quick ?
- Thread starter SLICKSALZ
- Start date
guys this is why I ask, I have a Lohman cd caller and it takes 8D batteries (which gets pricey after awhile) I would like to make the caller accept this batt
this little guy is 12v 1.3 ah
standby 13.5-13.8 no limit
cycle use 14.4-15.0 0.38capacity
I don't want to waste my time making the mods to the caller if the D batteries will out preform this one.
this little guy is 12v 1.3 ah
standby 13.5-13.8 no limit
cycle use 14.4-15.0 0.38capacity
I don't want to waste my time making the mods to the caller if the D batteries will out preform this one.
Nikonut
New member
I'm not an electronics engineer but I think you would do yourself well to go to the gel cell. Make sure you use a fuse in the circuit!
I have a homebuilt unit(automotive cassette player) powered by two 6v/5ah batteries in series and it works fine... just be sure there is a fuse on the positive side of the battery! With the higher amperage batteries you want to protect them from a short. Anything less could cause a fire or damage to your unit.
You might even be able to use a bigger battery! Are you planning to add a charging circuit or are you just going to unplug the battery to recharge?
It wouldn't take much to make a simple set of jumpers to test drive the setup before you do the final mods.
Nikonut /ubbthreads/images/graemlins/grinning-smiley-003.gif
I have a homebuilt unit(automotive cassette player) powered by two 6v/5ah batteries in series and it works fine... just be sure there is a fuse on the positive side of the battery! With the higher amperage batteries you want to protect them from a short. Anything less could cause a fire or damage to your unit.
You might even be able to use a bigger battery! Are you planning to add a charging circuit or are you just going to unplug the battery to recharge?
It wouldn't take much to make a simple set of jumpers to test drive the setup before you do the final mods.
Nikonut /ubbthreads/images/graemlins/grinning-smiley-003.gif
no on board charging unit. I have 2 of these batts and a wall charger (roll the batts in and out) I just dont want to take a step backwards (shorter run time) by using this batt. any guesses as to if this is an over performer or under performer as compared to 8 D sized batts?
mbowerma
New member
The Duracell alkaline D cell is a 5000 mAh unit. So that would give you using 8 batteries for 12 volts a .4 Ah battery. The 1.4 Ah your thinking of using would give you about 2.5 times more usage than the disposable batteries you are now using. Volts are the power and Amp hours are how much fuel is in the tank. Volts are the thing that could hurt your circuit not how much fuel is in the tank.
doggin coyotes
Well-known member
mbowerma thanks for that information.
Math. Man I hate math! Help me understand how you did that conversion if you don't mind. It's mostly where to put the decimal point is the part I'm confused about.
Thanks
Math. Man I hate math! Help me understand how you did that conversion if you don't mind. It's mostly where to put the decimal point is the part I'm confused about.
Thanks
cjdavis618
New member
If a AA or a D cell is 2500mAH, that makes that battery a 2.5AH battery. I'm not sure I follow your math mbowerma.
Am I missing something? Granted different types of batteries accommodate drain differently, but the measurements are the same.
(Taken form a battery site)
What is Capacity (mAh)?
The capacity of a battery is rated in mAh or Ah. If the capacity of a battery is 4400mAh (Milli-Amp Hour), it means that this battery can deliver mA (Milli-Amps) of current for 1 hour at the rated voltage. The actual amount of current a notebook draws depends on the usage. Things like LCD brightness, processor usage and hard drive usage affects the amount of current required.
To convert mAh to Ah, divide by 1000. To convert Ah to mAh, multiply by 1000. 4400mAh = 4.4Ah
Am I missing something? Granted different types of batteries accommodate drain differently, but the measurements are the same.
(Taken form a battery site)
What is Capacity (mAh)?
The capacity of a battery is rated in mAh or Ah. If the capacity of a battery is 4400mAh (Milli-Amp Hour), it means that this battery can deliver mA (Milli-Amps) of current for 1 hour at the rated voltage. The actual amount of current a notebook draws depends on the usage. Things like LCD brightness, processor usage and hard drive usage affects the amount of current required.
To convert mAh to Ah, divide by 1000. To convert Ah to mAh, multiply by 1000. 4400mAh = 4.4Ah
I have been a long time lurker on this site, and I have learned a lot from you guys and I feel this is a chance for me to give a little back. I recently graduated with a degree in engineering so this stuff is still fresh on my mind.
