Smart Battery charging
Submitted: Wednesday, Sep 06, 2006 at 10:54
ThreadID:
37475
Views:
3203
Replies:
3
FollowUps:
5
This Thread has been Archived
Member - Kelvin Y (NSW)
Hi all,
I have a Durst 25A smart charger, which is fixed permanently in my camper trailer. When at a powered site or using my Generator, I just plug in the smart charger an off it goes charging my 105Amp/hr deep cycle trailer battery. Leave and forget.
My question is, to those of you electrically minded. Can I hook my charger up to my vehicle Aux battery, at the same time as the trailer battery and charge both?
I realise it will take longer to charge both, but will it damage one battery if it is fully charged and then I connect the charger to the other battery, which is around 30%?
Regards
Kelvin
Reply By: Member - Beatit (QLD) - Wednesday, Sep 06, 2006 at 11:12
Wednesday, Sep 06, 2006 at 11:12
G'day Kelvin,
I had a simmilar question for a similar setup (I have a Durst 15A). Rang Durst and they advised for me to do them individually but I believe that some of their 25A models are capable (set up) to do two. Decided to set
mine up with another isolator in between - so making the trailer the primary and the 2nd car battery also the second battery for the trailer. This works OK because when the car is turned off the 2nd car batt is isolated by the car isolator. I have heard of better systems but this works for me.
Kind regards
AnswerID:
193113
Follow Up By: Member - Roachie (SA) - Wednesday, Sep 06, 2006 at 11:52
Wednesday, Sep 06, 2006 at 11:52
I've got 2 of these charges. One permanently mounted in my camper trailer, the other permanently mounted in the Patrol. The camper trailer has 2 x 105a/h batteries connected in parralel with the charger hooked up all the time and left on when the trailer is at home in the garage.
The Patrol's is connected to the 120a/h Fullriver in the cargo bay and is also left on most of the time. I have a manually operated solenoid linking the Fullriver to the starter battery. If the Patrol is going to sit idle for a week or so, I switch the solenoid on and the charger does both batteries.
If I wasn't so lazy, could wire up the starter battery so it has it's own circuit off the charger.......you will note that the back of the charger has 3 screw terminals. One is negative and the others are 2 separate positive terminals so you hook 2 batteries up to the one charger with a common ground/negative (exactly what most 4by's have.
FollowupID:
450936
Reply By: Member - Mike DID - Wednesday, Sep 06, 2006 at 12:04
Wednesday, Sep 06, 2006 at 12:04
Every 4WD that has dual batteries with an Isolator charges batteries in parallel without a problem - your 3 Stage Charger situation is no different.
Manuafacturers will always give you the no-liability answer.
If you apply 14.4 volts (that's what 3-stage chargers do) to a fully charged battery it will draw a fraction of an amp.
If you apply 14.4 volt to a discharged battery to discharged battery it will draw lots of current.
If you have a 25 amp charger it can never supply an unhealthy amount of current to a battery of around 100 amp-hour.
If you connect a fully charged battery to a discharged battery there will be some transfer of charge - maybe 20% of you leave it on for 8 hours.
AnswerID:
193129
Reply By: Derek from Affordable Batteries & Radiators - Wednesday, Sep 06, 2006 at 15:51
Wednesday, Sep 06, 2006 at 15:51
Hi Kelvin
Yes you can charge 2 at the same time. The Durst - ABR 25 amp Smart Charger will do up to 500 amp hours.
You will also have noticed that the charger has twin outputs so you could set it up so it monitors the 2 batteries independently but that is too much work and extra wiring.
Regards Derek.
AnswerID:
193162
Follow Up By: Member - Kelvin Y (NSW) - Wednesday, Sep 06, 2006 at 17:50
Wednesday, Sep 06, 2006 at 17:50
Thanks Derek,
Strange to see you on here.
My Durst charger is about 2 years old and does not have the 2 out puts. It only has one red and one black.
http://www.durst.com.au/pdf/BCS1225.pdf
This is the link for the model I have.
I phoned Durst and they said that if the one battery was fully charged and the other slightly discharged, it could damage the charged battery as it would detect a low charge and pump in charge at 14.4V.
What do you think about that?
Regards
Kelvin
FollowupID:
451014
Follow Up By: Derek from Affordable Batteries & Radiators - Wednesday, Sep 06, 2006 at 18:03
Wednesday, Sep 06, 2006 at 18:03
Yes yours is a 2 stage switch mode unit. You can still charge 2 batteries at the same time. If the 2 are linked for a few hours before you charge they will equalize and the 2 stage charger will work better.
This is the Durst - ABR unit with 2 outputs and is a 3 stage Smart Charger.
FollowupID:
451019
Follow Up By: Member - Roachie (SA) - Wednesday, Sep 06, 2006 at 19:28
Wednesday, Sep 06, 2006 at 19:28
The 2 that I've got "look" exactly like this, but are only 15amp version.
They are great.
FollowupID:
451032
Follow Up By: Derek from Affordable Batteries & Radiators - Wednesday, Sep 06, 2006 at 19:33
Wednesday, Sep 06, 2006 at 19:33
I agree. I have had them in 2 of my vans and they can take a hammering.
The Honda on eco throttle does not even feel them.
When at home I leave my fridge on in the 4wd and back up to the van at night to keep the battery charged.
Yes, Great !
FollowupID:
451034