Trickle Charger/maintainer Question

[Shewillbemine]

Hi Folks,

 

I'm connecting a solar trickle charger/maintainer to my boat and I'm not exactly sure which battery to hook it up to. I'd appreciate any input you may have.

 

I have 3 12v batteries on the boat: 1 starter battery and 2 12v batteries for my trolling motor. 

 

I also have a Perko switch that only has 2 settings: ON or OFF.

 

Do I place the alligator clips onto the starter battery only and expect the other 2 12v batteries to be charged as well?

 

Or should I eventually connect the alligator clips to the other 2 12v batteries in order to charge those as well?

 

An onboard charger is NOT an option right now as the boat is kept in storage without access to power. I'd like to avoid lugging the batteries on and off every time I have a fishing trip.

 

Thanks again!

[camovan]

You could probably make a simple parallel wiring harness that would allow all 3 to be charged at the same time.  My guess is the trickle charger from solar power is going to be pretty low current so small gauge wire and clips will work and be cheap.  There are some disadvantages to doing it this way but if it is in a storage unit without power the trade off might be worth it.  I would suggest giving them a full charge with a decent charger before storing and then leave the charger hooked up as a maintainer  if that is a possibility.

[slonezp]

I only see those units on boat lifts. I keep my boat in storage with no electric available because the HOA won't allow me to keep it in my driveway for more than a 24hr period. I pick up the boat the night before I head out and plug it in. Is that an option you might have?

[Sam]

Check  with the manufacturer to obtain their input.

 

I would think you would be able to charge only one battery at a time.

[Way2slow]

Couple of things you are going to need to do.

First, what is the current output of the solar charger. To maintain three batteries, its going to need to be at least 1 amp.

Next what is the maintenance voltage from the charger. Most deep cycle batteries require approximately 13.17 VDC for the proper maintenance voltage. Cranking batteries are usually 13.2-13.4 VDC, depending on the type battery. 13.2 will work on the deep cycles but you have to keep check on the electrolyte level.

As mentioned, the batteries will need to be fully charged before connecting to the maintainer.

The next thing is, how are the two TM batteries connected. If it's a 24 volt system, the batteries are connected in series and you will have to disconnect the interconnect cable between the two batteries before you can connect them in parallel to connect the maintainer. If it happens to be a 12/24V system with the run/charge switch on the front panel where the TM plugs in, then you should only need to put the switch in the CHARGE position. Provided someone hasn't gone in and bypassed it.

 

Please note, I had a typo error for the run/charge switch, switch must be in the Charge position, but like FR stated, do it carefully.  The safest way is to disconnect the inter connect cable between the two batteries.

[Fishing Rhino]

I'd be very wary of trying to hook up both trolling motor batteries simultaneously.  You'd have to disconnected the "jumper cable" that connects the two batteries in series.  You can hook up the cranking  battery and one of the tm batteries simultaneously.  As you charge the single tm battery, the higher charged battery will "bleed" power to the tm battery that is not hooked up to the charger. 

 

When a battery gets old it may still start an engine.  And it may seem fine when left for a short period of time.  But at some point, the "weak cell" in the battery pulls the remaining cells down.  After the vehicle has set overnight it will crank noticeably slower, and might not be able to start the engine.  It's the weakest link in the chain thing.  In the same way, the battery that is not charging will draw power from the battery being charged.

 

The reason you have multi bank chargers for boats is that each "bank" is separate from the others.  That's why you can connect them directly to batteries that are in series.