My experience and difficulties with 12v power

[MarkBC]

...Where do you have your batteries if they have to vent?

The batteries are in the storage area under the couch -- at the front end of that box, next to the cubicle where the original single (AGM) battery was placed by FWC.
Venting is provided by the turnbuckle access slider, which is next to the batteries, propped open about an inch.

Is this safe?
It's safe enough for me -- and I've run it this way for 6 years without a single explosion (at least, none that I recall).
The potential hazard is the small amount of hydrogen gas that evolves when the battery is being charged and water is split into hydrogen and oxygen. But hydrogen diffuses -- dissipates -- very fast (almost 5 times the diffusion rate of propane). And the LEL of hydrogen is 4 vol-%, which is higher (less flammable, by this measure) than most volatile substances (propane is 2 vol-%).

But I'm not suggesting to anyone else that they do what I do.
And if folks decide that my camper isn't safe to visit at the upcoming Rally, I won't be offended.

 

[Ethergore]

The batteries are in the storage area under the couch -- at the front end of that box, next to the cubicle where the original single (AGM) battery was placed by FWC.
Venting is provided by the turnbuckle access slider, which is next to the batteries, propped open about an inch.

Is this safe?
It's safe enough for me -- and I've run it this way for 6 years without a single explosion (at least, none that I recall).
The potential hazard is the small amount of hydrogen gas that evolves when the battery is being charged and water is split into hydrogen and oxygen. But hydrogen diffuses -- dissipates -- very fast (almost 5 times the diffusion rate of propane). And the LEL of hydrogen is 4 vol-%, which is higher (less flammable, by this measure) than most volatile substances (propane is 2 vol-%).

But I'm not suggesting to anyone else that they do what I do.
And if folks decide that my camper isn't safe to visit at the upcoming Rally, I won't be offended.

That's hilarious. I actually thought about doing it that way but am worried about getting a bunch of dust in there. I even considered doing a filtered vent or something.

Interesting to know others are doing that.

 

[MarkBC]

That's hilarious. I actually thought about doing it that way but am worried about getting a bunch of dust in there. I even considered doing a filtered vent or something.

Interesting to know others are doing that.

Thank you for not calling me an irresponsible reckless daredevil lunatic.

I haven't noticed much dust...but I only keep "rugged" stuff in that under-couch storage, and I have a high tolerance for filth anyway.
I've had rodents (squirrels, sage rats) come in (or at least poke their heads through) the driver-side turnbuckle access vents (which are open to the living space) a couple of times, so if I stored food under the couch rodent access there through the open vent might be a concern.

 

[Ethergore]

What's camping without wild life?

 

[DesertDave]

What batteries do you have to get 300 ah?

I have (2) Lifeline GPL-6CT batteries, they are 6 volt AGM batteries, with the same footprint as group 24 12V batteries, but a lot taller, nearly 13" tall. They fit into the drivers rear corner spot that FWC provides in their front dinette models. I expect they would easily fit into most of the other spots that FWC can provide dual batteries.

I think they are really great, except for their weight and their price. 90 lbs each and you don't want to know.

 

[billharr]

I have (2) Lifeline GPL-6CT batteries, they are 6 volt AGM batteries, with the same footprint as group 24 12V batteries, but a lot taller, nearly 13" tall. They fit into the drivers rear corner spot that FWC provides in their front dinette models. I expect they would easily fit into most of the other spots that FWC can provide dual batteries.

I think they are really great, except for their weight and their price. 90 lbs each and you don't want to know.

I looked about 10 minutes ago. Just got my breath back, you are right I did not want to know. Hope those batteries last a long time.

 

[Ethergore]

So I did more testing last night just to be redundant. Maybe you guys can let me know if I'm interpreting this right.

Battery- tested cold after sitting got 12.5 volts. (Wet cell) with air running, defroster on, high beams on, radio on I was at 12.3 and it slowly dropped to 12 over like 5 minutes. On cranking the battery never went below 12. To me, this is battery OK.

Alternator- At startup it sits at 13.7v (right after the load test). One it ran a while it sat at 13.5. From here on no matter what load I put on it it stayed at 13.5. From what everyone at tundra solutions this is perfect. Alternator OK.

Voltage drop- this is where I'm confused. If I disconnect the camper from the truck and test at the starting battery and then the plug I get 13.5 and 13.4 (small drop). If I leave everything connected and running I get 13.5 v at the starting battery and only 12.8v at the aux battery. So does this mean I have voltage drop our is it normal to read a different voltage across the length of the circuit depending on how close or far I am to the higher voltage battery? Seems like this is normal but can someone confirm?

