Lithium Battery Meters

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Feb 16, 2021
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Just bought a Weize 12v 100ah lithium for my 45lb thrust minn kota trolling motor. I have a LifeP04 10ah that runs my fish finder that I just had to warranty due to it being drained too low. I'd like a digital meter to be able to monitor both going forward. Kinda sucks fishing without either while a battery is in for warranty!

Anyone have recommendations on a meter for this application?

Currently looking at this AiLi unit. I like that it has an AH remaining and current amp draw readout. And I can get two for the price of some of the fancier units.

The Renogy looks nice but is pricey.
 

Rich M

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10 amp is a lil light for fish finder. We use those for pulsating duck butts.

100 ah battery runs my 55 pound tm for a couple days.

I have a livescan and may get a battery for it but will be 50 ah or more. Draws like 5 amps/hr x 10 hr day = 50 but i want some in reserve.

Im subscribing to see about a meter that can tell whats left in battery…. Good luck!
 
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SteveAndTheCrigBoys
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10 amp is a lil light for fish finder. We use those for pulsating duck butts.

100 ah battery runs my 55 pound tm for a couple days.

I have a livescan and may get a battery for it but will be 50 ah or more. Draws like 5 amps/hr x 10 hr day = 50 but i want some in reserve.

Im subscribing to see about a meter that can tell whats left in battery…. Good luck!
I have a Humminbird helix 5 downscan. Draws 600mA. So it should run about 16 hours on a 10ah. That’s double what my AGM would run the trolling motor for so it always gets charged between days anyway. If the 100ah trolling motor battery performs that well I may need to go bigger on it.

I also might upgrade to a helix 7 with side scan for walley boys and other reasons. That unit will cost about half the boat’s worth haha.
 
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SteveAndTheCrigBoys
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That Weize should have a BMS that prevents it from draining too low.
It does, I want it mostly to know where I’m at on long days or if I need to run the generator to charge it on camping trips. Hit baker lake and lake Wenatchee for socks every year and don’t normally have readily available power.

I also suck so I’m the guy out there at 2pm when everyone’s back at the launch drinking beer. Long days of run time.
 

Rich M

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I run both a garmin vivid striker 9 side scan and a garmin chart plotter that is compatible w side scan.

W troller im using a terrova 55# with spot lock.

Boat is Lund SSV-18. Im usually fishing in tidal areas or offshore spot locking, bottom fishing.

6-12 hrs for offshore. Inshore motor gets run 3-4 hours of day. Freshwater we troll for crappie 4-6 hrs but on low.
 
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It does, I want it mostly to know where I’m at on long days or if I need to run the generator to charge it on camping trips. Hit baker lake and lake Wenatchee for socks every year and don’t normally have readily available power.

I also suck so I’m the guy out there at 2pm when everyone’s back at the launch drinking beer. Long days of run time.
Gotcha. If you wanna go super low end and basic you could installing a panel with cigarette lighter plug and USB plugs with a voltage meter on it, that'll tell you the voltage and have the added benefit of charging your phone or whatever. I think full for LifeP04 is 13.3v at rest, 14.4 charging. The battery should list it's cutoff voltage so you'll have your range.

Just spit balling, something like this:
https://a.co/d/0f9Fi29Q

Or this:
 
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SteveAndTheCrigBoys
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Well I hope I don’t have to deal with their CS anytime soon.

Hi,

I'd like a digital display monitor that provides be with a % of charge left or Ah left for my 12v 100ah that I just ordered. Is there a recommended unit for this?

Hi,
Thank you for reaching out.
But sorry that we don't sell this monitor and are not familiar with it.
Could you please contact the seller to find the correct one?
Looking forward to your reply.
Best Regards
 
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OP, I have a 24v charge controller from these guys and I like it quite a bit, also have two of their 195 watt panels. I think the Renogy panels put out a bit more but it wasn't an apples to apples comparison when I had both systems up so can't say for sure. Anyhow, throwing it out as an option, they have two monitors you might consider taking a look at:

 
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Should of bought one of the Lifepo4 batteries that have Bluetooth for BMS monitoring. I got one for my TT and its awesome. Shows me all the info I need in real time.
 
Last edited:

dusky

FNG
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Dec 6, 2020
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Check out the Victron Smartshunt. I have one connected to my 3 12v lithiums running my trolling motor. Highly accurate, waterproof, and connects to my Bluetooth through the app on my phone. Little pricey, but it's quality. It tells you your state of charge, not just volts, which is important for lithium. I just wish that it could tell you how close the batteries are to being fully charged; it can only read how much has been drawn from the batteries. I have Li Time lithiums and they say do not leave lithium on a float charger once full. But because the Smartshunt will tell me how many amps have been drawn, and because I know how many amps per bank my on board charger charges per hour, I can pretty much predict about how long it will take to recharge of the batteries.
 

Macintosh

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A couple suggestions of using a voltage meter or tm voltage meter—fyi that does not work. Traditional batteries the voltage decreases in a linear fashion with % charge. So the charge-meters just read voltage to give you a charge. Lithium batteries maintain 12v + for most of their charge cycle, and the voltage only drops when they are close to dead—so if you use a battery life or voltage meter it’ll read 100% or close to it basically right up to the moment it dies. So any battery life indicator must be a model that specifically works with lithium batteries.
 
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A couple suggestions of using a voltage meter or tm voltage meter—fyi that does not work. Traditional batteries the voltage decreases in a linear fashion with % charge. So the charge-meters just read voltage to give you a charge. Lithium batteries maintain 12v + for most of their charge cycle, and the voltage only drops when they are close to dead—so if you use a battery life or voltage meter it’ll read 100% or close to it basically right up to the moment it dies. So any battery life indicator must be a model that specifically works with lithium batteries.
That might be true. I watch the voltage on my solar off grid camp, batteries are full at 13.3v resting or 14.4v charging and they're drained at around 12.8v, so I'm not looking for less than 12v I'm looking for 12.8v being the bottom. I figured as long as you know your battery voltage range it should be "close enough" indicator, but my equipment is all specifically for lithium so those cheap amazon volt meters may not work as I thought. Thanks for pointing that out.
 

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SteveAndTheCrigBoys
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Check out the Victron Smartshunt. I have one connected to my 3 12v lithiums running my trolling motor. Highly accurate, waterproof, and connects to my Bluetooth through the app on my phone. Little pricey, but it's quality. It tells you your state of charge, not just volts, which is important for lithium. I just wish that it could tell you how close the batteries are to being fully charged; it can only read how much has been drawn from the batteries. I have Li Time lithiums and they say do not leave lithium on a float charger once full. But because the Smartshunt will tell me how many amps have been drawn, and because I know how many amps per bank my on board charger charges per hour, I can pretty much predict about how long it will take to recharge of the batteries.
Looking into the Smartshunt now. I see there's a wiring diagram that includes measuring a main battery and starter battery...wondering if I could wire it up with my trolling motor battery as the main and the fish finder as the "starter". Not sure what the information would look like in the app though. Might be a scenario where I need two smartshunts though.
 
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SteveAndTheCrigBoys
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Made a decision.

Victron SmartShunt for the trolling motor battery.

Super cheap unit for the Helix battery. I figure I can check the accuracy of the % feature using the chart above or just use the chart and the voltage monitoring function. If it doesn't work well I'll just upgrade the battery to a 50Ah cause I just got a Helix 7 MSI G4 as well that draws slightly more amps.
 
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