dual battery system, charging, help needed

possumyvonne · Senior Member

dual battery system, charging, help needed

jimricho · Guru

It appears from your post that the aux (or "house") battery is located in the rear of the car. Make sure that the wiring from the main battery (via the Redarc) is heavy gauge, I would recommend at least 8 square mm or 8 gauge, both +ve and -ve. This is necessary to ensure the aux battery gets sufficient charge when the on the move. I would also recommend you "top up" the battery with a multi-stage charger when mains power is available, also if you go with the generator option referred to below.

That said, you will still need to supplement your charging with either solar and/or generator. I'll leave it to the solar experts to suggest the appropriate size panels. In the case of the generator you'll need to consider any restrictions on the use of generators in National Parks, also any noise impact on your fellow campers.

possumyvonne · Senior Member

hi jim, i was thinking of using the cteck 2500 which puts in 25 anps which is 12v +12v
because we will be looking at staying at national parks i cant really use generator in there
would like to here from any one that may have a set up smilar to what i am trying to use
when the auto sparky put the redark 112 in he ran 6mm, i really dont no ,but i hope it is, i gather he did it right as it was to go to the caravan but now the battery in in the back of the pajero
any thoughts and sugg would be great
possum, yvonne

jimricho · Guru

I wouldn't go the expense of upgrading the wiring or installing the Ctek unless you know for sure that there's a problem such as taking too long to recharge the battery.

Regardless of any recharging issue you still don't have sufficient battery capacity to run the fridges for the length of time you desire so solar may be the only solution. I could do some theoretical calculations to estimate the size of the panels you would require but as I don't have hands-on experience with solar, and there are other members of this forum who do, it would be better for them to advise you based on their experience.

Without going into all the pros and cons of 3way versus compressor fridges, maybe purchasing a portable 3-way fridge such as a Dometic/Waeco or similar would be a (part) solution as you can run it on gas and may be a cheaper option to setting up solar.

Jim

JRH · Guru

I have one 80 watt solar panel on the roof of our poptop and I also carry one 80 watt portable solar panel, you can purchase the portable panel from Jacar for a little over $600.

To date I have not run short of battery charge, I use one x 100ah deep cycle in the caravan and I run a 33 ah deep cycle x 1500 amps jump/starter pack in the car to run my Bushman 52 litre compressor fridge.

Hope this is of some use to you.

possumyvonne · Senior Member

thanks guys for all your advise and i will take note of what you have said
if i am drawing 7amps would an eighty watt panel do the trick
any more advise would be app
regards possum,yvonne

Cruising Granny · Guru

I can't help with the technical jargon, but I use my Waeco as a deep freeze, and it can be shut down for about 6 hrs before anything even begins to thaw.
Of course the unit must stay closed all that time.

lilly · Senior Member

Try to start new topic but for some reason my lap top wont let me ....so i will asked in this topic ..i wanting to get T.V that runs on 240 /and 12 volt any suggestions to what brand
thanks

Mick17 · Veteran Member

Hi,
I've have a 3 way dual battery system in the cruiser (one mains plus 2x100amp. Also in the caravan 2x120amp plus 80amp battery (Sleep Machine). Now all systems are charged by 2x85watts solar planes.

When free camping for a week or two, these are the items which are running off the solar system:
1. 12v lighting
2. radio
3. water pump (3 x tanks)
4. Sleep machine 12v system
5. Satellite which is attached the roof
6. Austar box plus my 1TB hard drive x a media player
7. Winegard TV system plus 12v set top box (diagonal box)
8. Engels fridge and freezer 60lts 12v and 240v
9. Laptop runs off 1000watts inverter
10. Satellite runs off 12v through the inverter when free camping

When on 240v I've a 30A Smart charger in the caravan also a 15A smart charger in the cruiser which chargers the 3 dual batteries.

I've, also very soldam use my 2KVA Honda "But" having good back up system is required. As this Generator come in handy when the weather is poor

Hope this helps
cheers
Mick

-- Edited by Mick17 on Friday 19th of November 2010 08:13:07 AM

Mick17 · Veteran Member

Hi guys,
Arrive at Eumundi (Sunshine Coast Qld) last Tuesday16th and only one day of sunshine,So you can have all the solar you like,"But when it rains" out comes the Generator and that's what happens you charge up your batteries and you go again on Battery power for 3 days if there's no Sun out.
cheers
Mick

possumyvonne · Senior Member

hi mick 17, i was looking at gettig on of those smate chargers, can you tell me how much they are and can i fit it myself, the 30amp would be good i think
i have the redark battery isolator s112 and an 90amp alternator so how many amps would the alternator put into my batt for my fridge and freezer
regards posum,yvonne

jimricho · Guru

Some links that may be helpful....

http://www.bainbridgetechnologies.com/chargers

http://www.batteryfaq.org/

http://www.batteriesdirect.com.au/shop/search/499/ctek-%28please-click-on-required-item%29.html

http://www.batteriesdirect.com.au/shop/search/504/sinergex.html

http://www.batteriesdirect.com.au/shop/search/622/smart-battery-charger.html

I have used Ctek products for several years without any problems. I have not dealt with Batteries Direct or had any experience with any of the other brands so I'm not in a position to recommend them or otherwise.

