Odyssey flat battery
Discussion
brett84 said:
Hey guys
I think a few of you are running the same battery as me (PC925), it's gone completely flat and i've left the accumate on for 72 hours, still not even registering on it. It won't do any harm connecting up a more powerful charger will it?
Did you leave it for a long period ? don`t think any battery likes being left in the cold ..I keep mine connected 24 hours a day.I think a few of you are running the same battery as me (PC925), it's gone completely flat and i've left the accumate on for 72 hours, still not even registering on it. It won't do any harm connecting up a more powerful charger will it?
Yep, they don't like that treatment 
worth a try 
Definitely don't put a high power charger on it, it says in big warnings in the manual not to boost charge them - not sure if it kills them or makes them explode or something? If its below 10.5v then it will unfortunately now be an expensive doorstop. I'm fitting a battery isolator to mine now so that if I leave it I can disconnect it from the car and stop myself ruining another one!
450Nick said:
Definitely don't put a high power charger on it, it says in big warnings in the manual not to boost charge them - not sure if it kills them or makes them explode or something? If its below 10.5v then it will unfortunately now be an expensive doorstop. I'm fitting a battery isolator to mine now so that if I leave it I can disconnect it from the car and stop myself ruining another one!
Apparently Nick they hate slow discharge i.e car alarms, clocks, radio memory back up etc 
probably the reason why they end up flat over a period, the master cut off is good advice 
450Nick said:
If its an Odyssey, it will be f
ked. I have a pc925 and flattened it and had to buy a new one - they cannot be discharged below 10.5ish volts or they expire!
Not true, Odyssey batteries are extremely high quality, they are however AGM type.ked. I have a pc925 and flattened it and had to buy a new one - they cannot be discharged below 10.5ish volts or they expire!Its a common misconception that deep discharged AGM batteries refuse to take a charge.
The truth is an AGM battery is far more resiliant to deep discharges than a conventional wet lead acid battery.
However, below 10.5v a deep discharged AGM battery will not be seen by your charger, so the charger simply refuses to charge it.
Its highly likely 450Nick's condemned deep discharged Odyssey could have easily been recovered by simply connecting a second fully charged battery in parralel.
Doing so would have stimulated the charger to deliver a charge, after a couple of hours the slave battery can be disconnected.
Like I say, an AGM battery is far more resilient to deep discharges, they have an extremely low internal resistance so you just need to know how to recover them & they nearly always give years more service even after a deep discharge that would kill a lesser wet type.
The challenges surrounding recovering a deep discharged AGM battery are well understood, you can read more about it here.
http://www.hotrod.com/techarticles/general/hrdp_10...
I recommend the OP uses the second (fully charged) parralel connected battery method to get the charging process started, and I'd put money on his Odyssey battery coming back to life and giving years more reliable service.
It's all explained very well here by Optima who's batteries are also AGM technology.
http://youtu.be/Slqd73ZOQvI
Edited by ChimpOnGas on Wednesday 3rd April 10:41
Thanks, that does look interesting! In my case we tried all sorts - jumping the car and running it for ages with the battery in, a week on a trickle charger and while it did take some charge, it would be flat the next morning (checked the ampage draw from the Chim and it was well down within acceptable levels). Ended up in the skip and got a new one!
450Nick said:
Thanks, that does look interesting! In my case we tried all sorts - jumping the car and running it for ages with the battery in, a week on a trickle charger and while it did take some charge, it would be flat the next morning (checked the ampage draw from the Chim and it was well down within acceptable levels). Ended up in the skip and got a new one!
Another extremely important rule is that AGM batteries should never be subjected to a charge current that exceeds 14.5v.Charging an AGM battery any higher than 14.5v is 100% guranteed to kill it in just one charge.
Also trying to charge a deep discharged battery lead acid battery using a trickle charger is hopeless, anything under 8 amps & you're pishing in the wind, if you're using a trickle charger to charge a deep discharged AGM battery you'll be completely wasting your time.
Jump starting a car with a deep discharged battery is brutal on any type of battery, it's also punishing on your alternator which is not designed for this type of work.
All you needed to do was use a decent AGM compatible charger or use the parallel battery trick & you its almost certain you could have saved that excellent Odyssey battery you threw in the skip.
The failure to hold charge you describe is a classic symptom of sulphation, all lead acid batteries will suffer sulphation to one degree or another when subjected to a deep discharge, AGM batteries are no exception.
Some high end battery chargers offer a de-sulphation mode, this feature is extremely successful in most cases & will pay for itself the first time you need to use it.
The real answer with all this is to never let your lead acid battery deep discharge, our cars all seem to suffer high levels of parasitic drain, they are also often used as occasional toys so suffer extended periods of inactivity.
This is a fatal combination, you really only have two choices if you don't use your TVR that regularly.
1) Use a decent mains powered maintenance charger
2) Disconnect the battery
I can highly recommend the BatteryBrain device, get the model with the remotes & you can remotely disconnect the battery from outside the car after you have locked it.
If you opt for the maintenance charger & have an AGM battery I recommend you put your hand in your pocket & buy a good quality AGM charger that also offers a de-sulphation feature & pulse charge in maintenance mode.
Short of buying an expensive proffesional tender charger, the best charger on the market that covers all bases is the CTEK MXS 10.
You can buy a CTEK MXS 10 off EBay for £105 delivered, still not a cheap charger, but the best is seldom cheap.
The bottom line is AGM batteries are streets ahead of the traditional wet type in every area, that's why Ferrari, Aston Martin, Bentley ect ect all exclusively use AGM batteries.
You just need to know how to charge them if they ever become deeply discharged and you will never look back.
If you are concidering an AGM battery Odyssey are amazing quality & are in anothe league when compared with the Mexican made overpriced AGM spiral cell Optima brand.
Hi Chaps, apologies for high jacking. I'm planning to buy an Odyssey battery and their website recommends a
25-PC1400T for a Range Rover V8 but it's twice the price of a PC925. I'm assuming as a number of you already have a 925 it's sufficient for a Chim...provided you don't overcharge or run flat?
Thanks.
25-PC1400T for a Range Rover V8 but it's twice the price of a PC925. I'm assuming as a number of you already have a 925 it's sufficient for a Chim...provided you don't overcharge or run flat?
Thanks.
Ive just brought a odyssey PC1200 battery off ebay paid £70 which thought was bargain. Its slightly bigger than the pc925. this works a treat spins the motor over really quick. at some point i will be moving it to the boot an fitting an isolator as its the 2nd battery ive knacked on the tiv.
penno said:
Ive just brought a odyssey PC1200 battery off ebay paid £70 which thought was bargain. Its slightly bigger than the pc925. this works a treat spins the motor over really quick. at some point i will be moving it to the boot an fitting an isolator as its the 2nd battery ive knacked on the tiv.
£70? I assume that wasn't for a new one?
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