Operating fish finder using lithium battery

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RE: Operating fish finder using lithium battery - wiperhunter2 - 06-17-2025

(06-17-2025, 03:39 AM)Mildog Wrote: Update on my battery issue li -time asked me to charge and balance my two problem
Persisted one battery draining much more than other way out of balance. They said after I’d did that they would replace battery, send me a return label and replace battery when they get “bad” one back.
I told them I need it fast so I wouldn’t miss fishing time . They said I could ores new one and they would refund it to me when “bad” battery is returned. I got the new battery in 2 days. Printed label they sent me this morning and used box from new one to pack “bad” up, fed ex will pick up tomorrow . They covered return ship.
I got the new battery Friday charged both and balanced all seems to be working fine on first trip out all good. I Will get refund shortly I presume after they receive return. So for what it’s worth chat and email with li-time customer service has been very good, and they are honoring warranty!

That's great, glad it all worked out. So, the brand name is Li-time?

RE: Operating fish finder using lithium battery - gmwahl - 06-17-2025

That s good news.

To answer your question as to where to get batteries tested, I've had good luck with interstate batteries in Logan, but I also have diagnostic chargers for my RC planes that will test capacity, resistance, amp output, etc. My other hobby besides fishing and hunting is rc aircraft, and I actually make my own LiFePo4 lithium batteries for my aircraft from new cells that I purchase. These range in size from simple 3 cell batteries all the way up to 25 volt, 32 cell batteries. The marine batteries are no different when it comes to the science, they are just made with different cells by the manufacturers and include an on-board BMS to make charging them easy and risk free.

Mike

RE: Operating fish finder using lithium battery - wiperhunter2 - 06-17-2025

(06-17-2025, 02:33 PM)gmwahl Wrote: That s good news.

To answer your question as to where to get batteries tested, I've had good luck with interstate batteries in Logan, but I also have diagnostic chargers for my RC planes that will test capacity, resistance, amp output, etc. My other hobby besides fishing and hunting is rc aircraft, and I actually make my own LiFePo4 lithium batteries for my aircraft from new cells that I purchase. These range in size from simple 3 cell batteries all the way up to 25 volt, 32 cell batteries. The marine batteries are no different when it comes to the science, they are just made with different cells by the manufacturers and include an on-board BMS to make charging them easy and risk free.

Mike

Thanks Mike, very interesting that you can make your own lithium batteries, I had not heard of anyone doing that. What does it cost you to build a 25 v lithium battery? What brand of diagnostic charger do you use?

RE: Operating fish finder using lithium battery - wiperhunter2 - 06-18-2025

Well I went to three different stores that sell batteries but could not find an interstate store around here. The interstate store that use to be on Wall ave is gone now and from looking them up on line the only place that sells them now, in my area, are automotive repair stores. But the good news is I ask my son if he could get the app to work and it worked on his phone. Here are the results from each battery. What I thought was funny, is that even though the batteries have nearly the exact same voltage, they have different capacity. Here are the screen shots of each battery. A question for you guys, what is SOC and what is the difference between normal capacity and residual capasity?

RE: Operating fish finder using lithium battery - EyLayo - 06-18-2025

SOC- state of charge. Nominal capacity is the max amp hours the bms is calculating it can produce from 100% soc. Residual is the current amount of amp hours given stated charge level.

Building batteries is relatively easy if you follow a few basic guidelines. As with most things these days, YouTube is a great resource. Be careful though, it's a rabbit hole that can be addictive. Soon your basement will be overflowing with goodies

RE: Operating fish finder using lithium battery - wiperhunter2 - 06-18-2025

(06-18-2025, 02:53 AM)EyLayo Wrote: SOC- state of charge. Nominal capacity is the max amp hours the bms is calculating it can produce from 100% soc. Residual is the current amount of amp hours given stated charge level.

