Reply
 
Thread Tools Display Modes
 
Old 10-07-2012, 10:11 PM   #1
Skoolie
 
Join Date: Jun 2012
Location: Cherry Hill, New Jersey
Posts: 115
Year: 1997
Coachwork: Crown by Carpenter
Chassis: Ford B-800
Engine: 5.9L Cummins
Rated Cap: 55
Battery monitoring?

I just got a 2000W inverter today and all it has on it is a fairly useless load meter that simply goes in 200W increments. Obviously with a laptop and a light, it'll never display anything.

I'm wanting something more sophisticated that tells me not just the current battery voltage, but also the current drawn, and a nice pretty visual meter that tells me the remaining capacity of the batteries. Something like this, perhaps:

http://www.clippermarineusa.com/product.php?id=44224



I'm curious what other people are using, assuming something like that isn't already integrated with their inverter. I need to know whether I'm in relative danger of losing power, or if I need to get back on-grid, recharge early on enough, or if I need to plan for installing more panels (currently I'm just trying out battery power with a car charger to replenish it), etc. It would ALSO be good to know what current each thing is actually pulling (by disconnecting everything but one thing), so I can expand my battery bank as needed.

The simultaneous display that this model has is ideal. I don't want to see only one number at a time, and have to click through different display modes to see other numbers. I also would prefer something digital and not just LED with 'full, half, empty'.
tomas_maly is offline   Reply With Quote
Old 10-08-2012, 12:02 PM   #2
Skoolie
 
Join Date: Jun 2012
Location: Cherry Hill, New Jersey
Posts: 115
Year: 1997
Coachwork: Crown by Carpenter
Chassis: Ford B-800
Engine: 5.9L Cummins
Rated Cap: 55
Re: Battery monitoring?

Seems that traditionally (from my research) that people get separate devices to measure each thing. a voltmeter, ammeter, etc.... That may be more cost effective anyway. This Clipper BM-2 only goes up to a 600 amp-hour system, which mine is going to be a bit beyond, anyway.
tomas_maly is offline   Reply With Quote
Old 10-09-2012, 11:02 AM   #3
Bus Crazy
 
roach711's Avatar
 
Join Date: May 2010
Location: Farmington Hills, Mi (Detroit area)
Posts: 1,572
Year: 2000
Coachwork: Eldorado Aerotech 24'
Chassis: Ford E-450 Cutaway Bus
Engine: 7.3L Powerstroke
Rated Cap: 19
Re: Battery monitoring?

Glenn - Your math is good. Connecting two batteries in series doubles the voltage while connecting them in parallel doubles the amp-hours.

I've got a Trimetric battery monitor that does all that the BM-2 does and also lets me monitor my chassis batteries (voltage only), but you have to click through to see the display you want. The BM-2 does have a much nicer display.

The Trimetric unit required some programming too.
__________________
The Roach Motel
roach711 is offline   Reply With Quote
Old 10-09-2012, 10:04 PM   #4
Skoolie
 
Join Date: Jun 2012
Location: Cherry Hill, New Jersey
Posts: 115
Year: 1997
Coachwork: Crown by Carpenter
Chassis: Ford B-800
Engine: 5.9L Cummins
Rated Cap: 55
Re: Battery monitoring?

I don't know how realistic it is, but it would be NICE if there was something that could beep an alarm when the batteries are drained past a certain point. I'd prefer two alarms, a warning at 60-75% and a more urgent alarm at 50% (or higher). I'd like to know before it's too late and we're in the middle of nowhere that we should head into town, etc to charge up, before it's too late. The alarms I've seen so far seem to not have much customization to it, ie and some go off at way too low a voltage.

The Clipper BM-2 is a nice display, but I will be having probably 1200 amps eventually, so that unit is not an option. And my inverter runs at 12V so I can't split the batteries into two sets.

I'm actually not concerned about amps as I am about watts. It'd be nice to know the load the inverter is drawing for everything. The inverter itself has a meter on it, but I'd like a digital one as well. And knowing the watts being used only really matters if I know how much longer the batteries will last (to 50%) at that load. Not just in percent, but also in minutes, hours, etc. That piece is critical.

