Wondering if anybody has used a DC charger to charge the starting and house battery.
The Yamaha 115 VMAX has a 35 amp alternator. So I’m wondering if the minn kota dc charger would charge these 2 batteries?
Also, wondering if I have to worry about interference on the electronics when trolling with the main motor?
The starting battery is already getting a charge off the alternator so you’re good there.
If you want to capture amps from the alternator for the house battery, the MK1 DC is the ticket. I did way too much research on this a couple years back so feel free to pass on the rest, it’s going to be long 
MK DC chargers take “surplus” amps once the main battery is charged. It has a sensor that acts like a gate, once the main battery is high enough then the charger activates to send amps downstream.
Up to 50% of your 35 amps needed to run the motor and the rest can to to batteries. MK has recommended minimums depending on how many banks. MK 1(bank) = 10 amps, MK2 = 20 amps.
ex. I have a 25 amp on my Yamaha 115 and the MK2 DC for my TM batteries. at 10 amp/bank I’ll never fully utilize the charger or meet the minimum recommended. Per call to MK, that’s okay as it will still use what is available. So I’ll still be getting approx 10-15 amps(5-7.5/bank) after my starting battery is charged while I’m making a long run.
Expectations – these are not miracle devices but more of a supplement. If you need 6 hours @ 10 amps to charge at the end of a hard day, one 40 minute run isn’t going to cut it. This is the domain of AC onboard or external chargers.
If you’re really hard on batteries then getting some ampsreplenished using gas you’re already burning, Bingo! If you remote camp and/or have limited access to AC power overnight, it’s almost a hard requirement. If you are out for 4 hours and don’t drain batteries very much, money may be spent elsewhere.
My setup:
1 starting and 2 tm batteries
3 bank MK 315d AC onboard charger(wish it were 330)
2 bank MK 2 DC to capture surplus amps up to the tm batteries
If you tie your starting battery and house battery to a Perko switch you can charge both with the motor.
Thanks for all the info! I am only planning to run electronics off the second battery, heading sensors, 2 helix 10 G2Ns.
Not sure how long they will run on a battery without charging but I would like to be able to get 6 to 8 hours between charges.
So the minnkota dc charger would only be on the starting and house battery 
Does the DC charger charge without the motor running? What we are trying to explain is that you don’t need the DC charger to do that.
https://minnkotamotors.johnsonoutdoors.com/battery-chargers/board-alternator
“Alternator chargers put every ounce of power to good use. While on the water, they take your alternator’s excess power and redistribute it to your trolling batteries. You get an extra boost, and better battery life.”
As long as your motor is running. Keep that in mind if you normally make short runs.
If you own a Yacht, lets say on the river, don’t you typically have a personal assistant monitor you batteries for you? 
To be clear, you are talking about a dedicated starter battery, and a dedicated house battery for electronics, NOT a starter and trolling motor batteries as some have mentioned above, correct?
Just got one of these and am wiring it up this winter. Does everything you want. Alternator tied to starter battery, will charge both once starter is fully charged. Battery charger tied to house battery and will top off starter when it is fully charged on land. Works both directions.
https://www.bluesea.com/products/7601/m-Series__Automatic_Charging_Relay_-_12_24V_DC_65A
Hi Tim,
You are correct just charging the starter and house battery when running
If you tie your starting battery and house battery to a Perko switch you can charge both with the motor.
Not a bad idea for the house battery question here. Less cost and less crap to wire.
Just got one of these and am wiring it up this winter. Does everything you want. Alternator tied to starter battery, will charge both once starter is fully charged. Battery charger tied to house battery and will top off starter when it is fully charged on land. Works both directions.
https://www.bluesea.com/products/7601/m-Series__Automatic_Charging_Relay_-_12_24V_DC_65A
When I looked at this one I didn’t realize it would wait until the starter is fully charged. Good to know. For a one bank application does the Minnkota hold any advantages over this? MK 1 DC is about $20 more.
I’m wondering if either of these kick over to the house battery while your trolling, would you experience any kind of interference on your graphs.
In theory, you are always hooked up to the battery, so there shouldn’t be any difference from a single battery. Just starts charging. Do you see interference while running with a single battery? Again, in theory you should not.
There always could be interference, but then turning on the noise rejection in the sonar would help. Understand there are a lot of variables, but it should be unnoticeable. I have yet to use mine, so don’t quote me just yet. 
Good luck and report back!
<div class=”d4p-bbt-quote-title”>SuperDave1959 wrote:</div>
If you tie your starting battery and house battery to a Perko switch you can charge both with the motor.Not a bad idea for the house battery question here. Less cost and less crap to wire.
The correct Perko has a A battery setting, a B battery setting and a Both setting. You can charge each battery individually or both at the same time.
You must be logged in to reply to this topic.
