Starter Motor Amp Draw...

[ozzie1989]

I'd like to have the facility on my split charge setup to 'jump-start' the car should I accidentally run the main battery down (I shouldn't because that's the whole point of a split charge - but just in case). I could go down the route of keeping some jump leads in there but I thought about integrating it into a 3 way switch (auto charge - off - jump) using one of Si's X-Charge. All it means is me adding a short piece of wire to activate the 'always on' part of the switch so very easy to do.

Some people say that starters draw 100s of amps, however others who've tested them say that inital surge is around 300a and then 120a when stalled... well within the remit of the x-eng split charge don't you think?

So does anyone know the definitive answer as to how much a TD5 starter motor draws, and if it's safe to use with the X-Charge in the way I intend... if not jump leads it is

Also, could anyone please give me your opinion on THESE unbranded batteries that I was thinking of using a pair of...

Many thanks

[J@mes]

I cannot see the ebay page, but notice in the title is says "leisure"

I dont think that leisure batteries are suitable for jump starting - something to do with the way that they are designed to cycle. Dont know the science behind it, or if its even true or not but it may be worth thinking about.

[ozzie1989]

Sorry, I've adjusted the link now.

The batteries are supposed to be dual purpose, also rated to 650cca?

[sotal]

Those batteries will be fine for starting engines, I have a similar one fitted in my Series.

No idea on the Amps question though? Although the battery has the capacity to supply 650cca so maybe you should be looking at the worst case scenario and getting a switch which handles 650amps?

[Guest WALFY]

On my challenge truck I have 2 batts running from the same alt (hopefully changing that soon). They are seperate in the fact that the main batt won't operate the winch. After rolling my truck at an event and then flattening the winch batt I installed a starter solonoid between the 2 batts. This is then operated by a small switch located on the dash. Which then allows me to tag both batts together for a heavy prolonged winch or if I let the main batt go flat I can jump start myself

[FridgeFreezer]

The X-Charge should be up to it although the stock cables supplied with it probably aren't. I would be a bit careful, and jump it by joining the two batteries with the X-Charge so the flat one can charge up a bit from the good one before you try the starter, that will reduce the load through the X-charge.

Or you could spend a fiver on a cheapo battery isolator switch and use that as the jumper.

[ltwt1981]

Or a bit more at a Chandlery on a boat isolator with off Batt1 batt 2 or both on it.

[FridgeFreezer]

Or a bit more at a Chandlery on a boat isolator with off Batt1 batt 2 or both on it.

Don't you mean a LOT more? In my experience anything at a chandlery costs 100% more than it would anywhere else. The cheap battery isolators can be had for £5 from paddocks etc.

[LandyManLuke]

Personally, I'd rather jump start myself from one charged battery, rather than two half charged ones.....

[Turbocharger]

I think TroddenMasses used two X-eng split charges, in order that he could turn himself on at the touch of a button. To me it seems somehow like electrical masturbation for your car, so I'm sticking with one battery and only jumping myself when other people are willing to lend a hand.

[Guest diesel_jim]

Just get one of those small battery cut-out switches with the removable red plastic key.

connect it in between both +ve's of the batteryes, and chuck the key into your cubby box.

then if you do get a flat, just insert the key, start the engine and remove again.

[ozzie1989]

Ok guys thanks for the suggestions... all duly taken on board

Quick question, if I installed 2 x-charge would that double my capacity ie if the are rated at 170amp continuous, would that give me 340amps...

Not quite familiar with the whole path of least resistance etc.

This isn't for the starting, just out of interest... I always wondered how they put 3 20amp fuses together to make 60amp in power supplies and assume they do it this way!

[ozzie1989]

Those batteries will be fine for starting engines, I have a similar one fitted in my Series.

Good stuff, I guessed the ratings would be ok... but am a bit sceptical as they aren't branded though I'd assume they still pass regulations etc. and they have a 4 year warranty! My main reason for going for them is the dimensions, I can fit them with plenty of headroom left in the standard TD5 battery box - no worries about the batteries jumping and hitting the seat box cover even though they'll be well secured.

Thanks

[simonr]

Just get one of those small battery cut-out switches with the removable red plastic key.

This is probably the simplest and most reliable solution - and one I've used previously. I put the switch in the side of the seat box so that the door will not close with the key in the switch.

An average starter motor will not draw more than about 150A, with a brief surge of about 250A. The X-Charge is capable of supplying the excess charge necessary - I'll even warranty it!

Remember, if you do this just to take the wire to the X-Charge live, not the connection to the Alternator - so use a 2 way switch to connect the wire to the alternator in one position and +ve in the other.

Si

[ozzie1989]

Si this is what I'd planned with a Carling switch... one will be an ignition fed supply (TD5) which I'm also toying with putting a cheap VSR in line, off in the middle, and one permanent for jump starting. The output of the switch will go to your x-charge.

If you 'think' it can do it then I'll do it - I've every confidence you know what your talking about. In fact I could probably test it quite easily myself first just to make sure by feeling for heat etc.!

[ozzie1989]

I think TroddenMasses used two X-eng split charges, in order that he could turn himself on at the touch of a button. To me it seems somehow like electrical masturbation for your car, so I'm sticking with one battery and only jumping myself when other people are willing to lend a hand.

P.S: Your funny comment didn't go a miss

[GBMUD]

they have a 4 year warranty!

Sorry to say that the warranty is only as good as your ability to return knackered batteries to the supplier. My bet is he is working on the fact that on average only people less than about 40 miles from his premises will be able to return them - check out the T+Cs of most couriers and you will see that they will not carry batteries, and those that will you will find charge more than the cost of a new battery to send.

Caveat emptor

Chris

[ozzie1989]

Good point there Chris...

Trouble is I cannot find 110ah (or 80ah) batteries low enough to fit comfortably in the battery box height wise, and these look a good deal, even if they do only last 2 years!

[ozzie1989]

I've ordered up an X-Charge and those batteries off eBay now... I plan to do something with them over bank holiday weekened weather permitting so I'll let you know how it goes fingers crossed!

[ozzie1989]

I'm looking at fitting the batteries this weekend, I'll be securing them with a ratchet strap - the reason for this is that I can position them any way I like and the bar across the top is less likely to damage the batteries.

A question I do have though is venting them. The batteries I ordered above did not come with vent attachments, or covers. Would you recommend sourcing some vent attachments and venting outside of the battery box? If so, is it safe to take some tubing from each vent into a manifold (4 into 1) that I can then take up into the engine bay?

Cheers