Building batteries is relatively easy if you follow a few basic guidelines. As with most things these days, YouTube is a great resource. Be careful though, it's a rabbit hole that can be addictive. Soon your basement will be overflowing with goodies

Thanks Shawn, so from what the app is telling us, what does everyone thing about these two batteries, is one bad or is that hard to tell without putting a load on the batteries?

RE: Operating fish finder using lithium battery - Mildog - 06-19-2025

My batteries showed same voltage but different capacity, charged both, then wired them together parallel to balance the discharged at dissimilar rates. Factory told me they would replace the one. I decided to drain the “bad” battery for return. I put a light bulb with about 9 amp draw watched the Bluetooth to monitor it is was slowing going down but when it hit about 50% and monitor said power would last several hours to drain it then crashed to ZERO CAPACITY 2 volts. So it was bad I’m sure, factory agreed. Got my new battery charged both, then wired parallel to balance overnight.
I have used them three trips all seems to be working and they are dropping at an equal amount. I have used for mostly steering from speed 2 to 5 for 2-3 hours a trip. Batteries are still at 65%. I’ll recharge after next trip. So far so good. Expecting credit for returned batter soon they should get it in next day or two. Then the warranty coverage will be complete.

RE: Operating fish finder using lithium battery - wiperhunter2 - 06-19-2025

(06-19-2025, 12:47 PM)Mildog Wrote: My batteries showed same voltage but different capacity, charged both, then wired them together parallel to balance the discharged at dissimilar rates. Factory told me they would replace the one. I decided to drain the “bad” battery for return. I put a light bulb with about 9 amp draw watched the Bluetooth to monitor it is was slowing going down but when it hit about 50% and monitor said power would last several hours to drain it then crashed to ZERO CAPACITY 2 volts. So it was bad I’m sure, factory agreed. Got my new battery charged both, then wired parallel to balance overnight.
I have used them three trips all seems to be working and they are dropping at an equal amount. I have used for mostly steering frspeed 2 to 5 for 2-3 hours a trip. Batteries are still at 65%. I’ll recharge after next trip. So far so good. Expecting credit for returned batter soon they should get it in next day or two. Then the warranty coverage will be complete.

That's great, glad it worked out for you. Looks like my battery company has gone out of business, so i can't return it. Now did you determine that battery was bad? Was it just the difference in capacity, with one being much lower? I took mine to Auto zone and they claimed they had a lithium battery test they could do on both of them, with a load test. I wanted a second opinion before I ordered a new one but after a dozen calls and visits to other local shores I have yet to find another one that can do the same test.

RE: Operating fish finder using lithium battery - dubob - 06-19-2025

(06-19-2025, 04:09 PM)wiperhunter2 Wrote: . . . after a dozen calls and visits to other local shores I have yet to find another one that can do the same test.

Have you tried 'National Battery Sales' at 1950 S 1900 W, West Haven, UT 84401, (801) 621-0010?

RE: Operating fish finder using lithium battery - wiperhunter2 - 06-19-2025

(06-19-2025, 08:03 PM)dubob Wrote:
(06-19-2025, 04:09 PM)wiperhunter2 Wrote: . . . after a dozen calls and visits to other local shores I have yet to find another one that can do the same test.
Have you tried 'National Battery Sales' at 1950 S 1900 W, West Haven, UT 84401, (801) 621-0010?

Yes, called them yesterday, they just got in their first lithium batteries this week and they have no testers. Since I haven't been able to find anyone locally to get a second opinion, I decided to go back to the Auto zone and talk to the guy that did the test but this time I ask to watch what he did. Sure enough they had a lithium function on their tester but as they were going through the test, one thing I noticed is the tester was only for 20 ah batteries. I guess the guy didn't notice that when he first tested it, so that threw the whole test out the window. Not sure what to do now, but I'm pulling out the on board lithium charger from the boat and seeing if something is wrong with it. I wish this was clear cut but with no one in the area that can test them i'm really not sure what I will do next but I will take Shawn up on his offer to charge the batteries, then go from there.