Coolschmax Waterproof IP67 Battery Tester 10-100V with 100A Shunt Energy Saving Capacity Monitor V/A/SoC/Ah for Lithium, LiFePO4, Lead Acid, Solar Batteries and Others in Golf Cart, Car, Motorcycle

I use a power wheelchair. It has used lead acid batteries since new, but they only last 12 to 18 months. I got a bit longer with a premium battery but it's a hassle to change them as you have to remove the seat to access the battery box, and then open the box and exchange the heavy batteries. I had considered Lithium batteries but they were priced out of my range.Then one of the major battery makers offered a set of LIFEPO batteries for about $35 more than the lead acid ones. They had 15 more amp hours and weighed less than half as much. I was required to purchase a LIFEPO charger as the one that came with the chair didn't put out enough voltage to properly charge the new batteries. The new charger has a harness and disconnect plug that connect directly to the batteries as the original port couldn't support the load.After I installed the LIFEPO batteries I ran the chair watching the capacity display on the Shark controller but after a week of use it still showed 100%. I figured that it wasn't accurate due to the different discharge curve of the Lithium batteries and this was proven correct when I connected the charger. I don't know what it was down to but it took a few hours to fully charge them.So I was browsing the meters when I came across this one. It would handle more voltages and battery types than most of the others, and it was water resistant in case you get caught in the rain or water splashes out of the sink. It has many types of battery profiles built in, but in case non of them works it has a custom section where you set the minimum and maximum voltages and it uses that instead. The LIFEPO batteries I purchased were in the latter category since they were designed to be as compatible as possible.The first thing you have to realize is that a very small voltage change indicates a fairly big drop in capacity as the LIFEPO batteries tend to have a close to flat curve until the very end. So after charging it will indicate 100%, but when you push the joystick the display will go down to maybe 75% or even lower at higher speeds, but when you stop it climbs back up to 100% at first, then as you continue to use it the percentage goes down.The meter will display percentage of charge, or if you press the button once it changes to the voltage display. There is a port with a sealing plug in it on the back so you can calibrate it with an accurate voltmeter and it remains accurate at different levels across the range.It has a nice backlight but you can turn this off if you are concerned about the drain or just want it dark by pressing the button twice. The display is very clear indoors but washes out some when outside but is readable, but you have to look at it more closely to make it out. When the backlight is off the meter draws 1 milliamp. It doesn't draw much when on.The button IS a bit stiff to press but I'm hoping it gets easier with age although once set up there isn't much need to press it.The main disadvantage I've encountered is that the one button does EVERYTHING. You set all the parameters with it so you have to do some careful pressing to set it up. However it has flash memory so it retains all your settings when disconnected from power so you won't have to do this multiple times.I was a bit concerned about how I was going to wire it up. I didn't really want any long wires running down to the battery pack and I suddenly realized that the charger port in the Shark controller had two wires that went to the battery in order to charge the old lead acid batteries. I had an extra connector for this port so I checked the charger one to see which was positive and negative and wired the meter into the spare connector and just plugged it into the charger port and it works perfectly and I didn't have to modify the wiring of the chair at all. I had a metal bracket left over from another project that I fastened to the arm of the chair. The meter has a threaded shaft and a wing nut to mount it to your installation. I can have the meter unplugged and off the chair in less than a minute. The bracket will take a little bit to remove but I felt like this was a winner.I have had good luck with this meter and would recommend it to anyone having a need for a way to monitor their batteries state of charge, regardless of the type of battery.

Very pleased with this. I wanted a gauge that didn't shut off after a minute and shows an accurate transition of battery voltage for a 24-volt electric work vehicle. This fits my needs. The unit does not shut down while the key is on but does when I shut the unit off (wired through the switch, not directly to the battery). Shows voltage drop as I load up the motor, such as going uphill, and then proper standing as I am sitting still. The gauge response seems appropriate for my application, and it looks good too.

Installed this to replace an old, ugly LED battery indicator on our old, ugly AF golf cart that we only use to tool around for fun w/ the runts.Installation was easy, using standard twist wire connectors, electrical tape, and some 3M tape to mount the actual monitor to the old metal mount already on the cart.Knocked one star off only because it's fairly small (smaller than I expected) and should have come with some better wire connectors on its own, such as the Lever Wire Connectors you can find on Amazon. Overall, though, price is right and it seems to work just fine, providing accurate information in a nice, readable fashion.

Best meter for the money. Very accurate, reads exactly what the app says. One recommendation I have is read directions first… lol. Installation is a breeze if you do. After 30 mins of playing I decided to read instructions an 5 min later it worked exactly like it was supposed to. Adds a cool look to any golf cart!!!

Update- Completely stopped working after just over 2 weeks. Save your money.Might work for applications in the dark but the display is so faint on an overcast day you can hardly see it unless your eyes are directly over it. I see some people's reviews with displays you can see, but here are two pictures of mine. One is slightly off center perspective and the other is directly overlooking it on an overcast day.I also agree with another reviewer who commented about the values changing a lot even if you are just connected to batteries with no load. Gives a rough idea of state of charge but not accurate at all

Works well for showing battery level. Installed several in different systems such as my boat for checking battery. The cons are it is hard to see in sunlight and biggest issue is if battery is lower such as 10 volts, this will not power on so cannot see actual voltage. I want it to show low and very low if needed.

Using to monitor a 100ah lifepo4 battery. Powering a Chinese diesel heater.Works well to track capacity left, and discharge/ charge rate.

Easy installation