Suggest you enquire at the first instance at any major battery supplier, such as Battery World, in your area.

A "smart" charger is a multi stage charger that can be left connected to the battery indefinitely without causing any damage or reduction in battery life (can extend battery life in some cases) although in the case of "wet" (unsealed) batteries you still need to occasionally check the liquid (elecrolyte) level.

possumyvonne · Senior Member

thanks jim for the links and the advise, it is very helpful
i will check it out, looks good
regards possum,yvonne

GrumpyOne · Senior Member

Hey Guys n Gals,

Just a example of what I am running in my Ssangyong Actyon Sports dual cab....

Standard alternator powering the standard battery and through a solenoid relay to the house battery which is a 150mah/1000cca running an 40 litre engel as a freezer running at -10 and a 60 litre evakool as the fridge at +1 degree.

It has been suggested i can get upto 7 days run out of the battery running both units without interim charge, I have an 80 watt solar panel and a 90 watt gen set that will be used to suplement the charge as required.

Hoo Roo Happy Days
Grumps

Ron and Shirley · Senior Member

We run a 14-year-old 36L Engel, enclosed in a transit bag, permanently mounted in the vehicle at around 2C. It is the beer and cryovac meat fridge so does not get opened that much. We have the vehicles back doors open whilst in camp plus a couple of windows partially open so the vehicle is not too much of an oven.

The Engel is powered by our second 115 AH wet cell Deep cycle battery in the vehicle and will in around 20-30C temps last about 3 days before the battery gets to about 50% state of charge (around 12.2v). Higher temps the fridge cycles more hence maybe 2 days before the 50% limit is reached.

We can get an extra day if we disconnect the Engel overnight to stop it cycling during the cool of the night and gain a further day by connecting our old 32W solar panel to the battery as soon as we set up camp.

However it is rare for us not to use the vehicle for more than three days, though on occasions we have propped for a week where, after a couple of days, we run the Engel off the vans 12v/solar system which usually has ample power.

If after some time in the bush we pull into a Caravan Park on 240v we also run the Engel via the vans 12v system whilst the van is operating/charging through a Ctek 2500, plus we connect a Ctek 1500 charger to the vehicles second battery overnight to bring it up to full charge before we head off again.

We also carry a Honda 20i generator but as yet we have not had to use it.

-- Edited by Ron and Shirley on Saturday 20th of November 2010 10:53:47 PM

jimricho · Guru

Hi Ron and Shirley,

I assume from what you're saying that the 32 watt panel is adequate for your needs. As I implied earlier in the thread I don't have solar but I'm considering it for when I may do a bit more "off mains power" camping, so I'm using the forum to gain any info.

Re the Ctek charger, I have a 7 amp Ctek permanently installed in the car wired in parallel with the aux battery. This serves to both charge the battery and as power supply for my "Bushman" fridge when mains power is available. (The Bushman runs on DC only and requires an external power supply to run on 240v AC mains, the Ctek serves this purpose)

cheers,

Jim

Ron and Shirley · Senior Member

jimricho wrote:

Hi Ron and Shirley,

I assume from what you're saying that the 32 watt panel is adequate for your needs.
<snip>

Yes Jim we work within the limits of what we have plus are very wary of letting the second battery in the vehicle getting below 12v. Our last secondary battery, also wet cell DC 115AH, lasted 9 years so was relatively happy with that.

The 32W Unisolar flexible panel was given to us about 12 years ago and lived under the mattress of the bed in the Campertrailer when not in use. With the Campertrailer we camp when in the bush so our electrical requirements were minimal except for the vehicles Engel fridge and this panel provides enough top up power to extend our stationary stay by a day, or maybe two at best, weather depending.

If I was to purchase a portable panel now I certainly would be looking at the 80-100W suitcase type but then they are not as easy to transport and store as this old flexible panel.

Our vans electrical requirements, fridge and lights in the main, are again minimal due to "camping" and to date are adequately covered by the vans solar system such that we can also power the vehicle Engel if required on occasions.

jimricho · Guru

Thanks for that info R & S...

It certainly pays to look after a battery in respect of avoiding excessive discharge. I have a Baintech low voltage cut-out fitted but like you I like to recharge the battery before it gets down to the trip voltage of the LVC.

I have a mate whose "house" batteries in his van are over 10 years old and still going strong. He mostly just charges off his solar panel including when in storage and only occasionally tops up using an "el-cheapo" charger. The batteries (wet, not sealed) are two 6v 200 ah connected in series to give him a total 200 ah capacity. At the risk of starting an argument I have always believed that series connecting 6v batteries is a better way than parallel connecting 12 v batteries.

Jim

PS: like that picture of the campsite, looks like a really nice spot.

