Is my battery really draining, and how?

[camper101]

Wonder if you might shed some light on if and how my battery is really losing power.

The State of Charge lights on my charge controller tell me it's dying but I can't imagine how. I get it charged up (green light), and I let the truck sit for a few days and it goes to the yellow light or even blinking red.

So the question is: are the SOC lights accurate? I assume they are, because if I go long enough without driving the truck my CO/LP alarm gives the low voltage alarm. Plus my heater won't work if the voltage is too low...

The next question would be: where is the power going?

I've measured the parasitic draws that I'm aware of with a voltmeter:

• Heater draws .02 amps parasitic (draws 1.7 when running)
• CO/LP alarm draws about .01 amps

The wires to run those are probably 15 feet long each.

There's nothing else connected to the battery as far as I know except:

• LED lights (which are turned off)
• a few 12v outlets, although one of the outlets is a USB outlet with a LED for some reason
• solar charge controller (Morningstar Sunsaver SS20L)
• An extra 5 ft of wire with spade connectors that isn't connected to anything (they are insulated/taped and not sending energy anywhere)

The battery is a 55 amp hour AGM bought new in December 2012 (I wonder if I should have gotten a larger one, but I don't need much power). There is a separator - SurePower 1314A.

Any ideas or suggestions on how to figure this out are appreciated.

One more piece of info: yesterday the SOC was blinking red. I connected a portable solar panel, looked again in about 30 seconds, and it was at yellow. The panel is a 100 watt panel, and it was partially shaded. Maybe 6 hours later with good sun, the SOC was slow-blinking green which I suppose means it's finishing up the charge.

Thank you.

 

[GR8ADV]

put a meter on the battery to check the draw. start unplugging things til you find that little gremlin. you might be surprised.

 

[camper101]

OK, sounds like I need to get systematic. Maybe next steps are:
Disconnect the fuse box and measure the draw going to that (might be more than the 2 appliances combined)
Disconnect the isolator and see if there's anything going out that way
Last, maybe I disconnect the charge controller to see what that's taking out... but I have to assume it's minimal

I'm also wondering if my assumptions are correct: I assume that if I have "minimal" parasitic draws of less than 1 amp total, then the battery should be fine for more than a few days. {Ignore the crappy math that follows, thank you ripperj} Let's say 1 amp for 10 days - that's only (less than) 20% of the 55ah battery capacity.

 

[unseenone]

I got 2 years out of my first AGM. Symptoms were seemingly excessive charging voltage while driving the vehicle, ie: 14.8+. It gradually increased to over 15volts. It never seemed to charge up fully. I took the battery and had it analyzed, and they said it was not working correctly. I swapped in a new AGM, and it charged, and the voltage drops to 13.8 after driving for a while. You should also check the specs for your battery, which kind of battery is it? Can you take the battery in and have it tested overnight at a battery place?

You might be able to add a low voltage cut off to reduce or eliminate the parasitic draws on the system. Some have a override switch when you want to manually switch it on. Here's a couple, just to give you an idea of what's out there, there are several options here. http://www.powerwerx.com/fuses-circuit-protection/pwrguard-protects-the-radio.html

Is your primary battery the one labeled "truck"?

Was this setup working correctly at some point?

 

[camper101]

unseenone, good questions that I don't completely know about.

I didn't install the isolator so I don't know the terms, but I believe the truck would be the primary (the idea is to charge the camper battery when the truck is running, and avoid killing the truck batttery).

Was it working before? The charge controller and lights are relatively new in the past 6 months. When I first got the battery I never knew how it was doing. I also didn't have a heater at first so the battery was more than enough for the lights and occasional phone charging. Once I got the heater and found out it will die after 2 nights or so without starting the truck (very long cold winter nights), I added a portable solar setup. So now I have those little lights to make me worry...

I'm sure I can find a place to get the battery tested - didn't realize you could do that.

 

[unseenone]

Here, Batteries Plus has a machine to test batteries. Most battery places should as well, such as interstate or auto stores. I would start there. I would consider making the solar setup permanently setup as well. You can always use the extra panel to supplement it if needed. I'm in the process of figuring out the same thing for my vehicle. Presently I've got the 2nd battery which is an AGM Optima yellow top, I use the low voltage cut off devices, and have the fridge, but no heater.

I would start at the simplest point, the battery. I live in TX a high heat area, batteries do not hold up well here. I was able to get my yellow top replaced under warranty, but for the time it took to get the paperwork located, and what not, I just bought another one, so now I have a spare.

Based on what I've learned, and been told for me Traxide battery device, you set the charge controller to AGM, and charge from the 2nd battery side. This can be plugged into the system anywhere, such as an Anderson plug in the rear, or at the battery, etc. Just throwing it out there for what it's worth.