Cycling of separator- I wanted to pinpoint at what voltage my separator will want to "cycle." I got halfway through this test but basically I am draining my battery a point at a time and seeing how low the voltage has to be for the system to want to separate the batteries. So far I'm at 12.3 with a load (the refrigerator) on and no cycling.

In addition, I have accessed my solar preslwiring in the roof and cabinet and lengthened my wires to reach my charge controller. Got the roof plug coming in today and mc4 connectors coming tomorrow.

Everything is coming down to the line since I'm leaving for 17 days on Friday. Wish me luck.

Oh ya. I'm consider springing for 2 six volt batteries if you guys have recommendations. The only place I've found local carries UPG for $210 each. Are these any good? They say they are made in "Asia." Us this Chinese crap or Japanese ggoodness?

 

[Ethergore]

Actually. I take it back. I called the place and they have Deka for $220 a piece. I think I'm pulling the trigger. US made goodness.

 

[PaulT]

Lurker who just registered to forum. Had to as DC power is one if my favorite subjects as a ham and as a new Hawk owner, I am trying to learn to live with the power I have.

Camped at Clear Lake, Oregon the last couple of days w/o hookups and lots of tall trees that limited solar charging. Unit sat without truck running for two days. Temp in high 80's during day. My 2 AGM batteries did fine as judged by how everything worked.

Zamp solar controller indicated batteries were down to 11.9 volts but FWC battery monitor LEDs indicated charge just dropped to half power. Noticed isolator relay cycling after starting truck but no indication on Zamp meter that charging was cycling. 100 watt panel charged at 6+ amps when stopped in full sun about noon. Plugged into AC on arrival in Hillsboro and finished charging.

As to measuring voltage drop, Ethergore's experience is normal. Voltage drop must be measured under load and is determined by wire size, length, and current being carried. There are apps for Apple and Android that help you pick a wire size for the current, run length, and allowable voltage drop. Pay attention to run length. Double the length of the wire run because you have to account for the return path.

This is a great forum. I have learned lots from the posts that helped me set up my Tundra and choose options for the camper.

Thanks,
Paul

 

[Ethergore]

Thanks for commenting Paul! I'm glad you let me know the correct way to measure voltage drop. I was thinking it was impossible to not have drop in that long of a run of a smaller gauge wire. Upon reading I found a nice voltage drop calculator if anyone wants to use it:
http://nooutage.com/vdrop.htm

In case anyone is interested I pulled the trigger on two Deka gc2 batteries with 200 ah each. I also accessed the prewiring for my solar but decided I will wait until I have a second panel to permanently mount it to the roof for instances where I park in shade. For now, i installed a plug on the side of my camper through the wood and ordered some mc4 connectors to make cables. I think my next upgrade will be a solar charger controller with smart charging to top off my batteries after my alternator does all the bulk charging, after that another panel should help me to match my energy usage.

All update on if the problem is solved after my trip.

 

[Smokecreek1]

Since I got back from Meadow Lake (see the Ted's TR), I've been watching this thread with great interest and confusion because i just was forced into upgrading my set up (see the "When I almost blew myself up" thread a couple of months ago when me and Wondering sagebrush where up at the Sheldon Ant. Range) over the last month and this was the first real trip out with my new set up. My set up now is a 2 way coolmatic 3.8 compressor frig/freezer (I think wired directly into the system., 1 Renology 30 amp comptroller/pwm/lcd, 1 100 watt Renology solar panel (on roof) and two blue top agm deep cycle 12v batteries and this is what happened when I took it all to the lake! I had an earlier short trip out with this set up with a 10 amp comptroller and things sort of worked-at least things stayed in the green on both comptroller and the fwc batt charge gage.

Okay, I was up at the lake for almost six days, parked in a mostly sunny campsite and drove nowhere and this was a test of how this set up worked. The batt voltage stayed pretty steady a 13.0/12.7 for the few days, but got down near 11.4 (at first light every morning- it went up and showed that it was charging as the sun kicked in the solar panel) and ranged between 11.7 and 12.4 and it dropped when he frig kicked in during the day and went back up when it went off. It seemed like I spent allot of the time adjusting the frig down from 4.5 to between 2 and 3, the last few days to keep both the fwc battery gage and comptroller LCD lights in the safe range. Again, i'm not to sure how accurate this gage is, but until i got the frig it always was in the green or yellow, but near the end of this trip was in the yellow and one morning was in the red. I confess here my lack of understanding on what my new comptroller was telling me and I missed the simple color system of my 10 amp (Green work, red/no color no work).

