Help with a battery charger
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I am just starting to learn about the stamp. I know it's possible to
build a battery conditioner/charger using the stamp as the brain of
the charger. However I have no idea how to do this. I want to be able
to push 50 amps at 24 volts into a large battery bank for an off grid
system. I will need a dump load for when the batteries are charged.
Any help will be greatly appriciated.
Tim
build a battery conditioner/charger using the stamp as the brain of
the charger. However I have no idea how to do this. I want to be able
to push 50 amps at 24 volts into a large battery bank for an off grid
system. I will need a dump load for when the batteries are charged.
Any help will be greatly appriciated.
Tim
Comments
>I am just starting to learn about the stamp. I know it's possible to
>build a battery conditioner/charger using the stamp as the brain of
>the charger. However I have no idea how to do this. I want to be able
>to push 50 amps at 24 volts into a large battery bank for an off grid
>system. I will need a dump load for when the batteries are charged.
>Any help will be greatly appriciated.
>
>Tim
I would be inclined to use dedicated controllers to control charge of these
batteries with the Stamp performing a higher level of supervisory, watch
and report status, duties. It should not be too difficult to get the Stamp
to monitor the current drawn from the batteries and recharged back into
them and be able to report at any time the percent of usable charge
remaining in the bank as a result.
I have worked with lead-acid batteries for most of 30 years and can lend
battery advice and some ideas for a black box approach to such a system, no
schematics, but here's the deal....
.... I'm absolutely punch drunk from being up over 36 hours participating
in the Field Day (ham radio) event this weekend so I better wait a few days
before trying to deal with things that need careful thought. If you will
mail me - or post to the list since there are many others who can help you
here - some details on what you want to accomplish, and your level of
expertise, I will look these over and make my contribution Monday or
Tuesday. OK? Right now I'm running on adrenaline and caffeine, trying to
relax a bit so I can go to sleep when I lie down.
Jim H
> At 01:59 06/22/02, tdale4 wrote:
> >I am just starting to learn about the stamp. I know it's possible
to
> >build a battery conditioner/charger using the stamp as the brain of
> >the charger. However I have no idea how to do this. I want to be
able
> >to push 50 amps at 24 volts into a large battery bank for an off
grid
> >system. I will need a dump load for when the batteries are charged.
> >Any help will be greatly appriciated.
> >
> >Tim
>
> I would be inclined to use dedicated controllers to control charge
of these
> batteries with the Stamp performing a higher level of supervisory,
watch
> and report status, duties. It should not be too difficult to get
the Stamp
> to monitor the current drawn from the batteries and recharged back
into
> them and be able to report at any time the percent of usable charge
> remaining in the bank as a result.
>
> I have worked with lead-acid batteries for most of 30 years and can
lend
> battery advice and some ideas for a black box approach to such a
system, no
> schematics, but here's the deal....
>
> .... I'm absolutely punch drunk from being up over 36 hours
participating
> in the Field Day (ham radio) event this weekend so I better wait a
few days
> before trying to deal with things that need careful thought. If
you will
> mail me - or post to the list since there are many others who can
help you
> here - some details on what you want to accomplish, and your level
of
> expertise, I will look these over and make my contribution Monday
or
> Tuesday. OK? Right now I'm running on adrenaline and caffeine,
trying to
> relax a bit so I can go to sleep when I lie down.
>
> Jim H
I am going to make a desulfator like the one shown here
http://shaka.com/~kalepa/desulf.htm here is the page with the stamp
instead of the 555
http://shaka.com/~kalepa/desulfparts.htm
Since I am going this far I want to take it a step farther and make a
whol charging/maintenence system. With a combination of solar pannels
and a windmill I will be charging between 50-75 amps at 24 volts into
a 24 volt battery bank. Is this to hard to do? I must admit I have
very limited experiance with the stamp but I am a fast learner and
very determined to do thinks for myself if possible. This way if
something breaks I can fix it myself:-)
Thanks for any help you can give me,
Tim
>I am going to make a desulfator like the one shown here
>http://shaka.com/~kalepa/desulf.htm here is the page with the stamp
>instead of the 555
>http://shaka.com/~kalepa/desulfparts.htm
A desulfator? Slowly I turned, step by step... inch by inch... ;-)
I have to ask. Why are you building a desulfator? Are your batteries
sulfated? If not, a standard properly adjusted charger will prevent
sulfation. If they are, a standard charger with its voltage turned up just
a bit over the normal charge voltage, or even just allowed to recharge at
the normal voltage for an extended period, will reverse that sulfation as
effectively as any so-called pulse chargers. These things are snake oil -
and I speak with 30 years of experience in the lead-acid battery
industry. No reputable battery manufacturer I know of sells or recommends
these devices.
