AGM requires special charger. T/F?
- Thread starter Schattenjager
- Start date
Schattenjager
Expedition Leader
Thanks for the great info! Going to order the minder unit today since it has several desirable features and covers all types of batteries.
shredwagon
Observer
2 Battery Charger
I'm about to install 2 Odyssey PC1500 in a diesel with 24V start, i.e. batteries in series for starting only and parallel the rest of the time.
Was looking into getting a BatteryMinder to keep the 2 new batteries topped up, until I read this.... Can someone recommend a compact charger that is better suited to a battery "bank"?
I'm about to install 2 Odyssey PC1500 in a diesel with 24V start, i.e. batteries in series for starting only and parallel the rest of the time.
Was looking into getting a BatteryMinder to keep the 2 new batteries topped up, until I read this.... Can someone recommend a compact charger that is better suited to a battery "bank"?
wrcsixeight
Adventurer
I've got 2 group 27 Crown flooded Deep cycle batteries. Crown recommends I charge them at 20 amps each up to 14.5 volts, and I find that they simply love it when I can provide them with this current. While my solar is usually enough to top them up by the end of the day, they behave much more admirable when I can feed them 25 amps each to begin with.
My Alternator is capable of feed the pair 100 amps at higher rpm when they are depleted. An early morning drive with this amp blast really seems to wake them up.
In my opinion, the slow and low method of charging might abuse the batteries less, but I think it is more important to get them back up to full charge quickly, and feeding them with the current the manufacturers recommend is the best way to get them there, and keep them performing well cycle after cycle.
I borrow and use the battery minder 12248, and it does top them off and hold them at full, but I prefer to use 2 chargers and feed depleted batteries as many amps as they are willing to accept at the correct specified voltages. 8 amps into my 2 deep cycle batteries is just too slow, and I cycle them regularly enough, and have an amp hour counting battery monitor I pay way too much attention to.
When the battery minder is in condition mode, after a full charge, the voltage swings up and down many times per hour. It actually puts a small load on the batteries, then starts charging again with the voltage doing a seesaw all night long, and my fans noticably speeding up and slowing down. perhaps this is one method of how it desulfates, if that is even possible. I think it is a way of ensuring the specific gravity reaches it's absolute maximum for whatever temp both the charger and battery are in.
My Alternator is capable of feed the pair 100 amps at higher rpm when they are depleted. An early morning drive with this amp blast really seems to wake them up.
In my opinion, the slow and low method of charging might abuse the batteries less, but I think it is more important to get them back up to full charge quickly, and feeding them with the current the manufacturers recommend is the best way to get them there, and keep them performing well cycle after cycle.
I borrow and use the battery minder 12248, and it does top them off and hold them at full, but I prefer to use 2 chargers and feed depleted batteries as many amps as they are willing to accept at the correct specified voltages. 8 amps into my 2 deep cycle batteries is just too slow, and I cycle them regularly enough, and have an amp hour counting battery monitor I pay way too much attention to.
When the battery minder is in condition mode, after a full charge, the voltage swings up and down many times per hour. It actually puts a small load on the batteries, then starts charging again with the voltage doing a seesaw all night long, and my fans noticably speeding up and slowing down. perhaps this is one method of how it desulfates, if that is even possible. I think it is a way of ensuring the specific gravity reaches it's absolute maximum for whatever temp both the charger and battery are in.
dwh
Tail-End Charlie
One of these days, I'll actually get around to replacing the antique charger in my camper. The charger I plan to buy is a Samlex SEC-1215a - 15a @ 12v.
http://www.samlexamerica.com/products/productdescription.asp?ProductsID=8001
Why? Several reasons...
1) It can do more than one battery.
It has one negative connection, but three positive connections. The positive connections are internally isolated, so there is no backfeed from one to another. Even if hooked up to 2 batteries, it still only puts out 15a max which gets shared between the batteries. I want to be able to top off my cranking battery whenever I charge my deep cycle, so I like the SEC for that.
2) It can be set to either two-stage charging or three-stage charging by flipping a dip switch.
A lot of 3-stage chargers have a problem when they are charging a battery that is supplying a load at the same time it's being charged. What happens, is that the charger will continue in absorb mode until it sees the amperage flow drop down below 1 or 2 amps (depends on who made the charger) then it drops to float. Well, if you've got 3a of loads running at the same time you are charging, the amp flow never does drop low enough, and the charger stays in absorb mode and overcharges the battery.
There is a workaround for that problem - put a timer on the absorb stage. Iotas (with the IQ/4 module) for example will drop down from absorb to float after 8 hours even if the amp flow hasn't dropped. The Battery MINDer will drop out of absorb after 5 hours.