Using 8 1.5V D cell batteries connected in series makes 12V 8x1.5V=12V. When batteries are connected in series, the entire bank of batteries has the same capacity as one of the connected batteries. Looking at D Cell specs on Duracell and Energizer websites (http://data.energizer.com/PDFs/E95.pdf) gives us a 10 Ah to 20 Ah capacity for Alkaline D cells depending upon the current draw of the electronics. I will use an average value 15 Ah. The small battery in the picture SLICKSALZ provided has a capacity of 1.3 Ah.
Comparing the 8D setup to the smaller single battery shows us that the 8D setup will last approximately 11.5 (15Ah/1.3Ah=11.54) times longer than the small battery at a minimum.
The little battery in the picture looks to be a lead-acid battery. A little research shows us that a lead-acid battery has about .365 times the energy density of an alkaline battery. That means that, given the same size lead acid and alkaline batteries, the lead acid will have only .365 (http://www.allaboutbatteries.com/Battery-Energy.html) times the capacity of the alkaline battery. The battery in the picture looks to be about 1/4(.25) to 1/3(.333) the size of 8 D cell batteries. This allows us to estimate the 8 D cells to have about 11 ( 1/{.365*.25}=10.96) times the capacity of the small battery in the picture based size and battery type.
This explanation may be overdoing it a little, but I hope it helps.
Using 8 1.5V D cell batteries connected in series makes 12V 8x1.5V=12V. When batteries are connected in series, the entire bank of batteries has the same capacity as one of the connected batteries. Looking at D Cell specs on Duracell and Energizer websites (http://data.energizer.com/PDFs/E95.pdf) gives us a 10 Ah to 20 Ah capacity for Alkaline D cells depending upon the current draw of the electronics. I will use an average value 15 Ah. The small battery in the picture SLICKSALZ provided has a capacity of 1.3 Ah.
Comparing the 8D setup to the smaller single battery shows us that the 8D setup will last approximately 11.5 (15Ah/1.3Ah=11.54) times longer than the small battery at a minimum.
The little battery in the picture looks to be a lead-acid battery. A little research shows us that a lead-acid battery has about .365 times the energy density of an alkaline battery. That means that, given the same size lead acid and alkaline batteries, the lead acid will have only .365 (http://www.allaboutbatteries.com/Battery-Energy.html) times the capacity of the alkaline battery. The battery in the picture looks to be about 1/4(.25) to 1/3(.333) the size of 8 D cell batteries. This allows us to estimate the 8 D cells to have about 11 ( 1/{.365*.25}=10.96) times the capacity of the small battery in the picture based size and battery type.
This explanation may be overdoing it a little, but I hope it helps.
doggin coyotes
Well-known member
Very good stuff dwise. Thanks
So in this case the little 12 volt SLA battery is NOT a good choice for replacing the 8D cells? The 8D cells should/would run the CD caller close to 11 times longer than the little 12 volt battery?
That's a bunch of difference in run time!
So in this case the little 12 volt SLA battery is NOT a good choice for replacing the 8D cells? The 8D cells should/would run the CD caller close to 11 times longer than the little 12 volt battery?
That's a bunch of difference in run time!
Nikonut
New member
I see what Dwise is saying about the longevity of the smaller lead/acid battery. That really is a small battery.
I would still consider making up a simple wiring harness to try the setup out. You said you have two of these batteries... why not connect them in parallel and use both? It would still be a smaller lighter package and it would be fully rechargeable! You can also top off lead/acid cells between stands if needed. You can always pick up a new 12v 5ah battery for a little more than twenty bucks and swap it out, too.
Like I said about my homemade ecaller, I used two 6v,5ah lead/acid batteries in series and it will run an automotive cassette player for days! I also have a 12v/5ah battery that I can swap out but it is a lot heavier. Either power pack will also run a 12v, 1 million CP spotlight for about an hour.
Quote:
Volts are the power and Amp hours are how much fuel is in the tank. Volts are the thing that could hurt your circuit not how much fuel is in the tank.
That's very true! Over voltage can certainly fry a circuit. The biggest reason to use a fuse is so the amount of power(amperage)doesn't cause a fire or damage in case of a short circuit.
There's a lot more heat in a full tank! Kind of like the difference in touching a spark plug wire and shorting out a battery cable on your car... big difference! LOL /ubbthreads/images/graemlins/smile.gif
Let us know if you get this all working. It will be interesting to hear the actual results.
