50 amp+ charger for Gel Batteries - does it exist?

[Hideaway34]

Hi there,
We have a 20 amp charger for our gel batteries on board and with a generator, we only get 10 amps/hour.

This is not ideal and we're wondering if we can get a charger of 50 amps+, or if we'll need to change to AGM/Lead Acid batteries to get this kind of power from a charger?

Anyone know of a good charger for gel batteries?

Thanks,

Tasha (Turf to Surf)

[brantleychuck]

The sterling charger is very good and versatile charger, It does it all and at a good price. I like mine and I went for the optional remote controller. Here is a ebay link Sterling Power Pro Charge Ultra 12V 50A Marine Battery Charger 3 Banks | eBay

[skipmac]

Part of the problem may not be the charger but in how batteries and charging works.

When a battery is discharged then it can take a lot of amps but as the charge builds up in the battery the resistance to more charging also builds. So the more charged the battery is the fewer amps it will accept. Would not matter if you had a 200 amp charger the battery would only take so much.

Don't recall the exact numbers but once a battery is maybe 90-95% charge it may only accept a couple of amps or so. To get that last bit of charge to 100% will take hours and hours. Not really practical with a portable generator. Easiest just to plug in occasionally.

For cruising what most sailors so is cycle from mostly charged to not too discharged, say from 80-90% charged to no less than 60% discharged. That allows you to get the most charge into the battery in the shortest time without discharging so low that the battery is damaged.



NOTE: you could overcome this by turning up the volts on the battery charger really high but it would ruin up the batteries, maybe start a fire, and other terrible things.

[btrayfors]

Tasha,

I second the recommendation for a Sterling Pro Ultra charger. I've tested and installed several of these for customers...they are an excellent choice.

HOWEVER, that may not be your problem at all.

A battery will take what it's going to take in charging amperage, depending on its state-of-charge (SOC) and on the charging voltage. It will take no more, even if you were to connect a charger with 10X or 100X the capacity.

Gelled batteries in good condition will accept about 20-25% of their rated capacity in charging amperage when they are significantly discharged, say to 50% or so. As the SOC rises, they will accept less current.

How many gelled batteries do you have, and what is their capacity? Their age?

Bill

[Maine Sail]

Tasha,

Also keep in mind that if your charger is an older "two bank" model they are sometimes split down the middle meaning one bank gets 10A and the other bank gets 10A. They call it a 20A charger but really it is a 10 & 10 charger.... With these older chargers if the start bank only needs 1A, tough luck, 9 amps are wasted. Many older chargers were set up this way.

Newer chargers like the Sterling Pro Charge Ultra or ProMariner ProNautic P distribute the power based on demand so if the GEL bank could take 50A the charger would supply it to that bank.

[jongleur]

Bad idea to turn up the voltage. If I remember correctly, gel batteries do not like to see more than 14.2 volts, ever.

A neighbor had a gel battery that he tried to charge over 14.2 and it screamed for a while with a very high pitched whine until it died, pretty quickly.

[ranger58sb]

ProMariner offers a 60-amp charger, and their products are usually setabble for lead acid/AGM or gel. Probably other companies have similar products.

-Chris

[HopCar]

I'm partial to Newmar Chargers. They are very reliable and have a Gel setting.
They make a 7, 14, 25, 40 and 80 amp 12 volt chargers.
These are high end commercial duty chargers that meet ABS standards.
Newmar PT-40 Phase Three Smart 12 volt Battery Charger

[hellosailor]

Tasha-
"We have a 20 amp charger for our gel batteries on board and with a generator, we only get 10 amps/hour"
In the simplest case, what is wrong is that your generator can only supply thta much power to the charger, so what you will need is a larger generator.

But it could be that, or a defective charger, or the batteries not being able to suck up the larger charge, a number of things. Don't assume randomly throwing a more expensive part into the system will fix anything.

You could document and test the entire system, with some reading and some help online, or you could pay a marine electrician to check it out. But randomly buying "more stuff" ? Is often the slowest and most expensive way to go.