Battery; Checking If They Are Good

[LeeB]

I have 4 6 volt Interstate batteries which [b]I think [/] are only 1yrs old. I bought my MH in March of 2009 and the dealer said he installed all new batteries. Here is what is going on.

We do not boon dock very much but will be next year at Quartzite and traveling etc.

I parked my MH 3 weeks ago and the batteries were fully charged. I DID NOT disconnect the batteries and my MH was NOT plugged in. (Normally it is and the water level is fine) anyway the inside lights were dull when I turned them on. The MH is now plugged in and batteries are charging.

My question is after a week from now I plan on unplugging the MH. HOW DO I check to see if the batteries are any good? If they need replacing I want to do it NOW instead of out in the middle of the desert. I have never used a Hydrometer to test batteries. HOW DO I USE ONE? or is there a better way to check my batteries and see if they are any good.

Thanks Lee.......

[Diplomat Don]

LeeB......Go to Harbor Freight and pick up a battery load tester. Its a battery tester with two large cable connectors like you find on jumper cables. Fully charge your batteries and the pull at least one cable off of each battery so that they are all separated. Use the load tester and see if they'll hold a load. The load tester pretty much causes a dead short between the terminals and will get HOT. It will tell you if you have a bad battery in the group. Its a good tool to have.

[sc3283]

Lee, use caution with a load tester....Don't be alarmed....but DO NOT I repeat DO NOT remove either clamp that connects tester to the battery when a load test is being performed. A LARGE spark will occur. When a load test is being performed, the battery will gas or fume, which is normal. Sparks are a NO NO around batteries.

If using a hydrometer....make sure the hydrometer tube is clean, slip tube into battery, squeeze the bulb, draw battery liquid into the hydormeter to full level, read the gravity and notate it. Squeeze bulb and put the liquid back into the cell it came from. Do not get the liquid on you.

Cheapy tools are just that...cheap....I personally wouldn't trust my $600+ worth of batteries to cheap test tools. I make a living with tools...good tools are a god send

[moisheh]

I have found the HF load tester to be of marginal quality. Not a true load tester and may give you false readings. A real load tester is very heavy. There are some good electronic units that are priced well. I would first see if the inverter is actually charging the batteries. There is a method to determine the dates on those batteries. Perhaps another member will post that info. A hydrometer is a must and they are very inexpensive. Did you check all your cable connections? Do you have a portable voltmeter?

[DBeauchamp]

Most batteries suppliers will test your batteries for free... One other detail, you don't really need a hygrometer if you have a voltmeter. You can test voltage between terminals (6 or 12 volts) but you can also test each cell individually with the voltmeter (each cell is 2 volts). Try connecting your ground probe to the GND terminal and then dip your + probe into each wet cell (until you touch the lead). The first cell closest to GND will indicate 0 volts (its connected to gnd) but each next will show 2 volts more if good. Between the last one and the POS on battery, you will get 2 volts....

[Mike Canter]

You must have something turned on that is draining your batteries. Did you have the saleman switch turned off and the house battery disconnect switch turned off? With an inverter you have to make sure the TVs and the sat dish and all are turned totally off and not just in standby. I have gone through my MH at night looking for glowing LEDs and have learned all that has to be turned off. I am lucky and have a solar panel that will keep my batteries topped up.

If your batteries are good which they most probably are and it is just something small draining them then reading battery voltage is the easiest way to tell the percentage of charge. Do you have a voltmeter mounted somewhere in the MH?

[CHCam42]

Lee why make work out of a job Interstate will do FREE. They have many locations, I had them test my 4 that were 7 yrs. old they passed with ease. Water, water, water. Turn off when not in use as stated above.

[LeeB]

Thanks ya'll like I said I didn't turn off the Batteries and it sat for 3 weeks. It very well could be a small drain somewhere. Yes I have a Volt Meter and will check them in a few days. I hadn't thought about taking it to a Battery Dealer so I may do that also.

I do know I need to go out there and clean them, but I am concerned about the solution running down between the batteries.

Thanks for all the answers.... Lee

[wa8yxm]

I use a chicago Tools 500 amp adjustable load Load tester (It has two meters and a knob on the front) from Harbor Freight.. NOTE that this tester is NOT big enough to properly load test a pair of GC-2 Size batteries (The size you have) but if they test good at maximum current they are good.

