Comparison of Battery Charging Methods
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Topic: Comparison of Battery Charging Methods
Posted By: CharlieM
Subject: Comparison of Battery Charging Methods
Date Posted: 28 Dec 2014 at 4:47pm
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Here are results of three different methods of charging
the camper batteries in the field: Direct connection to a vehicle
battery, running the built in converter from 120V shore power, and running the built in converter from a vehicle mounted inverter. 1) Discharged two 6V GC2 batteries to 12.1V unloaded (approx. 50% SOC). Residual camper current 0.150 Amps. 2) Connected to Tacoma battery, engine running, with 20 Ft. #2AWG copper jumper cables. Measured 55+ Amps charging. Disconnected. 3) Tacoma gas consumption while idling was 0.5 GPH. 4) Plugged in CL shore power cord into 120V 30A house circuit. Measured 39 Amps charging. Disconnected. 5) Plugged in CL shore power cord into 400 Watt Tacoma inverter. Measured 20 Amps charging. This test was run on a Camplite 21RBS with two 6 volt GC2 batteries in series and a 2013 Tacoma, but results should be similar on other rigs. The best method is the jumper to the truck battery with heavy cables. The second best was the built in converter running on good shore power and should be similar to a good generator. The third best method was using the 400 watt converter built into the Tacoma ($30,000 generator). I didn't measure the AC voltage, but it was probably sagging due to being close to its limit. The 0.5 GPH gas consumption of the truck while idling makes it a good and quiet generator for CG use with no mess or extra gas cans. Just fill 'er up before you set up. ------------- Charlie Northern Colorado OLD: 2013 RP-172, 2010 Honda Pilot 3.5L 4WD PRESENT: 2014 Camplite 21RBS, 2013 Supercharged Tacoma 4L V6 4WD |
Replies:
Posted By: Podster
Date Posted: 28 Dec 2014 at 6:14pm
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Hmm, interesting, when you say the "best" the resulting charge was based on what? The amount of energy and time expended or SOC after the batteries were charged? Looks like there is no substitute for pure amperage, however, I wonder how the different charging methods affect the life span, if at all, of the batteries. Thanks for sharing this Charlie, good to know!
P.S. I want to borrow your Super Charged Tacoma for my Summer Colorado trip!
 ------------- Cliff & Raelynn Ranger 4.0/178 (1/2 ton 5,800lb tow capacity) |
Posted By: CharlieM
Date Posted: 28 Dec 2014 at 8:50pm
"Best' was based on the ability to deliver a large charging current, particularly when away from home. If shore power is available I would opt for the built in converter, but if not I'd use the truck instead of a generator or off board inverter. Trojan recommends bulk charging at 10%-13% of C20 until the voltage reaches 14.4. The current from the truck starts off higher, but quickly drops as the camper battery charges. The truck charger and battery will not allow the voltage to go much above 14V, more likely 13.6, so it's self limiting. This will provide 90% SOC, but would take a while for full charge. If the battery is really dead you should watch for boiling and refill if necessary, but you can dump a lot of energy into the battery quickly. The on board converter will go to 14.4 so it could complete the absorption phase faster, but that assumes 120V is available. My investigation was really aimed at the case where I was out in the field and off the grid for several days. How would I recharge and what would the trade off be between recharging the 2 GC2s vs carrying 2 additional GC2s (Heavy!). As long as you fully recharge when you return home with the on board converter I don't think life would be adversely affected. I also just wanted to know how well the little 400W inverter in the truck would work. It's convenient, but not the best for this application. Further info is available at http://www.trojanbattery.com/pdf/TRJN0109_UsersGuide.pdf - http://www.trojanbattery.com/pdf/TRJN0109_UsersGuide.pdf I'm really looking forward to our Colorado trip this fall. I've got high expectations for the S/C. Full report will follow. ------------- Charlie Northern Colorado OLD: 2013 RP-172, 2010 Honda Pilot 3.5L 4WD PRESENT: 2014 Camplite 21RBS, 2013 Supercharged Tacoma 4L V6 4WD |
Posted By: Podster
Date Posted: 28 Dec 2014 at 9:01pm
S/C ? Any chance you can stop by the BIG Texas POD Rally at Tyler State Park while on the way to Colorado? ------------- Cliff & Raelynn Ranger 4.0/178 (1/2 ton 5,800lb tow capacity) |
Posted By: CharlieM
Date Posted: 28 Dec 2014 at 10:17pm
S/C is super charger. I see the Tex rally is late October. I'm not sure of our travel plans yet and I have to plan around double knee replacements (getting old is crap). Are you sure you guys want a Camplite in your party, even if I did love my Pod? ------------- Charlie Northern Colorado OLD: 2013 RP-172, 2010 Honda Pilot 3.5L 4WD PRESENT: 2014 Camplite 21RBS, 2013 Supercharged Tacoma 4L V6 4WD |
Posted By: Podster
Date Posted: 28 Dec 2014 at 11:30pm
Hmm, dunno...let me check with the group. WHAT?, YES, OF COURSE...once a podder always a podder. You can be our flag bearer!  Keep us honest, lead the way like Rudolph...come on, it would be an honor to have you there, Charlie!We can draw you up a cardboard facade, what do you want to be, a 178? ------------- Cliff & Raelynn Ranger 4.0/178 (1/2 ton 5,800lb tow capacity) |
Posted By: furpod
Date Posted: 29 Dec 2014 at 9:45am
as long as you have a dome.. no one will notice.. LOL Friend of mine sent this, knowing we will soon be going to a 21RBS ourselves..  ------------- |
Posted By: Podster
Date Posted: 29 Dec 2014 at 1:43pm
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furpod, you're right...this could pass for an R-POD easy! C'mon Charlie, what do you have to lose? Go for it! Besides, I want to check out the Super Charger on that Tacoma of yours...what's the base HP like 300!? ------------- Cliff & Raelynn Ranger 4.0/178 (1/2 ton 5,800lb tow capacity) |