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Which 12V Charge Controller ?

Submitted: Monday, Sep 04, 2006 at 01:33

_gmd_pps

Does anybody use a charge controller for your aux battery.
I don't mean an AC one .. just a 14-17V in and 12.7 out for better
charge and maintenance of the aux. I was looking at a 200AH aux AGM
battery and the max charge current is 37.5 A meaning that everything higher than that will heat up the battery too much and affect life span .. now with deep cycle the discharge is ok well under 50% meaning that the charge current will be higher than 37.5 from a decent alternator without limitation of charge current. The normal crank battery recharge is usually only short so the effect of higher charge current is usually not an issue unless it's real low ..
Charge controllers are used for solar setups and the same ones can also be used for aux batteries charged from the vehicle alternator or even a 12V output of a generator, but I was wondering if there are any special automotive ones ?
just wondering ?
gmd
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AnswerID: 192588   Submitted: Monday, Sep 04, 2006 at 02:44

Peter McG (Member, Melbourne) replied:

Are you using the battery as a 2nd battery in the car or as a second or third battery in a trailer or caravan?

If in the car - I assume not under the bonnet because that's a big battery - then I'd use something like a piranha battery charge controller.

If in a trailer or caravan then I'd wire it up from the car so it's charged when the car is running and you should get sufficient voltage to keep it charged while running. You could look at the ARRID Twincarge (Derek at ABR has a similar product). These supply 13.8v constant while connected to the car.

Let's see what others think.

Peter
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Reply 1 of 7
FollowupID: 450432   Submitted: Monday, Sep 04, 2006 at 03:10

_gmd_pps posted:

I do not mean isolators ..
Piranha and the Arrid Twincharge are Isolators not Charge "Controllers"
There is a distinct difference .. an Isolator switches a solinoid to link or isolate a second battery depending on voltage sensed but when linked it allows current to flow to the maximum of what the source is capable ... and thats what you want to avoid ... you do not want higher charge current than the battery spec e.g. 35 A or so ...
A charge controller regulates the current in 2 or 3 steps like the 3 step or 4 step AC controllers and avoids overheating when deeply discharged ... this is particularly important when you run a dual alternator or high current alternator and want to charge a wich battery or alike in short periods of time but do not want to exceed the max charge current of the battery ..

Redarc etc and other isolators are just doing a bad job and most people believe that a battery is stuffed after 3-4 years anyway .. this is only true because they are usually not maintained properly and charged wrongly ... the normal car alternator/regulator setup does not limit charge current and when deep discharged a battery is likely to get too much charge current and will suffer .. do it too often and you cut the life of your battery short ... I have run such a system with cheaper batteries up to 100 ah .. now I am in the process to install a bunch of 200ah on a boat, camper and the truck and these batteries deserve a bit more attention (say they are a bit more expensive) so I do not want to risk overcharge, which happens when you do not have an intelligent charge controller ..

regards
gmd
FollowUp 1 of 2
FollowupID: 450593   Submitted: Monday, Sep 04, 2006 at 18:29

Member - Stillthinkinaboutit posted:

Hi gmd,

You are not quite correct, the arrid twin charge will limit the charge current to a max of 20 amps.

Regards,
Mark
FollowUp 2 of 2
AnswerID: 192589   Submitted: Monday, Sep 04, 2006 at 03:15

_gmd_pps replied:

Correction ... the Arrid twin charge controller caps the charge current
I double checked and did not remember correctly .. the problem though
was with that one that the charge current is only 20Amp and also can not
be adjusted ... is there anything else out there with 30-35 Amp ?
thanks
gmd
Reply 2 of 7
FollowupID: 450433   Submitted: Monday, Sep 04, 2006 at 03:29

Peter McG (Member, Melbourne) posted:

I suggest then that you read the publications by Collyn Rivers - do a search.
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FollowupID: 450434   Submitted: Monday, Sep 04, 2006 at 05:00

_gmd_pps posted:

I did before I posted and forgot that I had discarded the 20amp 3 stage
and then I mixed up the other Arrid I was looking at. Collyn mentions all
the right things except a higher current 3 stage charge controller ...
probably there is no such animal, but thats what I try to find out ..
I could not find anything on the web so far (including this site) except charge controllers used in solar applications .. I have 3 banks of batteries and mainly one
is going to be discharged quite often to 30% or even less (Gel batteries are ok with even 20% or so ..) .. to charge mainly this bank (2x200Ah ) will take a while and a difference of some 30 or more % in initial charge current makes a lot of time difference as long as the charge current stays below the recommended limits ..
The other two banks are usually less discharged and will charge in parallel on the same controller, if such exists, or on separate controllers ..
thanks for answering
gmd
FollowUp 2 of 4
FollowupID: 450435   Submitted: Monday, Sep 04, 2006 at 06:41

