The NorthStar AGM Battery + Voltage Booster Upgrade

Hey AGM gurus - I've got 188ah of AGM batteries in my truck, but I'm noticing that they are discharging pretty damn fast - for example this weekend I was running a 1.5amp warming mat for my dog and my dometic fridge and went from around 12.4v to 10.0v in a matter of a few hours. That seems extreme from my past experience. Could this be a battery health issue?

 

As an aside. Carrier pigeons fly an impressive 600-700 miles a day. Australia is 10,250 miles from Florida. Meaning if a pigeon averaged 650 miles a day, a carrier pigeon could theoretically make the trip in about 16 days. Aka, pigeons would be faster.

That isn't right at all. Even if you had one bad battery, it would seem unlikely both would drain so low so quickly. How old are the batteries? Are you sure the fridge is in proper working order? If the compressor was failing or running continuously it may draw excessive power. I'd consider measuring the power draw of your gear to see if either is faulty and drawing excessive amperage. Crunching numbers in the past a single Northstar 27F should be able to sustain a fridge overnight for well over 12 hours. To drain two batteries in a few hours is extreme.

 

I would love to!! I just don't think a straight trade would be fair... isn't the adjustable one more expensive that the 0.5v one??

Also, not an engineer, so... I haven't really taken any readings at all, I am just making assumptions that the data that you compiled at the beginning of this tread would work for me. All I'm using is the info I see on my SCANGAUGE II. To have a baseline what do you recommend I do, and how do I keep that data for reference. Not really technical guy...

LOL! True engineer...

 

I agree - seemed way off. The batteries are 1-2yr old with some use prior but nothing crazy. Fridge is working fine from what I can tell, and it has not been running continuously when on. I'm wondering if there's an issue somewhere in the wiring, but when the battery sits without anything running on it I'm not seeing any voltage drop at all.

I'm going to run a test to see if there's maybe some reason why my solar setup could be leaking power via a poor connection or something. Generally an input wouldn't cause a faulty output but who knows.

 

Ordered from HKB Electronics 1.6.20 received today 1.25.20

 

That seems pretty like a pretty low powered warming blanket. Are you sure thats accurate?

 

Suggest checking your voltages before and after changing the fuse... i was having voltage problems, had to recheck the fuse... now it works as indicated...

 

I have intermittent/unusual battery draw from time to time and I have been suspecting my Dometic. most recently I had the most extreme act yet, draining from 12.8 to 10v overnight while it was 35 degrees out. I've read reviews for the CFX on Amazon where people see crazy draw after a couple months age. It can be days, weeks, or even months between behavior. I am trying to rig up a current draw monitor and will probably be exchanging the fridge under the REI 1 year no questions return either way.

 

The adjustable one is 2x the price. I'd rather have the fixed one for my case though, so it saves me buying one.

Confirmed carrier pigeon is faster.

 

yup
https://www.gundogsupply.com/hound-warmer-deluxe-12-volt-dog-crate-mat-dog-heater.html

Hm - this is super interesting. Has it only happened once? I'm also running a CFX...this would be a pretty similar symptom as the drain that I noticed over the week. Can you PM me where you saw this described on Amazon?

 

So after going through this awesome tread from beginning to end for the 4th time already, I see that @TrailYeti and @SR-71A use ScanGaugeII and @Norton uses UltraGauge.

What I need to do now is compare the voltage reading on my SGII for accuracy against the voltage reading directly from the Northstar 27F with my Fluke multi-meter, and see if there is a difference between the two readings. See if there is a small difference, a big difference, or none at all between readings, so I can have an accurate reference and "boost" appropriately, either with the 0.5v or the adjustable one - probably set to 0.6v.

Like, I mentioned before a couple of posts before to @crashnburn80, on colder mornings (Florida cold, so 40F to 50F) the highest I have ever seen the voltage reading on my SGII is 14.0v, maybe once I saw 14.1v. So, to get on the sweet spot mentioned by OP, I think in my case I will definitely benefit better with the adjustable booster since it will put me on the "lower" end of the 14.6v to 14.8v range.

So like @TrailYeti, @SR-71A, and @Norton, I can rely on an external gauge like SGII or UltraGauge? Correct?

In the mean time, I will have to wait for the boosters to arrive from Oz. @crashnburn80 got me thinking that in my specific case the 0.5v booster might not be enough, because I have really low cold start voltage reading to begin with - I order 0.5v and adjustable boosters so I can experiment with both and see which one works best for my particular setup.

Any thoughts or feedback?

Thanks,

Rick

 

As far as I know, neither the ScangaugeII or Ultragage are directly reading the system voltage. They are interpreting data on the OBDII data bus. So either one should be as accurate at the sensors the truck is using to read the voltage.

 

Got a link for that rocker switch housing? That's nice, tight fitting blank for the switches.

 

Just these...nothing special.

 

Thanks!

 

Well, I just want to see how accurate is the SGII reading compared with a direct reading from the battery posts using a Fluke multimeter. I don't think it would matter how the data is being displayed in the SGII as long as the reading is accurate.

I'm sure that the SGII is reading the voltage at the port, but I think that there should not be a huge difference between a reading taken directly at the battery and the reading coming from the port.

I'll check when I get home and see at the results.

 

What I am saying is the devices don't do the reading. They don't have sensors. They don't read engine RPM, they don't read intake air temperature, they don't read engine oil or transimisison temperature directly. Sensors in the vehicle take a reading, just like a fluke connected to the battery. The various ECU modules in the vehicle interpret the value from the sensors, and send them via the OBDII data bus to other ECU modules. The Scangauge and Ultragauge capture data from the OBDII data bus, interpret the data, and display it on the screen.

 

I understand, all I want to know is if I can use the data captured from the OBDII data bus to set the booster appropriately?

 

I'd give it a couple days to settle out. When I first got mine I thought it was set too low but after a couple of days things seemed to even out so I just left it at the recommended setting.

 

Being in a Southern climate Id think the fixed 0.5V would be fine for you. I wish I had gone for the adjustable one to be honest. Cold starts below about 35-40*F up here in the north give me 14.8-14.9V which seems on the high end. Thats as reported by my SGII, as you said I have no idea how accurate that might be.