starter battery died - positive terminal arc

Mr.Anderson · 10-29-2023, 04:55 PM

Hey all,

So last week I'm using the van to go to work and I notice the key fob isn't unlocking the doors so I figure dead battery I'll jump it off the house battery. I hit the bypass button on my isolator switch (battery doctor iso switch) to connect the starter to the house and it immediately re-opens the connection which means the voltage of the starter battery is so low that the hose battery isolate switch will not connect the two (I forget the exact voltage for that condition but I think it's below 10V or 9V).

I pop the hood and check the starter battery voltage which is reading 3.66V... pretty fried.

I also notice there's an arc between one of the connections to the positive terminal and the terminal itself (see photo). I don't know how this arc could have occurred given that the arc took place across a point that was electrically connected. I've gotten a new starter battery but I'm suspecting there's a short or some other underlying issue which caused the starter battery to fail catastrophically like this so I haven't installed the new battery yet.

I started measuring the resistivity between the starter battery positive terminal clamp (without removing the individual load / accessory wires) and the ground terminal wire and was measuring Mega-Ohm and to 1.5 Kilo-Ohm (measurements were a bit jumpy but I think 1.5KOhm was the lowest I saw).

I'm not sure measuring the resistivity is the best way to try to ID a short but even so shouldn't it be measuring open if there isn't a battery installed?

Has anyone experienced this and/or have any recommendations on how to test with a multi-meter to figure out what's going on? The house battery and it's associated accessories are isolated from the starter when the van isn't running and are working fine.

I have the following accessories connected to the starter:

Music system (powered bass & amp)
OHV flood lights
Alarm system
4 gauge wire connecting stater to house battery (with isolator switch in line)
2 other stock wires (alternator & main fuse box)

I hadn't driven the van in about 2 weeks and the last time I did it seemed fine.

The dash battery light has been on intermittently for the last year and I wasn't sure if that was a bad alternator or faulty wiring on the dash but the van had been running fine so unfortunately I had been largely ignoring that dash light but did buy a spare alternator which I keep in the van in case it's the alternator crapping out.

The deformation on the positive terminal is weird, it looks like someone whacked it with a hammer but then there's the melted bit as well and a arc scorch on the accessory bolt.

carringb · 10-29-2023, 05:07 PM

The battery post can melt when you have a loose connection at the terminal, low voltage during cranking causes the amps to shoot up. I’ve had it happen on mine too. In my case, the terminal was simply fatigued, because it was a budget aftermarket terminal. On your battery, I’d be suspect of that quick-release on your terminal, which also doesn’t appear to be lead, which further reduces good contact to the post. You might want to look at switching to military terminals, which are lead, and can accommodate more connections.

Note: you need one of each since the battery posts aren’t quite the same size.
https://www.napaonline.com/en/p/NW_728222
https://www.napaonline.com/en/p/NW_728223

REF · 10-29-2023, 05:25 PM

Replace with a good quality AGM starting/cycling battery. Do you know if you have 2 starting batteries? Would be mounted next to the house battery under the van. If so, you’ll want to replace both at the same time.

Mr.Anderson · 10-29-2023, 07:38 PM

Quote:

Originally Posted by carringb

The battery post can melt when you have a loose connection at the terminal, low voltage during cranking causes the amps to shoot up. I’ve had it happen on mine too. ...

Ah thanks for the info, yeah I'll try out one of those all lead military terminal posts and see if that helps, that would make sense if the connection is poor it could happen: Inadequate contact leads too much current.

Quote:

Originally Posted by REF

Replace with a good quality AGM starting/cycling battery. Do you know if you have 2 starting batteries? Would be mounted next to the house battery under the van. If so, you’ll want to replace both at the same time.

