Battery power ?

[frankS]

Hope someone can help me with a possible battery problem. I tested my new Watersnake bow mount electric motor out yesterday.

It is the Geo spot gps 65 lb 60 inch shaft model the boat is a 4.85 savage Scorpion 2 people on board with light breeze and low chop in Botany bay.

Approx 5 hours use both trolling at verious speeds from 1.7 k's per hour up to 4.8 k's per hour and a bit of spot lock that used the motor to hold position .

My battery is a 180 amp hour which was fully chargged to start with. At the end of my 6 hours on the water approx 5 hours of using the electric my battery went down to one light displayed on the motor and the remote told me the current had dropped down to 11.5 volts.

This seems excessive power loss to me as I used to run my old bow mount on much small boat all day with a 115 amp hour battery sometimes 2-3 days away using electric motor on and off without the battery ever being fully discharged.

I bought the battery on line from an Auction site so I am thinking that maybe the battery is some how less than standard and it may have been a reject battery some how ?.

What is the thoughts of other electric motor uses 

? should a large battery last longer than 5 hours use on a 4.85m boat 

? Or am I just being Perrenoud and expecting too much from the battery ? . 

Frank

[Rebel]

Frank,

You need to speak to somebody like Battery World.

They will advise you.

Good luck.

[slothparade]

I have the same issue on my car. I'd say that the battery has had it, guessing it's a lead acid? 

The power usage on your motor shouldn't be that bad through. Have you checked you don't have anything else wired to it? 

Have a look at the draw from the motor then add a bit for conditions, that should be an indicator of how long your battery should last. Leave a bit of wiggle room but if it's significantly different, (lasted a lot less than it should have) that will indicate you have a did battery. 

How old is the battery? They loose a bit of amp hours each charge, might also indicate you need a new battery.

Hope this helps, probably not the worst idea to talk to a store as mentioned before 

[frankS]

I bought the battery as a NEW battery about 12 months ago and has been sitting in my workshop with just the occasional 12volt drill being used from it.

Charged it up to full capacity the day prior to putting it in the boat.

The charger unit is a 100 amp charger for majority of charge then I put it on my small Ctec charger for final trickle charge which red full charge before putting in boat.

The battery

The charger

Charger size comparison gas bottle is full size bbq bottle think 9kg so it's not a toy charger

Frank

 

[xerotao]

Thats a donkey of a battery? Whats its amp hour rating? Charge it to full and do a draw test to work out its true rating

[frankS]

Pardon my ignorance but how do you go about doing a " draw test " ?. and what do I need to do this test ?.

Battery bought as a 180 amp hour .

Frank

[Fab1]

You have a 180amp battery.Your leccy draws up to 50 amps of power.In theory your battery will be pretty much flat in 3hrs and 40 min of continuous use.

A 180amp battery can deliver 180amp for 1 hour.You have a motor drawing 50amp.(3 hrs you’ve used 3x50amp=150amps).

  It doesn’t take long to have a flat battery without it being charged from motor while running.

  From what I’ve seen they use a lot of power those leccys and good batteries ain’t cheap.

I’ll stick with the wind and anchor on mine.

Hope I’ve made sense as it’s been decades since I learnt a little about electricity.

[frankS]

Fab1 OK mate, that sorta makes sense to me the way you put it. I did have the leckie going constantly most of the time I was out there, varied speed of troll and power from setting 2 right up to 10 ( max ) at times and a few spot locks to test the thing out.

It is a reasonably large boat for a 12 volt electric motor and now I realize how much battery it can draw I will not use it as much in the future.

Yesterday was more about testing the electric and my new 9" Lowrance sounder out, spent most of the day playing with the new toys rather than concentrating on catching fish, so I will use that as my excuse for having an ordinary day as a fish catcher.

Frank

[Fab1]

7 minutes ago, frankS said:

Fab1 OK mate, that sorta makes sense to me the way you put it. I did have the leckie going constantly most of the time I was out there, varied speed of troll and power from setting 2 right up to 10 ( max ) at times and a few spot locks to test the thing out.

It is a reasonably large boat for a 12 volt electric motor and now I realize how much battery it can draw I will not use it as much in the future.

