Batteries

[mikke60]

A little off topic maybe, but what are most of you using for batteries onboard?
Thanks, mike

[hanleyclifford]

group 31, flooded, deep cycle

[romantic comedy]

group 24 starting battery lead acid flooded

Trojan 6 volt deep cycle lead acid flooded (golf cart size) I think that they are T-105

[The Garbone]

Have mix of 2 group 27s and a Group 24 starter battery. All of unknown age but still working well as I got them with the boat 3 years ago. All the battery trays and wiring is new though and I am waiting for the 27s to die so I can put in some golf cart batteries.

[joe_db]

Gel 31 for house and gel U1 for start. Note gel is NOT the same as AGM

[ndutton]

Mike, please consider your current charging system if thinking of changing your battery type. Said another way, changing the battery type may require a complete charging system change for the new batts to perform well. I learned this the hard way. The dimension of AGM's solved a fitment problem and I'd read only wonderful reviews of them, deep cycling, 3X life, faster recharge and they would would fit where I wanted to put them, a perfect solution @ $240.00 per.

Yeah, until I spent a weekend at Catalina.

What all the glowing reports didn't say was the AGM preferred a higher charging voltage and different charging profile than my system (that worked well with conventional flooded batteries) delivered. Hours of engine run time produced a poor recharge, the battery lasted barely 2 hours after recharging, refrigeration shut down (low voltage shut down protection circuitry), lighting was dim, water pump barely ran at all. I decided I was unwilling to spend more on a new charging system just to make these expensive batteries perform up to the advertising claim - - or even back to the level of the old batteries we've all used in the past.

As you can surmise, I continue to use conventional flooded batteries.

[hanleyclifford]

At $240 a pop the fancy stuff would have to last over twice the time of the el cheapo flooded - and perform. Dollar for dollar and amp hour for amp hour I don't see how you beat the boutique flooded 31s.

[ndutton]

At $240 a pop the fancy stuff would have to last over twice the time of the el cheapo flooded - and perform. Dollar for dollar and amp hour for amp hour I don't see how you beat the boutique flooded 31s.

The attraction was fitment. The AGM would fit where ANY flooded batt of decent amp-hours would not. After trying the AGM my conclusion turned out to be the same as yours, it wasn't worth it. A different battery location was in order.

The good news was I only bought one AGM, not an entire boat's worth. It now sits on my spare engine stand in starting duty.

[The Garbone]

I work for the phone company and we started putting new gen batteries at all our "critical" locations. You are dead on about the recharge rate as the same amp hours in battery bank required many more rectifiers to feed initially causing very high loads on the power supply and heat failures as well as harness failures etc. Sure the cells last 10 years as apposed to 4 or 5 years but the power plants had to be expanded or replaced to adjust for the new cells, in the end costing well over 10 years of battery bank prices for lead acid would have. Turned out to be overkill on retrofitting but for new plant its ok.

Same applies to boats imo, when it takes decades to recover sunk cost it is not that good of a deal. I prefer to let early adopters take it in the shorts.


The sales lady for the battery manufacturer was a pretty lady, sure that had nothing to do with spending millions on the batteries though, remember sitting in class asking "but what about that charge constant chart and loading of the rectifiers" got a dirty look.....

[edwardc]

Two Gr 31 gels paralleled into a single 194AH bank (per Nigel Caulder), and a U1 gel for starting. Very similar to joe_db's setup.

When charged with the proper profile, and never discharged below 50%, they have about twice the lifetime of AGMs. I got 12 years(!) of service out of the last set, although capacity was definitely degraded in the last year.

Still not quite the bang-per-buck of flooded cells, but close. And beats AGMs easily.


Comparison data from East Penn/Deka

[joe_db]

Yes - gels can charge faster than wet cells, which is both good and bad. One bad effect is your charging system sees lower internal resistance and a basic charger can overload itself.
AGMs can also charge faster, so you may see the same effect

I work for the phone company and we started putting new gen batteries at all our "critical" locations. You are dead on about the recharge rate as the same amp hours in battery bank required many more rectifiers to feed initially causing very high loads on the power supply and heat failures as well as harness failures etc. Sure the cells last 10 years as apposed to 4 or 5 years but the power plants had to be expanded or replaced to adjust for the new cells, in the end costing well over 10 years of battery bank prices for lead acid would have. Turned out to be overkill on retrofitting but for new plant its ok.

Same applies to boats imo, when it takes decades to recover sunk cost it is not that good of a deal. I prefer to let early adopters take it in the shorts.


The sales lady for the battery manufacturer was a pretty lady, sure that had nothing to do with spending millions on the batteries though, remember sitting in class asking "but what about that charge constant chart and loading of the rectifiers" got a dirty look.....

[Administrator]

FWIW, I had occasion to look, up close and personal, at a Duffy electric boat recently. The boat was packed with twelve 6-volt batteries.

Is there an advantage to pairing up 6-volt batteries instead of using the 12-volt alternative?

All were wet cells, BTW. Duffy offers a remarkably expensive "single point" system for topping off the wet cells. They'll sell you that, but don't ask for a compass.

Bill

[Al Schober]

Engine start is Gp 24 flooded. House is 2 of Gp 31 flooded. 65A alternator controlled by Balmar (series IV?), feeds to the house bank. A combiner sends charge to the start battery.
The Gp 31s are getting old and tired - probably down to 60 or 70% capacity. I'm thinking of replacing them with 3 of Gp 24 flooded - those Gp 31s are just too heavy!

[The Garbone]

FWIW, I had occasion to look, up close and personal, at a Duffy electric boat recently. The boat was packed with twelve 6-volt batteries.

Is there an advantage to pairing up 6-volt batteries instead of using the 12-volt alternative?

All were wet cells, BTW. Duffy offers a remarkably expensive "single point" system for topping off the wet cells. They'll sell you that, but don't ask for a compass.

Bill

I think it is just to get a few more amp hours out of the space as there are fewer plates (cells) in a 6volt and they can make the plate thicker and a little harder to kill. My experience with 6 volts is you may get an extra year or two out of a string before they go bad.

[romantic comedy]

Bill, I always figured that weight and size were the issue with 6 volt vs 12 volt.

I use the Trojan T 105 6 volts. I had two L-16 (I think) 6 volts batteries. They were tall and 125 pounds a piece. Called traction batteries.

I have also seen batteries where you have each cell removable. I have seen one boat that had Rolls batteries t hat were this way.

Ever see the ads in the magazines? You buy them by the 2 volt cell.