I'd also want an analog voltage reading with the appropriate color coordinated ranges, ie 'charging' vs 'low' vs 'fully charged', etc... A voltage reading doesn't mean much unless it gives me an idea as to whether the level is good or bad, and to what extent.

I'm looking through a book "RV Electrical Systems" by Bill Moeller, which seems to be pretty thorough in monitoring options. Sometimes you need to know what EXACTLY to look for because search engines can often give really useless results.
tomas_maly is offline   Reply With Quote
Old 10-09-2012, 10:16 PM   #5
Skoolie
 
Join Date: Jun 2012
Location: Cherry Hill, New Jersey
Posts: 115
Year: 1997
Coachwork: Crown by Carpenter
Chassis: Ford B-800
Engine: 5.9L Cummins
Rated Cap: 55
Re: Battery monitoring?

http://www.bogartengineering.com/pro...tric_trimetric

I'm looking at Bogart's PentaMetric models, and it seems like those are the ones with the alarms? I don't mind the programming as long as I can get information that means something useful, relatively quickly. If I have to press a few buttons, that's ok, as long as I get warned when things are bad (or almost bad), and as long as the number on the display means something useful, like present load in watts or estimated time before batteries need charging or amp-hour loss relative to the full charge.

I may supplement this type of thing with an analog voltmeter with the right color ranges.

It also sounds like the Pentametric specifically can turn on a generator when needed via a relay. Of course if I can't get my butt outside to flip a switch, then we've got problems.

How do the Trimetric and Pentametrics compare? Are there other manufacturers? Would they handle more than the 600 amp-hour capacity?
tomas_maly is offline   Reply With Quote
Old 10-11-2012, 12:17 AM   #6
Skoolie
 
Join Date: Jun 2012
Location: Cherry Hill, New Jersey
Posts: 115
Year: 1997
Coachwork: Crown by Carpenter
Chassis: Ford B-800
Engine: 5.9L Cummins
Rated Cap: 55
Re: Battery monitoring?

I found these too:

http://www.xantrex.com/power-product...y-monitor.aspx



This honestly seems less COMPLICATED than the Bogarts. It doesn't have a built in audible alarm, but it does have a 1 amp relay that gets tripped when the batteries reach low (which itself is programmable what % that is). The relay can go to any sort of external 12V alarm that is < 1A, visible or audible. Or it can trigger a generator, apparently. The PRO version is also rated for 10,000 amps (the LITE is only 1,000 amps). Amazon has it for about $250. AND it has a bit more screen space for simultaneous display (battery level AND amps consumed).
tomas_maly is offline   Reply With Quote
Old 07-19-2014, 08:29 PM   #7
Bus Crazy
 
Join Date: Apr 2013
Location: Colorado
Posts: 1,402
Year: 1993
Coachwork: bluebird
Engine: 5.9 Cummins, Allison 545
Rated Cap: 2
Re: Battery monitoring?

any updates from users here.....

looking at the same things.... i sure like the looks of bm-1, and the xantrex

not sure but maybe in my circumstance, a simple generator controller would work better than a read out that i have to manually monitor.........

xantrex makes a generator controller:

http://www.xantrex.com/power-product...tor-start.aspx

that senses voltage and runs the generator automatically. the monitor would be redundant.

anybody try these or feed back on any of the monitors?

thanks
__________________
.
Turfmobile Build Thread
turf is offline   Reply With Quote
Old 07-19-2014, 10:04 PM   #8
Bus Crazy
 
Join Date: Jan 2008
Location: Upstate NY (Mohawk Valley)
Posts: 1,096
Re: Battery monitoring?

I note that the Xantrex requires being mated to a Xantrex inverter, and it has a 3-wire Onan generator control output. Remote start wiring for generators can be 2-wire or 3-wire.

Most old Onans are 3-wire. You hold the "start" wire to "common" to crank the starter until the engine is running and showing oil pressure, which kills the starter and allows continued running. You hold the "stop" wire to "common" to kill the spark until the engine finishes all its sputtering. If you let go of the switch too soon, the genny either doesn't start or doesn't stop. The remote panels for RV gennys are usually a spring-loaded center-off rocker switch for the 3-wire control.

