Power in my camper trailer ...

[Prime]

hi all ... new to this forum so forgive me if this topic has been thoroughly discussed in the past ...

I'm building my camper trailer and am looking to put multiple batteries (probably 3) in parallel so that I can be confident I'll never be wanting for more Amp Hour's ...

A good friend of mine swears by his CTEK D250S DCDC charger ... does anyone know if this type of charger is compatible (or not) with a multiple battery set-up?

thanks ...

Luke

[tonyrh58]

Hi Luke
Our Aussie Swag runs 3 X 105Ah batteries wired in parallel. The batteries are charged via a factory fitted CTEK D250S and it seems to manage the task well, either via solar or vehicle input.
Regards,
Tony

[Peterr]

Hi Luke
3 X 105Ah batteries wired in series.
Regards,
Tony

I'll bet they are actually wired in parallel !!!

[robcaz]

Hi Luke,

Depending on what size batteries you are going to use in your bank, the rule of thumb is you will need a battery charger around 10% to 15% of the battery capacity. So if you are setting up three 100 amp hour batteries you will need a charger at 30 amp minimum.

The Ctek D250S Dual has a max output of 20 amps while Redarc has the BCDC1225 with an output of 25 amps & the BCDC1240 with an output of 40 amps.

Both the Redarc chargers also come in LV low voltage models for some vehicles alternators that only have a low output ie 13.2 volts.

You will find a wiring diagram in my BCDC1225 install http://www.campertrailers.org/bcdc1225_install.htm

If you have a Google you will find the Redarc chargers at a cheaper price than that recommended.

BCDC1225 feedback http://www.campertrailers.org/bcdc1225_feedback.htm

[robcaz]

For complete charging of all batteries that are in bank it is recommended to wire them in parallel & the chargers positive goes to the positive terminal on the end battery & the chargers negative goes to the negative terminal on the battery at the opposite end http://www.smartgauge.co.uk/batt_con.html

[Prime]

Thanks all ... I was hoping it would work and with actual anecdotal examples ... I feel assured to go ahead.

Cheers

[bottlecreek]

My apologies if I hijack this thread but thought it an appropriate place to enquire on what each of you have found the ideal length of cable from your Solar Panel to your camper/caravan is?

I am in the process of installing a CTEK D250S DC - DC charger on my camper trailer and will be looking at a 160 w solar panel set up in the not too far future, fingers crossed. I already have 3 105 amp hour lead acid deep cycle batteries.

Please don't go focus on cable dimensions as I can look at the charts etc for that when I decide on the length. My concern is not having enough cable or too much.

Any input will be appreciated.

[robcaz]

We have a ten metre 6mm twin core cable lead & have found that length suitable for chasing the sun even around & between trees.

[bottlecreek]

Thank you Rob & Carol

[WomblingFree]

Whilst parallel charging works, there is a potential downside that you need to be aware of.

Just like a car without lockers, the most power will go to the battery with the least resistance.
You need to start out with identical batteries, preferably from the same manufactured batch. Essentially they need to be matched units.
If one battery has different characteristics to the other(s) then the charger may respond to that battery to the detriment of the other(s).
Should one battery go faulty then the charger may up its output trying to charge that battery hence boiling and ruining the other(s).

You can do it but you need to be aware of what can happen and occasionally disconnect all the batteries and measure their state of charge.
Like everything, you need to do the preventative maintenance. One problematic battery can take out the rest.