Solar controllers, Deepcycle batteries and Inverter Questions?

[n00bus m@x1mus 465]

Hey so im in the middle of a big camp trailer refurb and i will be fitting it out with 12v power with the aid of some deep cycle batteries and charging it with solar panels. Im sort of getting a grasp of what works in the camping game but im sure i dont understand it enough to make some well informed decisions about what I should be spending money on. So if anyone here is into this sort of stuff please share on how you have yours set up and what works and doesnt work cheers.

 

Currently i have acquired a pair of 180w panels that have regulators built into them and are wired to anderson plugs with about 2m of reach. I want to power a range of LED lights that im fitting into it and also an engle fridge/freezer which has a max draw of 2.5amps/hour if i understand that correctly. I dont have a want for 240v but i think i should install a half decent inverter for those odd things that you might want to power when out the middle of nowhere.

 

So what im needing is a pair of deep cycle batteries... what AH rating and construction im unsure on. Also a solar controller that will be suitable to best make use of the panels i have now. i was going to get a Ctek float charger aswell to hardwire into the system and use that to run the entire thing when at powered sites instead of setting up the panels... which model is recommended? apparently there are combined solar/14.4v/240v units that will accept all those inputs and regulate power to your batteries at the best output to ensure max charge rates and battery conditioning. I cant seem to find which unit that is or whether or not it is the best way to go over seperate units doing there own job.

[gerg 10,871]

A bloke at work keeps raving about Optima batteries. They're an Absorbed Glass Mat type "hybrid" (ie deep cycle but good cranking amps) and are priced pretty well. Ctek is also often mentioned and somehow knows what it's plugged into (ie deep cycle or conventional) so a good choice for deep cycle. Can't recommend any model though. Deep cycle need higher volts to charge (about 0.5v higher) so your regulator needs to account for this. I'd advise against putting too many smart gadgets in place as they'll likely fight each other and cause more dramas than solve. 2.5 amps/hour isn't a unit of measurement, however amp-hours is to do with battery capacity. 2.5 amps draw from the fridge though is about 30 watts. A couple of deep cycle batteries should have no trouble powering that over a weekend without charging. That's all I got

[n00bus m@x1mus 465]

Thanks for that much mate, yeah i dont understand the draw yet on the fridge, it says min 0.5amps - max 2.5amps. Im guessing that is its draw per hour and not its load on the system.

Ive priced optima AGMs and they are pretty well priced at around $280 a piece delivered on ebay for a yellow top unit but only has 55AH storage. Its ideal being a sealed gel type battery that wont leak or need maintenance so i can store it away and pretty much forget about it. But its pretty low on storage as far as deep cycle batteries go.... for instance a Century 120AH marine deep cycle lead acid goes for around $220.

 

Bang for buck says to got his way but i dont know how much maintenance something like that will need in a camp trailer. Its says on the sticker to check levels every 6 weeks and dont let is go too low twice in a row and all this crap. Im not really sure if its worth the hassle to go a lead acid in a camp trailer wihtout removing it and keeping it in service as a dual battery in a regularly operated vehicle.

 

I need to understand more about what my draw will be per day and be able to store it correctly between solar charges. from what ive read a 100AH battery is really only good for 50AH cycles, anything less and you really decrease the service life that have. And that the rating (100AH) is calculated at 100Amps draw over 20hrs time, so thats 5amps per hour total draw from 100% to 0%.

So then im supposed to halve that so it wont go below 50% so that a total 2.5amps draw per hour over 20 hrs and thats assuming you get a solid X amount of hours charge back into it per every 20hrs aswell. Im pretty sure ive got the charging side of it covered but my maths says i should safely need about 150AH+ storage to keep everything going per day providing i get the required solar input. if i dont then i believe i will be doing the batteries damage and should have had more in storage so it wont run below 50% and i have to shut it all down till the next hours of strong sunlight.

 

Is that all correct or am i not grasping it right?

