If you are planning to get deep cycle batteries, I would definitely recommend AGM batteries. They won't leak, and you don't have to worry about them being heeled over. :)
Next, you need to understand the concept of "Peukert Effect" - at least at a layman's level.
The "Peukert Co-efficient" of the battery tells you how well the battery can discharge at high amperage levels.
Here's a web page to reference:
https://www.batterystuff.com/kb/tools/peukert-s-law-a-nerds-attempt-to-explain-battery-capacity.html
Bottom line - Batteries do not discharge linearly. For example:
Assume you can apply a 20A load to your car battery for one hour before it is depleted to 50%.
You might expect that you could apply a 40A load for a half hour before discharging the batter to the same level.
But that is not the case. With twice the load (in the real world) - you might only get 20-25 minutes, instead of 30.
The details depend on the load and the specific battery.
Lithium batteries typically have a lower Peukert coefficient than lead batteries - and thus much less affected by this issue.
AGM batteries typically are better than traditional flooded lead acid batteries.
Bottom line - the lower the load you apply to your batteries, the longer they will last.
So - putting your two banks in parallel will generally give you a longer run time than running one battery, then switching to the second battery. In real life, you might see a 20% difference in run time.
That having been said... if you're not going to run the batteries completely down during your trip, those of us that are paranoid still like the idea of holding one of the banks in reserve.
If you only have two battery banks, having a Batt1/Batt2/off/BOTH switch can be a nice thing.
The one thing to be CAREFUL about here is that you do NOT want to parallel two LARGE battery banks that are at different voltage levels!!! Sparks can fly... If you parallel two battery banks that are at different voltage levels, the higher voltage battery will immediately try to discharge as fast as possible into the lower voltage battery to raise it's voltage. For example, if you have one battery that goes dead with a shorted cell, and flip your switch to put it in parallel with a large fully charged battery, the good battery will try to flood the dead battery with all the amps it possibly can. In EXTREME cases, the battery cables will overhead, and possibly start a fire. For this reason, it is NOT a good idea to leave your battery switch in the "BOTH" position when you leave the boat. You might be tempted to so that a single trickle charger could charge both batteries - but it's a BAD idea. Buy 2 trickle chargers.
On solar panels....
It depends.
It depends on the battery chemistry - AGM batteries are probably much more tolerant of cheap solar charging panels. If you use Lithium batteries, you should invest in a GOOD charger.
It depends on how deeply you discharge your batteries. If you only use the batteries to get in and out of the marina, and do not heavily discharge them, then a modest solar panel will do just fine.
It also depends on how long you have for the batteries to charge. If you only sail on the weekends, or not more than once or twice a week, a solar panel should be able to top off your batteries during the week while you are gone. If you want to sail daily, or if you deeply discharge a large bank, you'll need a lot more panel acreage to manage your needs.
One other side topic to mention - since you are using this on a SAILBOAT.
Be aware that when you are SAILING - just a little bit of power on your electric motor can help increase your sailing speed by .5-1mph, and will make tacking in light air substantially easier.
If you have a trolling motor or outboard that you can fully pull out of the water, it's not as much of a gain. However, if your prop stays in the water - just a small amount of electric power changes the prop from being a "brake" to providing helpful assistance. It's a BIG win.
Note - we're talking about a small amount of power to augment your sailing. And at LOW power settings, your battery will last a LONG time - again, a good gain!
Good luck!
John
On Monday, March 11, 2019, 10:01:26 AM CDT, 'Capt.Len' trikini2008@embarqmail.com [electricboats] <electricboats@yahoogroups.com> wrote:
Thanks the 18A is from my mobility scooter and will run that motor for several hours. About a 12 mile run. that is for 2 in series running a 24 V motor. It has terminals that work and this is a one time test.
Question two If I use am I better off getting 2-5/600 AH batteries and go through a selector so can run 1-2 or both (In Parellel for 12 V only. I was thinking 2 so if one goes down I know time to go back on the second. Or 1 1000 ah . Either case would be marine deep cycle.
I am leaning toward the 2 battery rig.
If that works figuring on adding a solar panel or two and have no idea what that would entail. Would like to get a full kit like the 100W I see from Harbor for instance.
Ask me for sailboat/multihull am in my element but this electric solar thing is all new Please be patient with me. Old dog learning new tricks LOL
TY
----- oak oak_box@yahoo.com [electricboats] <electricboats@yahoogroups.com> wrote:
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
If both batteries are the same voltage - then in theory, both batteries should work - WITH the CAVEAT that your 18AM battery has sufficient terminals on it and can provide enough current for the trolling motor. (this is a significant point)
There's a PDF for the Minn Kota here:
I was impressed - on page 10 - it lists the max Amp draw for the various motors.
The 40# motor is rated to draw 42A max at 12V. That's approximately 500W.
Your 18AH mobility battery is rated to provide at most - 18A at 12V for one hour: 216W
Is the mobility battery lead acid or lithium? If it's lead acid, you don't want to run it down more than 50%.
So that gives you about 100W for an hour. You wouldn't want to run more than about 12 minutes at full power. The battery might allow you to run longer than that - but you would risk impacting the battery lifetime (if it is lead acid). If the battery is Lithium, you can possibly deplete it to 75% - which at 500W would get you about 30 min.
Again - this is ASSUMING the battery is able to supply 42A continuous for 30 min. Without knowing anything about the battery, we can only speculate that you would be pushing it a bit.
Now... If you run the motor at LOW speed, and only consume 12A instead of 42A, then you could possibly run a half hour instead of only 12 minutes.
Will it work for a 5 min. test - probably.
Would you want to use 2 or 3 of them as your primary battery, no.
John
>
>
>
>
>
> On Monday, March 11, 2019, 9:03:58 AM EDT, captnlen trikini2008@embarqmail.com [electricboats] <electricboats@yahoogroups.com> wrote:
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
I have a small 10.5 Cat with a 40 lb Minne Kota
> trolling motor set up.
>
>
>
Want to see what it does. don't want to buy a
> battery if not enough.
>
>
>
Have an 18AH mobility Scooter Battery, If I use
> that are the performance figures what I would get with a 1000AH
> deep Cycle valid. Not endurance, but speed and maneuverability
>
>
>
Thanks
>
>
--
> Capt.Len Susman Rtd
> Trikini Trimarans
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
__._,_.___
Posted by: oak <oak_box@yahoo.com>
| Reply via web post | • | Reply to sender | • | Reply to group | • | Start a New Topic | • | Messages in this topic (4) |
Have you tried the highest rated email app?
With 4.5 stars in iTunes, the Yahoo Mail app is the highest rated email app on the market. What are you waiting for? Now you can access all your inboxes (Gmail, Outlook, AOL and more) in one place. Never delete an email again with 1000GB of free cloud storage.
SPONSORED LINKS
.
__,_._,___
No comments:
Post a Comment