Schematic Review

[oside trailer]

i'm getting ready to setup the electrical system for my trailer but was hoping to get a second (third, fourth, fifth...) set of eyes to review my schematic before i begin.

(alt+p)

i have 2 deep cycle batteries which are 125 amp hours and i'm going to be charging them with a 500w 30amp converter/charger. the converter/charger comes with a 110v 3 prong plug attached to it and positive/negative terminals to run to the 12V batteries. do i need to put a circuit breaker in front of this, or can i just plug it directly into an extension cord and into an outlet at my house?

also, i plan to run a 700watt inverter to charge laptops/phones and potentially run a computer printer or maybe a video game console. it has it's own automatic shut down and overload circuit protection. does this inverter need to run through the fuse box or can in simply attach directly to the battery? and if not through the fuse box, what about an in-line fuse?

finally, i have 6 fuses in my fuse box and only 5 terminals on my ground bus. is it ok to piggy back one of the terminals? say with the fans and the lights paired up?

[Miriam C.]

finally, i have 6 fuses in my fuse box and only 5 terminals on my ground bus. is it ok to piggy back one of the terminals? say with the fans and the lights paired up?

Now hopefully I am reading this right, yes you can piggyback the grounds. As long as there is a good connection it will work fine.

btw---now that is real purty.. The schematic that is.

[Sonetpro]

Looks good to me. The only thing I would change is a inline fuse on the inverter. I also have one on the battery positive from the battery to the fuse box. I use those 175A ones like they use on the big subwoofer setups. Maybe not needed but if it ever blows I'll be glad it was there.
You can run the ground together. My ground block is a 8" copper bar with 6ga going to the battery.

I gotta ask what is the winch for?

Welcome to the forum. (I can't believe I beat Auntie M to it and she even posted first.)

[Miriam C.]

Oh dear I really do need to wake up huh! Welcome to the playground. In my defense I was fascinated with the fancy schematic.

[oside trailer]

thanks for the quick reply -- and for the kudos on the schematic (i work for a computer company and did this on my lunch break). i'll report back with pix during the install and will definitely be adding the in-line fuse to the inverter. did anyone have any thoughts on whether i need a breaker in front of the charger/converter????

so, the winch is going to be there because i have a tricky driveway to negotiate... up a hill with tight walls on either side and a slight bend at the top. i've managed to use my truck up until this point, but if anyone parks too close or across the street from my driveway (which is common) i can't get the trailer in or out. the winch (and a trailer dolly) will let me "pull" the trailer to the top of the driveway by hand, and lower it to the bottom when i'm ready to go... this makes it easier to maneuver and typically draws less of an audience (my neighbors always stare in disbelief when it comes time to back the trailer in).

once upon a time, i used to just pull the empty trailer up using good ol' fashioned back strength, but now that i've added windows, a couch and all the electronics, it's getting kinda heavy. plus, there are usually 2 or 3 motorcycles inside (plus gas), so a 3000lbs. winch is now going to do the bulk of the work for me. thought of leaving the winch attached to my house instead, but with it on the trailer i can use this technique wherever i go (which is often to the desert in deep sand). now mating the trailer to my 4x4 truck will also be a snap (even in soft terrain).

[Miriam C.]

Fortunately I live on flat ground. Can I get you to get a picture of the winch in action.

If you are fusing the inverter and not using 120vac you really don't need a breaker. I would add one just in case I wanted to use 120 power though. Cause it is easy---thats why Course you could always run a cord with a breaker on it.

[oside trailer]

so.... i've just had a wonderful moment and a troubling moment, all within a 10 minute span of each other.

i decided to load test my 500w converter/charger with just one of the two deep cycle batteries (120 amp hours) i'll be running in my trailer. the battery sat on the charger/converter for more than 3 hours before i disconnected it and attached the 700w inverter with some alligator clips. this is the baseline system i figured i needed to test before wiring out the rest of my schematic... enough to charge my laptop computer while out in the bush so i could work remotely from my "mobile office".

it was complete over-kill, but i plugged an LCD computer monitor, a TV tuner, and a Sony PlayStation 2 (original box, not slim-line) into the inverter (via powerstrip) to test the lifespan of one battery. naturally, when everything powered-up and i was completely unplugged from the grid and enjoying a game of "MX vs. ATV" in the driveway, the feeling of independence put a smile on my face...

unfortunately it only lasted about 10 minutes before the inverter's low battery alarm started sounding.

maybe i didn't charge it long enough, but 10 minutes of play time from one battery is completely lame. of course, they sell 12v adapters for the game console to fit in a cigarette lighter, so i could bypass some of the excess drain caused by the inverter that way. but i plan on running a 12v fridge, lights inside and out, a car stereo/AV system and some 12v auxiliary outlets (plus the inverter!!!) for 2-3 days at a time without a charge. are these 2 batteries going to be enough????

the other question that comes to mind is this: did i really need a converter/charger? or would i have been better off with a good charger? like a 3-stage model? sure, it's nice to think that i could run everything in my trailer via hook-ups, but the reality is that's not going to be the case very often. i ride dirt bikes at a combination of local southern california race tracks and single-track trails in backwoods areas. this trailer is meant to be a temporary respite from the dust and the elements in between motos. what i need is a fast/powerful charge!

any thoughts?

[Dooner]

Here is what I did. Yours looks better than mine, so it must be good.

[jeep_bluetj]

Schematic looks fine.

As far as your 10 min debacle, the numbers don't work out to 10 min for a 120 AH battery with a 700W load.

So I can think of a few possibilities, in no particular order:

1. The "low battery" alarm voltage on the inverter is faulty, and registering at the wrong voltage. Use a DMM to monitor the battery voltage while using the inverter to test it.

2. Converter/Charger sucks, and didn't charge the battery properly. Stick a DMM on there during charge and monitor the voltage. If you have a decent ammeter you could measure current into the battery. This isn't very likely if the battery is new, because it should come with a pretty good charge in it.

3. Your battery is defective (shorted plate, weak electrolyte, etc).

4. The leads to your inverter are too small, are heating up, and you're seeing a voltage drop on them. (Measure voltage at battery and inverter and compare the diff. )

5. Something else....

[Wimperdink]

not sure if I read that right, but it looks like the trailer lights are hooked to onboard power... Those would need to be connected to the TV. If I read it wrong, I appologize and i'll just bite my tounge.

[Dooner]

not sure if I read that right, but it looks like the trailer lights are hooked to onboard power... Those would need to be connected to the TV. If I read it wrong, I appologize and i'll just bite my tounge.

I had to look at that real close too. Those are the two 12v outlets he is using.

[oside trailer]

once again -- thanks to all for the quick and thorough reply.

i believe i have found the source of the problem: there was NO WATER in my battery. it's my own fault for not paying attention to the basics -- too caught up in fancy schematics, i guess.

hopefully this will solve the problem. more later...

[Miriam C.]

If my new battery didn't have water in it I would take it right back. For that matter if it needed charging I would take it right back. Sometimes it is about the service you will get next time.