I have a 24V custom e-bike set up on my trike that is basically used as a peddle assist. I often pull a trailer with a total load of about 200-250 pounds including my own weight & full trailer load w child, groceries, etc. With my current set up and brand new 24v batteries, I can get a little over 3 miles before depleating the batteries.
I'd like to increase my mileage and was wondering if it was possible to do this by adding another 12v battery to my set up? Will this burn out my motor, set me on fire, etc? =) Also, if this is a possibility, about how much more distance could I get from one more battery? Is it worth the $70 price tag?
Any ideas that don't include a whole new set up or front wheel hub kit,etc? I want to run my current set up/motor into the ground before I consider upgrading everything.
Thanks!
It's best to add more batteries in parallel to the existing ones. Your controller is meant to run at 24v and if you add another battery to the existing pack it will be a 36v pack. While we sometimes run controllers at higher voltage than they're meant to run, this sometimes results in a ruined controller (due to letting out the magic smoke).
Your existing pack is 24v and made of 2x 12v batteries connected in series. Adding batteries in parallel means to get two more 12v batteries and connect each in parallel to the existing batteries. To connect one battery in parallel with another is simple.. just connect the + to + and - to - of the batteries you want to connect in parallel.
- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki
Due to the risk, what kind of precautions would I need to take in order to try and avoid ruining the controller as you mentioned? Reducing my speed, the amount of the time that I use the throttle, or is it a gamble? =)
Also, I'm curious... I was looking at the TNC web site and the batteries they sell at 12V / 12 amp hour / 20 hour rated (enduring) and the price is only $35.
I just purchased two new batteries from a local store (Batteries Plus) that the guy essentially picked the new batteries to match the old batteries I had : 12v / 18 amp hour / 10 hour rated and the price was $70 each!
What does the 18 amp hour part mean on my current battery, and how would I know if the 12 amp hour one sold on TNC would work with my set up??
What do you mean by custom e-bike? What type of motor/drive?
Something sounds really wrong, if you are saying you use the motor for pedal assist and your total load is as much as 250 Lbs, then you range should be much farther then 3 miles.
You have two 12 volt batteries in series giving you 24 volts total. 24 volts times 18 amp hours = 432 watts. A electric bike will consume about 10 to 20 watts per mile, depending on weight, terrain, pedaling input... Now you are saying you are only getting 3 miles before the batteries are depleted. Something must be wrong with the controller or the batteries, even the charger could be bad.
Deron.
An 'amp-hour' is one amp for one hour. An 18 amp-hour battery gives 18 amps for 1 hour (or 1 amp for 18 hours) versus a 12 amp-hour battery that would give 12 amps for 1 hour (or 1 amp for 18 hours).
Hence an 18 amp-hour battery will last longer than the 12 amp-hour one. I'm sure you like things that last longer, eh? However the larger battery will weigh more. The number of amp-hours is sorta related to how much lead is in the battery, so more lead means more amp-hours.
So long as the voltage is the same the controller will be fine.
- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki
Pulling all that weight, I'm suprised you get as far as 3 miles. Going to 36v would help since hub motors make more heat than motion when they go too slow. I suspect that with only 24v and that load, you are slow.
The easy solution is more battery, either a larger ah sise, or more batteries, two paralell, and two paralell, then the two sets, series connected to provide more ah of 24v.
To go to 36v you may need a new controller. Some can take 36, some not. We need more info to say if you can take that chance. At 36v you will be able to use less wattage to get started, and get about 6-8 mile range at least.
Be the pack leader.
36 volt sla schwinn beach cruiser
36 volt lifepo4 mongoose mtb
24 volt sla + nicad EV Global
Thanks, that helps. So if I understand you correctly, the battery offered on TNC would not last as long as the two that I purchased from the local shop. At least now I know that the additional cost was a little worth it, even if it was 2x the price. =(
This is the controller that I purchased from TNC about two weeks ago and have been using it for about 3 - 4 days since I got the bike up and running : http://tncscooters.com/product.php?sku=101175
Due to finances I am using a recycled scooter motor that has been identified as a 24V United model with a 9.5A current as posted on the motor. But, a lot of the information had been scuffed off and I couldn't tell how many Watts it was. Based on a older thread (http://visforvoltage.org/forum/4789-please-help-ignorant-chick-electric-crap-unite-24v-motor-custom-ebike-mess) We determined that it was probably about 300 Watts, but certainly less than 500w.
