Background: We're kinda new at this, and I'm a complete pinhead where electricity is concerned. We boondock in Eastern Washington on our own land and far enough from anyone else that my generator noise is not an issue.
Question: How many amps does the 12v battery system draw when it's coming back from a complete drain?
The story: This season (our 2nd), we've left our TT on the property rather than towing it 200 miles each way every time we want to use it. This has been beneficial in several ways (not the least of which is reduced fuel costs and reduced stress from hauling this thing around.) Of course that means we aren't plugging it into our 120 at home during the down time. When we came out today our batteries were dead. Oops. Yeah, I know this is not a good way to extend your battery life. I'll be looking into some kind of solar trickle charger or something (yes, I'd love some suggestions, but they're not the real question of this thread.)
It was 98 degrees outside when we arrived today, and sage bushes don't cast much of a shade. Inside our aluminum TT it was rather warmer, as you might expect. Venting and powering on the AC were top priority.
I have a 4600/5000w Champion Propane generator. (Last year I had a 3500w Alton that never had issues with the A/C, and had lower power stats. Why don't I have that now...well, lets just say that I'm a bit of a pinhead and I really love Costco's generous return policy.)
Of course I'd tested this unit with the AC earlier in the year and it was fine, even with several lights and other things running.
This time, however, the AC ran for about 60 seconds and died. The breaker on the generator had tripped.
At this point I was running on a 50' extension cord rated for 15a. I've used this cord with much success in the past.
After a few retries and fails I was getting a bit panicy. I brought the generator closer to the TT and switched from the 120/20a duplex outlet to the 120/30a twist-lock outlet, now running only the 30a line from the TT and a 30a adapter for the outlet.
This did not work any better.
A little manual diving provided the following information.
120v 30a Twist-Lock: 22a breaker, 120v AC, 60Hz, single phase loads requiring up to 22 Amps or 2600 watts of power.
120v 20a Duplex: 22a breaker. Use each receptacle to operate 120v AC single phase 60Hz loads requiring up to 20a or 2400 watts of power, not to exceed 22a or 2600 watts for combined loads of these two receptacles.
To me, Mr. Baffled By Electricity, it sounds like I've only managed to pick up 2 amps in this switch, rather than the advertised 10 amps (20a to 30a is 10 in my book.)
Another manual indicated to me that nothing on this unit drew over 20 amps. (I believe this was referenced by explaining that the converter had no fuses over 20a, but I may be putting snippets of info together for that.) I had nothing else running, except the clock LED on the microwave, which I actually did unplug though it couldn't possibly be drawing much.
The only other thing I can think of was the charging of the 12v batteries. Yeah, I'll admit it, I have no idea what really charges these things, and I have even less of an idea of how many amps that system is drawing. My guess is it's more than 22 amps minus my Air Conditioner. (no idea on the AC either, but it's less than or equal to 20a.)
My workaround? I killed the A/C and just ran the fan for a while. I hooked up my wife's non-towing vehicle (we tried that once, then I bought a pickup) to the towing power lead in hopes of drawing on that to charge the batteries. (I'd swear I read once that that is a more effective charging method, though I'll never find that post.)
We ran that way for 20 or so minutes, then took another stab at the A/C. This time the results were better and eventually we got things running as expected. /Phew.
I would very much appreciate someone filling in some of the blanks here for me. As you can see, I'm a doughnut where some of this stuff is concerned, but I'm aware of my shortcomings and am not too proud to ask for advice, so maybe there's some hope for me yet.
My 55a onboard charger will consume about 750 watts while charging low batteries P(watts)=I (amps) X V (volts). A 13.5k btu AC will use about 1700 watts (14 amps at 120v) while running, and will have a brief surge when starting the compressor.
So these 2 items equal 2450 watts not counting the surge load of the AC which will be significant. Combine this with the 50' 15a extension cord and there will be issues.
I know your question is only about what the onboard charger requires for charging dead batteries, but why not quit using the 15a extension cord, and get an RV twist lock to 3 prong adapter and use your rig's 30 amp extension cord? You could even add another 30a cord to extend its reach if the genny must be further away from the rig. A 15a cord is marginal at best when running an AC.
I carry a small portable 25 amp 3 stage charger just for the issue you have. After a night of inverter use my built in 80 amp converter overloads the generator if I have the air-conditioner on at the same time. I simply switch off my converter and hookup the portable charger.
The converter charging dead batteries is the problem.
Just another reason why a converter should have manual control over the charging stages, like the PD 9100 series w/ the "charge wizard", or the 9200 series w/ the pendant control.
