Charging Boat Battery Question?

[LiveBait]

Hi Ifishers,

I have a two battery system on my alumaweld. One of the batteries has much easier access to charge. The other requires taking of a small panel. (not a huge deal, just takes time) Can I put the Pergo switch on all and only hook my battery charger to only one batter to charge both of them? Or do I need to hook the charger up to each battery seperate for optimum charging? Thanks in advance...

Kyle Mason (Hookem and Cookem)

[cptdarel]

GOOD question, I have done it for years, like throw the boat battery in the camper, plug it into a cigarett lighter, travel down the highway, when i go fish its all charged up, while charging the others, however if one is way down and the other is up it may overcharge the other, so some type of isolator is needed.
what we need is a BATTERY EXPERT to log on.

http://www.yachtsurvey.com/boat_battery_basics.htm

http://www.yachtsurvey.com/batteries.htm

[timinthegorge]

Very good info CptDarel.... Thanks.

I'm not sure whether it answered Livebait's question. If I re-state the question incorrectly, let me know Livebait....

Small boat (less than 24') with two batteries, with Perko switch:

Should the batteries be charged individually, with Perko in the "Off" position? Or can the charger (say 2amp, 6amp), re-charge both batteries, in the "Both" position?

I don't know, but I do know what I do, and it seems to work. I turn perko to Off, and charge one battery at a time..... But that's just me.... :laugh:

[Pagorits]

I turn to Both and charge them both. One of the reasons that I feel this is OK is that my fifthwheel trailer has two batteries and they are both charged at once. Good 'nuff for the trailer......Good 'nuff for the boat.

[Phil Layer]

I'm guessing you can charge both at the same time if they are both the same type of battery. It might not be a good idea if one is an RV type battery (slow discharge) and the other is a starting battery.

But then, I don't know much about anything, really. :jester:

[Okie]

If the batterys are installed in parallel and they are both the same type battery, the batterys will reach a level of both being the same charge. If this doesn't happen you have a defective battery in one of them. So it is correct in charging both at the same time. If one battery was in a lower charge and connected to a battery of the same type with a regular charge the lower charge should come up to the other battery so both are approximatly the same charge and the higher charged battery could come down in charge to match the lower charged battery unless a battery charger was conneted to them. (This will probably all confuse you but Ohms Law is in play here)
Good Luck;

[Good News Tuna]

Thats the way I've done it for years with no problem. My boat is mored in central Oregon all summer in full sun with a solar panel and a charge controller. My batteries are 4 years old and going strong.

[LiveBait]

Hi All,

Thanks for the great replies. Both batteries are alike so it seems to me that if your perko switch is set to all that the charge from the one batter would go to the battery with the less charge (due to the weaker battery having less resistance). That is till both are equal, then they would both go up till they have reached their full charge. I'm surprised this hasn't ever been asked before on Ifish. So if anyone has some additional info feel free to throw your two cents in. Thanks all for reading and for those who replied!

Kyle Mason

Happy :smash::smash::smash::smash::smash: Bonking

[FishTy]

here is what I've done for years!! I have a onboard charger( 1 bank 6amp).. I hooked it up to the out giong side of the Perko switch...That way I can use the charger to charge one then the other then when both are fully charged, I witch it to both to keep them up and it works pretty good that way.. I tried doing both at the same time, works ok if batteries are not very low,,but if both batteries are dead, seems to make the charger HOT! don;t worry about batteries too much, but don't want to burn up the charger!

[Gundog]

If you can afford one buy an onboard charger and forget it. Just plug in the boat when you get home and it is always charged. I bought mine on ebay from West Marine for $50. Mine is a Guest charger 2 bank 12 amp model and I bought the Guest through hull plug. The install is very easy the hardest part is the hole in the hull for the plug. The charger has a float position so it does not over charge the batteries and they are always ready to go.
Mike

[cptdarel]

WHAT A SMALL WORLD
Last night on the "Ship Shape" TV the question came up, can you charge both batteries at the same time. answer: YES as long as they are hooked up in parallel in which the PERKO IS, the charger thinks it's just a big battery and both can be charge at the same time.

[chucks electric]

hello, this is an unreliable way to get both batteries charged the battery that is being hooked up to will be the battery that the charger will reference to. the battery furthest from the connection will never recharge fully this is proven fact this is why multi output chargers are made. you need to use a dual output charger that way the charger can adjust independently to the needs of each battery because batteries will discharge at different rates and levels. batteries discharge in amp hours so they need the same energy to be put back in and not the same energy that the other battery used. the charger needs to be connected directly to each battery independently.

[ET]

I've read literature that concurs with Chuck. I have batteries that are difficult to reach so what I do is connect the charger to the posts on the engine and charge one battery at a time. I slow charge overnight with a trickle charger. You don't have to go directly to the battery to recharge... unless of course your cables are bad....