Charging batteries with a generator

[walker]

Does anyone know how long it takes to charge up a battery with a generator?

I know, I know, you are going to tell me there are heaps of variables like the type of battery and generator, but maybe give me some ideas.

I will mount a battery in the trailer I am building and rather than hook yet another battery up to the car, I thought it might be good to chatge it via a generator (which I will make a sounproof enclosure for). This way I can keep it charged if we camp for a long period.
When touring or travelling the fridge will be in the car running off the car dual battery system. The trailer battery would be for the lighting and water pump mostly although if stopped for a few days I would plug the fridge into it as well.

I am guessing an AGM battery would be best????

Do the cheap generators charge as good as the expensive ones???

Might be a good question for Drivesafe if he is around.

[Lotz-A-Landies]

Walker

If you are only going to use the generator for charging batteries then why not consider solar. More expensive upfront but in the long run cheaper.

My friend Wayne has 2 large solar panels on the roof of his Rangie, this supplies sufficient power to run his large Waeco fridge, keep the car topped up and run his Barrett HF and other transceiver radios. It also makes no noise and uses no fuel. If you use LED lamps you can also save on the size of your battery.

On your camper trailer they could be mounted over the top when travelling and repositioned when stopped and erected. They will also keep the battery/ies charged between trips.

Regards
Diana

[walker]

Yeah, I have thought of this and I agree, it probably is the best option.......but $$$$$$.

Maybe later on I will do it. It would mean removing the panels everytime we stopped and making up some sort of rack to hold them above the rooftop tent.

[Blknight.aus]

if your battery is big enough why not set up an aux charging feed from the vehicle?

my elcheapo 600w genny takes about 12 hours to charge my deep cycle battery from dead (10.8ish v) on the 8a built in charger and about 4 on my 30a 240v charger. end charge is 14.2v nominal

I only use the 8amp charger if I need the 240v for something else as the genny will just charge when im not making full draw on the 240v side or when i have the load off, drilling holes or between grinds.

the genny is one of those scorpian jobbies you can now get from super cheap, bunnings, and aldi.

individually it runs my 6 inch grinder (just),drill, 500 halogen worklight and the 30a battery charger.

[walker]

Yes, I was reading that you should not charge up batteries from the 12v side of a generator.

I would use a 3 step 240v charger with the Generator. If it only took 1-2 hours to charge up a partially drained battery then it would be ok. The AGM batteries will charge up a lot quicker than other types as they can take a much higher charge current. Also would not expect the battery to get that low if charged up every day.

[Blknight.aus]

When the trailer deep cycle was in good order it would run the fridge radio and 2 fluros for just on 3 days before the low volt cut out shut it down. as my charger is VERY primitive dad made me up a regulator do hicky that plugs inbetween the battery and 12-14.8vdc Dont ask me how, it did its dohickery and the battery was looked after.

My charging times were from low voltage cutout untill the dohicky charge light said it was full.

[drivesafe]

Hi Adam, this is just a suggestion.

You already have an auxiliary battery in the rear of your disco and as you are getting a battery charger, why not get an inverter instead of the generator, and use the auxiliary battery in the disco to power the inverter and just run an ordinary everyday 240v extension cord over to the charger in the trailer, to charge the trailer’s battery.

Lots of advantages to this type of set-up.

Cheers.

[walker]

The only thing I don't like about this is that the rear battery seems to have enough trouble on it's own just looking after the fridge.

Also, don't the battery charger need a fair bit of power? I already have a 600w inverter but at 240v that is only 2.5A, it seems a very inneficient use of power. But it is an interesting idea. So you didn't like the generator idea?

I guess I like the generator idea because it allows you to have power even if you don't go driving for a few day. Solar would do a similar thing.

I was trying to find some info on the Christie Generator which is a dedicated petrol powered 12v battery charger. It is meant to fully charge up a battery in 1 hour. Sounds expensive though.


On a similar note, what battery would people recommend? I have the Exide Orbital Blue top in the back of the Disco but I have never really been happy with it but it is the only AGM battery I could find at the time that fitted into the rear bins.

[drivesafe]

Hi again, no matter what type of battery you get, if it’s been discharged to anything under 80% of it’s full charged state, ( 20% used ) then it will take more than an hour to recharge it and at 50% or less, at least 2 to 3 hours charging is needed, depending on the battery and that’s just to put the bulk of the capacity back, not to fully charge it.

I’m not against generators and it doesn’t matter what means you use to charge a battery, if the battery is flat or fairly low, it’s going to take hours to recharge not an hour.

Before you get a battery, or if you already have one, go to the battery’s manufacture’s web site and you should get a better idea of the time needed to charge the battery.