However, that said.. You might just find some good deals in QZ the last half of Jan, on whatever you need.

[Robi.1014]

Taking the RV to "Interstate" for battery-checking? Great idea if you've got the time and/or the Interstate location w/i convenient travel distance. Using a HF tester? Also not a bad idea....but with some out-of-pocket costs.

But....
You have a great "on board" tester already. Suggest the following steps:
1. Charge batteries to absolute full charge.
2. Unplug from shore power. Turn Inverter ON.
3. Get a DC volt-meter handy.
4. Plug in a 1500 watt space heater in the galley-area of your rig.
5. Watch the Inverter's drawn AMPERAGE indicator go nuts.
6. Observe Inverter's reported battery voltage (guessing: around 11 volts).
7. Take volt-meter outside and measure each of the 6-volt batteries while the space-heater load is still present.
8. If any one of the 6-volt batts reads significantly less than the other 3, then it is suspect. If all are within 10% of each other: great. If any battery is boiling over? Stop the test. Replace this battery (i.e., you've got a "dead cell" in that puppy).
9. Otherwise, leave this load-test ON for 5 minutes. At minute 5 (and while still loaded), measure the 12V value at the batteries with the volt meter and also observe the Inverter's indicator-panel's volt reading. Compare as just FYI.

Our inverters automatically cut off if battery voltage drops below 10.5 volts. (Read your user manual for the exact value). If your house batts can't "pull" this heater load for 5 minutes, they are marginal for extended dry camping.

When not on shore power AND when not using the rig (i.e., "in storage"), ALWAYS turn off both battery-cutoff switches (the manually-turned switches in your battery bay). Your roof solar panel will keep the house batteries topped-off....and if you're using a Trik-L-Start device, your chassis batts will be ready too. Sorry. Sounds like I'm preaching a bit too much here.......

[Barlow46]

Quote:

Originally Posted by LeeB I have 4 6 volt Interstate batteries which [b]I think [/] are only 1yrs old. I bought my MH in March of 2009 and the dealer said he installed all new batteries. Here is what is going on. We do not boon dock very much but will be next year at Quartzite and traveling etc. I parked my MH 3 weeks ago and the batteries were fully charged. I DID NOT disconnect the batteries and my MH was NOT plugged in. (Normally it is and the water level is fine) anyway the inside lights were dull when I turned them on. The MH is now plugged in and batteries are charging. My question is after a week from now I plan on unplugging the MH. HOW DO I check to see if the batteries are any good? If they need replacing I want to do it NOW instead of out in the middle of the desert. I have never used a Hydrometer to test batteries. HOW DO I USE ONE? or is there a better way to check my batteries and see if they are any good. Thanks Lee.......

Lee,
Not that it makes a lot of difference in your case if you bought your coach new, but to find the actual manufacture date of your interstate batteries. Go here: Interstate Batteries FAQ :: How can I tell the age of my battery?
On Edit: If dealer replaced batteries in March of 2009, then they would be going on 3 yrs old this coming March. Your statement in your post is indicating they are about 1 year old. Did you buy new ones after the dealer install?

[Cayman09]

Quote:

Originally Posted by moisheh There is a method to determine the dates on those batteries. Perhaps another member will post that info.

Here's a link for battery manufacturing dates
Battery Date Codes

Basically the first two Characters are for the Month and Year or Year and Month. Month is A(January) to L(December) and year is Numerical.

Hope it helps.

[Diplomat Don]

LeeB......All good answers to your question. You can test a battery many ways, but NO ONE can test a battery that is not fully charged. Whatever method you deside to use, make sure the batteries are fully charged.

I only buy tools from Harbor Freight that I'm going to use once or very infrequently, like a load tester. To buy a better quality one would start at $200.00 or more, you might as well have a shop do it and charge you.

Taking it to a battery dealer is fine too, as long as they're willing to disconnect and isolate each battery before testing and have no interest in selling you a battery.

Your batteries are going to run down from parasitic draws on them. Completely disconnect them from the coach and see if you're still having issues.

[LeeB]

Thanks Don your right I did get some great answers. I have my MH plugged in right now and will do a better check of everything Friday. I have to work tomorrow and so it will be plugged in for a least 2 days. I can at least go in a check for small trickle draws. It's to darn late and cold out to do it tonight...

Thanks again....... Lee