The prob that I can see (for changing a battery)is that you cant guarantee the connection. If you happen to be unlucky and choose a point that isnt securely grounded, and get a high resistance contact then it is possible that you dont get 12Volts at the battery, end the electronics will not be maintained. Unfortunately you wont know this until its too late. Causing the very problem you want to avoid.
If you connect to the battery terminal, then you do, at least know that you have a good electrical contact.
so for jump starting, use the injun, for charging and for changing, use the battery terminal?
If you connect to the battery terminal, then you do, at least know that you have a good electrical contact.
so for jump starting, use the injun, for charging and for changing, use the battery terminal?
read the first line, i did say only jump from the chassis an + terminal and take the battery off to charge it. there is no need to keep power on the car when changing battery (assuming the car is in the condition it left the factory) you can however apply another battery to it whilst changing the battery to keep the system alive!
:doh::doh::doh:
backtracker!
Its always wise to keep the electronics alive when changing the battery - it can get bloody expensive if it needs to be re-synced!
Others above have charged a battery without disconnecting - I always have, too - better than re-syncing.
j the range
New Member
mhm. tis easy to re sync just plug gismo in turn key to number 2 and away you go
rasheed
Well-Known Member
Unfortunately i actually did jump start from another battery yesterday before reading this. + to +, - to -. Guess I was lucky! And today installed a new battery. Just took out the old one and plugged in the new. EKA, set windows and sunroof and away we went. But I do have a question. I do get the occasional overnight drain, everything still works but just short of enough juice to start the car. I know all about the EAS levelling every few seconds, the alarm monitoring everything and the RF signals interference and I haven't done anything about it because it doesn't really happen that often. One of the problems is that during the week my trips are very short so I reckon the alt doesn't really get a good chance to recharge anything. What I am wondering is can I fit a second battery, say in the boot? My alt's uprated to 120A and the new battery is 80A. Couldn't I hook another battery in parallel and so "never" run out of juice? Any thoughts? And how would I connect it, + to + and - (on the slave) to the body? I don't want to drill holes so was thinking of a seat anchor or something or would I just electrocute everyone?
Universally_Challenged
Active Member
this whole jumpstarting melarky is a bit of a myth.
there is a set procedure, which is pretty much the same in any car user guides. this is to basicly minimise shorting if a lead were to jump off during connection. (but usually if there are going to jump off it will be during cranking in which case it doesnt really matter what order u used anyway)
Positives first, either, not really important.
Negitive on the dead battery, then negative on the donor car.
As soon as they are all connected the dead batter will be pulling like F**k so the donor car need to be running first to you may not be able to crank that one.
if your battery is so dead that your not cranking then leave it for as long as possible before trying to crank the dead one. over a minute if possible. when you do crank, if it is struggeling to turn then stop and leave it for 5 mins to get some juice into your battery first. The donor car doesnt need to be reved like buggery like i see some people doing, but......... the donor will need to just be blipped up to maybe 2000 rpm for a second after starting to ensure the charging circut is up to 13 volts.
If your leads get warm when there are connected and you havent cranked yet then dont bother trying for 5 minutes. hot leads = high resistance = less juice.
The reason for not connecting it to the negative on the battery is that it just makes the circuit longer you have to come from there grounded engine block, up the earth to the batter, then across to yours and down your earth to the block. going block to block is less resistance, therefor more performance. (marginally, not that you would ever really see) there would also be a concern that if the donor car had lower rated battery and earth leads then you may overload there ground from the battey to the chassis as your be pulling more than the vehicle was rated for as your pulling mainly from their alternator.
still with me??
if you cant be arsed to remove the battery from the dead car for charging and just want to sort the alarm out then best disconnect the negative (not the positive) from the battery, the alarm siren if it has an internal backup should time out for die soon, then link up your leads and leave a donor car running charging the battery for 15 minutes or so. this should give you enough kick to then put the car back on its own battery, shut everything up, and re-mobilise the car, then pop th bonnet and jump her.
there is a set procedure, which is pretty much the same in any car user guides. this is to basicly minimise shorting if a lead were to jump off during connection. (but usually if there are going to jump off it will be during cranking in which case it doesnt really matter what order u used anyway)
Positives first, either, not really important.