>Since I am going this far I want to take it a step farther and make a
>whol charging/maintenence system. With a combination of solar pannels
>and a windmill I will be charging between 50-75 amps at 24 volts into
>a 24 volt battery bank. Is this to hard to do?
It isn't easy, but how hard it is depends on your expertise, or lack
thereof. For sure, if you want to be able to properly recharge a 24-volt
battery bank, you better have a charging system that can deliver all of 30
volts when needed.
What, specifically, will you be using for batteries? Will they be new or
will they be questionable surplus? Is doing the project a potentially
greater joy to you than the having of the final product? Are you on a very
limited budget as far as this project goes?
Remember, I said my contribution would be more in the area of battery
advice and black-box (conceptual) advice in other areas. My advice in all
areas is to forget desulfators.
A Google search on home built solar power or wind power reveals many
interesting sites. You will find a lot of good, directly usable,
information there for a little search effort. I can probably assist with
battery maintenance advice when it comes to using "proper" charge
controllers, but the only advice I can offer regarding desulfators is to
forget them completely.
Jim H
> At 21:06 06/24/02, tdale4 wrote:
>
> >I am going to make a desulfator like the one shown here
> >http://shaka.com/~kalepa/desulf.htm here is the page with the stamp
> >instead of the 555
> >http://shaka.com/~kalepa/desulfparts.htm
>
> A desulfator? Slowly I turned, step by step... inch by inch... ;-)
>
> I have to ask. Why are you building a desulfator? Are your
batteries
> sulfated? If not, a standard properly adjusted charger will
prevent
> sulfation. If they are, a standard charger with its voltage turned
up just
> a bit over the normal charge voltage, or even just allowed to
recharge at
> the normal voltage for an extended period, will reverse that
sulfation as
> effectively as any so-called pulse chargers. These things are
snake oil -
> and I speak with 30 years of experience in the lead-acid battery
> industry. No reputable battery manufacturer I know of sells or
recommends
> these devices.
>
> >Since I am going this far I want to take it a step farther and
make a
> >whol charging/maintenence system. With a combination of solar
pannels
> >and a windmill I will be charging between 50-75 amps at 24 volts
into
> >a 24 volt battery bank. Is this to hard to do?
>
> It isn't easy, but how hard it is depends on your expertise, or
lack
> thereof. For sure, if you want to be able to properly recharge a
24-volt
> battery bank, you better have a charging system that can deliver
all of 30
> volts when needed.
>
> What, specifically, will you be using for batteries? Will they be
new or
> will they be questionable surplus? Is doing the project a
potentially
> greater joy to you than the having of the final product? Are you
on a very
> limited budget as far as this project goes?
>
> Remember, I said my contribution would be more in the area of
battery
> advice and black-box (conceptual) advice in other areas. My advice
in all
Even if I just go with a regular charger the main reason I want to
DIY is the thrill of learning and making something that works as well
as a store bought item. My batts are 2 years old and have a little
sulfidation. They were bought at Costo for $45 ea, if I remember
correctly.
> areas is to forget desulfators.
>
> A Google search on home built solar power or wind power reveals
many
> interesting sites. You will find a lot of good, directly usable,
> information there for a little search effort. I can probably
assist with
> battery maintenance advice when it comes to using "proper" charge
> controllers, but the only advice I can offer regarding desulfators
is to
> forget them completely.
>
>
> Jim H
>--- In basicstamps@y..., Jim Higgins <HigginsJ@s...> wrote:
>
>>My advice in all areas is to forget desulfators.
>
>Even if I just go with a regular charger the main reason I want to
>DIY is the thrill of learning and making something that works as well
>as a store bought item.
Understood. I don't think I said anything against DIY per se, but you
asked for advice and I'm telling you that based on 30 years of experience,
and several evaluations of so-called "desulfators," that they are snake
oil. An equally worthwhile DIY project would be a conventional charger
that eliminates the element of "black magic," but it's your
decision. Please note, I think you mentioned the need for 75 amps of
current. That will require a significant scaling up of the design at the
URL you referenced. The high current pulses will require larger control
components than a conventional charger and will add cost for no
benefit. It's your decision.
Also, you need different charge controllers for controlling the charge from
your windmill and from your photo voltaic panels to your batteries. You
might want to research this sort of thing on the web before jumping in with
both feet. Do-overs are frustrating and expensive.
>My batts are 2 years old and have a little sulfidation. They were bought
>at Costo for $45 ea, if I remember correctly.
OK... but you're really doling out the information in awfully tiny
parcels. For example, my car is blue, bought in 1994, and needs
waxing. Was it a good choice for my transportation needs and how should I
improve engine performance? What I'm saying is that you need to be a bit
more forthcoming with some relevant details if you expect to get useful help.
