Charging multiple batteries with a plug in charger.

[FluffyChicken]

Is a setup like this possible? If so would that battery tender plus do the job or would I need something else? If the battery tender plus is the answer for the job, how long (hours) would it take to charge 3 deep cycles up? I want something i can just mount in the boat and i'll run a little cord along the side and plug it in when i park it in the driveway. Keep in mind these batteries will not be attached to the motor in any way. I want to charge them when i get home and have them ready to go for the next day. If they die while im out there then so be it but 3 125amp hour batteries should power my stereo and fish finder for quite some time.

 

[bruceb58]

Re: Charging multiple batteries with a plug in charger.

A battery tender plus is only 1.5 Amps.

If your batteries were discharged half way, it would take over a week to charge them back up. You need a lot bigger charger.

 

[Silvertip]

Re: Charging multiple batteries with a plug in charger.

That Battery Tender is also not water proof, nor is it ignition protected meaning it could cause an explosion if gas fumes gather in the area the unit is installed in. You need a three bank on-board charger with a minimum 5A rating per bank. These are "smart chargers" and can be plugged in indefinitely without harming the batteries. Guest, MinnKota and a host of others manufacture on-board chargers.

 

[dooma_Flatchy]

Re: Charging multiple batteries with a plug in charger.

Sorry Northcoast for jumping in on your thread..

Can I do this with a 2 battery system. I charge my batteries when I get home from a day on the water and I have to switch leads when one battery is charged . I would like to charge them and put them both on trickle charge until next time to use?

 

[FluffyChicken]

Re: Charging multiple batteries with a plug in charger.

If i get a 3 bank charger could i leave them hooked up in parallel and hook each battery up to its own bank? And if so how long would it take to charge them?

 

[bruceb58]

Re: Charging multiple batteries with a plug in charger.

You divide the capacity that you need to replace by 5 amps. It will actually be a little more than than that because of inefficiencies and heat generation.

 

[Silvertip]

Re: Charging multiple batteries with a plug in charger.

If you have three batteries in parallel and wish to use a three bank charger it doesn't matter whether you hook each output to a single battery, or if you parallel the charger outputs. They will be in parallel regardless how you connect to the batteries. Three bank chargers get expensive. Why not by one 15A smart charger for half the price and be done with it. As for length of time to charge, it again doesn't matter how the chargers are connected. A single 15A charger will charge three batteries in the same time as a three bank charger with 5A per output (5 x 3 = 15 where I went to school).

 

[FluffyChicken]

Re: Charging multiple batteries with a plug in charger.

Ok cool thanks now how do i figure out how long it will take to get a full charget back?

 

[Boatist]

Re: Charging multiple batteries with a plug in charger.

Three 125 amp hour batteries or 375 amp hours will take about 46 hours witha 15 amp charger. To fully top off about 72 hours. In reallity you should never discharge more than 50 percent if you want your batteries to last several years. So 50 percent of 375 amp hours = 187.5 amp hours, with a 15 amp smart charger will likely charge at about 8 average to replace most of the charge. It will start out near 15 amps and taper to 0 amps. To fully charge for the health of the batteries still likely to take 48 hours. If the battery was 50 percent discharged and the charger put out 15 amps the whole time which it will not it would still take 12.5 hours.

A 5 watt stereo would be heard anywhere on your Boat and elminate all the charging problems.