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Topic: How to monitor coach battery charge? (Read 574 times) previous topic - next topic

How to monitor coach battery charge?

I have an 2002 295. Unless I have missed something in the brief time I have owned the coach, and please correct me if I'm wrong, there is no way to determine the level of charge of the coach batteries correct? On an upcoming trip I will be boondocking a good bit so I will be on the batteries more than I have ever used them before.  My plan is to run a couple of "test" days here at the house to see how the coach performs.  Plan is to turn on the lights, the tv, etc., make a cup of coffee in the morning, make dinner..you get the idea. The goal is to see the level of the coach batteries after a night of normal battery usage, turn on the generator and see how long it takes for the generator to charge the batteries back to 100%.  It would be nice to know where I am before I start the test, before I start the generator, and knowing when to shut off the generator. ( if on auto generator will turn itself off correct?) I y'all could let me know what I am missing, or how you have addressed this issue I would appreciate it.
Thanks,
Finally cold in Texas! YEA!
dave
Dave
2002 295 36'
Build 6006
Motorcade Member 17931
Toad 2003 Jeep Wrangler
2008 BMW R1200 GSA

Re: How to monitor coach battery charge?

Reply #1 –
Xantrex Link Pro works pretty well. Keeps track of amp hours left and % of charge.
David Bethard
2003 U320 - 40ft. Build #6159
ISM 500hp
2006 Jeep Liberty CRD
2021 Honda Goldwing DCT

Re: How to monitor coach battery charge?

Reply #2 –
Quote from: dke1955 –
I have an 2002 295. Unless I have missed something in the brief time I have owned the coach, and please correct me if I'm wrong, there is no way to determine the level of charge of the coach batteries correct?
Smartgauge Battery Monitor | Balmar

I put one of these in our 1991 U300,  worked great. No shunts to install. I just ordered another one for our new Roadtrek. It learns your battery condition and usage patterns. 5% accurate after a few cycles.
Peter and Tammy Fleming
1991 U300 GV 40 - Sold, owned for 4 years
Downsized to Roadtrek Popular 210 class B

Re: How to monitor coach battery charge?

Reply #3 –
We use:

TriMetric Battery System | Bogart Engineering

Seems to do a good job.  :D

The Auto Gen start will start at 12.2+/- vdc and should shut it's self down when the batteries charged.  Lots of threads on that topic.  Many believe that recharging to 80% from 50% is the most efficient use of resources - diesel as your batteries over 80% gits you to the point of diminishing returns.  The batteries should be recharged to 100% but not every time you fire up the gen set to recharge.  Lots of threads here about auto gen start.  The Search function is your friend.  :-D
Scott & Carol Seibert
2001 42' double slide U320 - Sold
Previous - 2002 36' U320

Re: How to monitor coach battery charge?

Reply #4 –
And, when dry camping, you should not plan on trying to bring the batteries back 100%, except once a week.

Most efficient use of generator run time is discharge to 50%, recharge to 85%, repeat.

Yes, there are quite a few sophisticated monitoring systems out there. And, if not familiar with "living off the grid" and you are planning to do a lot of dry camping, likely a good idea.  But, by paying attention to battery voltage, you can do a reasonable job of estimating SOC (State Of Charge).  With batteries at rest (no charging and no discharging for at least 1 hour) 50% SOC is 12.2 VDC.

If you are camping with others who are also dry camping, consider "buddy charging".  Alternate running the generator. For the guy not running his generator that time, turn off all loads except the inverter/charger. Use a HD extension cord and just plug into one of the exterior outlets on the other coach.  This reduces generator run times by 50% and is better for the generator, as it gives a better load to the generator that is running-- important if just running the generator under light loads.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: How to monitor coach battery charge?

Reply #5 –
I would add to Brett's 12.2 volt info, that batteries are more resistive to charging as they get 'fuller', so it takes longer to get the last amps back into the battery.  And it could take over 24 hours to get the last 10% or 20% back into the batteries.  So in the end, with all of our 'big' batteries, we only get to use about 30% of their capacity between 50 & 80%.  BTW, this is similar to the way Toyota Prius manages their huge battery pack, before starting their gas engine.

Our way of surviving our two weeks of Quartzsite boondocking is to NOT run high amp appliances on the inverter, because this only brings the batteries down, which then we must just put back with generator.  We start our generator to run our microwave, coffee-pot, hairdryer, toaster, any appliance that creates heat, etc.  And leave the inverter for all the other comfort draws, like DVR, TV, computers, router, and electric refrigerator.

We also run our generator every evening, shut all off except for fridge overnight, and run gen again in morning.

Re: How to monitor coach battery charge?

Reply #6 –
I LOVE this forum....wow!!! THANK YOU for the replies. 
Dave
2002 295 36'
Build 6006
Motorcade Member 17931
Toad 2003 Jeep Wrangler
2008 BMW R1200 GSA

Re: How to monitor coach battery charge?

Reply #7 –
The manual that came with the old heart freedom 25 says the basically the same thing as Wolfe posted.  50-90%.

The batteries condition becomes the main thing in dry camping.

Oem on all of our coaches were 8g8'd's for a reason.  Double the cycle life at the same depth of discharge as AGM's.

Which means at a certain point in use the gels will have more capacity left than the AGM's.

Learned long ago in the Rv biz to replace the batteries in every used coach I was going rv'ing in. 

And cherry out the cabling.

I let the medium solar we have on the roof do the last changing from 90 to 100%

"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4
 

Re: How to monitor coach battery charge?

Reply #8 –
I learned a whole lot about charging and capacities and trons and such when I researched my solar install. HIGHLY recommend the Bogart Trimetric, it tells you everything you need to know. In the amps setting, it will tell you what the usage is for your currently energized appliances, and helps you to do an "audit" to figure what uses the most.
Through an audit, found my table lamps are just using .1 amps while overheads use 1.1 amps. My coffee maker sucks 60amps while making coffee (15 minutes), so it uses 15 amp hours (60 amps/ quarter hour).

Your batteries have a set amount of amp hours of charge. Knowing what you use, and what level the batteries are at helps you feel better and can help make informed decisions on use/charging.
AKA Chuck
1993 U280 40' WTB, Build 4345, CUM 8.3 "Falcor", 2010 Honda CRV TOAD (Spock), 970W solar on roof
Full-Time traveler between Quartzsite AZ, Longview WA, Ellendale ND, and Lake City SD
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