 

[Desertdave]

The solar controller has a self-consumption of 8-10 mA, according to the owners manual. If I read your notes correctly, you always have that drain plus the others you mentioned, but rarely have the solar panel connected to replace the power drain. I would do whatever is easiest for you, either connect your portable solar more frequently, or disconnect the loads when in storage.

 

[camper101]

This is helpful, thank you. Getting the battery tested will be easy. I can also unplug the charge controller easily if need be.

Stupid question: is the truck battery the "Main" battery and the camper battery "Auxiliary"? I finally got a look at the instructions for the separator: http://www.fourwheelcampers.com/batteryseparator1315.pdf.

I'm pretty sure it's installed correctly but always good to know how things work.

Thanks again all.

Edited to add: I'm probably (hopefully) wrong about the 10 gauge wire coming from the truck to the isolator - I assume it's bigger than that. I've only looked at the wiring inside the camper but I'll trust that they guy ran bigger cable from the alternator to the connection with the camper.

 

[unseenone]

The main battery should be your primary battery (starting battery). The Auxiliary battery or "house" battery is the one you normally would draw your accessories from. This unit works similarly to mine. It isolated the batteries from each other when the voltage drops. While you are at it, it cannot hurt to also test your main battery.

 

[ripperj]

I may have misread, but one amp drawn for one hour is one amp/hour. 24 hrs per day times 10 days equals 240 hours. So your 1 amp parasitic load for 10 days is 240 amp/hours

Sent from my Z10 using Tapatalk 2

 

[pugslyyy]

I'm suspicious of the USB port you have permanently wired in. It could be pulling as much as 0.89 Amps. Depending on how you are configured, the low SOC could be coming on at 50% which would be only 27.5 Ah.

As others have said, only way to test is fully charge and disconnect everything.

I just had my house batteries disconnected for over a week, and when I hooked back up to them they were still at 13.2 volts.

 

[camper101]

I may have misread, but one amp drawn for one hour is one amp/hour. 24 hrs per day times 10 days equals 240 hours. So your 1 amp parasitic load for 10 days is 240 amp/hours

Sent from my Z10 using Tapatalk 2

Heh... you didn't misread, I mis-figured. Thanks.

So even at .25 I'd lose 6 amp hrs per day. After 4 days I'd be approaching 50% which is faster than I expected.

I'll take a look at the USB port as well.

Thanks again.

 

[4x4junkie]

Edited to add: I'm probably (hopefully) wrong about the 10 gauge wire coming from the truck to the isolator - I assume it's bigger than that. I've only looked at the wiring inside the camper but I'll trust that they guy ran bigger cable from the alternator to the connection with the camper.

It may be bigger than #10, but I'd almost bet $$$ it's still not near big enough.

You should have wire that is sized large enough to provide no more than 0.3V drop at your alternator's full rated output (0.2V or less being ideal) if you want any decent amount of charge current to flow into your camper battery when the engine is running. This includes the wire going to and coming from your isolator, along with your ground return. If your camper battery is 20' away, and your alternator max output is 80A, you'll need 1/0 AWG minimum, 2/0 AWG is better still. If you have a 100A or better alt, then 2/0 AWG no matter what.
This might seem like overkill, but you have to figure that your alternator is only going to see your truck's starting battery if there's any appreciable resistance in the wiring going back to your camper battery. Once your starting battery reaches full charge the alt then goes into voltage limiting mode while your camper battery just sits there taking in maybe a few amps at best.

While this may not be the full extent of your problem (I agree with the others about checking for a parasitic draw), for sure it is preventing faster recovery of that battery when you run the engine (which over time will cause the battery to lose capacity due to it being chronically undercharged).

For your parasitic draw issue, you could maybe install a master cutoff switch right at the battery if you don't wish to unplug/disconnect everything individually.

 

[camper101]

Well, it turned out to be true that there are surprises. The CO/LP alarm takes more than I thought: it cycles through drawing .07 amps for about 90 seconds, then .15 amps for 60 seconds (this is after it's done the 7 or 10 minute warmup process when you reconnect to the power source).

I've disconnected the alarm and am letting the truck sit for a few days, and we'll see how things go. That's not a huge draw, but I can see how it'd add up on my little battery.

I wasn't able to read how much the charge controller is drawing. When I disconnected it from the battery and tried to put my multimeter into the circuit (on the 10AMP setting) nothing happened. Not sure if I need fancier equipment or more smarts, but I couldn't figure it out...

I also didn't get a reading of how much (if any) is going back to the truck through the isolator. Things are kind of tight in that area, and after accidentally making some sparks fly with my metal wrench I decided I'll just assume the isolator works for now.

Thanks for all the ideas. I probably need to look at the wire size from the alternator too. But everything feeds into the camper through a plug that was put in at installation (so if I increased the wire size, there'd still be a short run of smaller wire at least at the plug, but I assume it would still help).

Thanks again.