My battery keeps draining and dying! Comand? cl W215

[erwyn]

2000 cl500 W215. It used to die evay day, I updated with my01 cd and it was fine for a few weeks. Now its back to dying every couple of days! It won't let me re-update comand...

Can anyone help?

thanks Erwyn

 

[erwyn]

ps, the batttery is only 6 months old, but could it have been damaged by the previous problems?

 

[television]

Batteries can and do go faulty at any time during their 5 year average life, if the battery goes flat over night, then one can be sure that it is the battery and not some cmponent in the car draining it, for to discharge 70-90 amperes over a few hours would generate heat and smoke. One can always double check the drain from the alarm etc with an ameter in serries.

Any battery has a minimum of 12 months guarantee, take it back, I cant think of what you could do to damage one other than by overcharging, and by that I mean cooking it at 30 amps for several hours.

malcolm

 

[turnipsock]

Most car batteries will not stand being discharged to often. They rarely hold much charge after a few discharges. If you use a lead acid for a caravan or a boat, you need to pay through the nose for a deep discharge battery.

It sounds like, as you say, it has suffered from a previous problem.

 

[psmart]

Was your COMMAND originally fitted at time of manufacture? Does your steering wheel have controls to control the COMMAND? Some retro-fitted COMMAND systems use CAN-BUS adapters which drain batteries.

Also, if your COMMAND isnt switching off, the Amplifiers alone could drain your battery if not in quiescent mode as even though a battery is rated at 90+ amperes, this rating is a fallacy because it depends upon the battery drain rate. The more you suck out of it per unit time, the less capacity it has, ie. you could only see 50% or less of the actual battery capacity if draining too quickly. Its called a memory effect and when you recharge fully, you will then see the original battery power.

As turnipsock quoted, once a lead acid battery has gone into deep-discharge state, it wont hold or retain its complete charge state, depending upon its composition and design.

I've gone over to Carbon-Fibre batteries, as you can deep discharge these batteries regularly and they will fully recharge and come with 5 year warranty to boot. They also provide a higher current per unit time, with less of a memory effect. They are pound-per-pound weight wise higher Ampere rated.

Simple test, disconnect your COMMAND. If the battery lasts longer, then you've found your culprit. Get your battery changed under warranty, then have some one take a look at your COMMAND. If this doesnt do the trick, then its a process of elimination.

There is also the possibility that your alternator is faulty, or the charge/rectification circuit. Simple things first, try the COMMAND, then start pulling fuses to the big consumers when you park up for the night.

 

[television]

Lead acid car batteries do not have any memory effect worth talking about, a battery is at its best by being recycled. A battery left flat will deteirate, but that takes time and the plates start to expand. but this is not relervant here.

If the car came to me, What would I do, fit a known good battery,if OK after a couple of weeks that would be that. If not, take the car on a test run, connect an ameter in serries taking care that the meter is joined up before breaking contact, otherwise the leak path could stop. You can buy a meter for £3-£15 perfectly OK for this type of fault, why play around thinking it may be that,or it might be that.

Malcolm

 

[psmart]

Here's a manual explaining batteries: http://www.victronenergy.com/upload/documents/ElectricityonBoard_rev8_july2004.pdf

read the section on batteries, especially section 2.5.3. Memory effect may not have been the correct choice of words, as it tends to imply NiMH, or Cadmium type structures. I've been involved with camping for many many years now and had a fair bit of experience with 'electricity on board' and how the different batteries fair day to day. I've had 540Ah carbon fibre batteries in my m/h now for 3 years, and cant speak highly enough about them compared to the lead acid I made do with in yester-year.

If you start using an Ameter, you have to buy an good brand, something akin to Fluke with high current reading because the instantaneous currents demanded by a car can surge past the 10-15 amps limit on most Ameters.

Television is right to suggest trying another battery first, its the easiest option, so long as you can half-inch one from somewhere else (.... your wife got a car )

 

[television]

If you start using an Ameter, you have to buy an good brand, something akin to Fluke with high current reading because the instantaneous currents demanded by a car can surge past the 10-15 amps limit on most Ameters.

)

Not true with an ameter, it does not need to cost more than £14.00 even ones costing £4.0 have a 10 amp current rating, and that is more than enough. there is no surge in this case, and there is nothing drawing more than 10 amps even in fault condition. if there was you could use your nose to find the fault, as I said before the meter must be joined up before disconnecting battery.

Re meters, something I never think about, I have at least 10 including a fluke that cost me £2k. most of the day I use a £14.00 one,I can drop it, drive over it, and its accurate. Auto ranging are a pain in the butt, owing to the time taken to settle and I would lose ½ an hour a day.

Malcolm

 

[erwyn]

thanks for all your input guys.


the command is original with the car.

the battery is a Moura intelligent battery with silver alloy 740A CCA.

if i disconnect the command from the fuse box under the back seat, is it not still connected via another fuse under the bonnet?

how do I check the voltage drain with an ammeter? (I have one but am very confused by it....)

cheers
Erwyn

 

[psmart]

I'll leave that one to Television , I've blown up several Ammeters on cars, most notable my Fluke!! Televisions way of putting the ammeter in parallel BEFORE disconnecting the circuit/battery sounds best though, as my previous way led to surge currents ripping my ammeters apart!