Basically, cost is a major factor here. I am using this bike to take my daughter back and forth to school (about a mile one way), do grocery shopping, errands, etc. without having to use my SUV as much due to cost of gas & maintenance. I am not looking for more speed because I actually prefer to peddle along for the exercise. But, the extra load is a bit too much for me to peddle the entire trip on my own, which is why I opted for the motor assist. It actually goes almost too fast for me without the trailer and more than likely lasts a lot longer without that load too (I haven't tested/clocked it without the trailer). With the trailer, it is quite a bit slower but with my child on board I definately don't want more speed. I am just looking for a longer range because without the assist it's REALLY hard to keep that trailer moving on just MY peddle power alone.
I just called the local shop where I purchased my new batteries and found out that I have the option to trade in the two batteries that I just purchased and get 2 12v 26ah batteries instead of the 18ah I currently have. This option is only open to me today tho, so I'd have to make a decision quickly if I did this. Also, due to the added cost of upgrading the batteries... I wouldn't be able to afford to purchase a third one for another week or two. (assuming that I CAN run a third battery , total of 36V on my 24V set up?)
Comparing that option to the 3 battery option.... is the benefit of range better with the two 26ah, or with 3 of the 18ah? If its a matter of just adding the total of ah, then the two batteries is a total of 52ah at 24v, and the three would be 54ah at 36v.... again, assuming that I can run 36v on my current set up?
Suggestions welcome within the total price range of about $60 since thats all I have to play with right now. =)
Ah, we must teach you battery math.
This page may help
http://www.7gen.com/book/batteries-electric-vehicles/electrical-basics-covering-batteries-electric-vehicles/657
Basically when you connect batteries in series, the amp-hour rating stays the same and the voltage is added. When you connect them in parallel the voltage stays the same and the amp-hour rating stays the same.
2x 12v 18ah == 24v 18ah
2x 12v 26ah == 24v 26ah
2x 12v 18+26ah = 24v 44ah
- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki
I'm sorry, but I'm not sure I understand? If in a parallel connection the voltage AND the amp-hour stays the same... then what would be the benefit of adding a third battery using this type of connection? I understand that it wont affect my voltage, which means that I don't have to worry about upgrading anything to 36V, but how does it benefit my range if the amp-hour is still only 18ah?
Am I to understand that having a third battery allows the amps to be pulled evenly from each one, and that the more I have the longer my range will be in a parallel connection? But, this type of connection does not necessarily allow for more speed. The series connection would allow for more speed then, but not amp-hour.... right?
Based on your break down, are you saying that I could essentially keep the two 18ah batteries I have and add a third one of 26ah to increase my amp-hour/range? Does the amp-hour miss match cause any problems with running the motor or charging with my current charger that is currently working for my 18ah batteries?
What would be the best set up for a desire of more range? Two 18ah batteries and One 26ah connected in parallel - or Two 26ah connected in parallel?
Sorry about all the questions, I am trying to learn all of this as I go.
Hi David - did you mean to say when they are in parallel the voltage stays the same and the amp-hour is added for the two in parallel?
Green electric power and use thereof; what more do we need?
Oh yeah, and I've read some debate in posts about wire gage. Bigger is better? Should I rewire things with a larger gage wire? I'm currently using 14 gage wire??
But are they only added together if there are batteries with different ah specs? Because based on his break down it says that the amp-hour stays the same and things arn't increased until a third battery of 26ah is added to the Two 18ah batteries.... which was 18ah + 26ah = 44ah Right?
I think I'm getting more confused. =)
A "smaller" gage number means a "larger" wire, so if you want a larger wire than 14 gage, you would go to 12 or 10 gage. For a 10A design, use 12 gage.
Green electric power and use thereof; what more do we need?
Oops, yes I knew that the larger the gage the smaller the wire. 12gage... gotcha!
Oops.. yes of course I meant that but my fingers wrote something else. The 7gen.com page linked above has it right.
- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki
When you parallel two batteries, they basically become just one with a new amp-hour rating being the sum of each. Thus, if you parallel an 18AH and a 26AH, you have created a 44AH battery.
