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bridgeskd avatar image
bridgeskd asked

Electric Acting Up in Van

Hey there,

For the past few months the electricity in my van has been acting strange. Full transparency, I didn't do the buildout nor have a firm graph on the electric setup so I'll detail as best I can. (warning: it's a lot). Appreciate your help in advance!!


tl;dr - Electricity surges and drops overnight


Here is our setup:

Battery

(2) 6V Deep Cycle Batteries / 200 Amp Hour AGM battery bank (~3-4 years old)

12V 140 Amp Dual Battery Isolater - running off engine batter

Solar

  • (2) 275 watt Lg Solar panels
  • Victron SmartSolar Charge Connector MPPT 100 | 30


We're typically only running the main cabin lights, a Nova Kool R3800 Dc Refrigerator, Maxxair fan, and a small bathroom fan (only when bathroom is in use).


What's been happening:

- We first began experiencing what I'd call a 'surge' this Spring. The things mentioned above would be running fine then the lights would turn off/on rapidly, fan would turn off it is was in use (on if it wasn't in use), same for bathroom fan. This happened for 10 sec or so then repeat a handful of times. We typically turned off the fan breaker and turned off the lights until we needed them on again.


- On a trip last month, we weren't as much experiencing the 'surge' but instead woke up to water on our floor as our fridge defrosted overnight. This happened multiple times and the fridge struggled to function for the rest of the trip.


- We also had a few small water leaks in the van roof over the past few years. Only mentioning in case it sounds like a faulty wire (which I haven't yet seen).


- Lastly, the lights have turned on by themselves overnight. Outside of ghosts I can only imagine the system is turning on during a 'pulse'?!?

---

I've been doing more testing on the batteries. During the day (full sun), they're both tracking around 5.8-5.6v (per battery). In the early AM (around 6-7 before full sun), one remains around 5.8v while the other is lower at 4.6v. I have seen dips into the 8-9v when checking at night/early AM (which is the measurement for the 2 batteries combined). With full sun, we're typically 11-14v.

Lastly, I also noticed a quick drop in voltage around the pulses I've mentioned.


screenshot-20220912-071019.png



If you've made it this far in the post, thanks. Appreciate your time.

Is it as simple as I need new batteries or does it sound like something else is going on?

AGM Batterysmart solar charging behaviour
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2 Answers
marekp avatar image
marekp answered ·

@bridgeskd LA battery should never go below 10.5V on 12V battery.

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bridgeskd avatar image
bridgeskd answered ·

@MarekP Do you then think it's an issue with the battery(ies) and they should be replaced or do you think there's another issue which is draining the battery below 10.5v?

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marekp avatar image marekp commented ·
@bridgeskd

If they drop below 10.5V under usual load they are probably close to the end.

You can confirm it by charging them to full and perform controlled discharge to find out what capacity they now have.

There are also battery testers that will measure internal resistance. IR value will tell you the state of your battery.

If you have access to the electrolyte you can see if the level is right and you can measure its density at full charge and maybe getting the density up norm will fix your problem.

If you decide to buy a new battery look into the LFP type.


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