# AGM battery charging question

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#### Damian

Jan 1, 1970
0
Hi guys,
I would appreciate if I could get some advice on below question.
I have two AGM deep cycle batteries(identical). Thye 6V batteries about
300ah each. I am hoping to connect they on series to get 12V.
My question is that,
Is it safe to charge the batteries connected as above with a single 12V
charger without any damage to the batteries or the charger?!
I am hoping the charger simply treat the two 6V batteries as a single 12V
battery and charge they equally without any issues.

T

#### Toby Ponsenby

Jan 1, 1970
0
Hi guys,
I would appreciate if I could get some advice on below question.
I have two AGM deep cycle batteries(identical). Thye 6V batteries about
300ah each. I am hoping to connect they on series to get 12V.
My question is that,
Is it safe to charge the batteries connected as above with a single 12V
charger without any damage to the batteries or the charger?!
I am hoping the charger simply treat the two 6V batteries as a single 12V
battery and charge they equally without any issues.

ummm. AGM Batteries have slightly different characteristics to the
batteries the charger you're considering will work well with insofar as
charging requirements.
I'm guessing here, but IF the batteries are basically equal in their
resistance etc, then 12 Volt chargers might work well enough - depends
on just what actual voltage the charger belts out in response to the
internal resistance of the victim batteries - in other words how well
the charger is 'regulated'. All bets are off with the exceedingly cheap,
brightly coloured and nasty devices laughingly called chargers, commonly
found in the local accessories store right beside the plastic wheel
trims and furry steering wheel covers

Will be interesting to see their response.
Natch, my suggestion is that if you actually shelled out 'ard earned
for the batteries, you'd be treating them to a real live computer
controlled tricked up charger.
What do you intend to use this massive power source for, may I ask?

Wow,

D

#### Damian

Jan 1, 1970
0
Hi Toby,
I am planning to use the two batteries(yes they are massive) on my small
caravan for camping, etc.

I do have a charger which I paid around $50 and which is advertised as a good maintenance charger for AGM batteries Here is the link for the charger. http://www.ebay.com.au/itm/110969221327?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649 I also have a good regulated power supply(1V to 24V) which I built years ago and use as a battery charger as well. By manually manipulating the volatage and current with control knobs, I have been using it as a maintenance charger. Only thing I don't know much about is whether connecting two batteries in series to gain voltage is good or not. I read that unless the two batteries are identical in size, condition, etc it's bad news for both batteries. But, are they really 'identical' even when they are brand new?! That I am not sure. So, I need some real help. Thanks P #### PeterD Jan 1, 1970 0 Hi guys, I would appreciate if I could get some advice on below question. I have two AGM deep cycle batteries(identical). Thye 6V batteries about 300ah each. I am hoping to connect they on series to get 12V. My question is that, Is it safe to charge the batteries connected as above with a single 12V charger without any damage to the batteries or the charger?! I am hoping the charger simply treat the two 6V batteries as a single 12V battery and charge they equally without any issues. Thank you for any advice. If the batteries are the same yes, series will be fine. Most applications (UPSs etc.) they are series and charged as a bank. Before charging in series you must, however, ensure that each is identical in capabilities (as well as specifications) and that each has an identical level of charge. Any charger to charge an AGM battery must be designed to charge those types of batteries. You cannot use a generic charger, you need one with an AGM setting. T #### terryc Jan 1, 1970 0 Hi guys, I would appreciate if I could get some advice on below question. I have two AGM deep cycle batteries(identical). Thye 6V batteries about 300ah each. I am hoping to connect they on series to get 12V. My question is that, Is it safe to charge the batteries connected as above with a single 12V charger without any damage to the batteries or the charger?! I am hoping the charger simply treat the two 6V batteries as a single 12V battery and charge they equally without any issues. Yes and No. Yes, it works fine, as long as you have an appropriate charger. No, you need to make sure they stay as close as possible in voltage. That said, you should source a 6v charger to sync them from time to time. T #### terryc Jan 1, 1970 0 Hi Toby, I am planning to use the two batteries(yes they are massive) on my small caravan for camping, etc. I do have a charger which I paid around$50 and which is advertised as a
good maintenance charger for AGM batteries
Here is the link for the charger.

http://www.ebay.com.au/itm/110969221327?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

Erk. Rubbish. My rule of thumb is that you'll pay a similar amout for
the battery charger as you do for the battery.

I also have a good regulated power supply(1V to 24V) which I built years ago
and use as a battery charger as well. By manually manipulating the volatage
and current with control knobs, I have been using it as a maintenance
charger.

You really need a charger that performes the appropriate stages for your
type of battery.
Only thing I don't know much about is whether connecting two batteries in
series to gain voltage is good or not. I read that unless the two batteries
are identical in size, condition, etc it's bad news for both batteries. But,
are they really 'identical' even when they are brand new?! That I am not
sure. So, I need some real help.

