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Mon Oct 10, 2016 7:30 am

I am using Odyssey pc1200 batteries and from what I can tell 15 amps is about as low as amperage as acceptable for bulk charge.

However, they caveat that and say the less amperage increases charge time. Will a smaller amperage charger decrease the life of the battery?

I am looking at this Odyssey approved charger (for smaller AH batteries):

CTEK 7002

Mon Oct 10, 2016 7:36 am

No, unless it is not enough current to fully charge. I have that same battery with a 20 amp charger and it is a great combo. You just need to make sure it is hitting almost 15 volts to fully charge. Be aware that the PC1200 is a “High Performance” glassmat battery and as such requires a higher charging voltage that standard AGM.

For best performance and lifespan, the PC1200 needs to fully charge occasionally. Its unlikely your alternator will fully charge it, so the “shore power” charger takes up the slack.

Mon Oct 10, 2016 10:00 am

Odyssey makes it known what they want for maximum longevity in a deep cycle application.

That is 40 amps per 100Ah of battery capacity applied until battery reaches 14.7v, then hold 14.7 for 4 more hours.

The less deep the discharge the less important meeting the 40% charge rate is.

Anything less than this optimal recharge regiment is detrimental to the battery, but not an instant death either.

I would size a plug in charger to meet the ideal recharge demands of the battery, because no way solar or alternator will meet them.

Mon Oct 10, 2016 10:52 am

nocreditnodebt wrote: Odyssey makes it known what they want for maximum longevity in a deep cycle application.

That is 40 amps per 100Ah of battery capacity applied until battery reaches 14.7v, then hold 14.7 for 4 more hours.

The less deep the discharge the less important meeting the 40% charge rate is.

Anything less than this optimal recharge regiment is detrimental to the battery, but not an instant death either.

I would size a plug in charger to meet the ideal recharge demands of the battery, because no way solar or alternator will meet them.

Thank you. That makes sense. Since I won’t really deep cycle the battery deeply I bet I can get away with less. Also, the battery(s) will live most of its life in a high state of charge as the camper will only be used for day trips and maybe 6-8 2-3 day trips a year. Otherwise the will be topped off.

Mon Oct 10, 2016 11:30 am

I use a C-Tek as a trickle charger = works fine; high quality; good support (tho some English difficulties with support and/or manual - I believe they speak Scandahoovian)

Mon Oct 10, 2016 12:40 pm

I'm using the Iota 45 on my bigger Odyssey. Been working well. The voltages match almost perfectly.

Tue Oct 11, 2016 12:08 am

Stephenmarklay wrote:

Thank you. That makes sense. Since I won’t really deep cycle the battery deeply I bet I can get away with less.

Certainly the case. Just know the if you do deep cycle to the 50% range, the Odyssey/northstar/lifeline AGM batteries really respond well to a high amp recharge from a very discharged state, and not nearly as well to a low and slow to an apparent full.

I cycle a Northstar AGM hard, and have observed voltages held under certain loads for AH removed for close to 500 deep cycles now over 3 years.

The Voltage held always improves after a high amp recharge( from most depleted state) in my usage. When I get to full via low and slow solar and or or go not get to full nearly every recharge, voltage held for AH removed is much much poorer and gets worse until the high amp recharge until 14.7 is reached, and hold 14.7v until amps taper to a certain level.

I use an Adjustable voltage 40 amp power supply as a Manual charger, modified for more heat removal and easier voltage adjustment, 200 watts of solar, and a well wired alternator with on the fly adjustable voltage regulator.

It will outperform any other 50 amp charger in time to truly fully charged.

No premature float.

Great thing with Odyssey/northstar/Lifeline, they can take any amperage you can throw at them, just limit voltage.

A Fast spinning well wired alternator allowed to seek and hold 14.7 will soothe an Odyssey. A regular flooded marine/hybrid battery would not be nearly as appreciative. Plates could warp and it could barf some acid

Tue Oct 11, 2016 5:09 am

nocreditnodebt wrote: Stephenmarklay wrote:

Thank you. That makes sense. Since I won’t really deep cycle the battery deeply I bet I can get away with less.

