Series parallel batteries

[TheLastColdBeer]

Gonna go out for a day fishing with just a 24v Minn Kota troller. My suggestion was to throw 3 deep cycle 12v batteries along with a fully charged car battery, connect them in series parallel, with a combined amp rating around 360amp/hr Figure the motor is going to draw 20amp, so we should be fine for one day of fishing. Argument against was, dissimilar batteries, going to hurt them. My feeling is they're sitting around doing nothing anyway, not going to stress anything close to capacity, what difference does it make? Never tested a system yet (including forklifts) that had every battery perfect, so as long as they're electrically equal, what can limited use harm?

[WeednFeed]

So I assume you are doing what this video shows. The only issue is the non deep cycle battery? It will work voltage wise. I’m not really sure if it will hurt anything. The only thing I wonder about would be sensitive electronic devices. Obviously a 24 volt trolling motor likely has some type of minimal board/electronics.

I highly recommend using a proper 24 volt circuit breaker just in case of a battery failure which may drive some weird voltages to the motor. I installed a 12 volt minnkota CB on my trolling motor. On a personal note I wouldn’t do it. 
Good Luck

 

[major-mark63]

quickly here here an electricity law :

putting batteries in serial  you add voltage .

putting batteries in parralel you had power amps.

If you put two batteries in serial along with two others in parralel

you gonna have 24V and then power amp hours gonna equal two only one side of two parralel batteries.

lets say if you link four 12V 100Ah batteries serial/parralel youll end up with:

24V and 200Ah not 400Ah .

and your weakess link is the regular battery along with his discharge youll have a loss of voltage too .

 

[TheLastColdBeer]

1 hour ago, major-mark63 said:

quickly here here an electricity law :

putting batteries in serial  you add voltage .

putting batteries in parralel you had power amps.

If you put two batteries in serial along with two others in parralel

you gonna have 24V and then power amp hours gonna equal two only one side of two parralel batteries.

lets say if you link four 12V 100Ah batteries serial/parralel youll end up with:

24V and 200Ah not 400Ah .

and your weakess link is the regular battery along with his discharge youll have a loss of voltage too .

 

I didn't want to fill a page with numbers, You are correct. I will end up with 2 banks of 24v batteries, wired in parallel. My amperage will average out to 180amp, for an average runtime of 9hrs. Except we won't be pulling any amperage for any length of time. And yes, a 50amp breaker goes between batteries & motor.

[Timmah!]

Yeah, that title gave me pause; I've used series or parallel, but never both in one setup.

[TheLastColdBeer]

A better Idea was posed to me, forgot I had a 36lb thrust 12v transom mount Minn Kota hanging on the back wall. Putting the 24v foot controlled in the bow, wired with two compatible deep cycles. 36 goes on the stern of the Alumacraft hooked to the Motorcraft car battery, and the other deep cycle kept as a reserve. We should run out of daylight long before we run out of motive power. My first idea was to just throw a couple oars onboard, but that got me nothing but dirty looks.

[major-mark63]

Yes also protection of your battery circuit is a must , cause when battery are getting low the voltage gonna drop and current gonna raise to compensate the power consumed by the motor .

power Watts = volts x amps

[J3st3r]

The real question should be? Is it safe to mix battery types in circuit?

 

A regular car battery isn't designed to be drawn down flat and be recharged like a deep cycle battery is capable of doing. Normally a regular car battery will supply all of it's amps in short bursts. The car battery could overheat and when it dies the other battery adjacent to it in circuit will be doing double duty. 

 

Something will eventually have to give. Worse case scenario 1 of your batteries could explode. Realistically though since you will be pulling a max of 50amp with an 80lb 24v Minn Kota trolling motor it should be just fine. Just bring a volt meter and keep an eye on battery voltages. If the car battery starts to run low unhook it from circuit asap and get your butt back to shore.              

[KaptCrunch]

MM is correct on battery connections styles and protect with a fuse 60 amp on each battery used. if not like MM stated "voltage gonna drop and current gonna raise"  will be so hot will melt through the fiberglass boat when catches fire with out a fuse  protection.......waer a life jacket  

[KaptCrunch]

7 hours ago, Timmah! said:

Yeah, that title gave me pause; I've used series or parallel, but never both in one setup.

you can do both Tim ,  and must use same battery for all, also need to fuse them to protect against fire 

[KaptCrunch]

Quote

Just bring a volt meter and keep an eye on battery voltages. If the car battery starts to run low unhook it from circuit asap and get your butt back to shore.   

Jester  correct the car battery will take you down to the bottom of water     

TLCB  also use minuim 10 gage wire  your good up to 60ft  before wire becomes a heat element after that.  when you get in the water and use motor check connection / wire for heat ..don't touch wire if see it melting 

you  can add a disconect switch to circuit

Edited October 20, 2021 by KaptCrunch

[KaptCrunch]

1 hour ago, TheLastColdBeer said:

A better Idea was posed to me, forgot I had a 36lb thrust 12v transom mount Minn Kota hanging on the back wall. Putting the 24v foot controlled in the bow, wired with two compatible deep cycles. 36 goes on the stern of the Alumacraft hooked to the Motorcraft car battery, and the other deep cycle kept as a reserve. We should run out of daylight long before we run out of motive power. My first idea was to just throw a couple oars onboard, but that got me nothing but dirty looks.

