Battery Charging and VSR's

Submitted: Friday, Jul 25, 2014 at 09:47
ThreadID: 108875 Views:4092 Replies:7 FollowUps:12
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I currently have a late model Isuzu Dmax which is about 2 years old. Whilst driving from Darwin to Brisbane I noticed the battery was struggling some mornings. I decided to replace at Battery World (fantastic service at Indooroopilly btw).
I was a bit surprised that the original battery didn't last too long. Essentially, the tug gets driven about 5-10 km a day during the week, with a few camping trips and one long road trip a year. Hence, it's never really getting charged.

A mate suggested a battery charger and hook it up once in a while, which I will get.
I have a Century Ultra high Performance NS70LX under the bonnet for starting, and a Century Marine Pro 730 in the tray. Both connected by a Redarc Voltage Sensitive relay (VSR).

Two questions - Is it ok to hook the battery charger up to either battery as I am not sure that the VSR will interfere (for want of a better word) with the charging, or do I need to disconnect a battery before charging it?

Second - I am thinking along the lines of a Ctek MXS 15 or a Projecta 12v 15amp job. I am happy to leave it on charge over night, so it doesn't need to be recharging at a fast rate. Whilst at it, I may also use it to charge my Century Battery in the Toyota Aurion.
With batteries expensive I'm not in a hurry to replace another one any time soon.

All responses appreciated in advance. I'm not too much of a tech head so all advice welcome.
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Reply By: Member - bbuzz (NSW) - Friday, Jul 25, 2014 at 10:13

Friday, Jul 25, 2014 at 10:13
Hi Top End,

Look at the HKB Electronics thread or their website for the small chip that boosts the alternator voltage.

Cheap solution that may do what you want too.

Bill B

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AnswerID: 536560

Follow Up By: Top End Az - Friday, Jul 25, 2014 at 10:21

Friday, Jul 25, 2014 at 10:21
Thanks bbuzz - I was preferring the battery charger as I would like to use on my other vehicle as well. Thanks again, will have a look.
FollowupID: 820709

Reply By: Green Rv - Friday, Jul 25, 2014 at 10:23

Friday, Jul 25, 2014 at 10:23
Hi Top end
if the car is parked outside why not look at a small solar charger
you can get one that sits on the dash and plugs into cigarette lighter or you could look into something a little bigger this will help maintain the battery for a longer life
i would think the vsr would not let power go to the 2nd battery unless the main battery was over a certain voltage and for a set amount of time so you might have to put solar on both batteries
hope this helps
AnswerID: 536564

Follow Up By: Top End Az - Friday, Jul 25, 2014 at 10:39

Friday, Jul 25, 2014 at 10:39
Thanks Green Rv
Yes, considered solar, but it is parked undercover at work all day and again in the evening at home.
I'm not too worried about spending a bit of money to get the charger. Thanks for your suggestion
FollowupID: 820710

Follow Up By: fisho64 - Saturday, Jul 26, 2014 at 01:07

Saturday, Jul 26, 2014 at 01:07
wouldn't you have to leave it on acc to charge via the cig lighter?
FollowupID: 820777

Reply By: olcoolone - Friday, Jul 25, 2014 at 10:29

Friday, Jul 25, 2014 at 10:29
If you charge the starter battery with an external source it will also charge the auxiliary battery as well, it's no different to how it would work if charging of the alternator whilst driving.

There is no problems with this as long as you keep an eye on battery fluid levels.

Charging battery's of a 240v quality charger is a good idea and can increase the reliability and longevity of the battery's.
AnswerID: 536565

Follow Up By: Top End Az - Friday, Jul 25, 2014 at 10:56

Friday, Jul 25, 2014 at 10:56
Hi olcoolone

This is what I thought, as both batteries get charged off the alternator under normal driving; its just that the VSR obviously works to prevent the starter battery from going flat but just trying to cover off on anything I haven't thought of before I go ahead and buy it
FollowupID: 820711

Reply By: AlbyNSW - Friday, Jul 25, 2014 at 10:31

Friday, Jul 25, 2014 at 10:31
I am only summizing but I would suspect that if your cranking battery is a bit low the VSR would have isolated the second battery alrady so any charge you put into the second battery would not get to your cranker.
With battery chargers I went with the larger Projector 25 amp version, with this one you can manually select a charge rate as low as 2 amps up to 25 amps plus you can select the battery type to get the correct charge rate voltage etc.
I bought that one on recommendation as it has a lot more usable options for different situations.
AnswerID: 536566

Reply By: ABR - SIDEWINDER - Friday, Jul 25, 2014 at 10:32

Friday, Jul 25, 2014 at 10:32

Yes no problem to charge both at same time via the VSR, I run a fridge 24/7 in my Prado and hook it up to our ABC1220 charger every night via an Anderson plug at the front.

Have a look at our ABC1220 it is a great charger.

PS: We also sell a mini diode booster that will fit the D-max but that is not your problem, I would get the alternator checked if the start battery is not charging.