Certainly the case. Just know the if you do deep cycle to the 50% range, the Odyssey/northstar/lifeline AGM batteries really respond well to a high amp recharge from a very discharged state, and not nearly as well to a low and slow to an apparent full.

I cycle a Northstar AGM hard, and have observed voltages held under certain loads for AH removed for close to 500 deep cycles now over 3 years.

The Voltage held always improves after a high amp recharge( from most depleted state) in my usage. When I get to full via low and slow solar and or or go not get to full nearly every recharge, voltage held for AH removed is much much poorer and gets worse until the high amp recharge until 14.7 is reached, and hold 14.7v until amps taper to a certain level.

I use an Adjustable voltage 40 amp power supply as a Manual charger, modified for more heat removal and easier voltage adjustment, 200 watts of solar, and a well wired alternator with on the fly adjustable voltage regulator.

It will outperform any other 50 amp charger in time to truly fully charged.

No premature float.

Great thing with Odyssey/northstar/Lifeline, they can take any amperage you can throw at them, just limit voltage.

A Fast spinning well wired alternator allowed to seek and hold 14.7 will soothe an Odyssey. A regular flooded marine/hybrid battery would not be nearly as appreciative. Plates could warp and it could barf some acid

Barfing acid is no bueno.

Seriously, though thank you. I emailed Odyssey and they basically said the same thing. I guess I need to buck up.

Thanks for the advice on the alternator. My plan is to get an adjustable regulator and run a parallel line to the main battery to get up near that 14.7v range. Even with that there will be some voltage drop to the house battery with the 8 AWG line but I am hoping to keep it above 14.5. What is “on the fly adjustable”? I have seen the adjustable ones but I am not sure if you are speaking of a different method. Also, did you run a parallel line directly from the alternator and if so what size did you run?

Last, Odyssey says 16 amp min for a pc1200 (42 AH). I am now thinking the Ctek 25000 which is a 25 amp would be suitable. Thoughts?

Tue Oct 11, 2016 9:03 am

I use a transpo540hd voltage regulator.

it has a voltage trim potentiometer inside( 2k OhM) the casing

I nipped off this potentiometer and soldered wires to the legs, and have the new 2K ohm potentiometer on my dashboard next to voltmeters. Voltage range 12.8 to 15.3.

I currently use doubled 6awg, but will upgrade to 2awg. Not a VW

One basically cant have too high a charge rate on an Odyssey, not easily. the 25 amp ctek would be good but I think its max absorption voltage is 14.4, not 14.7.

Pretty hard to find the Odyssey ideal charger. Odyssey do have some rebranded schumachers with their voltage profiles, but they are obscenely $$$, and also only goto 25 amps, which would not be enough for their group 31 which want 40 amps when deeply cycled.

In my previous post I meant my 40 amp power supply would outperform a 50 amp charging source in time to full. It could be read as if the alternator could do that to. With adjustable regulation and spinning fast at freeway speeds it could, but it still takes ~4 hours from 80% to 100% chargedwhen held at absorption voltage, and I do not drive that much.

Tue Oct 11, 2016 5:39 pm

nocreditnodebt wrote: I use a transpo540hd voltage regulator.

it has a voltage trim potentiometer inside( 2k OhM) the casing

I nipped off this potentiometer and soldered wires to the legs, and have the new 2K ohm potentiometer on my dashboard next to voltmeters. Voltage range 12.8 to 15.3.

I currently use doubled 6awg, but will upgrade to 2awg. Not a VW

One basically cant have too high a charge rate on an Odyssey, not easily. the 25 amp ctek would be good but I think its max absorption voltage is 14.4, not 14.7.

Pretty hard to find the Odyssey ideal charger. Odyssey do have some rebranded schumachers with their voltage profiles, but they are obscenely $$$, and also only goto 25 amps, which would not be enough for their group 31 which want 40 amps when deeply cycled.

In my previous post I meant my 40 amp power supply would outperform a 50 amp charging source in time to full. It could be read as if the alternator could do that to. With adjustable regulation and spinning fast at freeway speeds it could, but it still takes ~4 hours from 80% to 100% chargedwhen held at absorption voltage, and I do not drive that much.

Thanks so much.