Normal battery reading

[jeepit]

I see 12.06 volts on a resting camper 12 battery.
What is normal. This battery has been on a maintainer charger. I think this reading is too low.
Going to put a load on it and recheck it later.

 

[TLane]

12.06 volts is too low - about 45% charged. I would expect 12.7 volts for a charged battery that is rested (no charger or loads for 12+ hrs.). Try charging it with a good charger and see if it will recover. Low voltage may indicate a shorted cell - which is what seems to happen to batteries left on a charger for a long period.

 

[Camperman]

Are you able to remove the caps and check the water level? Once a cell goes dry, it is downhill from there on battery life. I copied & pasted this a while back, and hope you find it useful. I keep our RV battery on a Battery tender when not in use, (& in the garage) and it has been staying at 12.95 and above while on the tender. Hope this helps.

Below is a batteries state of charge when hooking a volt-meter to the battery.
• 12.75 & Above 100% Charged
• 12.60 to 12.74 85 to 100% charged
• 12.40 to 12.59 75 to 85% Charged
• 12.20 to12.39 50 to75% Charged
• 12.00 to12.19 25 to 50% Charged
• 12.00 & Below Fully Discharged

 

[p-Bar]

Most tenders put too much current into the battery and cooks them off . Yes as said above check water level.

 

[Alan Reagan]

Northern Tool sells a tender that uses pulsed charging. Supposedly, this desulfates the plates. Since I use both AGM and regular lead acid batteries, I picked one up. My tractor battery was reading about the same as your battery in question. I put the tender on, per the instructions and let it do it's thing (desulfate the battery). Much to my surprise, the tractor battery came back to full charge and I haven't had any problem with it since. I really like this tender because once it reaches full charge, it drops into the "monitor" mode instead of a low constant charging current. Here's a link: http://www.northerntool.com/shop/tools/product_200589669_200589669 I have no affiliation with Northern Tool and I'm sure someone else makes a tender like this. I initially bought it for my motorcycle battery for winter battery tending. That battery is an AGM and requires a higher charging voltage than regular lead acid. This tender gives you a choice as to battery type as well as charging current. Now, I run through all of my stuff (wood splitter, tractor, generator) every few months and desulfate them.

 

[Camperman]

Am I missing something? I thought the battery tender brought the battery up to full charge, then switched over to storage charge, not putting charge back in, until needed. My 1999 motorcycle battery lasted 7 years, keeping it on a battery tender. (original Yuasa Battery.)

 

[Alan Reagan]

Camperman, That's what they are supposed to do but some tenders continuously trickle charge rather than monitor the battery and then turn on when needed. A good tender will do what you said it should do. A bad one can cook off a battery.

 

[Camperman]

Alan Reagan

1st, You spell Alan right.

Next, let my pick your brain a bit if I may. I keep my mower rider battery on a trickle charger, not a battery tender. It charges for 2 hour each AM, on a timer. When I check it with my volt meter, it is 16 + while the charger is on. When off, it is 13 or so. When I check my RV battery, on a battery tender is stays in the 12.90 + range , and seldom gets above 13. I do check water levels monthly, even on vehicles. What would you say would give indication of a battery tender NOT working correctly?

 

[jeepit]

Checked battery this morning. It's at 11.76.
I can look at water level but I think battery toast.
Question. When I have the battery hooked up to camper and I have an electrical site how is the camper electrical charging the battery. How do I know it is not over charging? Does it go in to a tender mode?
For reference I have a 26ft Jayco GT2 TT.

 

[Alan Reagan]

Alan Reagan

1st, You spell Alan right.

Next, let my pick your brain a bit if I may. I keep my mower rider battery on a trickle charger, not a battery tender. It charges for 2 hour each AM, on a timer. When I check it with my volt meter, it is 16 + while the charger is on. When off, it is 13 or so. When I check my RV battery, on a battery tender is stays in the 12.90 + range , and seldom gets above 13. I do check water levels monthly, even on vehicles. What would you say would give indication of a battery tender NOT working correctly?