Kiwi Kia posted:

As heat build up seems to be your major concern could you use a timer circuit to limit chargeing to a specified time with a cooling down period before starting another charge period? I know this is not what you want but would it work?
FollowUp 3 of 4
FollowupID: 450458   Submitted: Monday, Sep 04, 2006 at 09:50

Member - Craig D (SA) posted:

I have a Gen4 Arrid Twin Charge an it spits out 30 Amps - couldn't be happier.
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Craig D
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AnswerID: 192594   Submitted: Monday, Sep 04, 2006 at 07:27

Alloy c/t replied:

Solar regulator perhaps ? Steca specificly state NOT to be used with any other [gen/alt] solar panel/s only.
Reply 3 of 7
AnswerID: 192601   Submitted: Monday, Sep 04, 2006 at 09:02

Wok replied:

gmd,

I am using 3 stager [alternator driven] but only 20A output. The builder is Peter West from NZ. May be worthwhile contacting him if he has a biggy, he has 24-12V units as well.

peter-west[at]xtra[dot]co[dot]nz

The unit I have is utilitarian.........unpainted diecast box which is not waterproof.It is connected to 2X75Ah batteries.

eng
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AnswerID: 192624   Submitted: Monday, Sep 04, 2006 at 11:20

Member - Mike DID replied:

GMD - if you want current limiting to 25% C then an ARRID wil do that. I haven't heard of a 3-stage charger that takes 12 volt in, but the ARRID will come pretty close.

Are you are after 4 Stage charging in case you battery is over-discharged - the open circuit voltage is less than 11 volts, therefore the current should be kept to around 1% C ?? If so, then you might be best off using an Inverter to power a CTEK - they seem to have the most sophisticated charge control. Once the CTEK has brought it up to 13 volts, you connect the ARRID in parallel for faster charging.
Mike R
Reply 5 of 7
AnswerID: 192654   Submitted: Monday, Sep 04, 2006 at 13:11

_gmd_pps replied:

Thanks for all the posts...
the situation is the following: I have a 245Amp Alternator which does around 100Amp in idle ... I use 2x200Ah (could be a bit more depending on battery)
to run a device in the boat which needs 300W (25-28Amp constantly). I have the same 2x200 bank in the camper and another 200Ah in the truck as aux (not under the bonnet)... Depending on which battery I look at they have max charging current of 35 or up to 60 Amp .. the 60 Amp are dearer .. so I was conservative asking here for a 35 Amp .. I might as well go for larger one to speed up charge time .. but I have to limit the initial current down to the specs of the battery otherwise it will be cooked too quickly. Same applies for the boat although the alternator is only 160 Amp and "only" charges the 2x200 .. I am going to buy 5 (6) 200Ah (probably Gel) batteries and really want to make sure they will last a while ..
Most in vehicle charging systems are a compromise over the AC ones and usually don't consider high power Alternators. I had a standard alternator on my motorbike and it was running at full capacity all the time ... It was history after around 18months the I did replace it with a Compufire 1325Watt (60Amp idle) and never had a problem again .. its running 6 years now with the same first AGM battery which gradually reaches its use by date .. so in my current vehicle I have a high power alternator which I do not have to run at 100% load all the time even when charging 3 battery banks ...
So the primary concern is the heat built up through wasted load current when the battery gets more power in the beginning (after a deep cycle), because the chemical process can only absorb a certain amount of energy .. too much will cook it ..

thanks again for the answers .. I will follow the leads and see where I get to ..
tomorrow I will go and see a few 12V specialists and see what I get out of it ..
regards
gmd

Reply 6 of 7
AnswerID: 192756   Submitted: Monday, Sep 04, 2006 at 18:53

LastAussieWorker replied:

got tired of battery problems in the work trucks. previously tried Arrid twin charger and all other devices could find. ended up with sine wave inverter driving 3 stage 25a battery charger. never changed another battery. found we did not end up with flat battery at lunchtime. going to use the same system in my caravan.
Reply 7 of 7
FollowupID: 450688   Submitted: Tuesday, Sep 05, 2006 at 02:08

_gmd_pps posted:

Interesting comment ... I will give it some thought ...
thanks
gmd
FollowUp 1 of 1