-- Edited by jimricho on Sunday 21st of November 2010 06:58:03 PM

Mick17 · Veteran Member

Hi Peter,
Jim has supply some good info that will get you started as I"m not to sure what amp's you would be supplying to your batteries. But you can invest in a multi meter as I'm sure this will show you what amps of your battery is and then there is a Plasmatronics (PL20) that I have in the RV which tell me what amp's I"m inputing and what load is on the batteries.
Hope this helps
cheers
Mick

Jacko · Veteran Member

hubby fitted ctek D250s dual $340 and solar panels $1460 150a battery $400
$2200
had new system 9 weeks.
wished fitted before

mighty happy Jacko with smarty pants hubby here smiling over his handy work

-- Edited by Jacko on Sunday 21st of November 2010 10:08:42 PM

possumyvonne · Senior Member

hi all, back again with another question, hope yous arn't sick of them already
here goes
we have the pajero and our van,fridges x2 ,one batt 103amp in the rear and a small gen
question is if we want to set it all up so that we are self sufficient and can camp where we like, so to speak, how would you all suggest that i do it
ive read alot of what you guys and girls have said and if any one would mind on what advise on doing this would be great
do i need any thing else with solar as well as panel
regards possum,yvonne

DeBe · Guru

Hi Possum, This is my setup 100W of solar on back of van plus i do have 80W portable folding panell as well. You do need a suitably rated regulator aswell to stop batterys from being over charged. My regulator i built as a kit from Oatly electronics as were the panells. cost of panells & reg $1100 about 2 yrs ago, My battery is just an ordinary N70ZZ on the A frame of van 100W Solar Panels.JPG

bill12 · Guru

I don,t think you can have too much battery or solar power, and my vehicle has a 75 amp alternater, too.The old "kiss" principle works with this sort of system, also.(keep it simple, stupid).

Rolly · Guru

Just to stick my bib in here; remember that the vehicle alternator will not produce more than 13.8 Volts which is not sufficient to fully charge a battery during the course of a day's travel.
Having reached about 80% charge, the current is low enough to be effectively zero.
If, for the sake of longevity, you do not discharge the batteries below 50% depth of charge, that means that you will only be getting a usable 30Ah out of a 100Ah battery.
If you put a DC to DC smart charger into the line you may get close to 100% DoCh.
This means another 20Ah usable reserve.
12volt solar regulators will charge the battery/ies to 100% given a sufficient period of sunshine as the panels produce at more than 17volts (check the info on your particular kit) which is reduced by the regulator to the appropriate voltage required by the battery.

possumyvonne · Senior Member

hi all, was looking at solar panels today. it was an 80w panel and just wondering if some one could clarify something for me
i understand the 80 watts part but while looking at differant 80 watt panels i noticed they have differant volts out put, could some one explain why some are differant to others and does it make a differance to which one i buy.
regards possum,yvonne

jimricho · Guru

As I've said before I'm no expert on solar but it maybe just the different ways they measure the voltage, eg different load curents, temperatures etc. When matched with the appropriate regulator, the voltage should then be correct for the battery. It may also be that some units have the regulator built in and the voltage quoted is at the output of the regulator, eg the folding one from Jaycar I think comes complete with the regulator.

re Rolly's comment on the alternator voltage output, some, possibly many, alternators ouput as much as 14.4 volts, my Pajero is one such example. You'd need to check this with a digital voltmeter. However, regardless of this, Rolly's suggestion about using a DC to DC smart charger is still valid, especially if the aux battery is located in the rear of the vehicle. Both Ctek and Projecta (and possibly others as well) make such a unit.

-- Edited by jimricho on Wednesday 24th of November 2010 07:53:38 AM

DeBe · Guru

An 80 watt panell can be advertised in 2 dif ways. One is no load voltage & no regulator, Eg Jaycar ZM9097 80W voltage open circuit 21.8V. This panel will need a Regulator betwean it & the Battery. Other panells may be advertised as Built in Regulator which will be stuck on the back of the panel, 80W folding panel ZM9130. DeBe

DeBe · Guru

Heres a pic of the Jaycar ZM9130 80W folding solar panel showing the regulator stuck on the back of the panel. i thaught that the price was reasonable considering if something goes wrong you are dealing with an aust company. Idealy the regulator is beter at the battery & not on the panel. But for practicality this set up is reasonable. Daryl

PeterD · Guru

possumyvonne wrote:
I understand the 80 watts part but while looking at differant 80 watt panels I noticed they have differant volts out put, could some one explain why some are differant to others and does it make a differance to which one i buy.

There are panels with varying peak power point outputs. There are the usual 17 & 35 V panels for charging 12 & 24 V batteries with simple regulators. These will have 36 or 72 cells in them.

There are smaller panels with 32 cells in them. These are sold to trickle charge batteries without also having to purchase a regulator. Typical use for these is on starting batteries on motors that are not used very often. I have a 5 W one of these, it is connected to the spare vehicle that is left behind when we are touring.

The other main class of panels are those used with large systems like you see on housed feeding the power grid. There PPPs are anything apart from 17 or 25 V. A few years ago there were a batch of those foisted onto caravanners that had a PPP of around 14 V or a little more. These are fine if you are going to use an MPPT regulator but their output voltage is too low to charge a 12 V battery. Be careful you don't get caught with one of those if you have a simple regulator. However they are fine if you have an MPPT regulstor.