying to charge the battery.

You can use your TV to put an initial charge into the TT's battery with jumper cables, to a raise the batteries voltage, and then plug into shore power or your home outlet.

Make sure that all your battery connections are clean and tight, check your negative ground connection on the frame and check the water level of the battery, to make sure it is filled.

When ever possible use the TT's charge controller for your TT's batteries, as that is what they are designed for. Deep cycle batteries unlike Automotive batteries do not like a FAST charge.

After you get a charge in the battery, use your newly installed disconnect switch to isolate the battery from the TT. Take a battery voltage reading and then let the battery sit for 4 hours. After the 4 hours, take another voltage reading. It should be close to the voltage reading that you initially took.

If the both the battery voltage readings are close, there is a good chance that it may hold a charge. If there is a big difference between the voltage readings, replace your battery.

A battery being charged should be around 14 volts (BULK) and will drop to 13.2 volts (FLOAT) when it is fully charged. A fully charged 12Volt batery is 12.6Volts. You never want to discharge your battery lower than 12VDC.

Don

tylersdad · 09-08-2015, 10:33 AM

Quote:

Originally Posted by Mustang65

It may or it may not be able to charge your battery. That is the best answer I can give.

Most controllers have a low voltage point in the charge controller that when reached will automatically stop trying to charge the battery.

You can use your TV to put an initial charge into the TT's battery with jumper cables, to a raise the batteries voltage, and then plug into shore power or your home outlet.

Make sure that all your battery connections are clean and tight, check your negative ground connection on the frame and check the water level of the battery, to make sure it is filled.

When ever possible use the TT's charge controller for your TT's batteries, as that is what they are designed for. Deep cycle batteries unlike Automotive batteries do not like a FAST charge.

After you get a charge in the battery, use your newly installed disconnect switch to isolate the battery from the TT. Take a battery voltage reading and then let the battery sit for 4 hours. After the 4 hours, take another voltage reading. It should be close to the voltage reading that you initially took.

If the both the battery voltage readings are close, there is a good chance that it may hold a charge. If there is a big difference between the voltage readings, replace your battery.

A battery being charged should be around 14 volts (BULK) and will drop to 13.2 volts (FLOAT) when it is fully charged. A fully charged 12Volt batery is 12.6Volts. You never want to discharge your battery lower than 12VDC.

Don

Thanks for the very detailed advice.

The battery currently sits at 6.7V. If I try to charge it with jumper cables and my TV, what voltage should I charge to?

Jagiven · 09-08-2015, 11:26 AM

One more thing to check before and post charge, is the water level of each cell. ONLY use distilled water. I expect when you try to bring the battery up, you will boil the battery, and loose a bit of water, hence the post charge water level check. I do not recall how full is correct, but I like to have the water level to the bottom of the plastic ring. The slot will allow any gasses to escape.

TWP723 · 09-08-2015, 11:32 AM

Man, I need one of those battery cut-off switches! BIGTIME! My vehicle has been charging it but it's still a dead battery in my opinion.

**Mustang65** · 09-08-2015, 11:45 AM

Here is what Trojan battery company has to say about filling batteries.
Don
Oh, after you complete the charging of the battery it may show normal voltages, but you may notice that your battery no longer lasts as long when only running on battery. By discharging your battery that low, the batteries rated Ah, is probably going to be reduced some.
Don

Subaru297 · 09-08-2015, 12:51 PM

I don't think I would hook up a battery that is reading 6.7 volts to my vehicle. That battery needs to be brought back to life slowly!
Your vehicle battery will dump a LOT of amps into that battery and that could draw down your vehicle battery too much or pull too many amps out of it.

Getting a charger or plugging in your trailer are better options once you figure out why it wasn't charging in the first place.

Cheers

**Mustang65** · 09-08-2015, 06:55 PM

Quote:

Originally Posted by Subaru297

I don't think I would hook up a battery that is reading 6.7 volts to my vehicle. That battery needs to be brought back to life slowly!
Your vehicle battery will dump a LOT of amps into that battery and that could draw down your vehicle battery too much or pull too many amps out of it.

Getting a charger or plugging in your trailer are better options once you figure out why it wasn't charging in the first place.

Cheers

Here is how you can do it.

Without starting your TV engine, hook the battery cables to the TT's battery (or another fully charged 12Volt battery). Monitor the TT battery voltage and remove the jumper cables when the TT batteries get to 10 VDC. If the voltage does not get up to 10 volts in about 5 minutes, disconnect the jumper cables and charge the TV battery for 10 minutes and try once more. Since the TT battery is not a "0" volts, it should bounce up to 10 VDC pretty fast. Once it gets to 10VDC pull the jumper cables and turn on your TT's charge controller. The TT charge controller will charge the battery using its internal program to time each cycle. After 2 hours I would check the battery voltage (disconnect from TT for the open circuit voltage), it should be close to 12 volts. Also check the battery case temperature with you hand to see if it is hot. If it is leave the battery disconnected and let it rest for a few hours. Recheck the voltage and start the charging process again. At night, leave the battery disconnected and in the morning check the voltage, if it is around the same voltage as the night before, the battery should be good and you can continue charging it.

If you get a smart charger, and it is a 6 or 12VDC charger (with a selector swithc) it may think your battery is a 6 volt battery based on its current voltage, and not charge it, so you may have to get the voltage up to around 10VDC before using them.

You could take it to a Autoparts store and have them put it on a charger for an hour or 2 to get the voltage up to 10 or 12 volts (then use the TT to charge it properly the rest of the way), but you have to make sure that they use a voltage that is less than 15 volts, as deep cycle batteries do not like being charged FAST.

They can also check the specific gravity of each cell to see if there are any shorted cells. Be prepared... Past experience, they will tell you that the battery is toast and you need to buy one of their top of the line batteries. If you do, do not buy one with a CCA rating, as that is not a true deep cycle battery.

In any case keep checking the water level in the battery and its temperature throughout the process...

Good luck,

Don

jimp · 09-09-2015, 08:03 PM

A BatteryMinder brand charger/maintainer MAY bring the battery back to life, it will take some time, but it may. I've used this brand for several yrs now, and hooked one up to the cranking battery on my GH (original OEM battery) which was weak and old, would not hold a charger very long. Now this battery is strong and will crank the V10 just fine.

You may also like: