Batteries / Battery Charger

[denpooch]

Hey Folks I have a question regarding batteries. I borrowed a 'snap on' tools battery tester and I have two batteries that must be replaced. Last season I replaced port starter battery and bow thruster (they are wired in series for extra 'oomph' when engaging thruster). I went with AGM cells because I had read that they have a quick recovery when discharged. I figured this made sense for the thruster. I have recently learned that we should not mix battery types. If wet cell...all wet cells. If AGM... all AGM's That was not the case last season as I had the mix of both technologies.
I am thinking that I will replace the two bad batteries ( house and Starboard starter) with AGM. I called Carver today and spoke with Brian who mentioned that I should change the battery charging 'type' on the CHARLES 5000 charger which is permanently mounted in the engine room.
Who even knew that the unit needed to be adjusted for battery type? I must change setting to AGM. Question for the pros:
Did I damage batteries by having a mix of technologies? Since the charger is factory default to 'gel', are the batteries compromised? Is there any reason not to go with the AGM technology since all batteries in the bank will now be AGM.
What do you think? Thanks

[Viper]

I wouldn't sweat not having set it properly last year, but you should change it soon. The charge curves between the two types are pretty similar, the differences being 10ths of a volt. Having said that, it is correct that different types of batteries should not be mixed in the boat because each type has its designed/preferred charge voltage requirements. You should also not mix different batteries of the same type within the same bank, this applies to age as well. That tester would have given you a pretty good indication whether the new batteries were vastly affected or not.

AGMs are good batteries, they have some desirable qualities however in my experience I don't find they last any longer on average than flooded for the additional cost though most expect they will. Flooded is still the best bang for the buck IMO.

[denpooch]

Always good information Viper. Thank you.
I do think that one of the newer AGM batteries was affected as the 'state of health' meter is low on the (good) range.

[km1125]

What Viper says is good. The AGMs and Wet cell are the same chemistry, just a different packaging.

GEL are different and VERY sensitive to a higher voltage over long term. It will destroy them. That's probably why the charger is set to GEL by default. If you used it on another setting and had GEL batteries you'd destroy them quickly.

Setting it on GEL and using it on the other batteries (AGM or Wet) will not be the best for the batteries but it won't destroy them. You'll lose a bit of capacity over time though.

Is your thuster a 24v thruster? Are you paralleling that battery with the start battery, or are they in series? If they are in series, what do you use to charge the thruster battery?

The problem with using batteries of different type is in the recharging. If you're recharging them independently, then it's perfectly OK to have different battery types. If you're trying to use the same charger input (and the batteries are in parallel or in series) then it makes a huge difference if the batteries are not the same.

[Viper]

If you bought the AGMs last season, I would get a printout from a good battery tester and take the battery with the printout back for warranty. They'll want to do their own testing but if it's a good brand and retailer, they'll stick behind their product. I doubt it would have been affected that much but there are a lot of variables involved. Can't hurt to try.

[Viper]

QR_BBPOST....If you're recharging them independently, then it's perfectly OK to have different battery types....

I'm not sure I'm following but I might be reading it wrong. Unless you have a very expensive charger where you can program a different battery type for each bank, or are using multiple charges, all the batteries on the boat being maintained by the same charger with multiple bank outputs should all be the same type so the (single) charge curve setting suites all the batteries hooked up to that charger.

Having said all that, what do we do about the charging characteristics when the batteries are being charged by your conventional alternators that don't have settings for different battery types?
There are smart alternator charger systems out there now that are becoming more popular due to the higher costs of some battery types but very few people upgrade this part of their charging system when upgrading to expensive batteries.

[bud37]

Denpooch...... Let us know if you find a switch or some way on that Charles 5000 charger to change the profile.

[Cooler]

Bud37 - The battery chemistry selector switch is on the bottom. See page 6 of the manual for details: http://www.charlesindustries.com/marine ... argers.pdf er

[denpooch]

Yea COOLER that's it.
KM its a 12 volt thruster and the two starter batteries (900 CCA) are wired in series. Per the owners manual regarding the Charles 5000:
"...The voltage levels of both engine batteries and the “house” battery are monitored and maintained by a single battery charger.....The voltage level of the generator battery is monitored and maintained by a single battery charger.."
I figure if the battery charger is maintaining the starter battery then it is also wired to the thruster battery 'in series'.
Since the Genset battery tests 'good', I will set the 30A Genset battery charger to 'Lead Acid'.
Viper the owner manual also states: "...While the engines are running, their alternators generally supply enough power to replace the power used by the boat’s 12-volt equipment.."
So I guess they are not too worried about that. No 'smart' alternator for me.

[bud37]

QR_BBPOST Bud37 - The battery chemistry selector switch is on the bottom. See page 6 of the manual for details: http://www.charlesindustries.com/marine ... argers.pdf er

That is only if he has the newer SP model charger, which he may well have in a 2005.