Derek from ABR
AnswerID: 536567

Follow Up By: Top End Az - Friday, Jul 25, 2014 at 11:01

Friday, Jul 25, 2014 at 11:01
Thanks for that. I'll check our your charger. The alternator is fine. It's just that the missus drives it 3 km to work, and 3km home again, so it's not really getting the chance to properly charge ,which was confirmed from the tech staff at Battery World.
the staff said putting it on charge once in a while will help maintain the capacity of the battery, as the original battery was fully charged when I went in, but it was only 55% of original capacity according to their equipment. All the short trips being the cause. and yes, the original battery in modern cars aren't always the best available.
FollowupID: 820713

Follow Up By: ABR - SIDEWINDER - Friday, Jul 25, 2014 at 11:07

Friday, Jul 25, 2014 at 11:07
If you email me when you order I can make up an Anderson charge lead for you. Just let me know the length of the cable from the main battery to the place you want the plug to hang out.

FollowupID: 820715

Reply By: Ross M - Friday, Jul 25, 2014 at 10:40

Friday, Jul 25, 2014 at 10:40
One thing you can do, is buy from Jaycar, a small digital meter around $12.
That will tell you all the time what voltage the system is running at.

All DMax I know of run at around 14.3 or .4 v while charging. My 2011 Dmax 14.4v
That should keep any battery correctly charged.
I agree the OE battery isn't as good as it could be and does seem to be lower/hold voltage than expected while not being charged.

It is good to have a battery charger to charge either battery IF required, but periodically/spasmodically charging the battery isn't really going to achieve any noticeable benefit.

Maybe when connecting the charger to the main battery, above a certain voltage as it achieves VSR voltage the two batteries may become connected by the VSR and then both will be charged at the same time. It might cycle the VSR on and off a few times as the voltage rises.

Only if the Aurion battery is flat for some reason would you have to use the charger on it's battery, same as the Dmax. Their charging systems are designed to charge the battery. Our 7 year old Corolla has original battery and never had a charger on it.

A forum reply, recently mentioned their Ctek MXS15 had twice failed and the other brand was then used with continued success.
AnswerID: 536568

Follow Up By: Top End Az - Friday, Jul 25, 2014 at 11:10

Friday, Jul 25, 2014 at 11:10
Thanks Ross M
In Darwin, everything is only 5 min away in the car so they never really get a good run. I used to live in WA and commute 60km a day and my battery in my Mazda lasted over 7 years as well.

I also read the same forum reply as you about the Ctek, and I am more leaning towards the Projecta anyway as it seems to suit better for what I want.
FollowupID: 820716

Follow Up By: Thinkin - Friday, Jul 25, 2014 at 11:32

Friday, Jul 25, 2014 at 11:32
In defence of my Ctek MXS15 I have used and lent it to selected friends for some six years. I have no complaints of its performance, it works as expected.
FollowupID: 820717

Follow Up By: Top End Az - Friday, Jul 25, 2014 at 12:50

Friday, Jul 25, 2014 at 12:50
So the cranking battery and Marine Pro 100amp hour battery obviously have different capacity. Will the charger accommodate this?
FollowupID: 820726

Follow Up By: ABR - SIDEWINDER - Friday, Jul 25, 2014 at 20:00

Friday, Jul 25, 2014 at 20:00
The ABC1220 will yes. The Ctek 15A will also. I would not use anything smaller than 15A.

Regards Derek from ABR.
FollowupID: 820756

Follow Up By: Top End Az - Friday, Jul 25, 2014 at 20:25

Friday, Jul 25, 2014 at 20:25
Thanks Derek. Will check it out
FollowupID: 820762

Reply By: The Bantam - Saturday, Jul 26, 2014 at 09:46

Saturday, Jul 26, 2014 at 09:46
Just a thaught about these short runs. will find more problems than just the battery.

Diesels in general resent short runs a light loads.

Things generally attrbuted to short runs and light loads.

Clogging of Particulate filters or cat converters due to them not getting hot enough to burn the residue off.

Glassing of cylinder bores

Clogging of injectors.

Accumulation of moisture and thus sludge in the sump

Accumulation of fuel resudue in the sump due to rings not sealing and the engine not getting hot enough to boil it off.

Accumulation of other residue in the sump and on surface in the engine because the oil does not get hot enough for the additive to do their work cleaning the engine.

Yeh short runs are not at all good for diesels.

Might be an idea to get the vehicle out for a good fang up the highway or better still find a big hill to climb one a week.

OR cough up for some sort of town car or even a moped or bicycle for the short runs.

AnswerID: 536620

Follow Up By: Top End Az - Saturday, Jul 26, 2014 at 11:40

Saturday, Jul 26, 2014 at 11:40
My thoughts exactly Bantam. We're taking it out for a fang to Kakadu today and again next weekend. Just the usual problem of work commitments trying to get away.
FollowupID: 820800

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