New to AGM , and my first one is an Odyssey ODX-AGM34R, any one care to help, please ?

[Talat]

Hi everyone ☺️
I just joined this site two days back, thanks for a quick add by OP, hoping to find some help with some of my concerns.

I have bought an odyssey ODX-AGM34R and my alternator voltage is 14.3 on a cold start and then rest to 14.0 to 14.1

Now I read in this site and many other ones that the battery needs 14.4 to 14.8 to fully be charged on a charger and 14.2 to 14.5 v from alternator. Mine is just at the lower edge , so do I need a home charger to compensate the phases absence from the alternator.

Where I live it's very difficult to find those fancy batteries, I.e. odyssey's and optima's , even though I have the ability to buy them, so I don't want to risk this one (produced Dec 2022).

Upon checking with battery assessment equipment I have it shows good condition and both SOH and SOC at 100%.

I have read many threads here talking about charging and stock alternators, but want to have a peace of mind so I don't need to start searching again for another battery on the hope this one will serve me for 3 to 5 years.

Thank you for any thoughts, suggestions.

Cheers

 

[Talat]

PS, I have seen many clips on the GM diode to boost the alternator voltage by a 0.5 volt but that diode doesn't fit in my hyundai tucson diesel 2L fuse box using a micro size.

 

[dstefan]

I’d like to suggest not worrying about it too much. AGMs, and Odysseys in particular, are pretty robust and forgiving. There’s lots of handwringing about charging them out there that’s overblown. Yes they like a good high voltage charge from time to time, but it’s not that big of deal. Buy either Odyssey's 25 amp charger or Victron's 15 amp IP 65 Blue smart charger (maybe better as it’s customizeable for LiFePo batteries and others, but has a dedicated 14.7 v option that’s great for AGMs).

I’ve had 6 AGMs over the past 15 years in 3 different vehicles. One Diehard (when they were made by Northstar, which is owned by Odyssey and equally good), one Odyssey, one Optima, and 3 Northstars. Only the Odyssey and the Optima were dual/house batteries, the others were all starting batteries, though all were charged in Toyotas with too low voltage. Only the Optima crapped out, and that was after 6 years, including at least a year where it was boosting a weak starter battery (not an AGM) through a dual battery system. Never had a problem with any others. Never failed to have plenty of juice.

I finally talked to Odyssey about correctly charging when I replaced the Optima with the Odyssey as a house battery in a dual, underhood system with an isolator. Basically, they recommended occaisional charging to the correct voltage. BUT, despite several years of not doing so initially with an AGM starter, never had a problem.

We’ve been running a Northstar AGM in my wifes 4runner which is a grocery getter since 2018 with no problems. Get’s driven maybe 2 to 3 times a week for short distances and NEVER gets well charged by the alternator. I’ve charged to the 14.7v maybe twice. I do periodically (maybe every couple months) put it on a trickle charger (Battery Minder brand, recommended by Odyssey) for a few days. The worst it sits at is 12.6v. Never failed to work. Will last another 4 years easy is my guess.

My Tundra with camper sits for weeks (in Phoenix heat), so about every 6 weeks I give it a charge with the Victron charger I mentioned above. And I don’t do that until it hits about 12.0v (it has several parasitic draws from a battery monitor and alarm). Going strong for 3 years now. Always gets well charged on long trips (eg up to 12.8 or 12.9v).

You can make yourself crazy reading all the stuff about boosting your alternator voltage and in many cases, as I researched this, people who do the diodes have created other electrical problems. Just buy a good charger and a few times a year give it refresh charge.

Maybe there’s something different with your system/diesel and someone with experience with it will chime in, but otherwise I think you’re gonna be fine.

Edit: PS— if you ever need another AGM, Batteries Plus sells the X2 Power battery nationwide with a 5 year warranty and occaisonal discounts. These are Northstar batteries and a lot of people use them off-road. They are made by Odyssey’s parent company. They are what I run and they’re excellent. You can buy on-line and I believe get them shipped.

 

[Talat]

I’d like to suggest not worrying about it too much. AGMs, and Odysseys in particular, are pretty robust and forgiving. There’s lots of handwringing about charging them out there that’s overblown. Yes they like a good high voltage charge from time to time, but it’s not that big of deal. Buy either Odyssey's 25 amp charger or Victron's 15 amp IP 65 Blue smart charger (maybe better as it’s customizeable for LiFePo batteries and others, but has a dedicated 14.7 v option that’s great for AGMs).

I’ve had 6 AGMs over the past 15 years in 3 different vehicles. One Diehard (when they were made by Northstar, which is owned by Odyssey and equally good), one Odyssey, one Optima, and 3 Northstars. Only the Odyssey and the Optima were dual/house batteries, the others were all starting batteries, though all were charged in Toyotas with too low voltage. Only the Optima crapped out, and that was after 6 years, including at least a year where it was boosting a weak starter battery (not an AGM) through a dual battery system. Never had a problem with any others. Never failed to have plenty of juice.

I finally talked to Odyssey about correctly charging when I replaced the Optima with the Odyssey as a house battery in a dual, underhood system with an isolator. Basically, they recommended occaisional charging to the correct voltage. BUT, despite several years of not doing so initially with an AGM starter, never had a problem.

