My battery compartment in my boat isn't very tall. I wanted to put my battery in a battery center I bought awhile back. I had to cut the battery center box down. Now I need to find a battery that is 6 inches or less high. I won't get to use it as often as I would like, so I don't want an expensive one. Anyone know of any batteries that short, that will power a trolling motor with at least 40 lbs. thrust ? Thanks.    

Uh - no... best you can do for such a short space is a slimline AGM that you can lay on it's side. But those suckers start around $600 for a decent one.

That or buy a battery welder and make your own packs from 18650's.

Just now, Deephaven said:

That or buy a battery welder and make your own packs from 18650's.

That'd take some impressive soldering work...not to mention figuring out which ones to series-link and which ones to parallel-link.

2 minutes ago, MN Fisher said:

That'd take some impressive soldering work...not to mention figuring out which ones to series-link and which ones to parallel-link.

It's really pretty easy.  Ebikes only get sold in 750w form...I am a hp nut, so 7000w seemed more logical.  Only way to get there without wasting money is to make your own batteries.  My cost on the parts are about what an Ionic costs to buy though so for normal boat use it isn't worth it.  When you are limited in space though then it surely is.

Even lawn mower batteries are over 6" with most deep cycle batteries being a bit over 9" high.

Just now, Deephaven said:

It's really pretty easy.

Oh for someone experienced in electronics, it is. I could do it - I've designed, laid out, and etched my own PC boards...so I know the routine.

Didn't even know there was such a thing. If my choices are that expensive, I may just have to eat the expense of the battery power center, and just go back to a group 27 deep cycle.

They have little kit brackets to hold them.  Super easy even without a ton of knowledge.  Mechanical aptitude needed of course, but if you are willing to wire your own sonar or trolling motor it isn't all that much more complicated.

Take a look at VMax Tank Marine AGM batteries.

keep in mind AGM can be installed sideways or any position.

Tom

I basically built this one.  https://www.avdweb.nl/popular/spotwelder/diy-spot-welder

However, this was a number of years ago and I'm not sure how much support he offers now.

I didn't use his board. I drew up my own circuit board and had some made but used his software program to operate it.  I'm very good with electronics and design but I'm not a programmer.  Only very basic Arduino.

Sucker works great but I see he no longer offers his board, and while I had to order 10 boards to get 1, I ain't making somebody else one.

 

You can find all kinds of DIY battery spot welders but where you have to be careful is a lot of them depend on your skill and practice.  You will burn a hole through one in a heartbeat with most of them.

 

As for smaller deep cycles, I don't know of one.  The are normally group 24 - 31 which are pretty much all the same height.