Negitive on the dead battery, then negative on the donor car.
As soon as they are all connected the dead batter will be pulling like F**k so the donor car need to be running first to you may not be able to crank that one.
if your battery is so dead that your not cranking then leave it for as long as possible before trying to crank the dead one. over a minute if possible. when you do crank, if it is struggeling to turn then stop and leave it for 5 mins to get some juice into your battery first. The donor car doesnt need to be reved like buggery like i see some people doing, but......... the donor will need to just be blipped up to maybe 2000 rpm for a second after starting to ensure the charging circut is up to 13 volts.
If your leads get warm when there are connected and you havent cranked yet then dont bother trying for 5 minutes. hot leads = high resistance = less juice.
The reason for not connecting it to the negative on the battery is that it just makes the circuit longer you have to come from there grounded engine block, up the earth to the batter, then across to yours and down your earth to the block. going block to block is less resistance, therefor more performance. (marginally, not that you would ever really see) there would also be a concern that if the donor car had lower rated battery and earth leads then you may overload there ground from the battey to the chassis as your be pulling more than the vehicle was rated for as your pulling mainly from their alternator.
still with me??
if you cant be arsed to remove the battery from the dead car for charging and just want to sort the alarm out then best disconnect the negative (not the positive) from the battery, the alarm siren if it has an internal backup should time out for die soon, then link up your leads and leave a donor car running charging the battery for 15 minutes or so. this should give you enough kick to then put the car back on its own battery, shut everything up, and re-mobilise the car, then pop th bonnet and jump her.
Universally_Challenged
Active Member
wel, were you planning on having a two battery system to effectivly double your total amp/hrs or so you always have a carged battery to jump from.
First senareo, match your batterys, and your best finding a place in the engine bay (you may need to start moving stuff and thinking outside of the box. then connect the -ive to somthing like hefty, a massive bolt or engine mount or something connected to the block or chassis. the best place is exactly where the current -ive go's. Just remember you need to do a job as good, or even better than your existing -ive's earth point. when you crank your going to be pulling a metric s**t ton of juice through the joint so it has to be good.
As for the positives, just bridging straight to the existing battery would work, but................. if you totally drain both your batteries, by maybe using your headlight to light a skinnydipping adventure, then you suddenly going to be pulling twice the current from your alternator blowing a master fuse or melting/setting fire to something. this would be the case regardless of where you attach the +ive to. Best thing to do would be to buy a battery manager (available from most boating outlets) and plumb that in on the +ive side. this will manage the charge and drain from each battery.
Personally i'd just contact a battery specialist, as if you get a second 80ah battery, it would just be the same as buying a 160ah battery (which would probably be smaller than the size of 2 80's.
Second senario, Split relay charging. This on one hand will ensure one battery is always topped up, regardless of the state of the other. but, the one always charged will be the one you dont use for cranking. it would be a 'spare'. more of a super jump pack. if you do end up with a flat battery, just slam a positive across the second and flat batterys +ives and you away. alittle hard is its in the boot. Plus putting a SLA battery (Lead acid) battery inside a car may lead to smells and explosive gasses while charging.
the upside to a split relay charged battery is you could get funky and connect stuff to it that you want to use, but dont want to drain the main battery, ie rechargable torch, mini fridge, stereo main feed.
i'd just go for the bigger battery option. for less that a hundred quid you can get a device that txts you when the battery gets to a pre programmed voltage, ie 11.7 volts. giving you enough time to get to the car and take it for a drive.
Irishrover
Well-Known Member
I'll go along with what MHM says. My P38 is not used so much nowadays and I leave the battery attached with an auto cut out charger connected to the battery posts and left on trickle charge mode permanently. I have never had a problem with ECU's etc. frying.