[Demmo 295]

gday noobus   if you are planning on leaving your solars hooked up after dark make sure you have a cut-out on it  as my first panels on the camper used to draw power back through the panels and also added extra burden on the battery when combined with fridges an lights ect meant that had to monitor recharge each day.  also adding to the woes was the original wiring was too light and it suffered voltage drop ect      we rewired with larger cable, replaced optima with a 100 amp sealed gel battery, and I fitted a smart regulator to xh ute  all seems to work well at present.    not sure what vehicle you have to tow but my sons patrol has you Bute  electronic crap which would not allow sufficient charge to top up  the second battery  to overcome this the dealers fitted a 12 volt to 12 volt battery charger in the back which inturn charges the camper trailer battery to maximum     when trailer is stored in shed we have a 30 watt solar panel mounted on shed roof connected to a solar regulator and have found that this maintains the charge in battery

hope these points help you   and  a article I found interesting can be found at  www fridge an solar net

cheers demmo

[Ando81 2,949]

Just wondering how you went with this project mate. Call me tight but i am thinking of removing my 240v water pump off the rainwater tank that feeds my shed and converting to a 12v pump and solar charger for the battery. It's only gotta run water into a sink so doesn't need bulk pressure. The way electricity prices are going up and up makes rainwater more expensive than tap water hence my 240-12v conversion.

[n00bus m@x1mus 465]

Sorry mate this project has stalled at the moment, funding ran short and i had to get back into full time work so i havent had much time to play with it unfortunately.

what 12v pump did u have in mind cos i have to look into that too sometime to finish off the kitchen in the camp trailer.

[Ando81 2,949]

No worries mate, I work in agriculture and the brand selecta do a lot of 12v pumps rated from 15 litres a min to 65 litres a minute depending on how much you want to spend. They are very well priced and have automatic pressure switches etc. was gunna go for a 30 litre pump and it shouldn't have a big amperage draw when it starts up.

[Defective 1,692]

I'm gonna be setting up my trailer with solar as well, certainly gets complicated when you get right into it.

[gerg 10,871]

Sorry forgot to explain amps and amp-hours.

 

Amps = current flow (Coulombs/second)

Its's the same as water flowing through a pipe (ie Litres/sec)

 

Amp-Hours = battery capacity.

 

It's like saying a water tank can hold enough water to drain at one litre per hour for X amount of hours. The reason why they rate it that way is because a battery is more like an electricity sponge than a tank, and its actual capacity can only be charged/discharged over a long period of time.

[Ando81 2,949]

I've been told that a dc dc charger is best for a dual battery system on a caravan, 4x4 etc. an old fella told me that a lot of newer cars don't put enough current into a second battery coz the alternator is setup as to not put excessive load on the engine which burns more fuel blah blah. Can anyone add to this?

[Valvebouncer 2,389]

At work we sell predominantly batteries and chargers. We used to sell CTek chargers but have since dropped them as the quality just wasn't there, we now sell Redarc chargers, cheaper and good quality. <br />Late model batteries are predominantly calcium plate with only using lead as a bonding agent for the plates. The problem with these batteries is that when you discharge then the build up a high resistance to charge back up, a charging system in a car will be lucky to get the battery back up to 80% after being run flat. The only way is with a good battery charger for a calcium battery (most will go through 7 stages of charge and discharge to remove the resistance). If I were doing this I'd use batteries designed for a stop start system car. They are a good hybrid between your normal battery and a deep cycle. These will handle more discharges than a normal battery. Use the solar panel to power the battery charger and/or use the solar panel for direct power if it has enough grunt. In the topic of optima batteries, I know of 2 friends running aftermarket Ecuador that have both lost their programming and both tuners said to get rid of the optima batteries they were running. From the research I have done on them they just don't seem stable enough for my liking, I'd rather replace batteries more regularly than deal with electronic issues from a battery surging. You have to ask yourself, if they were that great wouldn't manufacturers fit them in the factory? Just my 2 cents worth

[Ando81 2,949]

Can anyone help me with a problem I have with a Projecta dc dc charger that I have installed on my father in law's 2006 rodeo. I wired it up so that the charger only turns on with the ignition on to supply power to an auxiliary battery but it's only putting out 12.6v but the manufacturer claims to put out 14.4v I hooked it up to a battery with 11.8v and the dc charger went into "float" mode and said it was fully charged. I sent it back to the manufacturer and they claim that it was bench tested to 20 amps and it was fine. My wiring is as recommended by Projecta and still doesn't seem to be working. Any help would be great, cheers.

[Outback Jack 6,352]

Is the battery new or old one?

First try running that second battery down to maybe 9-10V and see what it floats at after charging from a bit lower.

If you have a multi-meter use that to confirm the chargers voltage at the charger output and also the battery itself.

 

Jack.

[Ando81 2,949]

Hey Jack, battery is an old one. Tried it on a new battery and on a battery that had about 10v in it also, all resulting in it going to float charge within 30 seconds.