If they have removable filler caps, take them off and measure specific
gravity of the electrolyte and tell me what you find. If you find values
much below 1.100 I'd say the batteries are probably junk at this point.
Generically what you need to do is charge these batteries - NOW! You can
use a DIY "desulfator" if/when you build it, or you can use a standard
charger NOW. If the batteries are sulfated they need charging NOW before
the condition worsens. A week or two won't matter, but don't let another
month go by before fully recharging these batteries to bring the specific
gravity of the electrolyte back to the value recommended by the
manufacturer. This is probably about 1.270 - 1.280 for an auto starting
battery. If you don't have a 24-volt charger, arrange the batteries so you
can charge them in groups of 12 volts at a time using the charger you build
or a small, cheap charger you can get from your local auto supply
store. It will take more time than a bigger, more expensive charger, but
eliminating heavy sulfation (and that's what you have after 2 years if you
haven't been charging these batteries) is best done with low current. Put
the cost of a faster, bigger charger into your project, not into initial
battery recovery. OTOH, perhaps the cost of a charger, even a cheap one,
to try to salvage these batteries is best put toward new batteries. I'd
not be at all surprised to find this is the case.
You didn't say specifically, but if they have been standing on open circuit
without charge for two years, then they have been very severely abused,
perhaps not recoverable. How bad off these batteries are depends on a
number of things that include whether they are the old "regular" design
with easily removed filler caps for adding water or the newer "low
maintenance" sealed design. Then it can depend on whether they are sealed
recombinant, VRLA, gelled, flooded, etc. (With some of those designations
being redundant or nonexclusive for those who know a bit in this area.) It
also depends on the storage conditions; i.e.; were the batteries clean or
were their tops dirty, dry or wet, and the temperature plays a big role -
heat causes batteries to sulfate faster.
Once we get past this, bought at Costco two years ago for $45 each tells me
their age is working against them unless they have been kept charged. It
also hints that they're automotive starting batteries. Two of them,
12-volts each, right? If so, they are a very poor choice for a cycling
type service like you mention - charge during the day from photo voltaic
power, charge whenever from wind power, and with some degree of discharge
daily. If the sun and wind can't provide all power the load needs, the
batteries will discharge and later need to be recharged. Auto starting
batteries are designed to be discharges for a few seconds at high rates,
removing maybe a low single-digit percentage of their total capacity, not
for many hours of discharge removing a moderate to large double-digit
percentage of their capacity. In the latter application their life is very
short. Deep cycle batteries fare better, but industrial batteries
specifically designed for this sort of service are your best choice - and
represent quite a large initial expense.... which is why proper care in the
form of a "proper" charger and charge controller are vital to maintaining
your investment.
Next you mentioned a need for 75 amps of current. OK, an auto starting
battery, or deep cycle marine battery of similar size can do that... for
maybe an hour, more or less, depending on size. Is this what you planned
for? Or will the photo voltaic panel and windmill also be supplying
power? Will the windmill alone be enough at night? Etc, etc... Have you
totalled up your assorted loads and determined whether you will have enough
combined battery, windmill and solar panel capacity to not only handle your
loads, but also provide a positive power return to the battery before it is
discharged more than 70 - 80%?
Please don't take any of this as discouragement meant to keep you from
doing this project, but rather as factors you need to take into account in
the planning stage if you are to be successful.
> to
> > >build a battery conditioner/charger using the stamp as the brain
of
> > >the charger. However I have no idea how to do this. I want to be
> able
> > >to push 50 amps at 24 volts into a large battery bank for an off
> grid
> > >system. I will need a dump load for when the batteries are
charged.
> > >Any help will be greatly appriciated.
> > >
> I am going to make a desulfator like the one shown here
> http://shaka.com/~kalepa/desulf.htm here is the page with the stamp
> instead of the 555
> http://shaka.com/~kalepa/desulfparts.htm
> Since I am going this far I want to take it a step farther and make
a
> whol charging/maintenence system. With a combination of solar
pannels
> and a windmill I will be charging between 50-75 amps at 24 volts
into
> a 24 volt battery bank. Is this to hard to do? I must admit I have
> very limited experiance with the stamp but I am a fast learner and
> very determined to do thinks for myself if possible. This way if
> something breaks I can fix it myself:-)
>
> Thanks for any help you can give me,
> Tim
Hi Tim,
I would be more than happy to assist you in any aspect of pulse
charging or desulfation pulsing. I have written pulsing programs for
the BS1 to the BS2sx. The BS2sx is my personal favorite with the fine
grain tuning possible with the 0.8uSec PULSOUT command.
Please email me at desulfator@y...
I also monitor the BBS at,
http://pub36.ezboard.com/bleadacidbatterydesulfation
People from around the globe are available to answer questions you may
have. Many are of the engineering persuasion and are trying to refine
the process in order to speed it up.
