Carver Owners Forum

I seem to be going through batteries fairly quickly. Maybe 2 years out of AGM 8Ds. I have 2 separate 8D starting batteries and an 8D house battery. I just happened to touch my House battery yesterday and it was pretty hot. So I unwired both of the negative leads and let it sit. It cooled down. Then I put one of the 2 leads back on the negative and could operate most of my 12v systems. I'm thinking the other lead runs to the Vanner IQC12 inverter, because the leds are out on the remote panel. But the lights are still on on the actual inverter.
Any ideas what might be going on? Running through batteries is getting a little expensive.

How often do you look at the charging voltage? I put a couple USB charging ports on my boat and they came with little LED voltmeters on them. A quick glance and you'd know if the batteries were being charged (or not) and they'd show a higher-than-normal reading if your charger was overcharging them. Lots of "peace-of-mind" seeing those.

I suspect something is overcharging them. Is the inverter and inverter/charger or just an inverter? Do you have another battery charger in the system? If it's an inverter/charger, look at the manual... it's possible that it has an "equalize" mode that it is stuck on. The older Heart Interface inverter/chargers had such a feature, but you'd trigger it by manually flipping a switch on and off. However, if you left it on then anytime the inverter/charger was unplugged from shore power and replugged in, it would go back into the "equalize" mode. The equalize mode put a much higher voltage into the battery bank and it's intended to force all the cells to the same voltage and sheds deposits built up on the plates. It is ONLY intended to be used for a couple hours and ONLY once in a while though. Continuous or frequent use would toast batteries very quickly.

Welcome to the forum......from what you have described is seems to be a classic case of overcharging. Check the charger settings to make sure they are set for your batteries and monitor the charge voltage to check if the charger ever gets to float. Are you are running big loads all the time on the inverter side??. Newer sequipment may have temp sensors to control that.

Maybe have someone look at your system, it may be time for a change.

Have you had the boat long ?......is this something you have experienced since ownership ??

Do you have a separate charger other than the inverter/charger which I believe the Vanner IQC12 is? If so, what brand and model is it?

I don't think Vanner IQC12 incorporates an equalize function but worth checking. Having said that, this function is usually a momentary selection only so you're not able to actually leave it on for lengthy periods. It triggers a timer and the circuitry does the rest then shuts off automatically. Most units also go into this mode automatically after being plugged in for ex number of straight days. With this type, you shouldn't leave any voltage sensitive equipment turned on while you're away.

It does sound like over charging but that can be due to a number of things; old ferroresonant chargers, poor connections, failed charge output controller, lack of fluid level maintenance, battery not fully charged going into winter, incompatible batteries in the same bank, battery switches left on "BOTH/ALL", etc.

I like the cigarette lighter USB charging units with built in digital volt meters. I have one at each helm, and also bought a couple of these, one of which I'll be installing at the aft deck above the bar fridge.... https://www.amazon.com/Cllena-Charger-Voltmeter-Functions-Vehicles/dp/B0741C4F78/ref=sr_1_2_sspa?dchild=1&keywords=marine%2Busb%2Bcharging%2Bport%2Bvoltmeter&qid=1628731559&sr=8-2-spons&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyU1c1T0VFVENFUlhBJmVuY3J5cHRlZElkPUEwNDY5MTUxUFFRQlhUSUdHUEQ3JmVuY3J5cHRlZEFkSWQ9QTA2OTk2MDMxUjc5QlRMNUFGMlRLJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ&th=1

The IQC12 does have an equalize function, it is a toggle switch on the Control Board. It is recommended to leave it off except if there is a need and after equalizing, turn off again.

Interesting. I don't like the idea of leaving an equalizing switch on and having to remember to turn it off, not a good idea IMO.

Properly equalizing a battery bank needs to be monitored during the process to make sure things don't get out of hand temp and acid level wise. I would not set anything thing on auto or otherwise and walk away.....just my opinion.

The problem with a manual option is that very few will physically go down there and do it. Mine does it automatically so I never have to worry about it. If you switch everything off as you should when you're absent from the boat, you shouldn't have a problem. The items that do stay on regardless of what you do at the panel usually have the tolerance to accommodate the higher voltages. As for fluid levels, while a smart charger minimizes fluid loss, you should still check it regularly anyway.

There should be no loads attached while doing this.........my advice is that it is not such an important thing to do one way or the other so if you are not prepared to monitor closely for the duration of the process.....don't do it!!! A properly maintained bank should be fine with out the drama.

Just the process in general can be dangerous in inexperienced hands.

I agree proper maintenance is key, the problem is no matter what you do, you may be able to minimize it but lead acid batteries will sulfate.