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Correct specification for jump starting packs?

Post by Jester » Sat Jul 22, 2017 9:07 am
Joined: Wed Dec 19, 2012 10:57 am
Posts: 160
Hi all,

My battery continually runs down due, I assume, to a bad earth somewhere.

Tracking down electrical issues is going to be tough for me, but something I'll try and get sorted at some point.

I wanted to get a small power bank jump starter to keep in the van, in case my battery is ever unexpectedly flat or just needs a little help starting the van.

I have seen many variations of specifications for jump starters, 12v/24v, 200A/300A/600A peak etc.

What is best for the CF? And does the fact I have an electronic ignition fitted affect my choice?

I assume I need a 12v jump pack, but what kind of peak Amperage is required for the 2.3 slant?

Should I just get the 600A peak power one or is that overkill likely to damage the old wiring and electronic ignition, coil etc...

Electrics are not my strong point.

Thanks
Jim

Re: Correct specification for jump starting packs?

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Post by Phil Bradshaw » Club admin » Sat Jul 22, 2017 11:22 am
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 4681
If the battery continually runs down then either something is draining it (e.g. alarm system) or the battery is on its last legs.

First check the battery voltage when the engine is running at a fast idling speed: if the voltage is 14 to 14.5V then the alternator is doing things right.

Try disconnecting the battery earth cable when the van is to be parked for a while. If the battery still runs down then buy a new battery if controlled charging from the mains makes no difference to the battery running down.

If the battery maintains 12.6V and still will operate the starter motor when reconnected then find what is draining it in case it could go critical and fry the wiring (or worse).

Battery based jump starters work best with a vehicle battery in good condition that simply is discharged and can quickly 'top up' from the jump starter to aid starting.

If the van battery is well past its best then a jump starter will have to work much harder to spin the starter motor as well as cope with whatever load a defective battery imposes on the jump starter.
  • What is real is not the appearance but the idea, the essence of things. Constantin Brâncuși

Re: Correct specification for jump starting packs?

Post by Jester » Sat Jul 22, 2017 11:59 am
Joined: Wed Dec 19, 2012 10:57 am
Posts: 160
I'll try some of your suggestions, Phil, I can say it almost certainly isn't that the battery is on its last legs, a few years ago I bought a brand new very good quality battery, rrp was £130 or so, and it still continually ran that down, and I got a replacement battery from a mechanic friend last year and it's done the same to that too.

Basically if it's run frequently then no problem, but if it's left for a few weeks or a couple of months then there's very little in the battery, it gives a very weak turnover of the starter.

I've no alarm system on it, there is a 12v cigarette output on the dash that the previous owner fitted with three LEDs, red, yellow and green that are supposed to show battery strength, could that be running it down if it's trying to sense battery power and showing this with an LED?

Other than that it has a radio fitted, the radio can be switched on even if the key isn't in the ignition, possibly this is drawing power even when off?

Jim

Re: Correct specification for jump starting packs?

Post by RobX » Sat Jul 22, 2017 2:27 pm
Joined: Fri Aug 12, 2016 8:52 pm
Posts: 202
If you have a multi-meter:

1) set it up to read current,
2) disconnect the positive cable of your battery,
3) put the multi-meter between the positive battery post and the cable.

Now you're measuring the current of everything that's connected directly to the battery. If this is more than 30mA, this indicates there's likely a problem (I got that range . Then disconnect stuff until you find whatever's drawing too much. I suggest the PO may have fitted a battery strength meter for a reason..! For some folk, it's easier to manage a problem than resolve it...

Re: Correct specification for jump starting packs?

Post by Jester » Sat Jul 22, 2017 4:51 pm
Joined: Wed Dec 19, 2012 10:57 am
Posts: 160
I do have a multi meter, I got one to track down a brake light issue two years ago, and watched YouTube videos on how to use it, and I successful sorted the problem.

I also collect high power and modded torches which use unprotected 18650 batteries which need careful monitoring on my multi meter.

I'll google which setting measures current and have a go.

Thanks guys
Jim

Re: Correct specification for jump starting packs?

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Post by Phil Bradshaw » Club admin » Sat Jul 22, 2017 7:14 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 4681
If a low wattage test lamp lights when connected between the battery positive cable and terminal then a multimeter may not be necessary. Pound shop screwdriver tester with internal bulb will do the job well enough.

Test lamp won't indicate actual current draw unless using, e.g., a 21W bulb which will indicate draw of at least 1.75A at 12V, but can be left connected as an indicator when likely suspects are disconnected.

LED indicator could be responsible; a 5mm LED can draw up to 20mA, add a bit more for a control circuit; could shake out at about 1 Amp-hour per day which can be enough to flatten a battery within a few weeks if it wasn't fully charged to start with (default condition on alternator systems where other circuits demand power).
  • What is real is not the appearance but the idea, the essence of things. Constantin Brâncuși

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