A tender has several controls built in. First, if a battery is low, it goes to a bulk charge rate mode, charging typically at about 1.25 - 2.0 amps. Once the battery reaches within full charge, the tender will go into absorption mode charging at a rate of about .25 amps. When the tender detects the drop off of current from there, it will go into monitor or float mode. A drop of .1 volts will trigger it back into absorption mode charging until it detects the current drop off again indicating a full charge. Then it's back into float mode.

A trickle charger charges at a constant low rate. I don't care for them. They can destroy an AGM battery.

If a tender is working correctly, it should drop into float mode when the battery is fully charged. You would need an ammeter to check the current in the three modes. If a battery is heavily sulfated, a tender typically will not ever go into float mode but will stay in in the absorption mode charging. That's what I like about new tenders. They pulse the charging current thus breaking the sulfated down so that they are absorbed into solution rather than sticking to the plates.

Hope this helps.

 

[GCroyle]

I picked up a 12V digital meter that plugs into the Airstreams 12V TV plug. Don't want to post numbers that I haven't written down. Also have an analog AC meter, same idea.

 

[TLane]

jeepit -

When your camper is connected to "shore power" (i.e. in a site with electricity), the converter should charge the battery. Typically the converter is housed along with the breakers (AC) and fuses (DC). Lots of campers are sold with the cheapest Chinese converter made, and in spite of advertising claims, they don't always work well. I replaced my converter with one made by Progressive Dynamics. Do a search here for that name and see the discussions related to it.

You can do a basic check of the converter by measuring the battery voltage with the camper unplugged, then again with it plugged in. You should see the battery voltage go up as the converter charges the battery. NOTE: if you have a shorted cell, many converters will put as much current as they can into the battery attempting to charge it, which may result in a very hot battery (or worse).

 

[jeepit]

Back home from a week of camping at Peninsula State Park in Door County Wisconsin. Had electric for all but the last 2 nights. Battery died after the 2nd night. I had a backup battery along.
I found the manual on the camper convertor/charger and it said it would apply a 12.36 volt charge on battery to maintain it. Don't know if that is correct or not....just what I read about it.
Put battery on my charger at home and it could only bring it up to a 70% charge.

 

[jeepit]

Northern Tool sells a tender that uses pulsed charging. Supposedly, this desulfates the plates. Since I use both AGM and regular lead acid batteries, I picked one up. My tractor battery was reading about the same as your battery in question. I put the tender on, per the instructions and let it do it's thing (desulfate the battery). Much to my surprise, the tractor battery came back to full charge and I haven't had any problem with it since. I really like this tender because once it reaches full charge, it drops into the "monitor" mode instead of a low constant charging current. Here's a link: http://www.northerntool.com/shop/tools/product_200589669_200589669 I have no affiliation with Northern Tool and I'm sure someone else makes a tender like this. I initially bought it for my motorcycle battery for winter battery tending. That battery is an AGM and requires a higher charging voltage than regular lead acid. This tender gives you a choice as to battery type as well as charging current. Now, I run through all of my stuff (wood splitter, tractor, generator) every few months and desulfate them.

Alan,
Thanks for the link. I ended up purchasing this unit and so far appears to have nursed the battery back to life.
I will see how the battery lasts in a week.

 

[Alan Reagan]

Alan,
Thanks for the link. I ended up purchasing this unit and so far appears to have nursed the battery back to life.
I will see how the battery lasts in a week.

Glad you like it. I just used it to bring back a generator battery that I thought was toast. I ran it through a 24 cycle and the generator battery has been holding a charge for two weeks now. I like this charger. I use it on AGM and wet cell batteries and it works really good.

 

[inlinesix3million]

Alan,
Thanks for the link. I ended up purchasing this unit and so far appears to have nursed the battery back to life.
I will see how the battery lasts in a week.

I agree with your purchace also. You need a battery tender that operates this way to get the maximum life out of your various batteries. I would seriously consider upgrading your
built in charge controller on your camper to a compatible version from Progressive Dynamics. It does what your new tender does whenever you are plugged in to genny/shore power.
Many of the factory installed budget controllers will turn a 5 year battery into a 2 year battery. You can get a PD for a couple hundred bucks or less and install it yourself with just a
little research.