On day 5, when I saw red in the morning on the fwc gage and freaked and started up the truck to charge up the batteries! The Comptroller showed 11.4, but as usual from what I could figure out, the rest of the settings were fine and it continued to show a happy face (meaning things were working okay) and the battery voltage gage soon showed it was charging (as did the fwc gage) and soon reached 12.7. The whole trip my comptroller showed a happy face and as soon as i got home, I went on the web to try to learn (very slowly) about how comptrollers and electric things are supposed to work. Wish me luck. So should i just ignore my fwc batt gage and trust the new one as long as it has a happy face and shows that it is working and charging? Or continue to use both-like i do now.

A first stupid question though, the new comptroller shows the batt charging, but never shows the dc thing lighting up, but, i've got nothing hooked up to that port on the comptroller and my frig is wired to the battery so there is nothing to worry about right??? Right now with the camper battery switch off the battery reads 13.0; switch on, it drops a tad-still with a happy face, but it is raining here now and it is not getting much of a charge. Turn on the frig, and it drops to 12.4 or so and still shows a happy face. turn it off, happy face and 12.7. When the switch is on the fwc gage shows green with a tad of green showing in the charging area. Did I confuse you all enough, me thinks, I'll continue to read the manuals and stuff and hopefully if I explained what happened out there good enough, one of you will tell me if I need to worry or not. Maybe I should have left things connected to the old 10 volt comptroller with it's nice lights, but down the road I am thinking of adding another 100 watt solar panel, so this really is a test of things to come.

Thanks for any comments

Stupid about electric stuff

Smoke

 

[MarkBC]

Smoke, did a shop install your solar system? If it was my system and it was behaving strangely or different than my expectations, I'd take my rig to the place that sold me the system. And I'd ask them to explain what is going on.
I wouldn't let them sell me anything more, however...I'm always leery of people who want to sell me something.

I don't understand the symptoms (or your system) well enough to offer any smart help myself -- sorry, and good luck.

---

You mentioned "mostly sunny campsite". Was the panel in FULL sun for several hours? If a panel is partially shaded it reduces the output by a lot -- by more than the fraction shaded.

 

[billharr]

Smoke I made a small chart giving me % of charge by voltage. I may have an extra if you need one.


Bill

 

[Smokecreek1]

Mark/Bill-
Thanks' I think it's more me understanding how things work than anything else -you know the more i read the solar threads the more i don't know-but ever once in a while somethings sticks . For the last 8 months i've had that 100watt sp on the roof along with the solar connector it came with and things seemed to work fine. After the miss hap, had the rv folks put in the new additional batt and hook up the new frig and things again worked ok( i think), just up graded the comptroller and followed what Renology told me to do and just don't know enough to ask the right question to them or anyone for that matter, to find out if somethings not right. Bill, I've used something like that i got here to figure how much power i need to operate things on a system wide basis, but if it's no problem, maybe you could post it here and i could figure more things. i don't know but need to know, like how much power i'm getting or not getting from the dang thing. This teaching and old dog new tricks takes time, i guess it's forcing" me" mind to think--and that's good. I followed all the instructions i think,I feel so stupid, it should be working and probably is and just don't know it ! Well back to the threads and reading stuff from the "solar charge comptrollers information center" and hopefully more help from you guys. Maybe I should ask my dog "Bob" for some help- border collies are supposed to be smart right ?

thanks

Smoke

 

[billharr]

Smoke lets see if this works. I have the Chart on google docs, the link should take you there and you can print it.

Voltage sheet % charge two sizes.

 

[Smokecreek1]

got it-as a light goes off!

thanks

smoke

 

[Ethergore]

Smoke- the main things I learned so far is the importance of charging at the right voltage and the impact of voltage drop from the starting battery to the aux battery.

What I learned about my renogy charge controller so far on my trip (I'm writing on vacation now) is that it only charges at about 13 volts which handy Bob would frown on. A entail rule of thumb for deep cycle is 14.4 volts. Maybe your old controlled charged at closer to this voltage.

The voltage drop from the alternator in my setup with fwc design is 15%! This is doing me from getting fully charged even when driving long distance. I am currently compensating by having a large battery bank.

Our renogy solar panels would work a lot better with a morningstar charge controller and our alternator would charge better with larger gauge wiring.