I think this one is an "Urban Myth", all ECU's are designed to take small surges in voltage otherwise they would be frying like saveloys every time the voltage regulator or diode pack on an alternator goes tits up.
Of all the BECM's I have repaired, 99% have been in a locked status (Immobilised) and the remainder due to mosfet or capacitor failure.....none were "Fried" due to excess voltage.
I think this one is an "Urban Myth", all ECU's are designed to take small surges in voltage otherwise they would be frying like saveloys every time the voltage regulator or diode pack on an alternator goes tits up.
Of all the BECM's I have repaired, 99% have been in a locked status (Immobilised) and the remainder due to mosfet or capacitor failure.....none were "Fried" due to excess voltage.
wills
Well-Known Member
you will be talking about them and wishing you had one when you are on the side of the motorway with a slipped liner
-Wills
thanks every one for help , there was a lot to take in but im pritty much getting : not to attach the - jump lead to the battery (flat one on the l/r) but to some part on the body of the car?
use the key in the door to unlock the angine
do i need tho resync the fob and if so how?
use the key in the door to unlock the angine
do i need tho resync the fob and if so how?
Universally_Challenged
Active Member
there are two possible ways, first just try to start the car, putting it in the ignition and turning to stage to will resync the codes.
if you can start the car then but cant get the buttins to lock/unlock the car remotly do this. place the key in the lock, press and hold unlock, turn to unlock position and hold for 3 seconds, turn back and remove key, release unlock. if that doesnt work try doing the oppisite, turning to unlock and pressing unlock.
the car need to be unalarmed and mobilised before you try this. i usually start the engine, stop the engine, hop out and do it straight away. that way you know everything is off.
if you can start the car then but cant get the buttins to lock/unlock the car remotly do this. place the key in the lock, press and hold unlock, turn to unlock position and hold for 3 seconds, turn back and remove key, release unlock. if that doesnt work try doing the oppisite, turning to unlock and pressing unlock.
the car need to be unalarmed and mobilised before you try this. i usually start the engine, stop the engine, hop out and do it straight away. that way you know everything is off.
rasheed
Well-Known Member
Wow, cheers, UC, what a well thought out post! I was leaning towards the first scenario really but after reading this I think I'll stick to the second. And I'm not giving the car my mobile number thank you very much or she'll be texting me at any old hour! Clarification: Suppose I did keep the slave in the boot, I know you don't advise it but suppose I did, where'd you reckon I could earth it?
Matn9111, sorry we hijacked your thread. You've now plenty of tips on resyncing so I hope it works. If it doesn't then try to get someone with another RR and a bit more experience to just watch and check you're doing it right because it can get confusing. Still no joy then its probably a BECM glitch. It can be reprogrammed but needs software and expert knowledge. Irish'll know more.
Clarification: Suppose I did keep the slave in the boot, I know you don't advise it but suppose I did, where'd you reckon I could earth it?Matn9111, sorry we hijacked your thread. You've now plenty of tips on resyncing so I hope it works. If it doesn't then try to get someone with another RR and a bit more experience to just watch and check you're doing it right because it can get confusing. Still no joy then its probably a BECM glitch. It can be reprogrammed but needs software and expert knowledge. Irish'll know more.
rasheed
Well-Known Member
Universally_Challenged
Active Member
ok, well this second battery needto to be secured, best just strap it down. you dont want it falling over. and cover it with something to stop anyting falling on it. i know some people make little vented wooden boxes to keep it safe but also vent it.
it will only be trickle charged at about 10 amps tops. so you can just earth it to anywhere. pop the carpet and have a look for a bolt. i expect the area where the rear light cluster is would have a good earth point, or the other side where the RF receiver is hidden. make sure that wire is the same size or bigger than the one that comes with your split relay charger.
Dual Battery Installation for Range Rovers
still think you should just get a kick ass main battery.
might as well wire up a PP3 battery, it'll just as effective
