Batteries Will Not Take Charge

[Lenny_K]

I have a friend that has a Chinook Class B with two 12v batteries that will not take a charge over 13.4v even with a 40 amp battery charger attached. Needless to say they wake up in the morning to low battery beeping sounds.
Any ideas why they will not take over 13.3v charge.

[2oldman]

NinerBikes wrote:
Two very common sense basic requests have been made of you, and still, you type away.... folks need to help themselves first, with the most basic tests, long before even posting up here in the Tech section.

I LIKE it!

[NinerBikes]

Lenny K wrote:

2oldman wrote:

NinerBikes wrote:
Can't fix lazy.

I LIKE it!

Thank you to all the posters, except for the two above, for your thoughtful and useful responses. I will pass these onto the couple that I had posted for.

The problem is your "friends" won't help themselves... hearing it from you is just hearsay. Why even bother being the messenger?

Sorry, so sad that you can not handle the truth, you waste the time and wear out the patience of those who's help you seek. Two very common sense basic requests have been made of you, and still, you type away, instead of getting results for the requests. That equals FAIL in my book, and no, I am not sorry or apologetic, sometimes folks need to help themselves first, with the most basic tests, long before even posting up here in the Tech section. Batteries on RV's are far from rocket science.

We don't keep throwing fish here, every day, creating welfare RV camper dependents, when we can teach those that want to learn, how to fish, so that they can catch fish themselves, and feed themselves, for the rest of their Rving life.


Better yet, how about you take some initiative and try using the search function "battery testing" should get you all the answers your "friends" need.

There's plenty of us battery doctors here, but what's the point of seeing a doctor, when you won't answer the most basic questions asked of you by the doctor? You waste your time and the doctors time, except we don't get to bill you for the waste of time for unnecessary visits.

Seems retarded, to me. YMMV, just my perspective and IMHO...

[Lenny_K]

2oldman wrote:

NinerBikes wrote:
Can't fix lazy.

I LIKE it!

Thank you to all the posters, except for the two above, for your thoughtful and useful responses. I will pass these onto the couple that I had posted for.

[marcsbigfoot20b]

Sulphated?

[Canadian_Rainbi]

As mentioned several times above you need to give us more info as to what you are doing and seeing.

If you have a hydrometer, check, write down and report here the SG in each cell. Should be 1.265 to 1.275 range depending on the type of battery

24 hours after the charger and loads have been removed battery voltage should be 12.6 or better. If less (ie 11.5 or so) you have a shorted cell in one of the batteries.

Try charging one at a time, with no other connections. One may charge OK, the other will probably not--shorted cell.

[time2roll]

After these batteries are 'charged' what does the hydrometer say?
Or after charging and sitting disconnected 48 hours what is the resting voltage?

Or take them down to be tested and probably replaced.

[RoyB]

A typical good working order deep cycle 12VDC battery will DEMAND 17-20AMPS of DC CURRENT when first hit with 14.4VDC Charging Voltage.

You will want to use a multimeter across the battery battery terminals and see if the charging DC Voltage is present.

i.e. a fully charged deep cycle battery will read 12.6-7VDC at the terminals without shore power connected.

When you turn on SHORE POWER then the DC VOLTAGE at the Battery Terminal should jump to 13.6VDC or 14.4VDC depending what the charge mode of the CONVERTER is in.

The DC Current is determined by the BATTERY. Does not matter how much capacity the CHARGER has available to use. The BATTERY will DEMAND how much DC CURRENT is being drawn from the charging source.

This is why it is important to see the DC CHARGING VOLTAGE present at the battery terminals. It could be you have a blown fuse or bad connection between the Battery and the Converter/Charger. If you are reading DC CHARGING voltage at the battery terminals and it still is not charging then you may have a open circuit inside the battery that may have occurred by a shorted cell until it burned the path open. Checking the battery fluids is also a quick test. It a shorted cell has occurred the battery will get very hot and boil out the battery fluids. The outside case will also be warm to hot to touch when this happens as well. Some batteries may even explode on you when this happens.

Simple battery maintenance inspections is easy to do with the batteries.

Using the HYDROMETER is the best solution to determine the charge status but just having a multimeter can also lead you to make good diagnostics as well.

It behooves one to learn simple battery maintenance procedures especially when one depends on the batteries like when camping off the power grid. Sort of hard to deal with the Momabear when it goes dark on you real quick.

Roy Ken

[NinerBikes]

2oldman wrote:

NinerBikes wrote:
Can't fix lazy.

I LIKE it!

Dutch Directness is like battery acid on a fully charged Lead Acid battery, use some common sense and respect it, you'll be OK, get sloppy or lazy, and it will burn you. There's honesty, and then there's excuses, which isn't very honest, now is it?

[wa8yxm]

Two theories:
One: battery failure, Shorted cell
Two: Volt meter accuracy,, Some meters are +/- 20% 20% of 13 is 2.6 volts.
Even 5 percent is 0.8 volts, How accurate is the meter?

[2oldman]

NinerBikes wrote:
Can't fix lazy.

I LIKE it!

[NinerBikes]

Lenny K wrote:

rk911 wrote:

Dakota98 wrote:
Are these Lead Acid or AGM ?

Are "all connections" clean ?

and if not maintenance free check the cells with a hydrometer. how old are the batteries?

I don't have a hydrometer with me and the doesn't have one either and I don't know the age of the batteries.
I've been after to have a load test done on them but he hasn't to date.

Can't fix lazy. You should take some samples, get a date code, and get back to us.

[rk911]

Lenny K wrote:

rk911 wrote:

Dakota98 wrote:
Are these Lead Acid or AGM ?

Are "all connections" clean ?

and if not maintenance free check the cells with a hydrometer. how old are the batteries?

I don't have a hydrometer with me and the doesn't have one either and I don't know the age of the batteries.
I've been after to have a load test done on them but he hasn't to date.

the next time you're at the hardware store pick one up and put it in your tool box. it's a great tool.

[2oldman]

What is the maximum output voltage of the charger? If the batteries are old and shot, there's no accounting for their behavior.

Try a known good battery and see how it charges.

[Dakota98]

Assuming you've checked water levels then. Do you have a hydrometer? See what your readings are.

Even if you do, have them tested.

Depending on their age & charging profile used in the past, it may be time for new ones.