My van only has 1 starter battery, I should have mentioned in the OP but this battery is just a run of the mill 12V starter from Advanced Auto Parts (although I did get the "platinum" line which is supposed to be the best quality / strength but probably just a different sticker and more expensive LOL). The house battery I installed is a Renogy 12V AGM which has served me well over the years. My van is home built, not a professional job by sportsmobile or other outfitter.

I didn't realize AGM starter batteries were a thing, any that you would recommend? A quick search is showing up mostly 12V AGM batteries for marine applications.

carringb · 10-29-2023, 08:03 PM

I run AGM for my starting battery as well. I went with the Optima yellow top, with very good success. There’s other good alternatives now, but not so much when I first switched. They’re also stocked at the Napa down the street from me, and were price competitive with any other local AGMs I looked at. I went with the Yellow top (deep cycle) because it’s also my winch battery. I did damage one red-top doing too much winching, but they let me use the warranty towards a replacement yellow top.

REF · 10-29-2023, 08:34 PM

I’ve been using these Duracell branded AGM’s found at batteries plus in various vehicles, I believe they’re a rebranded Deka/East Penn.

https://www.batteriesplus.com/produc...ultra/sli65agm

Mr.Anderson · 10-29-2023, 09:53 PM

Great - thanks for the recommendations guys.

For better or worse the Advanced Auto Parts battery had a warranty so I got a new one replaced free but once this one dies (probably within the next 12 months...) it will definitely be time for an upgrade to AGM.

Once I get that new military terminal post installed I'll update this thread if there were any other issues.

kbeefy · 10-30-2023, 07:07 AM

Quote:

Originally Posted by Mr.Anderson

I started measuring the resistivity between the starter battery positive terminal clamp (without removing the individual load / accessory wires) and the ground terminal wire and was measuring Mega-Ohm and to 1.5 Kilo-Ohm (measurements were a bit jumpy but I think 1.5KOhm was the lowest I saw).

I'm not sure measuring the resistivity is the best way to try to ID a short but even so shouldn't it be measuring open if there isn't a battery installed?

That test wont tell you anything, as you discovered. You are also measuring all the other circuits in the van if you didn't disconnect the other wires. If there is a short you will know as soon as you reconnect a battery, I doubt there is.

I'd investigate that battery light. Do you have a voltmeter installed? The one on the dash is not any good for diagnosing.
The battery light usually comes on when the battery voltage is below 12v. It should be 13.6-14.4 when running.

When you get your battery reinstalled do a resting parasitic load test to make sure there isn't something drawing your starting battery down.
Normally I want less than 50mA of draw, but every vehicle is a bit different. Most of my Fords do to zero draw after about 5 minutes.

Your almost new battery should not have dropped to 3v even with a bad charging system. I usually look for a light left on or aftermarket something (radio or alarm) for that dead of a battery. Your alternator could also have an internal draw, I would check that during the parasitic draw test.

kbeefy · 10-30-2023, 07:10 AM

Cheap handy tool for draw testing, better than accidentally frying your multi meter.

If you get one make sure it's not the heavy duty version, it only measures to 0.1A. The 304b pictured goes down to 0.01A.

0.05a = 50mA

yonah · 10-31-2023, 10:58 PM

Batteries+ has an AGM line labelled "X2Power". I believe they are rebranded (I think) Northstar AGMs. I delved into this years ago when replaced the lead acid starter battery with an upsized AGM variant.

I mention the Batteries+ X2Power line as Northstar is a reputable manufacturer and there seems to be a Batteries+ franchises all over the country if you ever need to activate a warranty. They also routinely run 10% off coupons. IIRC, X2Power AGMs have a four year warranty, or at least they did last time I was in the market.

More info here:
https://www.tacomaworld.com/threads/...rience.454781/

I'd also look at the terminals offered by Slee Offroad and SDHQ. They're a lot beefier and more well-engineered than the terminal in your photo. Not sure of the compatibility with you application, but they're worth a look.

Links:
https://sleeoffroad.com/products/sok20002/

https://sdhqoffroad.com/collections/battery-terminals