overcharged 12V battery - Montana Owners Club

margerush · 05-15-2019, 05:37 AM

I overcharged our Marine deep cycle battery. Hubby removed the battery so I could clean up, neutralize spilled acid & repaint the metal. Hubby hurt his back removing the battery. My question: is this why many of you on the forum have gone to in-line 6Volt batteries? 12 volts are heavy 75-85#, how heavy is a good Marine 6 volt battery? Any suggestions on how to get that heavy battery back in? I don't see good enough structure for a block & tackle pully.

I have a hard time with batteries. The Monty was plugged into home/shore power & battery switch was "off" in the convenience center, I killed the first battery. I didn't realize there was a constant drain & we need to add an off switch to the battery. Now, I've overcharged the 2nd battery & acid spilled out of the battery & battery box & made a mess.

Theunz · 05-15-2019, 07:05 AM

You may of just over filled the water in the batteries. The onboard converter/ charger should not over charge. I had the same problem a year ago, cleaned up the mess and repainted like you did, put the batteries back in and all is fine a year latter. It's hard to see the water level when in the battery compartment. I removed the excess water from my battery's and was surprised by how much I had over filled them.

1retired06 · 05-15-2019, 07:33 AM

For most of us, one 12V battery is more than enough, if minimal or no dry camping is done. For those who do a lot of dry camping or have an inverter, six volt batteries in series provides a better DC power source. Agree, doubt you overcharged, the converter in your rig is designed to prevent that, at least the one in my 2015 is.

**AZ Traveler** · 05-15-2019, 08:01 AM

Marge,

You might want to consider going to AGM batteries which will significantly reduce the maintenance required. Before installing new batteries I would also check your converter to make sure it is not overcharging.

You will find 6 volt golf cart batteries are even heavier than 12 volt batteries. If they are too heavy for you to handle I would get some help.

BuilderBob · 05-15-2019, 12:13 PM

X2 with Zack. I have (4) 6 volt golf cart batteries.

margerush · 05-16-2019, 04:43 AM

Thank you ya'll for your responses.

I'm not an electrician, 1st where is the converter or inverter? & 2nd how do I check to see if it's working properly?

I filled the battery with distilled water just enough to cover the coils. Did I put too much water in?

yes, my next battery will be an AGM. I still need to get this heavy thing back in the battery compartment--I need a young "buffalo" with a strong back.

suny07 · 05-16-2019, 04:59 AM

Hi

depending on your budget and years you are planing to use Lithium Batteries are also a smart option.
They are half the weight and complete maintenance free.

Mike

margerush · 05-16-2019, 05:01 AM

Mike Lithium batteries as good as AGM batteries? Last as long?

suny07 · 05-19-2019, 05:45 AM

hi,

as I did shot 2 classic batteries as I did not thought about proper water and maintenance I was looking into the batterie topic.
So I found most RV's are putting 6V AGM batteries in.
A common battery configuration in RVs is to use of multiple 6V batteries connected in series to form 12V or even 24V systems.

To get true 100Ah I decided between a single Battle Born Lithium batterie 12V 100Ah and two 6V batteries connected in series. The lithium weighs 29 lbs and the two 6V weigh a combined 150 lbs.

Holy I thought... it is getting even worth when you double the capacity to 200Ah what we targeted for.

The cost is at the moment double for the same capacity for lithium.
The lifetime is 2 to 3.5 times longer for the lithium.
Plus 0 maintenance an no harmful acid gassing etc.

Once installed you can forget thinking about it.
No discharge sitting in storage its just ready to use and don't worry about to deep discharge or anything - I love it.

Mike

margerush · 05-20-2019, 05:27 AM

Thank you Mike. Looks like we'll be going to Lithium when this battery dies.

I found a strong-back young man to put my 75# lead acid deep cycle battery back in the Monty.

I love this site, so much good information from seasoned Montana campers.

laverdur · 05-26-2019, 02:39 PM

Lithium batteries require special converters due to different charge rates vs. lead acid or AGM.

laverdur · 05-26-2019, 02:44 PM

A properly functioning converter should keep the battery at approx. 13.6 volts. The voltage will be higher (14.4 volts) or so when it first starts charging. Over about 24 hours it tapers off to a maintenance (of float) charge rate which is when you will see the 13.6 volts. I'm wondering why the batteries keep overflowing. One should never fill the cells of a lead acid battery before charging it. Charging will cause the electrolyte level to rise. As long as the electrolyte is covering the plates before charging, that is sufficient. Then, after charging, if the level is still down, add distilled water until the fluid is about 1/4" below the narrow part of the filler.

gjennings · 05-26-2019, 04:26 PM

Quote:

Originally Posted by margerush

Thank you Mike. Looks like we'll be going to Lithium when this battery dies.

I found a strong-back young man to put my 75# lead acid deep cycle battery back in the Monty.

I love this site, so much good information from seasoned Montana campers.

You may or may not need a new converter to charge them, my 2018’s Progressive Dynamics converter is Lithium ready and does charge my Lithium just fine.

PNW Fireguy · 05-26-2019, 05:14 PM

If you are going the drop in replacement route like BB or Relion you will be fine with your existing converter as these drop-in types have onboard BMS that control the battery charging.

margerush · 05-27-2019, 06:23 AM

I filled the battery cells with distilled water, then charged the battery with a battery charger. I think this is when the water boiled out. This lead acid battery is too heavy to put back in the Monty--had to have a young man help me out.

When I kill this battery, I'm going to replace it with a lithium battery. Now I have another question. Can I just drop a lithium group 27 battery in or are there some special concerns I need to know? How do I find out if my converter can handle a lithium battery?

DebNJim B · 05-27-2019, 06:29 AM

Quote:

Originally Posted by margerush

Thank you ya'll for your responses.

I'm not an electrician, 1st where is the converter or inverter? & 2nd how do I check to see if it's working properly?

I filled the battery with distilled water just enough to cover the coils. Did I put too much water in?

yes, my next battery will be an AGM. I still need to get this heavy thing back in the battery compartment--I need a young "buffalo" with a strong back.

You might want to have your battery tested. I had one boil over and make a mess (stayed in the battery box though) but the converter was working fine. The battery had an internal short in the plates. Tossed that battery and never had another problem.

margerush · 05-27-2019, 06:32 AM

Thanks Jim. Battery is working fine. I had to remove it from Monty to clean up the acid spill--neutralize acid, wash off the baking soda, repaint & add Corosian resistant stuff.

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