Cheers.

[mr_sav]

Hi, have a look at one of my previous threads, regarding Dual Batteries and charging. Don't use a el cheapo Battery charger form Supercheap etc. either. Use a 3 Stage like you were considering. In short I have Anderson Plugs with Welding Cables (no Voltage Loss) connecting Trailer to Vehicle. I have a Redarc 3 Stage 10amp Continuous Charger. with a 3 way option to charge just the trailer Auxillary, or Vehicle Auxillay or Both. I then have a vehicle isolater, which I can disengage and will charge all auxillarys and main. It is a real cheap setup but works a treat. The Charger works from mains if I pull into say a caravan park in that blue moon for a swim, decent shower etc. Alternatively of the Generator.

Good Luck. Plenty of different options to choose from.

[walker]

Thanyou. Yes I think my biggest problem is the number of alternatives!!:o

When It comes to building the trailer I know exactly what I want and how to do it, but I have never understood 12v power and charging properly. It is a bit strange since I am an electrician by trade.:eek:

I think I just need to find someone to TELL me what to do. ie.

If you use a generator, use this gen, with this charger with this battery.

or

If you use solar use this, this and this.

I have estimated that my energy use should be around 25A/day

I think one of the important things is to monitor the battery. What is the best thing to use to monitor the state of the battery. From what I have seen volts is not that good because you do not see a significant drop in voltage until the battery is bellow 50% discharged.

[drivesafe]

Hi adam, to monitor the battery(s) with any realistic accuracy, you need something like an Xantrex battery monitoring system and you are looking at a starting price of around $500. Usually not a valid expense.

Now, as to the set-up that best meets your requirements, well that can be compered to the old saying “ How long is a piece of string “.

Now if you have an idea as to how you will be using the set-up and you have posted some details, then you can design the set-up around your needs.

The following would be how I would set up your power storage and charging system.

Fit an SC80 ( got to get a plug in ) under the bonnet, connected to the positive terminal of the cranking battery.

Fit a 50 amp circuit to the output of the SC80, then run at least 10mm2 twin cable from the circuit breaker to the battery in the rear of the disco.

At the rear battery, fit a 30 amp circuit breaker to the rear battery’s positive terminal and connect the twin cable’s red cable to the other side of the circuit breaker.

Now run another length of 10mm2 twin cable from the circuit breaker at the rear battery, to a 50 amp Anderson plug mounted near the trail plug.

On the trailer, fit another 30 amp Anderson plug to a length of 10mm2 twin cable and fix it to the trail to allow it to plug into the 50 amp Anderson plug on the back of the disco.

Run this twin cable into where you have your trailer’s battery mounted. Again, fit a 30 amp circuit breaker to the trailer battery’s positive terminal and connect the twin cable’s red cable to the other side of the circuit breaker.

You can connect any 12 volt accessories, via fuses, to the cable side of the circuit breaker in the rear of the disco and in the trailer.

If you have a 50 A/H battery in the rear of the disco and fit a 100 A/H battery in the trailer, using the SC80 will give 4 to 5 days operation before you need to start the disco to charge up the batteries and this is only taking the batteries down to 50%. If you don’t mind taking the rear battery and trailer battery down further, you can get another 1 or 2 days use before you have to charge all the batteries up and you will need to drive for at least 5 hours to get the bulk of the power ( 80% to 90% ) back into the batteries.

Not including the cost of the batteries, this set-up will cost you less that $300 to fit and will not need any special charging or the need for battery chargers, generators or solar panels, to be able to go for up to 8 days before charging is needed.

Best of all, this is a fit and forget system, the very thing most people want.

Cheers.

[walker]

Done and done!

See, I might argue with everyone, but if someone who i know knows what they are talking about, tells me what to do, I do listen.

I don't mind you plugging your stuff at all, and I would love to hear more. I already have a dual battery controller (will post up what brand as soon as my wife gets back with the Disco), but it is in the back of the Disco with the second battery....is this a problem and What makes the SC80 better? (I'm sure it is better but just wondering the differences).

I already have 10mm2 cable running from the front battery to the controler in the rear, but no circuit breaker.:o I also think that I have just realised why I have never been happy with the charging of the rear battery........I ran a 10mm2 wire between the positives but just ran a 10mm2 cable from the negative to the chassis.....I should have run it back to the front battery shouldn't I???


Thankyou again, I do appreciate the help you give. I will let you know the brand of battery controller I have and if you don't think it is up to the job then I will buy an SC80. I also have an Arrid voltage booster inline just before the second battery but if I run a negative back to the front battery then this is probably not necessary.

