Dc to dc

Submitted: Tuesday, May 27, 2014 at 21:33

ThreadID: 107979 Views:2191 Replies:2 FollowUps:4

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Nutta

Hi, wondering if anyone can help.

I have a 38 litre engel in my ute with a 100amp agm battery which just charges off the alternater via an isolator.

I'm worried the battery isnt getting charged high enough so was thinking of fitting a dc to dc charger, this same cable also runs to the van via anderson plug, the van has 2 x agm batteries also, all very heavy cabling installed by a qualified sparky.

What size dc charger would I need? If I bought this would it suffice,

http://www.ebay.com.au/itm/CTEK-SMARTPASS-DC-to-DC-Dual-Battery-Charger-Power-Management-System-Cycle-12v-/161251687589?pt=AU_Car_Parts_Accessories&hash=item258b597ca5&_uhb=1 .

The add states "Used together with a D250S, SmartPass provides optimal charging via CTEK's unique staged charging cycle, which also protects your batteries."

Do i need one of these as well? Is there something more suitable?

Thanks in advance, Wayne

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Reply By: HKB Electronics - Tuesday, May 27, 2014 at 21:52

Tuesday, May 27, 2014 at 21:52

Hi,

Nutta, why do you think your batteries aren't being fully charged, are you having real world issues, have you done any actual done measurements to confirm you have a issue or are you just reading the DCDC charger manufacturers glossies?

Without proving you actually have an issue your probably just going to waste your hard earned cash.

You need to take some voltage measurements, see what sort of charge voltage your getting at the cranking battery and at the van with the batteries fully charged.

Cheers
Leigh

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AnswerID: 533278

Follow Up By: Nutta - Wednesday, May 28, 2014 at 06:43

Wednesday, May 28, 2014 at 06:43

Thanks HKB, I'll check today after a good run and see what its reading, cheers.

FollowupID: 816617

Reply By: Honky - Wednesday, May 28, 2014 at 10:53

Wednesday, May 28, 2014 at 10:53

This is my opinion from experience and I am no expert.
A DC DC charge will put in less charge than straight from the alternator.
it limits the charge to say 20 amps but will top up to 100% ( and slowly). The alternator direct will put in about 50 amps and this is what I need as I was only driving 1 to 2 hours a day.
if you drive a lot and do not have a solar panel I would stick to the alternator/isolator.

Honky

AnswerID: 533306

Follow Up By: Nutta - Wednesday, May 28, 2014 at 23:36

Wednesday, May 28, 2014 at 23:36

Appreciate that, just not sure if the alternator puts out enough volts for an agm?

FollowupID: 816692

Follow Up By: HKB Electronics - Thursday, May 29, 2014 at 00:00

Thursday, May 29, 2014 at 00:00

Measure the charge voltage, if you have a low voltage type alternator you may be able to fit one of my booster diodes to raise its output if required.

Cheers
Leigh

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FollowupID: 816693