Odyssey and CTEK charging

[steveoverland]

Hi folks, hope your all well. I have a 300tdi defender with dual pc1500 odyssey batteries, charged by a ctek split charge with Smartpass, ctek MXS 5 battery Charger when connected to mains and solar power when camping. Sadly, once again, the battery that is connected to the fridge and other none vehicle electricals has died, this is the second one in three years, so is getting expensive. Anyone have any thoughts on what could be causing this???

 

[jonyjoe101]

Are you measuring the battery voltage at the battery terminals. The odyseys need 14.7 volts to fully charge. I know from my own experience with solar, there is always voltage drop.

If the batteries are never reaching 14.7 volts (full charge) but used normally during discharge they eventually lose capacity and will not last long. The alternator will give them a good charge to 80 percent but the mains/solar need to get it up to 14.7 volts (on the terminals) and hold 14.7 volts for hours.

I have a smaller fullriver agm that requires 14.7 volts, and the alternator doesnt charge it fully, It gives me a slow crank if parked too long because of the undercharging. Now I keep a dc 2 amp 14.7 volt charger connected 24/7. I get a good strong crank everytime no matter how long the van sits. The agm's love that 14.7 volts. A trickle/float charger at lower voltages won't help.

 

[steveoverland]

I leave the vehicle permanently plugged into the mains so the ctek MXS5 should charge it sufficiently, and has been fine for a year,also the ctek splitcharge and Smartpass deliver higher charge rates with some clever (to clever for me) electrical magic......

 

[john61ct]

AGM really wants high amp rates for maximum longevity, as in .4C or higher, up to say 0.6-7C

so 40A per 100Ah would be minimum.

The most critical factor is average DoD%, should hardly ever - only in emergencies - go below 50%.

A decent BM will help a lot, and need to periodically lower the Ah capacity setting as that declines IRL, even with a top notch brand like Odyssey, when new, discount their cap rating by 10% or so.

Finally, getting to **true 100% Full** at least a few times a week is very important, every cycle would be ideal.

So if your CV setpoint is say 14.6V, hold that (in Absorb cycle) until amps rate drops to 0.005C, or half an amp per 100Ah.

And don't let them sit below Full for long, recharge as soon as possible.

 

[john61ct]

Unless Odyssey docs / tech support contradicts

I would hold Absorb V well over 14.4V, but no higher than 14.7V

Float at 13.5V and 13.8V, lower is better.

Make sure any "equalization" or "desulfation" feature is fully disabled. Yes chargers can be too "intelligent".

 

[john61ct]

If you can't care for them properly as above (adjustable setpoint charging is key IMO)

then better to spend minimum per Ah, still get true deep cycling but flooded (FLA) is longer lived and better value per Ah per year by far compared to AGM.

The best battery value by far is Duracell (actually Deka/East Penn) FLA deep cycle golf cart batteries, 2x6V, around $200 per 200+AH @12V pair from BatteriesPlus or Sam's Club. NAPA relabels it here: https://www.napaonline.com/en/p/NBP8144 Deka self-labeled also sold at Lowes.

AGM is always going to cost more per Ah per year, IMO should only be used where actually required.

 

[steveoverland]

Interesting points.... is there a deep cycle battery that likes a bit of abuse ....

 

[steveoverland]

Not that I do, but occasionally the sun doesn’t shine and the solar panels cannot charge the batteries when the fridge is running....

 

[john61ct]

Those FLA GCs certainly withstand a much wider range of profile voltages

and do not need (cannot even use) charge rates over 0.15 - 0.20C

But all lead needs to get to 100% Full (however the mfg specs that) as often and as quickly as possible

and suffers going below 50% too frequently

if you want the bank to last longer than a few years.

Getting your charge sources and spec'd bank charging voltages lined up is a pretty basic foundation.

Then again, if a 200+ Ah bank is only costing you say $250 every time you replace it, look at it like tires brakes and oil changes, maybe $5-10 per month?