Do regular voltage checks and work them monthly or quarterly.

T

#### Toby Ponsenby

Jan 1, 1970
0
Hi Toby,
I am planning to use the two batteries(yes they are massive) on my small
caravan for camping, etc.

I do have a charger which I paid around \$50 and which is advertised as a
good maintenance charger for AGM batteries
Here is the link for the charger.

http://www.ebay.com.au/itm/110969221327?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

I also have a good regulated power supply(1V to 24V) which I built years ago
and use as a battery charger as well. By manually manipulating the volatage
and current with control knobs, I have been using it as a maintenance
charger.
Only thing I don't know much about is whether connecting two batteries in
series to gain voltage is good or not. I read that unless the two batteries
are identical in size, condition, etc it's bad news for both batteries. But,
are they really 'identical' even when they are brand new?! That I am not
sure. So, I need some real help.
Thanks

Ok - thought so re the Van - or perhaps a trailable boat.
The trick there is to use one of the new 'innovations' while on the
You don't need monster cables to get sufficient Voltage to the caravan
any more.
There a device on the market which via trickery (OK, an invertor+ a few
bits) which supplies 'correct' voltage to the batteries in the van/boat.
Actually it does heaps more than that. Maybe there's one in the range
that doesn't run a few power sources. Have a dig about on and near this
The important thing is the ability of the thing to FULLY charge your
batteries.

< http://www.batteriesdirect.com.au/shop/product/12569/d250s-dual.html >
Richie would say bloody maarvelos. Really.

D

#### Damian

Jan 1, 1970
0
Hi Neil,
Thanks for the information.
Dont they(AGM batteries) suppose to last for 5-10 years without needing any
maintenance(privided it's kept charged properly)?
I thought we pay extra money to get sealed AGM deep cycle batteries because
they suppose to last lot longer than wet cell batteries.
You don't think that's the case?!
Thanks

D

#### Damian

Jan 1, 1970
0
Thanks

terryc said:
Yes and No.
Yes, it works fine, as long as you have an appropriate charger.
No, you need to make sure they stay as close as possible in voltage. That
said, you should source a 6v charger to sync them from time to time.

D

Jan 1, 1970
0

D

#### Damian

Jan 1, 1970
0
Thank you. I think this is a great product even though it's bit pricy. I
think I'm going get a one.

T

#### Toby Ponsenby

Jan 1, 1970
0
Thank you. I think this is a great product even though it's bit pricy. I
think I'm going get a one.

Them's the goods - there may be others out there, as I'm sure there will
be others attempting to compete with the function, which is essentially
a better way to charge remote batteries than previouly existed outside
of uber epensive commercial stuff.
The people who've installed the stuff I linked to are mightly pleased
with it.
Only downside I can see so far is that the device should be in a well
ventilated location. Goes without saying that given what it does,
there'll be a little heat to dispose of.
Additionally the solar cell charging function ain't so redundant soon
given the prive of the PV arrays falling day by day.

D

#### Damian

Jan 1, 1970
0
Hi Neil,
I got little confused here.
I personally like the idea of maintaining the battery myself exactly the way
you mentioned.
I thought batteries with screw caps on the top are usualy automotive
starting batteries. And the sealed batteries are the ones usually used for
solar, caravan, UPS, etc. I thought AGM(and deep cycle) batteries are
usually sealed.
Do the semi traction batteries give out Hidrogen gas when it's been charged?
If so, do I need to install in outside the caravan or uder the bonnet like
starting batteries?
How is this semi traction battery different from typical vehicle starting
batteries?
Can you please send me a link to purchase a semi traction battery like
yours?!
I'm in Melbourne, Australia.
Thanks
Damian

T

#### terryc

Jan 1, 1970
0
I
suspect a 300Ah battery would be considerably more expensive than 3 x
110Ah batteries together, but you would have to research that
yourself.

125Ah are the largest common Deep discharge wet cells in Aust. Rather
than put tweo in parallel to get larger capacity. I preferred to buy two
6Volt 225 Amphour batteries. that was to prevent the problem of one
failing and pulling down and maybe destroying the other.

Another factor is my ability to lift individual batteries in and out of
locations. I remember that the 12V 125AmpHr batteries weighed 35kg each
Can not remember the figure for each 6V 225Amphour battery.

The differences between battery types are basically this:
Leisure batteries are designed for prolonged but light current drain,
Traction batteries are designed for electric propulsion and other
Vehicle starting batteries capable of delivering very high currents

My rule of thumb is that if the battery is rated in amphours, then it is
designed for "deep discharge" use. If it is rated in CCA, then it is a
ICE starter battery.

All lead/acid batteries have the potential to emit hydrogen and oxygen
when they are overcharged. This is actually beneficial when
equalising a battery, but requires the ability to be able to replace
the water lost in so doing.

