Truck Battery Issue

[mpoliver]

Howdy,
I'm wondering if my truck battery might be getting drained due to the camper.
We have an ATC Bobcat on a Toyota Tacoma. We bought the camper new and had the folks at ATC install it. We have had the camper two years now and it has been on the truck full time.
We bought the camper with an auxiliary battery and the only things electric in the camper our the lights and Fantastic Fan, neither of which we use much.
Last year I replaced a dead truck battery (it was old so I didn't think much of it), but today, when I had my oil changed, the mechanic said the truck battery "health" was bad and we should replace the battery.
Seeing as the battery is only a year old and I haven't left the truck lights on accidentally for any period of time I'm wondering if the camper is draining the truck battery.
Any thoughts would be appreciated!

 

[Wandering Sagebrush]

I don't think it's your Bobcat, but not saying it isn't. You might have an issue with the isolation relay, but with no real load from the camper, that shouldn't kill your battery. You might stop by a good auto electric shop and have them check battery, alternator and relay. You could also unplug the battery to camper (not the running lights) connection and see if your battery voltage is still dropping.

 

[nikonron]

It could also be that your alternator is never getting the battery to full charge because it's trying to charge both batteries. Tacoma's don't really put out enough to properly charge AGM batteries. Ron

 

[ntsqd]

If the isolation relay is staying closed it can kill the batteries with no obvious load. When the two batteries are different one will always be at a different state of charge than the other. If allowed to progress normally they will see-saw back and forth, with the tiny line losses consuming charge until they're both dead. BT, DT, bought the batteries to prove it. This is the real reason to have some form of battery isolation.

 

[crazybill]

This is also why I use a manually operated battery isolation relay. I start and drive the truck long enough to ensure the truck battery is charged, then I flip the switch to top off the camper battery. When I turn off the truck the relay opens and the batteries are isolated.
It's a bit more "hands on" but saves battery life.
I notice you said that your mechanic pointed the problem out. Did you notice a problem before he said something?
-Bill-

 

[ski3pin]

Every one here is offering good advise on what to look for.

For me, this would be an instance where I would start at the basic, simple stuff and if they check out move to the more complex. First, confirm there is a oroblem with the battery. Next, confirm the truck's charging system is working properly. Then start looking for power drains. Good luck getting this sorted out, hope it goes well and is an easy fix.

 

[pvstoy]

First of all everybody should own and have in their vehicle a simple volt meter. Even if it is a five dollar one from Harbor Frieght.

If this was my problem first I would take the volt meter and while the truck is parked (not running) see what voltage the truck battery reads. Then check the camper battery to see what it reads. If they both match reading the same voltage then you could say that they are connected and the separator, isolator is defective and fix that problem.

If they have different voltage then good the separator/isolator is working.

Next I would start the truck and using the volt meter on the truck battery see what the voltage is. Some where around 14.5 volts then yes the alternator is working. You can also check the camper battery and see if you are getting charge from the alternator.

If this checks out then I would take the truck battery cables off the battery and clean them really good. There is nothing like bad dirty connections to not allow the amps needed to charge a battery. Also check ground wire to the frame or where yours goes. Bad ground bad charge.

A good new 1 year old battery will go south if not the proper charge gets to it.

With a volt meter can watch voltage drop if you have a short. Hook it to the battery and turn things on and off and notice the voltage change. While the engine is off watch the voltage over time and see if and how much, and time rate the drop is. Could pull fuses and see if it stops and note what is on the circuit.

But then again after checking all this and no problems are discovered then it could just be a bad battery weather a dead or dry cell. Could have been assembled while workers were watching the World Series games

That is why everybody should have a simple volt meter to quickly check things out.

 

[mpoliver]

Thanks All, I appreciate all the information and advice.
I haven't had a chance to do anything yet and I admit I don't yet have a volt meter...I will correct that problem today and go from there.
I will let you know what I find out. Thanks!

 

[Wandering Sagebrush]

A digital multimeter (versus analog) is easier to get more accurate readings

 

[Happyjax]

This should be done with the truck off......

You can unhook the positive post of the truck battery and put your voltmeter on amps. Place the leads (which are secured in the proper position to take a current measurement) between the positive post of the battery and the connector you removed. They will read any current flowing. There will likely be some draw but not much. If you disconnect the camper battery and the draw lessens by any significant amount then you have leakage.

I also like the voltage comparison suggestion above but this seems more definitive to me......

 

[crazybill]

Guys I guess I've missed something. What exactly is the problem? The only thing I see is that your mechanic told you that your battery is "unhealthy".
You stated that he had the truck to do an oil change.
You didn't say you took it to him for a battery problem.
You didn't say you had any problems at all except having changed an old battery a year ago.
So what problem are you experiencing?
There are a lot of good suggestions here on finding a problem, but what is it we are looking for?