[drivesafe]

Hi Adam, here’s a diagram of a set-up that would suit your vehicle.

https://www.aulro.com/afvb/images/imported/2006/10/124.jpg

[walker]

Thankyou. When I get it bit closer to the electrics I will order an SC80. Is there a distributor in Melbourne or is it better to order directly through you?

Also, the rear 2 batteries will be joined at all times (when Anderson Plug is in) is this a problem if the batteries are of different size or age?

[Redback]

Mr Walker, my 2 cents, we camp for long periods when we go places most of the time, i have a 75AH deepcycle in the camper for running exactly what you do lights and water pump.

we have 3 Nelson lights that are used alot, one is used as a around the camp fire light, and we also use a laptop to watch DVDs sometimes as well, now to my point we have a small 10 watt solar panel (no regulator required with this size) that puts out around .8 to 1 amp and is used to top up the battery during the day when we are off driving, the 12v fridge is in the car so there's no drain on the battery during the day, as well we have a 3way fridge which is on gas when camped, we have camped for 10 days and have never flattened the battery as yet, if you only have the one fridge then you really don't need to have it hooked up to the camper just leave it in the car seeing as you have a dual battery setup in it.

I'm not a big fan of gennies mostly because it's another thing you have to carry and more fuel you need as well, not to mention the bloody noise they make too, and the abuse some get because of them.

Anyway that's us, not alot of money to setup like us and it's simple too, treebruiser has almost the same setup except he has 2 Trojan AGM deepcycles setup via drivesafes SC80 Traxide unit as he has a 12v fridge in the camper as well as in the car, i think he can go for around 6 days before recharging, i think he's looking at getting a solar panel to top up during the day too.

To me this is the cheapest and most simple setup i know, tie it in with the Traxide and it's even better

Hope this helps

Baz.

[drivesafe]

First off Adam, exactly what Baz said. Thanks RED.

Next, buy direct from me as I give all AULRO members a 10% discount.

Also, take your time because I have had so many enquires from a number of sites about info on a standard basic set-up that I have done this diagram to coincide with a Kit that I should have ready soon.

Any ideas on adjusting or adding to the above diagram will be appreciated.

Cheers.

[walker]

If you had 2 100A/h batteries linked in parrallel in the trailer would the setup be the same.....ie you would use the same size c/b or larger?

Also, the question I asked before, is there any problem if the 2nd battery in the car is different and older than a new battery I would put in the trailer?

Oh, and also, is it ok if the SC80 is mounted fust before the 2nd battery in the rear of the car rather than under the bonnet?

[drivesafe]

Hi Adam, First last. You can mount the SC80 near your rear battery but just make sure you have the circuit breakers in place at each battery for safety.

If you already have 10mm2 cable fitted, it will work fine but will reduce the charging current, but this is only a problem if the trailer batteries are VERY low when you start driving and even then, all it will do is extend the charging time, again only if the batteries are very low.

To date, I have never had a problem with any of my systems that was related to the use of different types and ages of batteries, so you shouldn’t either.

Cheers.

PS, if you are planning to run new cable then go for something like 16mm2.

[Skiboy]

Hi Adam
An alternative I have been looking - (I have similar problem to you and yet to decide on the solution) - is to use a petrol powered alternator to charge your AGM aux batteries (as these take a fast charge - forget normal deep cycle - also they don't let off hydrogen gas).

There is a company called Christie Engineering - web site http://www.christieengineering.com.au/2.5hp.htm (http://www.christieengineering.com.au/2.5hp.htm) that sells a 55amp Alternator coupled to a 2.5 hp Honda motor. It puts out a DC charge. Basically similar to running your vehicle to charge the batteries.

I am told by the guys at Christie (I have been on the phone and email to them this week - they are in Sydney but have distributors around the country) that 1 hr of their charger should top up a AGM to full each day.

Cost $890 to $990 depending on model.

Advantage over solar is that work when no sun (rain etc). Also not need to do all the storage and transport of delicate panels.

I am considering on of these for use when doing 1-2 week largely stationary camping (ie no regular 5 hr drives to charge the deep cycle battery.

If you want to see some good notes on the technical side there is a great site by Fridge and Solar at http://www.fridge-and-solar.net/info.htm (http://www.fridge-and-solar.net/info.htm)
I have read all this and largely it parallels what Drivesafe has said already.

Anyway will be interested to see what you decide as not 100% sure yet myself.

The only thing I wonder is why can’t I set up the SC80 to charge the trailer mounted battery and leave it for an hour? I assume the answer is that it does not put out 55amps? So can’t one increase the Alternator in the vehicle to ensure this stuff charges faster when vehicle going?