We’ve been running a Northstar AGM in my wifes 4runner which is a grocery getter since 2018 with no problems. Get’s driven maybe 2 to 3 times a week for short distances and NEVER gets well charged by the alternator. I’ve charged to the 14.7v maybe twice. I do periodically (maybe every couple months) put it on a trickle charger (Battery Minder brand, recommended by Odyssey) for a few days. The worst it sits at is 12.6v. Never failed to work. Will last another 4 years easy is my guess.

My Tundra with camper sits for weeks (in Phoenix heat), so about every 6 weeks I give it a charge with the Victron charger I mentioned above. And I don’t do that until it hits about 12.0v (it has several parasitic draws from a battery monitor and alarm). Going strong for 3 years now. Always gets well charged on long trips (eg up to 12.8 or 12.9v).

You can make yourself crazy reading all the stuff about boosting your alternator voltage and in many cases, as I researched this, people who do the diodes have created other electrical problems. Just buy a good charger and a few times a year give it refresh charge.

Maybe there’s something different with your system/diesel and someone with experience with it will chime in, but otherwise I think you’re gonna be fine.

Edit: PS— if you ever need another AGM, Batteries Plus sells the X2 Power battery nationwide with a 5 year warranty and occaisonal discounts. These are Northstar batteries and a lot of people use them off-road. They are made by Odyssey’s parent company. They are what I run and they’re excellent. You can buy on-line and I believe get them shipped.

Thanks man you made my day ❤️

I will take your personal experience as guidance in my first usage of an AGM. I will try to order one of the chargers you've suggested in the very near future

 

[dstefan]

Well, you know, my motto is “everyone is entitled to my opinion”.🤣

Glad it helped!

 

[Howard70]

I agree with Dstefan. we have two 100 AH Odyssey Extremes in parallel as the start bank for our 2017 Fuso FG Canter based Earth Cruiser. The batteries were first put in service in 2017 in our previous 2014 EarthCruiser. We moved them over to the current truck in 2018. They've now gone 5 years in the current truck plus a year in the first truck and they honestly behave like new. 95% of their charging comes from the stock Fuso 140 amp alternator. Rarely above 14.2 amps, mostly closer to 13.9 - 14.1.

I monitor their voltage sporadically while the truck sits for months (I'm embarrassed to admit that I let an EarthCruiser sit unused for months). Without any supplemental charge the batteries are often at 12.8 volts after a month - it can take two to three months for them to get down to 12.6. Once there I'll parallel them with the house bank (which is maintained on shore power via a Magnum Inverter/Charger) for a day.

While these weren't cheap back in 2017 (I think they were about $300 each) they've definitely served us well and I suspect it will be several more years before I even think about replacing them.

Howard

 

[Talat]

I agree with Dstefan. we have two 100 AH Odyssey Extremes in parallel as the start bank for our 2017 Fuso FG Canter based Earth Cruiser. The batteries were first put in service in 2017 in our previous 2014 EarthCruiser. We moved them over to the current truck in 2018. They've now gone 5 years in the current truck plus a year in the first truck and they honestly behave like new. 95% of their charging comes from the stock Fuso 140 amp alternator. Rarely above 14.2 amps, mostly closer to 13.9 - 14.1.

I monitor their voltage sporadically while the truck sits for months (I'm embarrassed to admit that I let an EarthCruiser sit unused for months). Without any supplemental charge the batteries are often at 12.8 volts after a month - it can take two to three months for them to get down to 12.6. Once there I'll parallel them with the house bank (which is maintained on shore power via a Magnum Inverter/Charger) for a day.

While these weren't cheap back in 2017 (I think they were about $300 each) they've definitely served us well and I suspect it will be several more years before I even think about replacing them.

Howard

Thank you Howard for your helpful input. I was worried to undercharge my odyssey with my 14.0 -14.2 v but it seems they are very tolerant and friendly products. Since those are very difficult to find in Saudi Arabia and if found will be over priced compared to prices in the US.

I'm installing a direct line to the battery with one of those cheap gauges on cigarettes lighter inside the car to keep an eye on charging until I get something better from aliexpress with 4 digit display.

Cheers

 

[roymitchell]

Based on what you're describing, it sounds like your alternator is just on the edge of what's needed to keep that AGM battery in optimal shape. While 14.0–14.1V should be fine in most cases, AGMs like the Odyssey do thrive with a bit more voltage.

If you’re working on your engine and charging setup, and you're into cars like a lot of folks here, you might want to check out a Hyundai Engine Specialist. They’ve got some useful tips that could be helpful depending on what other vehicles you’re working with or planning to upgrade.

 

[jonyjoe101]

I have a fullriver 27ah agm (clone of the oddysey) I bought it in 2013 and used mostly as a jump battery but have been using it as a start battery in my astrovan for the past 3 years.
I do have to top it off to 14.7 volts every 3 to 4 days, If I don't top it off it wlll give me weak cranks during starting. The top off with a 5 amp dc to dc charger is minimal 10 to 15 minutes.
When I bought it, it was old stock and I only paid 45 dollars for it, so its at least 11 years old.
I do recommend to top it off to 14.7 volts at least once a week. And measure the voltage directly from the terminals. Some chargers might not be putting out the exact voltage they advertised.

 

[pluton]

If your system is really charging at 14-14.1V when fully warm, that's way better than my '97 Toyota which charges at about 13.2-13.5 when hot. An occasional full charge on a smart charger wouldn't hurt, but may not be strictly necessary.