Cold Start - BCU undervoltage?

Hi All

Well here we are again in the beginnings of the cold weather.

Symptoms:

• On the odd very cold morning she fails to crank on the first attempt (normally if car hasn't run the previous day).
  
• Glow light takes a little longer (5 seconds) to go out - this is expected.
  
• Dash board lights go crazy on first start attempt - suspect under voltage.
  
• Wait a while, try again and often still fails to crank again.
  
• Wait another 5 mins, third time lucky, cranks and starts fine.

Does anyone know the minimum voltage requirement for the ECU/BCU/ its brown-out voltage?

Checked battery voltage after 12 hour standing 12.5v = approx 90% charged.

Drop tested battery and it passes (only just) - almost hits the 'weak' area.

Second crank (successful start - I missed the first crank which was also 'annoyingly' successful this morning) battery voltage measured using DVM at interior light (without bulb) dropped to 10.3V - see here: Landrover Discovery 2 - Cold Start - YouTube

Removed and charged batt overnight - started fine the following day. Batt nice and warm as at house temperature.

No starting problems all year until now.

Batt just within (I hope) 2 year warrantee - Lyon Batt 664 from Eurocarparts

Is it time for a new one - maybe something with high CCA like the C31-1000 Numax? C31-1000 Numax Car Battery 12V 120Ah - Car Batteries - Numax Car Batteries

Any thoughts welcomed.
Lea

if the battery dont have around 13.5 volt in it then not strong enough to start a d2 imo

if the battery dont have around 13.5 volt in it then not strong enough to start a d2 imo

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Hi

The reading was taken after a 12hr rest so the cells would have stabilised and as such near Open Circuit results can be used to determine charge: File:Lead-acid voltage vs SOC.PNG - Wikipedia, the free encyclopedia

12.7v would be considered fully charged ;-)

I'd also suspect the battery is giving up, as you say once the temp starts to drop close to 0 they start to fail.

I've got a Numax leisure battery in my D2 at the moment, the Numax CXV24MF Sealed Leisure Battery 12V 86Ah 1000MCA 500 Cycles XV24MF - Leisure Batteries - Numax Leisure Batteries. Its a nice battery, 86Ah and about 800A CCA (not the 900 marine CCA listed!). I bought it for my D1 but after having issues with the alternator on the D2 I fitted the Numax one temporarily as it has a higher Ah then my Odyssey one (65Ah) so lasts slightly longer I'll have to get around to swapping out the alternator soon tho!

HTH

i am also running with a liesure battery far stronger mine dont even turn over once and its started

Cheers guys.

Does anyone know the brownout voltage for the bcu?

Down to 9.6v at crank this morning and only 10 Deg C outside...

get that Numax which you mentioned in your first post then... it's brilliant, i have it too... untill we are not certain about the battery everything is in vain...under 10V while cranking is not enough for a proper function of the electronics

May do, but it's worth a look around the market for commercial/agricultural batteries too. Spotted this: Alphaline Heavy Duty Battery / Alphaline Batteries / Batteries by Application

Has anyone used Alphaline?

I like the 4 year warranty but it's shipping the thing back which is always a problem when buying on-line!

Can even buy one (from same company) via Amazon: MF31-1000 High Performance Engine Start Battery 1000CCA: Amazon.co.uk: Car & Motorbike

any minimum 100AH and min. 900CCA would be good... anything below these figures may give you trouble in time especially if it's cold and you use the car for short journeys

That's the weird thing, work journeys are constantly 50 mile round trips coupled with the odd weekend start/stop shuffle the kids around driving, yet the 664 (760CCA) died within 1.5 years :-(

Yep, I'm not taking anymore risks now - 1000CCA tractor battery for me!

If you use amazon, if it has to go back they pay postage from a collect+ store.

That amazon one looks good, I need to order a battery asap.

LeaUK said:

That's the weird thing, work journeys are constantly 50 mile round trips coupled with the odd weekend start/stop shuffle the kids around driving, yet the 664 (760CCA) died within 1.5 years :-(

Yep, I'm not taking anymore risks now - 1000CCA tractor battery for me!

Click to expand...

When you get your new battery, if I may I'll offer you a tip?

Irrespective of what the battery supplier says, always, always put a new battery on charge for 24 hours, before installing it in the car.

I offer this suggestion so that you ENSURE that the battery is in optimum condition. I have done this ever since installing brand new batteries that lost their charge almost immediately.

It costs nothing so why wouldn't you?

Also, after the charging, leave it for an hour to settle before installing it in the car.

Cheers
Dave

Got a feeling it just fits in the P38 too Steve, think I saw a thread about it. Google the part number and P38 to check.. ;-)

I suspect Amazon's reject/returns would be an improvement over the original supplier too ;-)

Thanks Dave good advice, who knows how long the 'new' battery has been sitting in storage for....

Well today's failure of cranking has led me to the solenoid! Outside temp 9 deg C so not particularly cold. First start of the day took 5 attempts to get her to crank once. On third attempt got DVM out and measured voltage 12.3v (after three cycles of glow plugs) so that's ok bearing in mind battery hasn't had time to recover. Voltage dipped to only 11.5v at ignition start position which indicates minimal current to starter is flowing.

Second start attempt 4 hours later and it took 6/7 ignition attempts to crank - this is now getting seriously worse and has become a major risk of total failure!

Although the low cranking voltage of the battery isn't great I now don't think it's wholly attributed to the failure of crank. I'm now suspecting high resistance at solenoid contacts, probably caused by missing contact surface area where the current has eaten it away or/and carbon build up. Repair kit can be found here: Starter Motor Solenoid Repait Kit Td5 NAD101240KIT Island 4x4 - Specialists in Land Rover and Range Rover Parts and accessories for all models. UK and worldwide mail order.

Looks like a nightmare to get to anything around the starter motor - dropped car in local friendly garage!!

Lea

Local friendly garage confirmed solenoid failure. Fully recon starter motor including new solenoid (with warentee) 75 quid +VAT so it really wasn't worth simply replacing the solenoid once I'd paid for labour.

Solved!

Guys,

How long have you had the Numax Leisure batteries for, and how are they performing ?

I've got a D1 300tdi Auto that is currently on a sluggish Varta E24. It failed to start this morning, so that's one week outside its 4 year guarantee.......

Mostly short journey, and stop / start.

Need a new powercell, and have seen the Numax mentioned several times, but never seen any long term feedback / charging info.
Googling "Leisure batteries in a car", gives the advice that it's a No No, something to do with different discharge / charging concepts.

Really wanted to know what users have experienced beyond the "It's my first week of owning one, and it's great" reviews.

cheers.