Nikonut /ubbthreads/images/graemlins/grinning-smiley-003.gif
I would still consider making up a simple wiring harness to try the setup out. You said you have two of these batteries... why not connect them in parallel and use both? It would still be a smaller lighter package and it would be fully rechargeable! You can also top off lead/acid cells between stands if needed. You can always pick up a new 12v 5ah battery for a little more than twenty bucks and swap it out, too.
Like I said about my homemade ecaller, I used two 6v,5ah lead/acid batteries in series and it will run an automotive cassette player for days! I also have a 12v/5ah battery that I can swap out but it is a lot heavier. Either power pack will also run a 12v, 1 million CP spotlight for about an hour.
Quote:
Volts are the power and Amp hours are how much fuel is in the tank. Volts are the thing that could hurt your circuit not how much fuel is in the tank.
That's very true! Over voltage can certainly fry a circuit. The biggest reason to use a fuse is so the amount of power(amperage)doesn't cause a fire or damage in case of a short circuit.
There's a lot more heat in a full tank! Kind of like the difference in touching a spark plug wire and shorting out a battery cable on your car... big difference! LOL /ubbthreads/images/graemlins/smile.gif
Let us know if you get this all working. It will be interesting to hear the actual results.
Nikonut /ubbthreads/images/graemlins/grinning-smiley-003.gif
doggin,
The short answer to your first question would be that, in IMHO the little SLA (sealed lead acid) baterry would NOT be a good choice for replacing the 8 D cells.
As to the second question, there are some things that we would need to know about the small SLA battery and the power consumption (watts or amp draw) of the caller to be certain about exactly how much longer the 8 D cells would run the caller. My reply above was just a ballpark estimate based on an average capacity value for the D cells. It could be more or less than the approx. 11 times that I calculated.
As best I can determine by doing some Google searches, lead acid battery capacities are based on a 20 hr discharge rate (I am not totally sure about this). That means that the little SLA above could provide a constant current of .065A for 20h (1.3Ah/20h=.065A=65mA). Looking at the specs for a Duracell D Cell on Duracell's website (http://www.duracell.com/oem/Pdf/new/MN1300_US_CT.pdf) shows that the 8 D's can provide a current of about .55A for 20h. I used the red line of the upper right graph on the second page to determine that value because it is the average of the three lines. Then, using the .55A value and looking at the red line on the middle left graph on the second page we can estimate a capacity of the D cells at about 12 Ah. That means that the 8 D cells could last about 9 times longer (12Ah/1.3Ah=9.23) than the little SLA battery. Lead acid batteries can, however, have their capacities improved if used intermittently (call for 30 min then go to the next stand 10-20 min away and call again). Here is a link that mentions something about that (http://www.batteryuniversity.com/partone-16a.htm). I am not sure if alkaline batteries do the same thing.
Even if the SLA battery's capacity was improved by intermittent use, I still think that we could safely say that the 8 D cells will last at least 5 times longer. In my opinion, that little SLA battery is just too small.
The short answer to your first question would be that, in IMHO the little SLA (sealed lead acid) baterry would NOT be a good choice for replacing the 8 D cells.
As to the second question, there are some things that we would need to know about the small SLA battery and the power consumption (watts or amp draw) of the caller to be certain about exactly how much longer the 8 D cells would run the caller. My reply above was just a ballpark estimate based on an average capacity value for the D cells. It could be more or less than the approx. 11 times that I calculated.
As best I can determine by doing some Google searches, lead acid battery capacities are based on a 20 hr discharge rate (I am not totally sure about this). That means that the little SLA above could provide a constant current of .065A for 20h (1.3Ah/20h=.065A=65mA). Looking at the specs for a Duracell D Cell on Duracell's website (http://www.duracell.com/oem/Pdf/new/MN1300_US_CT.pdf) shows that the 8 D's can provide a current of about .55A for 20h. I used the red line of the upper right graph on the second page to determine that value because it is the average of the three lines. Then, using the .55A value and looking at the red line on the middle left graph on the second page we can estimate a capacity of the D cells at about 12 Ah. That means that the 8 D cells could last about 9 times longer (12Ah/1.3Ah=9.23) than the little SLA battery. Lead acid batteries can, however, have their capacities improved if used intermittently (call for 30 min then go to the next stand 10-20 min away and call again). Here is a link that mentions something about that (http://www.batteryuniversity.com/partone-16a.htm). I am not sure if alkaline batteries do the same thing.