The Samlex has what they call "UPS Mode" - basically, you set it to 2-stage, do bulk and then straight to float and skip the absorb stage. Iota chargers by default are 2-stage. You have to add the IQ/4 module to make them 3-stage.
But that's okay. I WANT a 2-stage charger. The reason is, that my cranking and deep cycle batteries are not identical. If I try to pump a full 3-stage charge into both of them at the same time, the cranking battery is going to get overcharged. That won't happen if I run a 2-stage charger.
The instructions for the Samlex specifically state that if you do hook up more than one battery, then set the charger to 2-stage.
Since I'll be charging two batteries, I'll want it in 2-stage most of the time. Once in a while, I plan to disconnect the lead to the cranking battery, flip the dip switch to 3-stage and do a full 3-stage charge on the deep cycle. Just for jollies.
3) It only costs about $100.
They also make it in a 30a @ 12v version and a 15a @ 24v version:
http://www.samlexamerica.com/products/subcategory.asp?CategoryID=8
http://www.samlexamerica.com/products/productdescription.asp?ProductsID=8001
Why? Several reasons...
1) It can do more than one battery.
It has one negative connection, but three positive connections. The positive connections are internally isolated, so there is no backfeed from one to another. Even if hooked up to 2 batteries, it still only puts out 15a max which gets shared between the batteries. I want to be able to top off my cranking battery whenever I charge my deep cycle, so I like the SEC for that.
2) It can be set to either two-stage charging or three-stage charging by flipping a dip switch.
A lot of 3-stage chargers have a problem when they are charging a battery that is supplying a load at the same time it's being charged. What happens, is that the charger will continue in absorb mode until it sees the amperage flow drop down below 1 or 2 amps (depends on who made the charger) then it drops to float. Well, if you've got 3a of loads running at the same time you are charging, the amp flow never does drop low enough, and the charger stays in absorb mode and overcharges the battery.
There is a workaround for that problem - put a timer on the absorb stage. Iotas (with the IQ/4 module) for example will drop down from absorb to float after 8 hours even if the amp flow hasn't dropped. The Battery MINDer will drop out of absorb after 5 hours.
The Samlex has what they call "UPS Mode" - basically, you set it to 2-stage, do bulk and then straight to float and skip the absorb stage. Iota chargers by default are 2-stage. You have to add the IQ/4 module to make them 3-stage.
But that's okay. I WANT a 2-stage charger. The reason is, that my cranking and deep cycle batteries are not identical. If I try to pump a full 3-stage charge into both of them at the same time, the cranking battery is going to get overcharged. That won't happen if I run a 2-stage charger.
The instructions for the Samlex specifically state that if you do hook up more than one battery, then set the charger to 2-stage.
Since I'll be charging two batteries, I'll want it in 2-stage most of the time. Once in a while, I plan to disconnect the lead to the cranking battery, flip the dip switch to 3-stage and do a full 3-stage charge on the deep cycle. Just for jollies.
3) It only costs about $100.
They also make it in a 30a @ 12v version and a 15a @ 24v version:
http://www.samlexamerica.com/products/subcategory.asp?CategoryID=8
Lorenz
New member
Digging up an oldie but goodie with this question.
I love my BatterMINDER. IT's brought back multiple batteries from the dead for me. That said, I didnt have any luck bringing back an Optima Yellow top that I drained by leaving the lights on in my camper while stored. Oops.
I have yet been able to bring any of my 3 odyssey 925 batteries back from the dead in as many years. Parasitic draw killed these guysnin my Race car and Baja bug while stored. I cant get an Odyssey battery to live more than a season or 2. Whats the trick gents? I have 3 cars with Odyssey 925 battery trays that are specific to that sized battery. If it were my choice I wouldnt have built the cars with these specific battery trays, alas, they're small and light comparatively and the off road builders like the size.
How can I get my Odyssey PC925 AGM batteries to live in the off season? I'd love to replace them all with deep cycle batteries that would fit in thier place.
I love my BatterMINDER. IT's brought back multiple batteries from the dead for me. That said, I didnt have any luck bringing back an Optima Yellow top that I drained by leaving the lights on in my camper while stored. Oops.
I have yet been able to bring any of my 3 odyssey 925 batteries back from the dead in as many years. Parasitic draw killed these guysnin my Race car and Baja bug while stored. I cant get an Odyssey battery to live more than a season or 2. Whats the trick gents? I have 3 cars with Odyssey 925 battery trays that are specific to that sized battery. If it were my choice I wouldnt have built the cars with these specific battery trays, alas, they're small and light comparatively and the off road builders like the size.
How can I get my Odyssey PC925 AGM batteries to live in the off season? I'd love to replace them all with deep cycle batteries that would fit in thier place.
