Batteries discharge quickly

Greetings, all.
Batteries discharge quickly. As far as I can tell, the six batteries in my 2002 e4 are receiving a full charge: reading 100%. After charging, the voltages ranges from 13.15 to 12.75. After a less than 2-mile roundtrip, I start up the hill to home. Voltage % reading is 92; as I drive on, the voltage % drops to 80, then 65, then the car stops; 45% reading. I check the voltage on the six batteries: from 12.92 to 12.69; don’t seem dead to me. The battery set is 1.5 yr old; one battery exploxed 7 mo ago and one went dead about 3 mo ago; both replaced with the same battery. Zevan charger was calibrated to the battery set when the batteries were purchased. The batteries are not Trojan. Advise? Opinion? Thanks.

What kind of batteries do you have? Flooded or Gel? Group #?

Thank you, LuvMyTj.
The batteries are sealed, lead-acid, purchased from Batteries Plus with specifications that matched GEM e4 requirements.

Sealed lead acid batteries are not common for this application. Most flooded cells require frequent checking and top off’s. Since you had such issues with some of the other batts in your pack I would suggest having Batteries Plus come check them all out. The BP near my Mom’s place will come out to your house, maybe your will too?

Sealed (maintenance-free) batteries, otherwise known as VRLA (valve regulated lead-acid) batteries come in many flavors. A true electric vehicle battery in Group 30H or Group-31 size will weight about 80 to 90 pounds apiece and specifically say they’re deep-cycle batteries. Those with CCA and MCA ratings are usually starting or dual-purpose batteries and may not last as long as purpose-built medium-high discharge rate EV batteries.

The Zivan chargers from 2004 vintage GEMs should have a removable plastic tab on the top left with a rotary switch under it. For conventional flooded-cell batteries you’ll want it to be on E or F (depending on battery capacity I think). For gel-cells, you want C and for AGM you want D.

I can’t tell you what setting is best for SLA lead-antimony type batteries but I think they may have a slightly different voltage/current curve than the ‘normal’ batteries the Zivan NG-1 was programmed for.

Even VRLA batteries with the eye where you can see if there’s still sufficient water have removable caps. They’re usually hidden, however, under rectangular caps which are not designed to be removed. The only way you’ll really know if the batteries are truly being charged fully is to measure the specific gravity. I suspect you’ll find either one or more bad batteries or cells in the string or some empty cells. Either way, that’s the way it goes with non-standard batteries sometimes.

Money is always an issue it seems when replacing these batteries. You can get Group-31 starting batteries for as little as $80 or $90 dollars but they won’t last. I, personally, put Group-31 marine deep-cycle flooded cells in my GEM but I haven’t gotten any miles on them yet so the jury is still out on their performance and longevity. The Sam’s Club GC-12’s are a bargain at $184 each and the AGM batteries can be had for around $200 to $249 each. The Trojan GEM-specific batteries are even more expensive but as the old saying goes, “You get what you pay for”.

Better batteries will likely last longer before failure. Cheaper ones or ‘wrong’ ones simply won’t last and can give you false economy. If you save $500 but they last only half as long, you’re kidding yourself.

Remember that the state of charge number on the display is based on measured voltage of the 6 batteries in series, nothing more. A bad cell will drop the voltage by over 2 volts or 10% since the voltage range is from 13.6 volts per battery at 100% to about 11 volts per battery for 0% SOC. You really need to load-test each battery to find the bad battery or batteries and swap them out.

I really appreciate the indepth reply. Most likely, I will get a new set of batteries by summer and I will definately consider the Group-31 series.
Thank you for your time.



Sulfation or a Voltage Leak might have something to do with this!

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Hi i guess there might be any short wiring may also occur due to which your batteries are consuming more charging. do check it wiring as well.