Batteries losing charge while in storage

[tvfrfireman]

My four six volt AGM batteries are losing there charge while the trailer is parked in storage. I disconnected all the wires from the positive terminal but still find them slowly discharging. In a second compartment I have to more batteries and noticed a wire from the positive terminal that goes directly to the hydraulic pump that is used in the level up system. Could this be draining the batteries? I have the trailer up on all 6 jacks to unweight the tires while it is not in use and am wondering if I should disconnect this wire from my battery. I have a 12 volt disconnect switch but it is down stream from t his hydraulic pump. Thanks for any tips....David

[DryCamper11]

tvfrfireman wrote:
I charged all four batteries and then disconnected them and let them sit for a few days. They all read the same volts. The two I mentioned that read differently were hooked up to the leveling system while the other two in another compartment were disconnected. The only wire I can find upstream of the battery shutoff switch is two the leveling system. Would those post mounted shutoffs suffice in this situation or should I go with the more expensive wall mounted switches?

This indicates that the batteries are not self-discharging beyond normal rates. Since you are seeing much faster discharging when connected, even with your "disconnect" actuated, you've got a current drain. If you are correct that the only wire that the "disconnect" doesn't shut off goes to the leveling system, that should be your problem. Personally, I'd check it by measuring the current drain with a meter. Once you have identified it as your problem, you get to choose a solution.

I think everyone here will agree that the "the more expensive wall mounted switches" are better. You can buy good quality units that will last a long time and not fail when you need them. It's probably what I'd buy if I bought a disconnect switch. I like quality.

OTOH, I don't have the room for mounting one, don't really like running more cables around, don't want to incur the expense, and don't like the cheap post mounted switches. So, I get by with just removing the battery cables when I need the battery disconnected. Sometimes simple is good.

You may consider putting a second switch in the wire that's draining your battery. Then you'd need to throw two switches to "disconnect". Or you can move that wire to the other side of your existing switch.

[time2roll]

Any switch will work. Just a matter of your preference to look and funtion.

[tvfrfireman]

I charged all four batteries and then disconnected them and let them sit for a few days. They all read the same volts. The two I mentioned that read differently were hooked up to the leveling system while the other two in another compartment were disconnected. The only wire I can find upstream of the battery shutoff switch is two the leveling system. Would those post mounted shutoffs suffice in this situation or should I go with the more expensive wall mounted switches?

[MEXICOWANDERER]

That's a roger

BUT BUT BUT

With today's electronics and stereo 2 farad capacitors you have to be careful. You can cut off a correctly wired switch and there may still be power showing for quite awhile afterward until the capacitor bleeds down. Inverter caps also delay system voltage bleed down.

Many years ago I wired a Vogue motor home. I installed a marine grade high amperage switch. The owner subsequently added more stuff and removed electrical items. One day he and BH awoke to the smell of electrical smoke. They dashed to the door (where the switch was) turned it off and exited. Later on he found out he had forgotten to fuse his newly installed leveler system. He had connected the wires to the power bus bars after the switch. One of the leveler wires got pinched and shorted.

[time2roll]

MEXICOWANDERER wrote:
A battery switch must sever all the power, period. 100%. I'll say it again, ONE SINGLE WIRE FROM ALL THE BATTERY'S POST GO TO A SWITCH. The switch cuts off all the power......

Use this hint to verify if there is truly a single wire to the switch. Any branch circuits before the switch are suspect.

Also verify the switch actually cuts power. Battery voltage will remain on one side and voltage should drop to zero on the other side when off.

[mena661]

BFL13 wrote:
Too bad that 5.9 one is an AGM. If a Wet, you could use an hydrometer and see what's wrong. No idea what to do with an AGM like that. Some AGM guys will no doubt know...

I'd put the two bad one's together, charge them as full as possible on a portable charger, disconnect both from each other, let them sit for a couple of days and check the voltage. They each should be no lower than 6.4V. Anything lower is a problem. Could be those batteries are sulfated and need a recovery. Here's a blurb from MEX on AGM conditioning (recovery):

Trends and tendencies: An AGM battery under conditioning cycle will allow the voltage to rise until it seemingly hits a brick wall, sometimes as low as 14.5 volts. There the voltage stops climbing and this is what you are shooting for. When the voltage resumes its climb a good portion of the occluded plates have been "conditioned" about as well as they're ever going to get. Continue on to 15.5 if voltage is increasing slowly but if voltage is steadily rising quickly, the exercise is over. No sense in jamming unwanted wattage into the battery.

[BFL13]

Too bad that 5.9 one is an AGM. If a Wet, you could use an hydrometer and see what's wrong. No idea what to do with an AGM like that. Some AGM guys will no doubt know...