Even if the SLA battery's capacity was improved by intermittent use, I still think that we could safely say that the 8 D cells will last at least 5 times longer. In my opinion, that little SLA battery is just too small.
I think Nikonut is right. The best way to be certain is to try out the battery with a simple wiring harness. Maybe just use some alligator clips to connect it.
Nikonut,
One reason that I think your 5Ah batteries will run so long is because the initial capacity I a lot higher. If you look at Table 3 of this link (http://www.batteryuniversity.com/partone-16a.htm) it kind of shows why. The blue line graphs the discharge rate (in C) versus the discharge time. The discharge rate in C refers to the initial capacity of the battery. If we discharged your 5Ah battery at 5 amps it would have a discharge rate of 1C. If we discharge your battery at 1.3 amps it would have a discharge rate of .26C (1.3/5=.26C) while the small 1.3Ah battery in the picture would have a discharge rate of 1C. Using the Table 3 we can determine how much longer than the 1.3Ah battery the 5Ah battery would run using a .5A current draw. Using the dashed red (intermittent use) line, at a discharge rate of .1C (.5/5=.1C) the 5Ah battery would have a capacity of about 95% of the rated capacity. At a discharge rate of .38C(.5/1.3=.38 the 1.3 Ah battery would have a capacity of about 65% the rated capacity. This means the 5Ah battery would run 9.5h (95%*5Ah/.5A=9.5h) and the 1.3Ah battery would run about 1.7h (65%*1.3Ah/.5A=1.69h). This means that the 5Ah battery will run about 5.6 (9.5h/1.69h=5.62) times longer than the 1.3 Ah battery. If we compare the two batteries based on rated capacity alone, we would estimate that the 5Ah battery would have run only about 3.85 (5Ah/1.3Ah=3.85) times longer than the 1.3Ah battery. So...not only do you get more run time because of the greater capacity of the larger battery, but you get an additional boost in run time because the discharge rate (in C) is lower on the larger battery.
Nikonut,
One reason that I think your 5Ah batteries will run so long is because the initial capacity I a lot higher. If you look at Table 3 of this link (http://www.batteryuniversity.com/partone-16a.htm) it kind of shows why. The blue line graphs the discharge rate (in C) versus the discharge time. The discharge rate in C refers to the initial capacity of the battery. If we discharged your 5Ah battery at 5 amps it would have a discharge rate of 1C. If we discharge your battery at 1.3 amps it would have a discharge rate of .26C (1.3/5=.26C) while the small 1.3Ah battery in the picture would have a discharge rate of 1C. Using the Table 3 we can determine how much longer than the 1.3Ah battery the 5Ah battery would run using a .5A current draw. Using the dashed red (intermittent use) line, at a discharge rate of .1C (.5/5=.1C) the 5Ah battery would have a capacity of about 95% of the rated capacity. At a discharge rate of .38C(.5/1.3=.38 the 1.3 Ah battery would have a capacity of about 65% the rated capacity. This means the 5Ah battery would run 9.5h (95%*5Ah/.5A=9.5h) and the 1.3Ah battery would run about 1.7h (65%*1.3Ah/.5A=1.69h). This means that the 5Ah battery will run about 5.6 (9.5h/1.69h=5.62) times longer than the 1.3 Ah battery. If we compare the two batteries based on rated capacity alone, we would estimate that the 5Ah battery would have run only about 3.85 (5Ah/1.3Ah=3.85) times longer than the 1.3Ah battery. So...not only do you get more run time because of the greater capacity of the larger battery, but you get an additional boost in run time because the discharge rate (in C) is lower on the larger battery.
Nikonut
New member
Hey Dwise!
Good info. I hope you didn't take my previous post wrong... I agree with you that the D-cells will probably outlast the small sla battery. The point I was trying to make is the lead/acid cells are rechargeable and cost was also a concern.
It's young guys like you that are interested in improving mobile power technology and can also relate it to our hunting needs that are a big asset to us all! I hope you continue to post what you find so we all can learn! /ubbthreads/images/graemlins/grinning-smiley-003.gif
By the way you are talking way over my head, well some of it anyway! /ubbthreads/images/graemlins/smile.gif
I'm also a big fan of gel cells compared to any of the other rechargeables. There isn't much worse than being out in the middle of nowhere with a dead rechargeable battery! /ubbthreads/images/graemlins/smiliesmack.gif
I also agree and if it were me doing it, I would make a harness and try it. He said he already had two of those batteries so the cost would only be a few pieces of wire and a fuse holder.
