Battery Chargers - Suprising differences

[sschefer]

I don't want to start a big debate over this. I can only tell you what just happened.

My batteries are one group 24 start/deepcycle (starting) and 2 group 29 start/deepcycles (house). I charged them individually with my $100.00 Shumacher charger that I got at O'reilys. They were out of the boat and they all csme up to 100% at 13.4v according to the readout on the charger.

I installed my new Minn-Kota MK 345D tripple charger, put the batteries in the boat and the amber indicator lights went to solid amber indicating it was flood charging. after about 15 min the lights begin to flash indicating the charger was in absorbtion mode. According to the manual the charger goes from flood to absorbtion at 75% charge. I pulled the plug and broke out my hydrometer tester and sure enough the batteries were at about 75% charge. I never checked them with the hydrometer since I got the Shumacher charger I just trusted it.

So I guess the standard automotive chargers can't do deep cycles correctly even though the manual clearly states that it will and even has a position for large batteries that is supposed to be correct for the batteries that I have.

I'm not going to tell you to go out and pay 400.00 for a charger but if you're batteries aren't lasting as long as you think they should this might be your problem.

As a side note, this is the second charger I've had. I took the first one back because I suspected something was wrong with it. I don't know why I didn't use the hydrometer then, brain fart I guess.

 

[fishrdan]

Re: Battery Chargers - Suprising differences

Interesting, here's my experience.

I bought a couple 20 amp Schumacher battery chargers at Sams Club 5 years ago ($10 on clearance ) that have worked great for my jon boat trolling batteries, gp29 start/deep cycle. I hydro'd the batts about a year ago and they were doing great, hope I didn't just jinx myself... My Schumacher's have a battery type selector (regular, deep cycle, AGM), does your charger have that button? Since buying those chargers, and using them religiously after a trip, I haven't had battery issues with that boat.

I put a MK330, 3x10 amps, in my 18'er 3 years ago, and while it's worked well, I did completely cook a battery with it. The gp29 start/deep cycle battery wasn't very old, but out of warranty of course. I'm thinking the batt got an internal short that the charger ran away with. I check the batt's electrolyte level a couple times a year, but when the charger wouldn't go to a charged state on that bank, I checked again and the battery was bone dry. (Aluminum boat + battery acid = very bad, so I flushed the carp out of it, to make sure the acid was washed out.) Other than that one cooked batt, the charger has worked great. My MK charger is older than yours as it does not blink when it goes to absorption, just amber when it's charging and green when the cycle is complete.

Different charger models, different experiences I guess. I do agree, if batteries are not lasting long, the charger could be the problem,, and that it's a good idea to use a hydrometer. President Reagan said it best, trust but verify...

 

[sschefer]

Re: Battery Chargers - Suprising differences

fishrdan, yes, my Shumacher was the top of the line enthusiast (my term) type charger with all the bells and whistles. West Marine sells the same charger in a different box (made by Shumacher) and I threw it away when it started doing crazy stuff to my Optima's in and out of the boat. It was telling me they were sulfated and they were only about a month old and besides, they were AGM's.

I just went out and checked all three batteries and had green flashing lights on the charger indicating the batteries were fully charged. They hydro'd as fulyl charged also. On this charger the lights will go solid green after 24 hours of flashing green. That tells me it's in maintenance mode. It then shuts off and monitors the voltage. If it drops below 12.6 it will come back on and bring them back up to 13.4v.

I was also plesantly suprised when I pushed the button on the trolling motor and the battery level indicator on the 4th light wasn't flickering. That's the first time it hasn't done that since I installed it which I think is another sign that I'm back on the game plan now.

 

[Faztbullet]

Re: Battery Chargers - Suprising differences

This could have been your problem with your Optima battery Steve (from Optima website)
An OPTIMA battery is an AGM battery, not a gel battery or regular flooded battery. A deeply discharged OPTIMA battery (less than 10.5 volts) will not test or recharge properly if treated as a gel battery or regular flooded battery. A handheld electronic battery tester will most likely provide inaccurate test results.
Most high-quality, modern battery chargers now have built-in features to charge AGM batteries like OPTIMA batteries. Some have specific AGM settings which should be used to charge an OPTIMA battery. Do not use gel or gel/AGM settings, as they will not fully charge an OPTIMA battery and could damage it over time. However, even some AGM-compatible chargers will not recharge deeply discharged (less than 10.5 volts) OPTIMA batteries. It may be necessary to follow the instructions provided in Section #3.

For regular charging we recommend a maximum of 10-amps, 13.8-15.0 volts. For float charging, we recommend 1 amp maximum, 13.2-13.8 volts.

 

[Todd4]

Re: Battery Chargers - Suprising differences

I had (still have) a top of the line Shumacher battery charger that worked fine for about a year (charging AGM deep cycle batteries) and then suddenly it appeared that it would stop charging before reaching a full charge (even though it indicated a full charge). After switching to another charger (CTEK) my batteries appear to fully charge again. They are AGM so I can't check the electrolyte, only volts. Hopefully my CTEK charger will last longer than my Shumacher did. Now I'm adding a MK onboard quad battery charger that should make charging all those batteries a LOT easier.

Todd