Yesterday was more about testing the electric and my new 9" Lowrance sounder out, spent most of the day playing with the new toys rather than concentrating on catching fish, so I will use that as my excuse for having an ordinary day as a fish catcher.

Frank

Considering how much you used it and for how long….I don’t think the battery is a dud mate.Enjoy yourself out there mate regardless if you catch anything or not.

[Sharknado]

Ground issue maybe??

[zmk1962]

@Fab1 is on the money, I too think its consumption related ... especially if the motor was going hard for 5hrs of the day.  

@Sharknado ground issue? ... are you thinking something like a poor ground ... or that the Watersnake itself is somehow grounded to the hull - perhaps internally or through the mounting bolts?  I don't feel a ground issue would be contributing that much AMP loss - Frank said the only other device running (that could be drawing current AMPs through the hull) was the Lowrance and it consumes like 1-2AMPs/hr... definitely not in the 20-30s.  Also I would have thought that amount of AMPs (20-30) flowing through the hull would result in visible electrolysis somewhere, but they're just my thoughts,  maybe you have some real life experience regarding this that you could share and we can learn from.

Cheers Zoran

[Fab1]

Like I said above a 40 amp draw  to power a leccy is a fair chunk to drain a 180 amp battery relatively quickly that hasn’t got any voltage going in to help it stay charged longer.
 

 It’s like leaving your headlights on in the car with engine off it won’t be long before you’re greeted with a flat battery.Start the car up to supply voltage form the alternator to keep the battery levels up and as you know you’ll be able to use headlights indefinitely.

 As @zmk1962and myself have said it would be consumption for sure with the amount of hours you used it and the Amps drawn.

[noelm]

In reality, it's a very simple DC series circuit, all parts, both positive and negative are equally important, break either one, anywhere, nothing works! Just going by Fabs data, the battery use is pretty close to being right.

[frankS]

The electric motor is connected to the battery via an anderson plug and nothing else is connected to it.

Frank

[Fab1]

4 minutes ago, frankS said:

The electric motor is connected to the battery via an anderson plug and nothing else is connected to it.

Frank

It’s just consumption mate.If it’s too much you need to use leccy sparingly or run dual batteries.

[frankS]

Yes I realize that after your explanation earlier.

I thought it would do much better but I do realize it's a pretty big boat for 12 volt electric and I did put it through it's paces to check it out, normally i would not push it to it limits like I did.

I bought this electric mainly for it's spot lock feature and it's tracking feature. It proved itself to me as a good investment as a spot lock.

Things may be a bit different off shore with a moderate chop.

I am just going to have to take my battery charger with me when I go away for days on end and charge it each night.

PS I do have the other 115 amp battery from my other bow mount, I might throw that in the boat as well as the 180 amp when I plan on doing a long day.

Frank

Edited December 3, 2022 by frankS

[Billmack]

Hi Frank, not sure on your battery knowledge and I’m no expert either, but I know some basics. 
A battery can be destroyed overnight with incorrect charging, an agm especially needs a stepped and programmed charge. Not sure if yours is an agm. If I may suggest a new charger, a projecta procharge 21A works for me, has settings to suit most sized batteries. I work on a max of about 10% charge rate of battery rating. A dc meter with a two decimal point readout is also a must, I’m sure you have one.
A few basic voltages need to be remembered, all readings have to be taken after the battery has been rested, from either charging or discharging, at 12.8 V battery is fully charged, 12.2 V battery is 50% discharged, 11.8 V the battery is flat, everything in between is common sense. An agm should not be discharged below 50%, but it will happen sometimes. 
Once you are confident your battery is charged correctly, I think you can then work on the batteries performance, I’m sure a normal days fishing will not bring it down too far, 50amp draw is the MAX, it would average out a lot less than this. 
I hope this has helped. 

[Sharknado]

On 12/3/2022 at 5:22 PM, zmk1962 said:

@Fab1 is on the money, I too think its consumption related ... especially if the motor was going hard for 5hrs of the day.  

@Sharknado ground issue? ... are you thinking something like a poor ground ... or that the Watersnake itself is somehow grounded to the hull - perhaps internally or through the mounting bolts?  I don't feel a ground issue would be contributing that much AMP loss - Frank said the only other device running (that could be drawing current AMPs through the hull) was the Lowrance and it consumes like 1-2AMPs/hr... definitely not in the 20-30s.  Also I would have thought that amount of AMPs (20-30) flowing through the hull would result in visible electrolysis somewhere, but they're just my thoughts,  maybe you have some real life experience regarding this that you could share and we can learn from.

