Charging marine batteries

[northernpike56]

Hi guys, I just got a 12 volt trolling motor from a friend for my canoe, but I dont have a marine battery for it yet. 2 questions for the pros out there:

1.) is one full size marine battery good enough for a couple hours of use of the trolling motor? It is 32 lb thrust.

2.) in terms of charging the marine battery, can I just hook it up to my battery tender for my car, and set the battery tender to 2 amp trickle charge and charge it that way, or do I need to buy a designated battery charger for whatever marine battery I decide to buy?

 

Thanks,

Matt

P.S. Any other tips would be appreciated as well (long term storage of batteries, good brands, etc etc)!!

[Fisherman]

Q1. Yes

Q2. You can use your Battery Tender for that. If it's a "smart" Battery Tender that has the maintainer mode, you can leave it hooked up all winter.

[NANUK]

1- how long a battery will last depends on " Amp hour rating " of your battery and " Amp draw " of motor.

Example :

battery rated @ 120 amp per hour

Motor rated @ 40 amps ( full speed )

Battery should last for 3 hours at full speed, or almost twice as long @ half speed .

 

2- a battery tender @ 2amps will eventually charge the battery, but it will take 60 hours to charge that 120 amp hour battery when fully drained, ( just an example )

That is not a good way to charge a deep cycle battery,

Ideally you want to fast charge a deep cycle to 85% ( I use 10amp or 15amp rate of charge ) and than trickle charge it to 100 %. A good automatic charger will do that for you.

Trickle chargers are for storage / maintenance purpose .

[Lape0019]

I agree with stonefish.

 

The higher the reserve capacity, the longer the battery will last. You have to figure out how you plan on using this motor. If you are going to use it for your main power (instead of paddling), get the biggest battery you can. A group 31 with the highest reserve capacity you can find/want to spend the money on is what I would recomend but be warned, they do get expensive.

 

Most people I have seen use an electric on a canoe only run one battery because they are bulky and heavy.

 

As for your tender, it will work but as said above, will take forever to charge a deep cycle. I use a 10 amp (mk330 which is 3 banks for my 3 batteries at 10 amps per bank) charger and after a full days use, it usually takes about 3-6 hours to charge back to full.

 

 

Adam

[BillM]

Depends on which Battery Tender model you're talking about. You definitely don't want to set it to a 2A trickle charger however.

[northernpike56]

Awesome thanks so much guys, the battery tender I have is one of the "smart" ones with a 2A, 4A, and 6A option, and will float the charge when it detects the battery is fully charged. I use it on my car that I don't drive during the winter. It sounds like maybe I should look into getting a 10 or 15 amp one that is "smart" and will maintain the charge

[NANUK]

I wouldn't use a charger more than 20% of battery's reserve capacity.