rigrunner 12v outlet

[frater secessus]

I believe I'd be running separate wires for each use and combine where I can like lights.

I ran a few 10ga "spokes" from the main fuse block out to distribution blocks in the more distant places in the van and then distribute from the blocks with 16ga. The electrical system is the most complex part of my build and running individual wires would not have been practical (that many wires would not have fit in ribs).

Have you read the ramblings of HandyBob? Grumpy old fella but lots of good information on his blog.

I've made an attempt to summarize the info in his RV Battery Charging Puzzle page.

[frater secessus]

Over time as you get fsmiliar with your unique setup you may get a feel fo guessing where your bank SoC is.

But no way is it anything accurate like a proper SoC meter.

A proper SoC meter is not as accurate as hiring a Trojan battery Ph.D engineer to sit in the van with a portable lab providing realtime analysis.  I suggest chasing ultimate accuracy is a diminishing returns situation for vandwellers.   Geeks and tinkerers (like us) notwithstanding.

How accurate is a tool between recalibrations (rezeroes) anyhow?  We don't know (by definition), but we can probably say "close enough for our purposes."   So now what if "close enough" costs $150 less?  I think it depends on the user's definition of close enough.  A vandweller "close enough" is likely different from a marine grade "close enough", which is different from an aeronautical/military/NASA grade "close enough".

SoC monitoring reminds me a bit of flying an airplane.  Watching the SoC meter would be flying on instruments and watching volts/amps would be looking out the windows.  Both work fine in their particular context.  In some contexts I imagine a meter could be required, but the vast number of recreational pilots do not require an instrument rating.  The average vandweller might be better off looking out the window and keeping that $150 in his/her pocket.

I think sternwake nailed it here:

The Shunted battery monitors are great, when they are wired up properly, set up properly, and rezeroed occassionally. The person who can do this well, can also make an accurate guess as to state of charge, if they are regularly looking at just a voltmeter and an ammeter.

A corrolary would be that folks who can't make the accurate guess probably wouldn't be able to configure and use a meter correctly either.

[sternwake]

That was my intent.  I;ve seen so many people setting them up incorretly or havng not rezeroed them, likely ever, have complete faith in the SOC%, which was off by 20 or more %, and as a result of this blind faith in the reading, had prematurely sulfated batteries on which they spent a lot of effort trying to recover the lost capacity.

That recovery process, requires holding absorption voltage as long as required and then likely an EQ charge for an extended period.

I have a shunted AH counter.  It drifts .


How do I know? the amps the battery requires when held at absorption voltage.

The most I have seen it off was about 14AH, but 2 or 3 can be common.

With only 90Ah of capacity 2 or 3 low means it would be chronically undercharged and my current battery would likely be at the recyclers had i blindly trusted the Ah counter and not held absorption voltage until amps tapered to 0.5% of capacity or less.

Few actually require a shunted AH counter.  A simple ammeter and seeing how many amps the battery is delivering, or accepting at that voltage, noticing the trends and tendencies, one could guestimate very accurately where the batttery is, and how healthy it is.

It takes some time to develop this skill, watching the current flow during charge and discharge, and it is of great benefit to be able to bring the battery to absorption voltage then and there with how ever many amps are required to do so.

I read Handybob's diatribe a while ago before I had really gotten a fine grasp  on the realtionship between amps and voltage and state of charge and battery life.

The main takeaway was get the batteries to absorption voltage each recharge for as long as it takes to actually fully charge the battery.  Anything less will compromise longevity and performance. A false belief the batteries are full, either by a faulty programmed or rezeroeed or wired battery monitor, or the damn blinking green light on automatic charging soureces, has prematurely killed a LOT of lead acid batteries the world over, and is happening the world over.
 as you read this.

Occassionally Verify that when you think the battery is full by whatever device is making such a claim, that it is actually full, as what it takes to get full changes as the battery ages.  it requires more and more time at absorption voltage as it ages.  lack of holding longer absorption voltage  as the battery ages, will have the battery at the edge of the capacity cliff saying "hold my beer,  and watch this."'

[John61CT]

While I completely agree that expensive SoC BMs are overkill, not required at all.

But for those who care to be precise, can afford them and have a large expensive bank to care for, say over a grand or two, they are IMO worthwhile.

For lead SmartGauge is shuntless and only shows SoC, no need to program AH capacity thus no need to measure that as it declines, and no Full resets required. No AH counting but more accurate.

The Victron 702-BMV is best IMO for LFP, or those that want AH counting, but does require programming detailed batt data, regular Full resets and valid AH capacity numbers to calc SoC accurately.

I recommend both together, can actually back-figure declining AH capacity by comparing the two, saves running 20-hour load testing as the bank ages.

But yes, few want to spend even $200 on that level of monitoring precision.

But if interested, keep an eye on eBay and marine gear yards you may find a bargain.

This page is a goldmine of info, http://www.pbase.com/mainecruising/boat_projects

Search the page for "battery monitor" to learn more, but it's all worth reading.

This is the new site, https://marinehowto.com/ but not all the old posts have been migrated yet.

[Blacktank]

it can in today,smaller then i thought,4x2 3/4,solid plastic case,plugs nice and firm no wiggle


and of course since it was in perfect working order i took it apart




for someone who sucks at soldering $30 is about right for the unit
gives me 4 dc outlets,now i just need a powerpole crimper and some powerpoles

i have a free standing fantastic fan and can see the ciggy plug from here and cant wait to destroy it

crazyhamsales.com  takes you to his ebay page