My set up I am looking at one deep cycle in 4x4 and 2x100 amp hr AGMs on trailer. I want to run a couple of fluros, shower pump and a 50L fridge possibly on freeze. We also have a gas fridge for other food/drink. I want to be able to camp for several days (say a week or two camp) – even when cloudy/raining – and not have to worry about the fridge draining the battery.

Initially I thought solar but I am not convinced I can get enough charge for a reasonable price. And I don’t want to be caught out!. Hence my interest in the Christie DC charger as it would mean we can charge without having to move.

Interested in views of others before $ change hands.

Keith

[rangieman]

Hi Adam
An alternative I have been looking - (I have similar problem to you and yet to decide on the solution) - is to use a petrol powered alternator to charge your AGM aux batteries (as these take a fast charge - forget normal deep cycle - also they don't let off hydrogen gas).

There is a company called Christie Engineering - web site http://www.christieengineering.com.au/2.5hp.htm (http://www.christieengineering.com.au/2.5hp.htm) that sells a 55amp Alternator coupled to a 2.5 hp Honda motor. It puts out a DC charge. Basically similar to running your vehicle to charge the batteries.

I am told by the guys at Christie (I have been on the phone and email to them this week - they are in Sydney but have distributors around the country) that 1 hr of their charger should top up a AGM to full each day.

Cost $890 to $990 depending on model.

Advantage over solar is that work when no sun (rain etc). Also not need to do all the storage and transport of delicate panels.

I am considering on of these for use when doing 1-2 week largely stationary camping (ie no regular 5 hr drives to charge the deep cycle battery.

If you want to see some good notes on the technical side there is a great site by Fridge and Solar at http://www.fridge-and-solar.net/info.htm (http://www.fridge-and-solar.net/info.htm)
I have read all this and largely it parallels what Drivesafe has said already.

Anyway will be interested to see what you decide as not 100% sure yet myself.

The only thing I wonder is why can’t I set up the SC80 to charge the trailer mounted battery and leave it for an hour? I assume the answer is that it does not put out 55amps? So can’t one increase the Alternator in the vehicle to ensure this stuff charges faster when vehicle going?

My set up I am looking at one deep cycle in 4x4 and 2x100 amp hr AGMs on trailer. I want to run a couple of fluros, shower pump and a 50L fridge possibly on freeze. We also have a gas fridge for other food/drink. I want to be able to camp for several days (say a week or two camp) – even when cloudy/raining – and not have to worry about the fridge draining the battery.

Initially I thought solar but I am not convinced I can get enough charge for a reasonable price. And I don’t want to be caught out!. Hence my interest in the Christie DC charger as it would mean we can charge without having to move.

Interested in views of others before $ change hands.

Keith


i made one of these years ago cause i could and it was easy as

i just got a old victor mower engine mounted it on a bit of steel then mounted a alternator to the steel and i used a fan belt of a holden had a battery connected to it
it worked a treat i ran head lights on poles for lighting when camping

maybe walker being as handy as he has shown could do the same unless he has too much cash that he needs to get rid of :D

[walker]

Yeah yeah...thanks mate :p

No, I don't have to much cash. I did consider making one...and still might a little down the track, I was going to use the motor from an old whipper Snipper I have. But I can't be stuffed at the moment, the trailer is taking all my time. The other thing is I would rather have a 4 stroke motor so will look into it next year.

[Redback]

Adam, just one more thing, i have around 8 12v outlets in the camper, 4 at the rear for the lights/pump or other devices and 4 in the front inside the tent section for lights and 12v TV/Laptop DVD all connected to 1 battery that we mounted on the front right side in a alloy checker plate box.

The solar panel is a 10 Watt Supercrap one, we got it on special for $69, i think they retail for $110, the battery is an el-cheapo lead acid deepcycle that is now 2 1/2yrs old and our average stays at camps is around 5 days, 2 days here 3 days there 5 days over there and sometimes only travelling 2 to 5 hours to the next camp.

We like to base camp and explore, as i mentioned 10 days is the longest we've stayed in one spot, if we go away for 2 weeks we normally move once, 3 weeks twice spending up to a week in one spot at a time, minimum is 2 days preferably 3 days.

We only do overnighters if going to a spot or going home and maybe a play weekend of 4wheeling close to home, but try to make it a 2 nighter if we can by leaving early friday arvo, it makes it more relaxing having all day saturday to do what you want and pack up sunday arvo after lunch around 2 or 3 o'clock.

I believe in the KISS method;) cause i ain't no electronic expert by a long shot

Oh and make sure you have plenty of pics of the trailer too:thumbsup:

Baz.