Nikonut /ubbthreads/images/graemlins/wink.gif
P.S. I just edited mine since we were posting at the same time!
Good info. I hope you didn't take my previous post wrong... I agree with you that the D-cells will probably outlast the small sla battery. The point I was trying to make is the lead/acid cells are rechargeable and cost was also a concern.
It's young guys like you that are interested in improving mobile power technology and can also relate it to our hunting needs that are a big asset to us all! I hope you continue to post what you find so we all can learn! /ubbthreads/images/graemlins/grinning-smiley-003.gif
By the way you are talking way over my head, well some of it anyway! /ubbthreads/images/graemlins/smile.gif
I'm also a big fan of gel cells compared to any of the other rechargeables. There isn't much worse than being out in the middle of nowhere with a dead rechargeable battery! /ubbthreads/images/graemlins/smiliesmack.gif
I also agree and if it were me doing it, I would make a harness and try it. He said he already had two of those batteries so the cost would only be a few pieces of wire and a fuse holder.
Nikonut /ubbthreads/images/graemlins/wink.gif
P.S. I just edited mine since we were posting at the same time!
Last edited:
Nikonut
New member
WOW!
That was a great read and good reference material. I saved that website! That answers many of the things I thought were happening. It also explains why my spotlight eventually runs down like it does and then the caller will still work... the load is much less using the ecaller.
This also is good stuff to understand about rechrgeables.
Quote:
At 1C, a 10Ah battery discharges at the nominal rating of 10A in less than one hour. At 0.1C, the same battery discharges at 1A for roughly 10 hours. While the discharge voltage of lead acid decreases in a rounded profile towards the end-of-discharge cut-off, nickel and lithium-based chemistries provide a more steady voltage level through most of the discharge and then drop rapidly at the end of discharge.
Thanks again!
Nikonut /ubbthreads/images/graemlins/grinning-smiley-003.gif
That was a great read and good reference material. I saved that website! That answers many of the things I thought were happening. It also explains why my spotlight eventually runs down like it does and then the caller will still work... the load is much less using the ecaller.
This also is good stuff to understand about rechrgeables.
Quote:
At 1C, a 10Ah battery discharges at the nominal rating of 10A in less than one hour. At 0.1C, the same battery discharges at 1A for roughly 10 hours. While the discharge voltage of lead acid decreases in a rounded profile towards the end-of-discharge cut-off, nickel and lithium-based chemistries provide a more steady voltage level through most of the discharge and then drop rapidly at the end of discharge.
Thanks again!
Nikonut /ubbthreads/images/graemlins/grinning-smiley-003.gif
Nikonut,
I didn't take your post the wrong way. I am a fan of the lead acid batteries, too. Like you said, they are rechargeable so you save money in batteries that way. Also, the chargers for them are fairly inexpensive. You could even use your car battery charger if it has the 1 amp trickle charge setting.
I have a home made caller that I used a 12V 5Ah sealed lead acid battery in for a long time. I never had the battery run dead in a day of calling. I ended up switching it out for 8 AA rechargeables to lose some weight since I don't need the extra capacity.
I am glad I can help out. If I ever say anything that us confusing,just let me know and I will try to explain it or at least provide a link that does. Otherwise, I tend to get a little long-winded.
I didn't take your post the wrong way. I am a fan of the lead acid batteries, too. Like you said, they are rechargeable so you save money in batteries that way. Also, the chargers for them are fairly inexpensive. You could even use your car battery charger if it has the 1 amp trickle charge setting.
I have a home made caller that I used a 12V 5Ah sealed lead acid battery in for a long time. I never had the battery run dead in a day of calling. I ended up switching it out for 8 AA rechargeables to lose some weight since I don't need the extra capacity.
I am glad I can help out. If I ever say anything that us confusing,just let me know and I will try to explain it or at least provide a link that does. Otherwise, I tend to get a little long-winded.
wow look what I started. glad were all learning something. I've run it for 45min at 1\2 vol with no problems yet. how do I set my volt meter up to see what its drawing at 1\2 vol? I'm guessing in series between the batt (hot out put ) and the caller (hot in put)? thank you all for all the input so far.