Ducky's Dad
Explorer
Your Odyssey 925s are deep cycle batteries because ALL Odyssey batteries are deep cycle. The trick is to put them on a proper maintenance charger once they have been reconditioned or replaced. Odyssey used to sell a series of 3-bank chargers developed specifically for their batteries, but those have been discontinued. I have one of those in the 40-amp version and there may still be some out there as closeouts or on eBay. If you go to the Odyssey website, they have a list of chargers that they specifically approve/recommend for each of their batteries. They also have a new line of chargers on their website, but they are single bank only, no 3-banks in the new lineup. I just got one of their new 20-amp chargers a few days ago but have not used it yet. Odyssey had these chargers designed and built by ProMariner, and they look nice but are pretty expensive (as were the old ones built or them by Schumacher). Odyssey told me that these new chargers have magical properties and that my life will never be the same after using one. We'll see about that. The unit does seem to be very well made, compact, with good features, 6-stage charging and conditioning, fully solid state, no fan. I have a lot of history with Odyssey batteries in the 1500 and 2150 versions, and the 1500s have never exhibited any charging or maintenance problems, while the 2150s have all been a complete pain in the *** to keep happy. Odyssey says their batteries require special charging (particularly 14.7V+ and relatively high amperage), so pay attention to what you get. One key to maintaining the Odysseys seems to be topping it off before it drops below about 12.3V. Odyssey tells me that if your battery does drop below 12.2-12.3V, a low-amp charger will not be able to completely recover the battery's ability to take a full charge to 12.85V or better. My current 2150 will charge to about 12.86V, but it drops to 12.65V the next day and then loses about 0.1V per week if the truck is not driven (parasitic drain). So now I put it on the charger every couple of weeks.
The new Odyssey chargers won't charge any battery that has dropped below 2.5V, but there are ways to spoof the charger by connecting two batteries simultaneously so that the software senses a good battery that needs a charge. You may need to do that with your Optima Yellow. I brought back a few retired Optima Yellows last summer with my little Ctek 7002, worked pretty well.
The new Odyssey chargers won't charge any battery that has dropped below 2.5V, but there are ways to spoof the charger by connecting two batteries simultaneously so that the software senses a good battery that needs a charge. You may need to do that with your Optima Yellow. I brought back a few retired Optima Yellows last summer with my little Ctek 7002, worked pretty well.
Real noob question here... Am interested in this charger: Samlex SEC-1215a - 15a for topping off/ maintaining the jetski and buggy batteries during the winter months. At least one of my lead-acid batteries states "max 1.5A charging". Here's the way-naive bit: can this battery charged on this Samlex (which has a max 15A rating) ?? Thanks to all in advance...
Joe917
Explorer
All battery manufacturers provide charging information for their batteries. Buy a quality charger that can meet the battery manufacturers charging curves.
Simple. AGM's generally charge at 14.4v, flooded with higher internal resistance charge at 14.8v. Different battery manufacturers will have slightly different numbers. Temperature has a huge affect on charging voltages, if the charger does not have temperature compensation forget it. AGM's are nothing special, follow the battery charge profile and you're golden.
Desulfation is the poor man's equalization. Equalizing flooded batteries regularly will massively extend lifespan. Lifeline actually recommend equalization on some of their deep cycle AGM's.
AGM's can be inverted, require no maintenance and have a lower internal resistance( of little value since it only comes into play occasionally)
Flooded spill at high angles, need to have water level maintained( no big deal), have higher internal resistance( overcome with higher charging voltages), can be equalized, cost less per amp hr.
Both need to be charged according to the BATTERY MANUFACTURER'S spec.
Basically it does not matter if it is flooded, AGM, Gell or dilithium, the battery manufacturer will spec the charging requirements. Buy your charger accordingly.
Simple. AGM's generally charge at 14.4v, flooded with higher internal resistance charge at 14.8v. Different battery manufacturers will have slightly different numbers. Temperature has a huge affect on charging voltages, if the charger does not have temperature compensation forget it. AGM's are nothing special, follow the battery charge profile and you're golden.
Desulfation is the poor man's equalization. Equalizing flooded batteries regularly will massively extend lifespan. Lifeline actually recommend equalization on some of their deep cycle AGM's.
AGM's can be inverted, require no maintenance and have a lower internal resistance( of little value since it only comes into play occasionally)
Flooded spill at high angles, need to have water level maintained( no big deal), have higher internal resistance( overcome with higher charging voltages), can be equalized, cost less per amp hr.
Both need to be charged according to the BATTERY MANUFACTURER'S spec.
Basically it does not matter if it is flooded, AGM, Gell or dilithium, the battery manufacturer will spec the charging requirements. Buy your charger accordingly.