I along with others have been researching and refining both areas for
a few years now. From what I am given to understand the technology is
about 20 years old. Many are not aware that lead acid batteries
properly conditioned have a 20 to 70 year life span.
Many commercial charger manufacturers are begining to incorporate that
technology in their equipment.
AND I (and literaly tens of thousands of others) can assure you that
the process works. I personally have about 50 to 60 batts here.
About a dozen or so are the large deep discharge types that others had
thrown away. They have since been recovered and are used for research
and when someone hits a power pole and kills the utility power.
I suspect you will find that battery people don't like to talk about
it as it has the potential to severly reduce sales. Most batteries
are discarded with many many years of life left in them if they are
pulse conditioned
Happy Pulsing,
Don Denhardt
is about 1.19. I will take you susgestion and only make a charge
controller. The batteries are 6 volt "golf cart" batteries, so I
assume that they are deep cycle, I know their not as good as an
industrial forklift battery, but they will do. I still would like to
build my own charger, I really enjoy building my own things:-)
>Thank you for all your advice. I measured the specific gravity and it
>is about 1.19. I will take you susgestion and only make a charge
>controller. The batteries are 6 volt "golf cart" batteries, so I
>assume that they are deep cycle, I know their not as good as an
>industrial forklift battery, but they will do. I still would like to
>build my own charger, I really enjoy building my own things:-)
You're welcome. Depending on the Mfgr of those batteries, they may be well
designed for deep cycle service, or only moderately well designed. Trojan
is probably the best out there. For best life, "deep cycle" means you
remove at most 80% of the rated amp-hours before recharging. Bear in mind
that the true amp-hour rating depends on the rate at which you discharge
them. A 60 amp-hour battery rated to deliver say 3 amps over 20 hours will
deliver 10 amps for something very considerably less than 6 hours. The
higher the current draw the lower the amp-hour rating at that current
draw. The Mfgr's web site may provide tables relating time vs current vs
amp-hours.
There's nothing wrong with building your own charger. And, if you keep
your charge current within reasonable limits, you won't hurt the batteries
by using a pulse charger - you just won't gain anything from doing so
except added complexity in the charger.
But in the meantime, you need to charge those batteries. They are a long
way from being fully charged and if they drifted to this state just by
standing they are well on their way to being severely sulfated. Borrow a
charger if you need to, but get them recharged. Use a transformer with a
full wave or half wave rectifier on the secondary and something like a 60 -
100 watt bulb in series with the primary if you need to, but get them
charged until they bubble, and their specific gravity rises and
stabilizes. It may not come to 1.285, but if it reaches a stable value
after bubbling a while you can consider them fully charged. Stable means
essentially the same value over a 3-hr additional charge period. Take
specific gravity readings in a few cells (not necessary to check every one,
but check the same ones every time) every few hours after they start
bubbling and keep doing so until they're stable. (Normally I'd say stable
for 1 - 2 hour, but let's get these things well charged. Limit current to
about 5% of the amp-hour rating and if they get over say 100 degrees F, or
more than 20 degrees above the ambient temperature, put a lower wattage
bulb in series to cut the current by at least 25%. For driving out sulfate
a lower charge current is more efficient. No need to severely overheat
these things or electrolyze a lot of water. See the notes below about when
to add water. Their specific gravity when fully charged probably should be
something like 1.280 - 1.290, but you really need to find the Mfgr's web
site and get the real Mfgr's specified value.
When stable, note the current if you can measure it (not vital) then read
and record the voltage, temperature and specific gravity of every
cell. Keep track of which reading goes with which cell. If all are
similar, all well and good. If a few are out of whack, some investigation
is needed. A single cell with low specific gravity probably indicates a
problem with that cell, whereas all cells a bit low probably indicates
spillage some time in the past that was made up by adding water.
A hard and fast rule - as long as liquid covers the tops of the plates,
never add water except near the end of a recharge when the battery is
bubbling fairly vigorously. If you water up to the mark while not on
charge, the later gassing will cause the acid to rise up and bubble out of
the cell. If you water while bubbling it won't rise any higher and thus
won't bubble out. After adding water, I'd allow maybe 4 hours for full and
complete mixing. The circulation of electrolyte in Golf Car cells is
generally not very good due to separator design and very close plate
spacing. I wouldn't be in any rush to add water, except to cover the tops
of the plates, if the specific gravity is low because you'll just have to
remove electrolyte later to add stronger acid (1.350 - 1.400 SG is typical)
to bring the SG up to spec. It's better to have to add water to lower the
gravity to avoid sucking acid out and possibly disposing of it.
Feel free to ask questions and/or post end of recharge readings if you wish.
Jim H