TLCB

 can you  make a diagram of your perposed  set-up  with  each item marked by voltage.  eg

 

[TheLastColdBeer]

This is what I WAS going to do, and yes it works fine. Since I'm putting the 12v troller on the transom, and 2 batteries connected in series in the bow for the 24v troller, this is NOT what I'm going to be using on the lake. Two separate systems, two different motors. One dude runs the stern, and one dude runs the footy while in the coves. Fisherman in the center gets to relax, cast in peace, and maybe run the cooler.

 

[KaptCrunch]

TLCB 

can use a solar panels  while casting and sipping beer and make a canopy of then for shade and run a coolatron cooler need to add a 

run - charge  switch 

hell if have some money buy enough solar panels and run 100% solar with 960 watt   panel

Edited October 21, 2021 by KaptCrunch

[TheLastColdBeer]

One trip, one ping only Vassili. End of season quickie to a wake-less local lake. Not huge, but lots of coves. Bluegill are tiny, going to spend a lot of time laughing about the children we're catching. Shore Gestapo gets all bent out of shape about wakes & speed. They'll barrel down on you with their 100hp Merc @ 30knots, swamping everything nearby if you break their association rules. Hence, the 16' Alumacraft & trollers. Using what's handy & available for ONE day of leisurely fishing. Gets dark here around 18:30, so it won't be a forever day. 

I did have to laugh about melting cables & exploding batteries, holy shite folks, did I not mention this isn't a power trip? Not my first day playing with electrons, and I'm quite used to operating sub-par setups. Nothing is getting stressed, particularly me.

[major-mark63]

8 hours ago, TheLastColdBeer said:

This is what I WAS going to do, and yes it works fine. Since I'm putting the 12v troller on the transom, and 2 batteries connected in series in the bow for the 24v troller, this is NOT what I'm going to be using on the lake. Two separate systems, two different motors. One dude runs the stern, and one dude runs the footy while in the coves. Fisherman in the center gets to relax, cast in peace, and maybe run the cooler.

 

this is correct connection but 4 similar batteries needed , never mix regular and deep cycling .  They are not built the same way.

[Labob]

Did you catch any fish ?

[KaptCrunch]

Labob  yes he did  us  suckers helping him made a better  leisure time with dual power set-up 

TLCB no worries just want to keep you safe, thought i jump on the band wagon of fear mongering LoL

an you not say about the coolatron cooler idea unles you beat me to it  like this thread  

Edited October 21, 2021 by KaptCrunch

[TheLastColdBeer]

11 hours ago, major-mark63 said:

this is correct connection but 4 similar batteries needed , never mix regular and deep cycling .  They are not built the same way.

Quite correct, and I wouldn't consider using them in a full load, extended use condition. Car batteries are amp intensive for a brief period, they don't care for long draws, even with minimal amp demands. This was a once only consideration, but got shelved when I was reminded of the 12v trolling motor hanging on the wall. I have no problem using a car battery on a 12v troller, because we've never made more than a couple of hours use of them. If they peter out...so what. I also use heaver gauge wire on a 12v system vs. a 24v, because you're drawing heavier amperage across a lower voltage. 24v gets the job done at lower amps, so less heat is created. I'm agreeing with everyone, using matching batteries for one system, a single battery for the other, because it's a safer option.

[rexbowan]

What a team! Nice informational team.

[KaptCrunch]

well said the last smart cookie  lol 

on 24vdc  VS  12vdc  systems

lowering the heat  (current draw) on 24v  set-up  

a tip for connection use  anderson  for painless connections and safe .....idiot proof 

SB120  

SB50

note crimp lug then heat and fill with non-acid solder and heat shrink connector only 2/3 of crimp so can get it to lock in connector 

will keep out mositer to prevent corrasion

Edited October 23, 2021 by KaptCrunch

[KaptCrunch]

On 10/21/2021 at 8:33 AM, TheLastColdBeer said:

I did have to laugh about melting cables & exploding batteries, holy shite folks, did I not mention this isn't a power trip? Not my first day playing with electrons, and I'm quite used to operating sub-par setups. Nothing is getting stressed, particularly me.

ah'em TLCB  use a  fuse always for when a battery desides to short out  it will melt into a fireball without a fuse  (note your extra AWG wire will hold that current  till ashes)

besafe  protect self from loss of life or property when doing any electricial design.......  use a fuse will save you greif. speaking from experience.

not a laughing matter only being cheap not using  a fuse in deign

this is for those not using a fuse in any design 

Edited October 23, 2021 by KaptCrunch

[Red]

On 10/21/2021 at 11:40 AM, KaptCrunch said:

TLCB 

can use a solar panels  while casting and sipping beer and make a canopy of then for shade and run a coolatron cooler need to add a 

run - charge  switch 

hell if have some money buy enough solar panels and run 100% solar with 960 watt   panel

hell if have some money buy enough solar panels and run 100% solar with 960 watt   panel

You need a bigger boat

Edited October 24, 2021 by Red99

[Red]

On 10/21/2021 at 3:37 PM, Labob said:

Did you catch any fish ?

I think not only volt and amps