Using one of these converters, you can manually turn down the charge rate, which will let you use the A/C at the same time.
Using these converters will also let you charge batteries w/ a 60 amp converter using a much smaller generator, such as a 1000 watt Honda, because you can manually stay out of the hi charge mode untill the batteries state of charge comes up a little.
Rich
'98 Flair, 454, Onan Microlite 4k, Intel PD 9155 w/ wizard, Sta-power 1500 watt Inv, 2 6v batts, ammeters, KingDome/sat, Oly Catalytic Heat, hauling 2 Bent Bikes and sometimes towing a Tracker F&S boat.
Often, the answer on 12 volts is the last two digits of the model number (NOTE: Often does not mean always) example. ON my coach that's 80 amps (Progressive Dynamics 9180 with charge wizard) so in 120 vac that translates to around 8 amps (1/10th, however there is a second number in there that kicks that up to around 10-12 amps AC (it called power factor you need to multiply by it's inverse)
The easy way to comput the 120 volt amp draw is this..
Turn off EVERYTHING in the rig save the converter.. With the batteries low use an adapter to plug the rig into a KILL-A-WATT meter.. (Which is inturned plugged into a standard 15 amp outlet) There on your display is... The answer
Nothin adds excitment like something that is none of your business John is Near Kenwood TS-2000 housed in a 2005 Damon Intruder 377
As far as your generator goes, the rating of the outlet (20a/30a) has nothing to do with how much power is available from the generator (22a).
My guess is the generator is setup to put half the rated power to the 30a outlet and the other half to the 2 20a outlets. That's where the 2400 watts comes in.
Your old generator probably put all of its power out one set of outlets.
Well you can focus on getting all the 4000+ watts out of the generator or you can manage power use to get by on the 22 amp output.
If there is a way to rewire the generator to provide full output to a single connector I am sure it is covered in the thread titled 3000W Chinese Gensets Info.
Otherwise you can manage your power use to stay within the 22 amps. If you leave the trailer with fully charged battery and disconnect a cable, the battery should be OK for when you return. This would allow you to leave the converter off and run the air. After the air starts cycling in the evening then turn on the breaker to the converter. Or wait until morning when you can run the generator without the air for a couple hours to charge the battery. One the day you are leaving be sure to run the generator charging the battery for at least 4 hours and shut down and disconnect a battery cable just as you leave. Then you will be in good shape upon return.
2001 F150 SuperCrew 5.4 Lariat Offroad 4x4 Tow Package 4.10 Truetrac
2006 Keystone Springdale 249FWBHLS
12K SuperGlide, KGE3000Ti 2.3kw rated 2.6kw max
Frank's voltage booster, Prosine 1800 powered by 4 GC2 batteries
So these 2 items equal 2450 watts not counting the surge load of the AC which will be significant. Combine this with the 50' 15a extension cord and there will be issues.
I know your question is only about what the onboard charger requires for charging dead batteries, but why not quit using the 15a extension cord, and get an RV twist lock to 3 prong adapter and use your rig's 30 amp extension cord? You could even add another 30a cord to extend its reach if the genny must be further away from the rig. A 15a cord is marginal at best when running an AC.
While working this issue I did bring the gen closer and used my 30a cord with a 30a adapter to a twist lock, but things did not quickly improve. I'll be looking at a 30a extension today.
My converter is a WFCO WF-8955AN-P. It states that it has three 3 modes, but there is no manual control of these. Clearly this was my issue yesterday.
I see that there is a breaker (15a) labeled CONV which one would assume will disable the battery charging system. Using that as described in these other posts could probably have served as a workaround.
I also have breakers labeled GFI and GEN, both 15a. What might these be?
I'll be reading up a bit, but my internet connection out here is shaky at best. (Go Go Gadget cell-card!) I've not had issues with power management prior to this. (Turning AC off to run the microwave was always assumed.) I see the deficiency in my extension cord now. I bought that on the advice of the hardware guy before my TT was delivered. Live, learn.
What is the feeling about solar powered trickle chargers? They proclaim 300 days of sunshine a year here.
GFI, is Ground Fault Interrupter and probably connects outlets for kitchen, bathroom and outside.
GEN probably is the other GENeral outlets in the bedroom, entertainment center, near the dinette etc.
Small solar panels to keep the battery up work excellent as long as the battery is otherwise disconnected from any loads. 15 watts is plenty to keep my battery charged but would be hard pressed to do any real charging if the battery is left low. For actual recharging you need to be in the 85+ watt range. 5 watts per battery is about minimum for maintenance.
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