ARB Smart Solenoid Dual Battereis?

Submitted: Friday, May 16, 2003 at 04:15
ThreadID: 4937 Views:1739 Replies:6 FollowUps:3
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Hi all,
Does anyone know how many amps this solenoid charges the second battery at?
I have heard that it is only trickle charged?
Just wondering as I have a third battery in my trailer connected to my auxillary battery and Im not sure of the charge rate produced.
When driving I usualy have my Chescold 3 way fridge connected which _Affordable_Storage_Drawers.aspx approx 10 amps.
I just wonder if this leaves any amps to charge my aux batteries?
P.S my alternator is rated at at 70 ams.

Thanks
Chris.
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Reply By: Peter - Friday, May 16, 2003 at 07:40

Friday, May 16, 2003 at 07:40
According to the web http://www.surepower.com/pdf/ebr_sep.pdf

100 ah continious and 400 ah peak.
AnswerID: 20180

Reply By: Solar King - Friday, May 16, 2003 at 10:23

Friday, May 16, 2003 at 10:23
You cannot effectively connect two auxillary batteries together and get them to charge. You need a battery isolator like a Redarc about $115 and then a manual or 70 amp Bosch type relay to switch between the two auxillary batteries. You will need to connect the auxillary batteries with a minimum of 10mm2 wire or 2 x 6mm2 TWIN sheathed wire to give you a 12mm2 cable.
To go from the vehicle to the trailer will need a 50 amp Anderson plug. You cannot use the spare pins in your trailer plug.
It is essential to use twin core cable and connect it to the negative and positive terminals on your battery.

Your battery in the trailer will still charge properly and run your fridge if you have the system wired as per the above. You can have up to 50 amps going to the second battery if the second battery is flat. As the auxillary battery starts to get up to full charge the current does significantly reduce, but still more than sufficient to fully charge the battery. There is no other cost effective alternative solution to the above. Any other solution will cost substantially more, and only achieve a marginally better system.
AnswerID: 20189

Reply By: Peter - Friday, May 16, 2003 at 13:14

Friday, May 16, 2003 at 13:14
Sorry my mistake not reading again.

The consus for output of charge lead on alt is about 8ah. So using one of the smarter Solenoids ie arb or Redarc etc (depends on how much you wish to spend) the current draw will not burnout one of these items.

I concur withe the above setup as a good cheaper way than a full independant charging system.

May be a Volt meter on second batt side with a switch batt A batt b to see what the Voltage is.

The larger issue is that in parallel modes such as this each batt when flat takes about 4-5 hrs to charge.
AnswerID: 20204

Reply By: Member - Rohan K - Friday, May 16, 2003 at 16:53

Friday, May 16, 2003 at 16:53
Cobes, they have been several threads about similar issues, over the past few days. A Forum search on "batteries", "solenoid", etc will provide a raft of information.Be good, or be quick.
Rohan (Sydney)
AnswerID: 20227

Reply By: brett - Friday, May 16, 2003 at 16:59

Friday, May 16, 2003 at 16:59
So why is it not possible to put 3 batteries in parallel and charge, how is this different to 2 in parallel or 4. Assuming the alternator has enough capacity, 70A may be a bit low, 120A would be good, with the main charged and 2 flat aux batteries, there would be 40A at least available to each aux (assuming 120A alternator), the flat batteries will bring the terminal voltage of the main down and hence the alternator will provide the current. This may not be a perfect charging situation but it works and I can't see how 3 in parallel is different to 2, you still have batteries in parallel of a different type and charge state.I'd like to a hear a good technical response as to why this won't work. The only problem I can see is alternator capacity and most modern 4wd are up around 120A now.
AnswerID: 20229

Follow Up By: Autolec - Friday, May 16, 2003 at 21:09

Friday, May 16, 2003 at 21:09
Brett anything is possible and you can, but do not expect it to perform to anywhere near expectations.
1) these batteries are not of identical type (and/or should not be)
2) these batteries are at distance from each other
3) the auxiliary batteries are to be used independently
4) having two auxiliary batteries connected in parallel when one could be flat and the other fully charged and you only drive a short distance then you will end up with two half charged batteries with little capacity. Remembering here there is a large distance by 12 volt standards between the two of the three batteries.
5) loss of charging voltage arises because of the different temperature of batteries and alternator. Consider the difference of the battery in the engine compartment to the one down the back of his vehicle and the one in the camper trailer.
6) the main battery should ideally be a maintenance free and the auxiliary batteries should preferably be standard wet cell type deep cycle. That would allow the regulator to be set at 14.6 for the maintenance free and would be better for the cable loss to the auxiliary batteries only requiring 14.2 thus bringing the auxiliary batteries up to full capacity.
7) never seen the setup of a main battery and two auxiliary batteries at a distance to each other charge to full capacity. At best you would expect to get 75% battery capacity. Work out the resistance between the batteries assuming the correct size cable and you will see my approximation of 75% is on or close to the mark.
8) to get a main and two auxiliary batteries to charge fully you would need to have the auxiliary batteries of both the same type and size next to each other and would need to discharge them together.

Capacity of the alternator is not relevant except to speed of charging.
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FollowupID: 12968

Reply By: Member -BJ (Sydney) - Friday, May 16, 2003 at 20:01

Friday, May 16, 2003 at 20:01
We just brought a camper it's wired main batt to circuit breaker, anderson plug, charger in trailer, asked my auto elec if alternator in 3.0ltd gu would be enough to charge 3 batteries, he said 90 amp ok as i can't get a bigger one anyway .Regards Bob
Wish i was still here / Gulf in July
AnswerID: 20248

Follow Up By: Autolec - Friday, May 16, 2003 at 21:22

Friday, May 16, 2003 at 21:22
Size of the alternator is irrelevent other than to speed of charging batteries. If you have all three batteries connected as pointed out well by Solar King do not expect them to charge properly and get to full capacity.
What is the "charger in trailer"?

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FollowupID: 12969

Follow Up By: Member -BJ (Sydney) - Saturday, May 17, 2003 at 11:10

Saturday, May 17, 2003 at 11:10
not sure of brand but it changes on 240 or 12 volts , as it's a Kimberly Kamper i suppose it's a good one. Regards Bob
Wish i was still here / Gulf in July
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FollowupID: 12999

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