Cheers Zoran

Hi Zoran, Im not overly experienced in 12V but know just enough to get myself into trouble 😅.

From my experience any power loss or poor performance comes down to many possibilities - bad cells, poor grounding, poor contacts, a short in connected equipment, incorrect charging, sulfation to name a few. 

Re reading the post (properly this time) & Fab's comment I would say its accurate with the amount draw in the figures.

 

@frankS It is very important imo to have a good battery monitor to know what SOC you are at as billmack suggests with an AGM you only have 50% of useable power before you start to reduce you batteries lifespan if constantly drawn below that. How many volts is an AGM at 50% SOC? Well thats debatable, I have seen figures as low as 11.95V to 12.51V. I am going with my AGM's battery manufacturer that states 12.05V is 50% SOC.

https://www.victronenergy.com/battery-monitors/bmv-700h#pd-nav-image

The other thing I have learnt about AGM's or anything 12V for that matter is that whats on the label & what any manufacturer can state in their specs on AH capacity & charge/discharge rates etc is subjective & they usually over inflate the figures.

Eg. One branded 140Ah AMG can weigh 35kg while another branded 140Ah AGM can weigh 45kg. How can the 35kg battery be a true 140Ah??

Its a similar thing for solar panel/blankets to. 

Edited December 4, 2022 by Sharknado

[noelm]

Once again, it's a series circuit, the ground is no more important than the positive, current is the same, end to end.

[XD351]

5hrs of leaning on the lekkie will drain all but a big dual battery set up. Provided nothing is getting hot you have no ground or wiring issues . You should have a fuse or breaker in there nearest to the battery just in case something does short out - better to blow a fuse than burn your boat down !

That is one big ass charger ! That is what I call a battery boiler !
I wouldn’t even be tempted to pump 100A into any battery for more than a few seconds as batteries have a maximum current rating over time so a start battery will have say 500cca for x amount of time and a storage battery will have similar but much lower amp rating - maybe 80-100 amp  for x amount of time . The Lithium battery I just purchased (200ah) has a rating of 300A for 10 seconds and constant draw of 150A - I will never go past 50A on this and it is not much heavier than a box of beer ( stubbies). Is it a marine battery ? They are more robustly constructed and handle vibration and shock loading better than your run of the mill car or truck battery -  I have had a car battery drop a plate while using it in a boat and it instantly turned it into a 10v battery.

[xerotao]

On 12/2/2022 at 3:43 PM, frankS said:

Pardon my ignorance but how do you go about doing a " draw test " ?. and what do I need to do this test ?.

Battery bought as a 180 amp hour .

Frank

Sorry for the late reply as iv been away.

A draw test for example is you grab a load (a spot light) with specs you know the current draw (10amp hr) fully charge battery and turn it on using battery. When battery has gone flat you know how much amp hour the battery has.

if your 10amp light dies in 9hrs. You multiply your amp load with usage time (10amp x 9hrs) you have a 90ah battery

[dunc333]

hi Frank im with fab1 battery draw sounds pretty right .could you add a solar panel to the boat any where which would at least give you a bit longer usage for the day .or lithuim is the go but big bucks cheers dunc333

[noelm]

A solar panel wouldn't supply anywhere near enough power to be useful.

[slowjigger]

Doesn't seem to be overly excessive power use. Also, your batteries capacity might be overrated if it's not an established brand. A clue can be if it is significantly lighter than other batteries of its rating. 

[frankS]

14 minutes ago, slowjigger said:

Doesn't seem to be overly excessive power use. Also, your batteries capacity might be overrated if it's not an established brand. A clue can be if it is significantly lighter than other batteries of its rating. 

I have trouble lifting it. Will try and weigh it tomorrow.

Thanks everyone for the input and help on this one.

I am not too worried about the energy used now that everything has been explained to me.

I will just use it when needed in future.

BTW I only set the charger to 2 or 3 for about 45 minutes then rest it and if it needs more charge I put it on again. I think 3 is approx 15 amps going by the guage.

Will also measure the battery.

Frank