Have two large batteries connected in parallel, attached to a 1.5 amp automatic maintainer. DMM shows 14 volts, and I can hear the batteries bubbling. Not sure how long they've been bubbling, as this maintaner has been connected a long time. Did not expect voltage this high, nor bubbling, with this little automatic maintainer. What is the recommended course of action?
Maintainer Cooking Batteries?
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My guess is one battery has failed and the charger is cooking the good battery trying to charge the dead battery. Separate and try again. Don't rule out the possibility that the charger is at fault too.
A maintainer should settle down to around 13.2. If it's at 14 it's still charging, hence the bubbling. Maybe check the voltage on the batteries after they've sat for a few hours; maybe one has a bad cell.
Was the charger purchased at Harbor Freight?
Apologies to anyone who has seen me say the same thing on several of these threads - I have a Motomaster (Canadian Tire store brand) automatic maintainer which was doing the same thing (causing the batteries to bubble with no end in sight) with a pair of 6v deep cycles wired in series. I then bought a few different NOCO automatic smart chargers/maintainers of various sizes, and they settle into maintenance mode after topping up the batteries. My conclusion is that the Motomaster is either defective, or just of poor quality right out of the gate.
My Schumacher bubbled a deep cycle battery once. The next season it had lost a lot of capacity. Then the next season I thought to check the water level and the plates were exposed.
"They say" bubbling is normal during one of the stages of charging but I just dunno.
"They say" bubbling is normal during one of the stages of charging but I just dunno.
A maintainer should have a voltage of less than 13.8 volts. Somewhere in the range of 13.6V to 13.2 would be preferable.
Stop using that maintainer, and it may have caused a need to top off the cells now too.
Leave them disconnected from it for a few hours and measure voltage. If either isn't fully charged, bad battery.
Leave them disconnected from it for a few hours and measure voltage. If either isn't fully charged, bad battery.
Why am I not surprised to see a store brand or "off" brand battery maintainer fry a battery?
Yep - I would have thought a large chain would conduct a bit more due diligence before putting their name on something. Lesson learned. Thankfully in my case, I was keeping an eye on them and didn't loose too much water before pulling the charger off and topping them up.
^ Hard to predict failures though, could have been heat or a power line surge or who knows, assuming it formerly worked properly.
Sometimes I think the inexpensive smart chargers are even worse than something far cruder. For my mower in off-season, I just took a leftover 12V wall wart, the old unregulated type that floats up around 16V with no load, took the capacitor out, and put a resistor in series so in testing it was giving the battery about a dozen mA near (but not quite) full charge. That $25 battery lasted somewhere around 10 years.
Sometimes I think the inexpensive smart chargers are even worse than something far cruder. For my mower in off-season, I just took a leftover 12V wall wart, the old unregulated type that floats up around 16V with no load, took the capacitor out, and put a resistor in series so in testing it was giving the battery about a dozen mA near (but not quite) full charge. That $25 battery lasted somewhere around 10 years.
This is why I put my battery maintenaners on a timer. They charge one day a week for 4-6 hours.
And my stuff always starts.
No batteries boiling and less wear and tear on the chargers at they are only plugged in 6 hours a week vs 168 hours a week.
And my stuff always starts.
No batteries boiling and less wear and tear on the chargers at they are only plugged in 6 hours a week vs 168 hours a week.
If you buy good ones you don't need to do this. Same for solar ones, since they turn off at night anyway.
this is what the Basement Watchdog battery sump pump chargers would do, except they held 14.6v. their answer to the constant offgassing was to install a water level sensor in one cell... so there was a 5/6 chance the charger would boil off the electrolyte in a cell before the sensor detected it, hence every time there's a big thunderstorm all the basement watchdog batteries at home depot sell out.
UPDATE: Batteries were separated and removed from maintainer. A day later, they both show about 12.85V.
Did not check electrolyte level, as there's a label covering the caps. Is electrolyte level likely low after this?
Maintainer was actually holding them as 14.2V. Defective maintainer?
gathermewool
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I would check the electrolyte levels and add distilled water to low cells, which I feel is likely.
dump that ”maintainer” and buy a NOCO or CTEK or, if you want to keep the maintainer you have, add a timer.
dump that ”maintainer” and buy a NOCO or CTEK or, if you want to keep the maintainer you have, add a timer.
Yes
If you need to add water, just add enough to cover the plates by a quarter inch or so. No need to filler' up.
Tell us the electrolyte level. I think it will be fine.
I will add Battery Minder to the list of quality battery chargers and maintainers. But not cheap.
I think you can use a HF battery maintainer. But just plug it in once or twice a month for 12 hours or similar.
Also annoying if you leave the battery maintainer on is to find the alligator clips eaten away.
I will add Battery Minder to the list of quality battery chargers and maintainers. But not cheap.
I think you can use a HF battery maintainer. But just plug it in once or twice a month for 12 hours or similar.
Also annoying if you leave the battery maintainer on is to find the alligator clips eaten away.
Would like to see the electrolyte level, but I'll have to rip off the top label to do that. Incidentally, do jumper cables with alligator clips typically provide sufficient contact to connect batteries in parallel such they they can be maintained simultaneously? Just connect maintainer to either battery or to the alligator clips themselves?
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