[tvfrfireman]

DryCamper11 wrote:

tvfrfireman wrote:
Yes, I have an inverter. I have now separated all the batteries and am going to take them to Les Swab tire center to have them load tested.

If they are 6 volts, be careful. Most tire center employees will never have seen a 6 volt battery, and load testing deep cycle 6 volt isn't the same as load testing starter type SLI 12 volt batteries. If you have checked the voltage of the individual batteries, you will have ruled out or found any bad cells.

If you are simply fighting a discharge problem, start by finding out the current drain first, or just let them sit, disconnected, and watch the voltage. (If you've already done that, sorry for the duplication). Personally, I'd never let a tire center employee anywhere near my deep cycle 6 volts.

Dry camper11: Thanks for the help. I went to the trailer this afternoon and checked the batteries. The two on the door side of the trailer that had been disconnected read 6.5 volts each. The other side where they had the wire from the hot side to the hydraulic system that I disconnected yesterday read 6.3 volts and 5.9 volts. They are now all disconnected from each other and I will check them in a few days and see if they lose anymore of their charge. Thanks again. David

[DryCamper11]

tvfrfireman wrote:
Yes, I have an inverter. I have now separated all the batteries and am going to take them to Les Swab tire center to have them load tested.

If they are 6 volts, be careful. Most tire center employees will never have seen a 6 volt battery, and load testing deep cycle 6 volt isn't the same as load testing starter type SLI 12 volt batteries. If you have checked the voltage of the individual batteries, you will have ruled out or found any bad cells.

If you are simply fighting a discharge problem, start by finding out the current drain first, or just let them sit, disconnected, and watch the voltage. (If you've already done that, sorry for the duplication). Personally, I'd never let a tire center employee anywhere near my deep cycle 6 volts.

[DryCamper11]

tenbear wrote:
I should have mentioned, be sure you get one that measures DC current. Less expensive ones may only measure AC current.

Sears sells a decent DC clamp meter. I wouldn't buy one just for this job, unless you are a tech type and want one for the future. Here's what I'd do: many meters have a 10 amp input. It's usually separate from the normal scale. Buy or borrow one, preferably one with a fuse. Unplug all the 12 volt fuses in your panel. Connect the 10A meter in line with the battery - between the battery and the battery cable. Then slowly replace fuses until you see some current showing. The drain is on that fuse. If you get all the fuses back in and see no current, then it's not a drain problem and you have to look at the battery. The problem should have shown in the initial test of just watching the battery voltages with the batteries disconnected.

[tvfrfireman]

tenbear wrote:
Probably the first thing to check is the voltage of each of the batteries while disconnected. If one is substantially lower than the others it is probably bad.

If the batteries have been recently charged, within the past day, they will have a higher than normal voltage. It is called surface charge and will leak off within several hours. A fully charged 6v battery should read 6.3v after the surface charge is gone.

If I am embarrassing you with this basic stuff, I apologize.

You are not embarrassing me in the least. I have a lot of knowledge but just not in this area. One has to start somewhere. Keep embarrassing me all you want. This is how I learn. I am off to the storage lot to try my new found knowledge. Thanks again.. I am grateful.

[tenbear]

Probably the first thing to check is the voltage of each of the batteries while disconnected. If one is substantially lower than the others it is probably bad.

If the batteries have been recently charged, within the past day, they will have a higher than normal voltage. It is called surface charge and will leak off within several hours. A fully charged 6v battery should read 6.3v after the surface charge is gone.

If I am embarrassing you with this basic stuff, I apologize.

[MEXICOWANDERER]

tvfrfireman wrote:

tenbear wrote:
Time to invest in a clamp-on ammeter and see what the drain is.

I will check into this tool. I am pretty sure that the drain must be the hydraulic system as one other person with same brand has the same problem on the DRV forum. The only thing hooked to the battery is the hydraulic system. I don't understand why so many things are wired upstream of the 12 volt cut off switch.. Thanks for you response..

"You don't understand 'why'?"

The WHY is the manufacturer let the sales department think for the company.

A battery switch must sever all the power, period. 100%. I'll say it again, ONE SINGLE WIRE FROM ALL THE BATTERY'S POST GO TO A SWITCH. The switch cuts off all the power. "Oh I have an ignition switch that really and truly does not shut down all of the engine" This is silly garbage engineering.

[tenbear]

tvfrfireman wrote:
I almost forgot, thanks so much for your help. I have a meter and am going to do what testing I can before I take the batteries in. I will have to learn how to use the ammeter function first. Thanks again. David

Most multimeters do not have very high current scale. Be careful when using a multimeter to measure current. Some have a 10 amp scale which is not fused. It is very easy to damage the meter by exceeding the current limit.