Testing the battery

https://www.harborfreight.com/500-amp-carbon-pile-load-tester-91129.html


500 Amp Carbon Pile Load Tester
Cen-Tech® - item#91129
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Test 12 volt batteries, alternators, regulators and starters under load


https://shop.harborfreight.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/i/m/image_21239.jpgOnly: $49.99





Now how many dollars in gasoline and how many minutes in wasted time are you going to spend getting a battery tested WRONG at a parts store with a pimple faced adolescent flipping a toggle switch on a fixed amperage Cheese Grater load tester?

This tester will load test at a sane amperage recommended by the BCI and will test everything from a UL1 utility battery to an 8-D. Yes it will test series GC220 batteries and series L16 batteries as well.

Using a Freas hydrometer or a refractomer and this load tester the results of testing will be absolute. Beats the Magic 8-Ball fantasy all to hell.

Google up "Battery Load Tester" and get one of the small portable ones. Many available in the $30-50 range and all are satisfactory. For a precise test, disconnect one pole of the battery, either will do. If you only have one battery, you don't even have to disconnect anything. Just make sure everything in the rig you can turn off is turned off.

I've carried one of these for years and diagnosed a bad cell in one of my starting batteries while on the road in the southwest. By knowing exactly what my problem was, I could baby the rig all the way home and then get replacement batteries from a well known shop that stands behind their products. Not always true from fly-by-night sellers selling who-knows-what from who-knows-where at Oh-My-God prices.

Use the National Enquirer Test to determine your life span?

Rely on the key of F minor thump with a bat to check tire pressure?

Use an algorithm to determine your checking account balance?

Ooooooooo Kayyyyyyyyyy...

swimmer_spe wrote:
It seems to be fine.

As long as this condition persists I call testing is complete.

wa8yxm wrote:
Is there a way to test it using only the on board equipement?

Basically no. I'd not trust any of the "on board" stuff

YOu can however test it without removal

I use a dual-meter adjustable load tester from Harbor Freight. Not big enough for my big Golf Car batteries but for everythign else it can draw up to around 450 amps and takes only 15 seconds to do the test. (plus hookup and dial up time).

Exactly, forget all this turn one light on, now two, stand on one foot, and scratch your bum. Now look at the green light turn yellow and back to green. OK, switch feet.

Get a battery tester that can load test and be sure. You can also use a volt meter or hydrometer to see the state of charge/discharge. With the a good tester you can also check CA CCA.

Is there a way to test it using only the on board equipement?

Basically no. I'd not trust any of the "on board" stuff

YOu can however test it without removal

I use a dual-meter adjustable load tester from Harbor Freight. Not big enough for my big Golf Car batteries but for everythign else it can draw up to around 450 amps and takes only 15 seconds to do the test. (plus hookup and dial up time).

swimmer_spe wrote:
...Is there a way to "test" the battery with it installed and using just the trailer's on board equipment?

Absolutely!

First, make sure the battery is 100% charged by your estimation.

Turn everything off in the camper that runs on 12 volt. Unplug the camper from shore power. Turn on a single light. Now turn on a second light. If both lights dim considerably after turning on the second light, you know your battery is not fully charged. Add a 3rd light and if it dims considerably even more, you have validation your battery is pretty weak. It needs to be charged more.

Keep the battery on a charger until you feel it should be 100% charged again. Do the light test again. If the light dim down again considerably, you most likely have a bad battery. A cell could be dead, or not charging completely. 3 twelve volt light bulbs should not dim down much. Think how many 12 volt light bulbs there are on your car when you open the door and turn on your lights before starting the engine?

Second test:

Now, leave your lights on and see how long it takes for the battery to discharge enough lighting it is truly a noticeable change. I would not advise running batteries completely down, but if you do, at least you know how long they will last. If they run completely down and lights go completely dim within a few minutes, your battery is definitely failing.

Third test:

Make sure you "feel" your battery is charged 100%. Test by turning on a light. Make sure it's good and bright. Maybe turn on 2 or 3 lights, see how bright they all are together. Now you have a base line.

Now turn everything off in your camper. With everything turned off in your camper ... everything ... flip the battery kill switch if you have one, or disconnect the battery completely. Let the battery sit for a couple days.

Now, after a couple days, go reconnect the battery and turn on those same 3 light, or whatever you had on before as your baseline. Are they even more dim? If so ... you've got a failing battery. No need to test it any farther, get a new one.

Of course, to try this takes time to test it out. But you "did" ask how to test with JUST the onboard equipment. This is how you do it.


Edit:

I got a new battery for my camper last Fall. I keep my camper plugged into power 24x7x365. So, if my battery is failing, I'd probably never know it as the converter puts out a strong 12 volt flow.

Last Fall, when setting up the camper at home after returning from an outing, I forgot to plug the camper into shore power first. When I flipped on the inside light and they were barely visible, I knew something was wrong immediately. I then tried retracting a slide, and it just groaned. I knew the battery had lost it's life.

I then also realized, I forgot to plug into my shore power at home. As soon as I plugged in, light brightened up, slide out worked just fine. It didn't take a rocket scientist to figure out my battery was officially dead.

I replaced it the next day with a new one. Worked fine every since. New battery hold a charge for several days now, even with all the parasitic draw from the appliances.

Shore power on, idiot lights should show Full (from converter voltage). Turn off all DC loads and disconnect shore power. Idiot light might drop to Green "Good" or soon will after turning on a light or two.

Turn on some lights and fans. Idiot light should drop one light from Green to Yellow "Fair". If it drops to Red last light, that is not a good sign.

Turn off those lights and fans. Idiot light should go back to Green "Good" from Yellow "Fair".

If you leave the lights and fans on for a long time the light will stay at Yellow "Fair"---that would be normal from the battery being run down about half way. Recharge it.

If it is Yellow Fair and drops to Red under lights and fans load, you went down too far (battery less than half full) but it should bounce back to Yellow no loads. If it stays Red and does not go back to Yellow, it is really low.

the onboard stuff are idiot lights. they don't really give an accurate reading of the battery.

use a multimeter or hydrometer.

or you can install an actual good battery monitor. there are numerous choices.