This is why cheap battery chargers are a bad idea. They do not limit the
final trickle voltage and can run wet cells dry.
I don't have any links for you, I got my battery from a local caravan
spares dealer.

I actually go to a battery specialist who originally had traction as
well as alarm batteries but a seems to have moved more to alarm and
specilist motor starters(changing market in the area). Look in yellow
pages, etc for battery supliers in industrial areas and avoid main
street battery shops.

D

#### Damian

Jan 1, 1970
0
Thanks mate.
The two massive 6V batteries that I mentioned aren't in my hands yet. I have
been considering getting them to maintain a good long lasting power source
for the van. But, now I think it may be an overkill and a pretty heavy job
as well.
I think I am better off with a 125Ah sealed deep cycle battery and may be a
backup one. I reckon it's better to rely on a small generator rather than
carrying massive heavy batteries like I was planning to do.
What do you think about that?
Thanks

D

#### Damian

Jan 1, 1970
0
Hi Neil,
Thanks for clarifying that for me. I now know lot more about batteries than
I did before. I think I will get a sealed maintenance free battery as it's
bit challenging for me to install the battery outside the van and installing
it under the bonnet is not a choice either as there's no room.
So, I won't be able to get a battery with the ability to maintain like
yours.
I am thinking a maintenance free AGM deep cycle battery(or two). Does that
sounds like a good idea for my application?
Thanks

T

#### terryc

Jan 1, 1970
0
Thanks mate.
The two massive 6V batteries that I mentioned aren't in my hands yet. I have
been considering getting them to maintain a good long lasting power source
for the van. But, now I think it may be an overkill and a pretty heavy job
as well.

You need to look at your power requirements and work them out.
Refridgerator
Lighting
The dooles like mobile phones, torches, the radio(s)(AM/FM/UHF, etc)
(Where did they all come from)
The laptop
The 12 volt TV.
Medical machines.

Even stuff like fans on diesel/gas space heater and/or 12V electric
blanket. Sigh, there is even 12v hair dryers.

When it comes to stuff like aircon, then you need to run a generator of
sufficent size to run it. Add in the microwave to that as well.

Over here, camp sites can be divided into those that allow generators,
where mos caavans go and thse that don't, where most campers go. man
people don't like one destroying the peace and quiet.
I think I am better off with a 125Ah sealed deep cycle battery and may be a
backup one. I reckon it's better to rely on a small generator rather than
carrying massive heavy batteries like I was planning to do.
What do you think about that?

Batteries and a solar panels are a basic way to go here if you have
light demands like a refridgerator, lighting amd the doodles.. Most
times you will have no problems if you have adequately specced the
batteries to give you a couple of day's requirements.

It is when you are camped for the week, then you can run into problems
from it being heavily overcast all week. I have something like the honda
generator on my plans as a emergency back up.

I have also gone for four days capacity, so that effectively means that
at worst case I only loose the peace and quiet for one day in four.

If you are travelling every day/few days, like doing the big loop, that
C-tek D250S that was linked is the way to go as it tops up your caravan
battery from the solar panels when you're stopped or from the car
alternator when you are travelling. you need an auto isolator that
switches the car feed in after the car alternator has recharged your
starter battery.

OTOH, some places here, it just means that instead of stopping in the
bush camps, you pay for a powered site overnight and charge your
batteries up then.

I'll point out that I'm talking from the Australian perspective where we
have 30 million population spread over an area the size of
Europe/Mainland USA, but mostly in a few big cities and little facilties
in between.

D

#### Damian

Jan 1, 1970
0
Hi Neil,
If I understood you correctly, you meant a mechanical unit similar to the
built in alternator, right?!
I couldn't find any on ebay using the keyword 'supercharger' or 'super
charger'. It shows all the turbo stuff.
Thanks

D

#### Damian

Jan 1, 1970
0
Hi Neil,
By the looks of it, this is an idependent unit. Basically it is a smart
charger generator, am I right?
I am amazed to see that its available on LPG as well.
I wonder how they manage to compact all that stuff into a small unit. Must
be an ingenious design.
I definitely want to get hold of one.
Only thing I am wondering right now is that where to install this unit.
It's not cheap, but for obvious reasons.
I am sure Chinese clone makers are dismantlng it right now to find out how
to copy it. )
Cheers
Damian

D

#### Damian

Jan 1, 1970
0
Hi Neil.
I haven't been aware these units are available here.
I'm looking into it right now to find it.
It should be cheaper for locals. I wonder why the Aussie one is more
expensive.
Caravans are expensive here too. UK built ones are usually better quality
and not as expensive as the ones in here. I don't know the reason.
Everything seems to be expensive in Oz right now.
Perhaps that's how they kept the economy going witout going into a
recession. )
Cheers
Damian

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