Observation of battery behavior

[mena661]

With all this talk of battery monitors, it reminded me of some behavior I observed a few months ago and possibly some justification for having one. I had a problem where one of the battery bank interconnect cables had partially pulled out of the lug. Of course, I didn't know this at the time. What got me curious was that the amps into the batteries on the Victron monitor were fluctuating (converter was always putting out a fraction of an amp). It doesn't normally do that. When the batts are full, the meter is at a steady zero amps. There might be an occasional blip but normally steady. After a few days of noticing it, I opened the battery compartment and checked all the cables. Found one that was pulled out from the lug a bit. Grabbed a spare wire for confirmation and sure enough the converter went into bulk. Interestingly only one pair was low, the other was full. Ended up having to use the manual charger (it has a 6V setting) to get the individual batteries back to full. Even charging as one pair left one 6V lower than the other.

[mena661]

MEXICOWANDERER wrote:
Pulled out? Musta been some kinda pull force to break a properly soldered lug!

Yeah, I'm pulling your chain Mena 🙂

:B 😉

[MEXICOWANDERER]

Pulled out? Musta been some kinda pull force to break a properly soldered lug!

Yeah, I'm pulling your chain Mena 🙂

[mena661]

KendallP wrote:
Hmm. That DOES sound pretty weird.

Is it safe to ASSume that the charging power was wired with positive on one pair and negative on the other?

That is correct good sir. I'm using the wiring configuration here:

SCVJeff wrote:
Had that exact problem with the jumper that ties in the 2nd set of 6v. The difference was 1/100v, maybe a little more, don't remember. But it was enough over time to make a noticeable difference in the SG of that battery set, and that's what caused me to pull out the 4.5 digit Fluke and poke around.

Always good to have some confirmation. I'm betting I would've seen the same thing if I had let the batts wear off the surface charge.

[SCVJeff]

Had that exact problem with the jumper that ties in the 2nd set of 6v. The difference was 1/100v, maybe a little more, don't remember. But it was enough over time to make a noticeable difference in the SG of that battery set, and that's what caused me to pull out the 4.5 digit Fluke and poke around.

Another factory wedge (as opposed to swedge) crimp bites the dust.

[KendallP]

Hmm. That DOES sound pretty weird.

Is it safe to ASSume that the charging power was wired with positive on one pair and negative on the other?