Other generators with 2-wire control have a "common" and a "request to run." You must hold the "request to run" to "common" continuously for as long as you need AC. If you had one wired in an RV, the remote run request switch would just be a common "On" or "Off." Most stationary backup generators are 2-wire, getting a "request to run" from the emergency transfer switch when commercial power fails, and releasing it after a cool-down timer resets a short time after the utility power returns.

Any battery system monitor with a settable external alarm point should be able to be wired as a "request to run" generator controller. A 12-volt relay that can handle the signal current can be switched by the alarm output.

Home brewing 3-wire remote start from a 2-wire output takes more thought. I have used a double-throw relay that holds "start" forever during request to run events, and holds "stop" forever when the event ends and the interface relay releases. But if your interface relay is continuously enforcing the "stop" command, there is no way to run the generator from any parallel switch unless you also provide a way to disconnect the "stop" command from the relay. If I recall correctly, an old Onan will still crank, but shut down as soon as the oil pressure relay engages.

But you have to ask yourself, do you want to give the genny authority to suddenly fire up at 3 AM without warning while you are trying to sleep? It's a choice, and may be preferable to a damaged battery bank. I think I once saw documents on a purpose-built generator controller that had the ability to assign quiet hours, so the genny will wait until a better time to start.

Another option is low-voltage disconnects. These are built into most DC-AC inverters, so if the battery gets too low, they will shut down the AC output and stop drawing DC. External Low Voltage Disconnects can be ordered for other loads, too. You could have one or more LVDs dump unnecessary loads during the night, and attend to the genny when you get up.

The problem with LVD panels when boondocking is that they are generally designed old school, and have a big mother relay that is active and drawing current the whole time that DC loads are authorized to connect to the battery bank. Newer solid-state units may go a long way to reduce this "phantom power" load, but I cannot think of a specific model without doing some research.

Edit 1: Some combination of keystrokes made the reply post before I had finished proofreading it.
Edit 2: I forgot to add that any home brew generator controller that uses a battery voltage set point as a trigger will also need some kind of minimum run timer. Shortly after a charger comes on line, the battery will appear to have a healthy voltage at the monitor point.
__________________
Someone said "Making good decisions comes from experience, experience comes from bad decisions." I say there are three kinds of people: those who learn from their mistakes, those who learn from the mistakes of others, and those who never learn.
Redbear is offline   Reply With Quote
Old 07-20-2014, 10:01 AM   #9
Bus Geek
 
lornaschinske's Avatar
 
Join Date: Jun 2004
Location: Roswell, NM
Posts: 3,587
Year: 1986
Coachwork: BlueBird
Chassis: 40 ft All American FE
Engine: 8.2LTA Fuel Pincher DD V8
Rated Cap: 89
Re: Battery monitoring?

Handy Bob's Solar has some good info on battery monitoring (most of it in The RV Battery Charging Puzzle). He did add some new info for this year (2014 Solar Ideas, Batteries & Other Things).
__________________
This post is my opinion. It is not intended to influence anyone's judgment nor do I advocate anyone do what I propose.
Fulltime since 2006
The goal of life is living in agreement with nature. Zeno (335BC-264BC)
http://lorndavi.wordpress.com/blog/
http://i570.photobucket.com/albums/s...ps0340a6ff.jpg
lornaschinske is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Monitoring Fuel Consumption/Mileage edfrank Conversion General Discussions 14 07-06-2012 09:35 PM
Seperate battery or starting battery for gen BUSBOZO Electrical, Charging and Solar 4 10-12-2010 10:24 PM
Inverter/charger/monitoring systems BUSBOZO Conversion General Discussions 1 02-26-2010 08:23 PM
Main Battery - Starting Battery Group 31? 8D? Tone Conversion Tutorials and How-to's 5 04-16-2009 06:02 PM
re: 8d battery help please! captainkf Conversion General Discussions 2 11-09-2005 08:56 PM

» Virginia Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 01:47 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.