However, when you parallel batteries in a series set, you must parallel a 26AH across EACH 18AH so they all look the same (you will always have even numbers of batteries when paralleling).
You can not parallel one 26AH across just one. If you do this, you will have basically a 18AH in series with a 44AH and the total AH is only as good as the weakest one.
Also, do NOT parallel the one 26AH across the whole string! you can only parallel one across one, not one across two.
Green electric power and use thereof; what more do we need?
Oh boy, I'm really sorry but I don't understand what you mean.
I can parallel two or four batteries... but not three? If thats the case then based on my available funds the best thing to do at this point would be to take the shops offer of allowing me to trade in my two 18ah batteries for two 26ah for a slight increase in range?
Yes, if you have 2 batteries now and want to increase your range you will need two more. Your best bet is to trade the 18AH for the 26AH and this will increase your range by 44%.
Or, buy two more 18AH and put them in parallel with your current ones and get twice the range.
How much is the 26AH ones?
Green electric power and use thereof; what more do we need?
I have a another idea. Buy the 12AH ones you mentioned above and put those in parallel with your 18AH. You will need two but the price was good.
This will then give you 30AH and a 67% increase in range.
Green electric power and use thereof; what more do we need?
The 18ah ones that I already purchased were $70 each = $140
I can trade those in (today only) for two 26ah at about $85 each = an additional $30
If I opt instead to purchase two of the 12ah from TNC, then the total would be an additional $97 with shipping.
The most that I could immediately afford was about $60, which excludes the last option for now. But, if I get the 26ah now and then upgrade my range with two of thos 12ah at a later date.... well, then I'd be sitting pretty huh? =)
Go for the 26Ah upgrade! ;)
Green electric power and use thereof; what more do we need?
Awesome!
Now.... all of this got me thinking about the trailer. At a later date, can I add those two 12ah batteries and mount them to my trailer using a connection only when the trailer is in use? This way I only have to carry two batteries on my bike without the trailer, but when I hook up my trailer I have those extra batteries for the range I need from the added load.
How would I wire the bike battery set up AND the trailer set up so that they can be easily connected & unconnected quickly? Can I splice in a second battery connector on the bike set up and leave it unplugged when the trailer isn't in use? Will this work in a parallel set up by simply connecting that second battery connector to the trailer?
Like this?
Like this, make sure your 2 packs are reading the same voltage before you connect the two, or you'll get a massive rush of current.
XM-3000...
-DC-DC converter replaced with a Dell D220P-01 power supply.
-72V mod
-Expensive bank charger until I come up with something better... Still trying.
-
Thanks for the diagram! Is Anderson Powerpole a brand of connector or controller?
How do I check the voltage? And how do I fix it if they arn't... sit around and wait for something to charge & catch up?
Also, would/can I connect everything together in order to charge them or is there a simplified way of putting a charging port on the trailer set up? A charging port would require another controller and all that mess, wouldn't it? =(
Anderson Powerpole is the company and product line of the quick connect you're looking for.
You can check with a multimeter, Sears has them for $7 on occasion, but they can be picked up for under $20 at any hardware store.
As for making them the same voltage, it's going to be a little tricky.
If you rode your bicycle without the trailer / you're connecting the trailer for the first time:
Assuming your charger is a fairly accurate one, charge your bicycle pack, and charge your booster pack separately, let them sit over night so you get a resting voltage and if they are within 0.3V max of each other it's safe to connect the two.
If you leave the trailer connected:
Charge the bicycle as normal, but leave the trailer connected. This will assure equal charge on both packs.
XM-3000...
-DC-DC converter replaced with a Dell D220P-01 power supply.
-72V mod
-Expensive bank charger until I come up with something better... Still trying.
-
Hmmm, maybe my bright idea isn't so great after all. It sounds very complicated and I was hoping for a simple solution that didn't require me to contantly carry all of those batteries on my bike when the trailer wasn't in use.
I use the trailer about 80% of the time, but it would have been nice to make quick runs without it. However, all the measuring of volts, equal charging, etc. don't seem to be worth the convenience of being able to have seperate battery packs. lol
Thanks anyway. =)
That's sad. There isn't a whole lot to it. Maybe I overcomplicated it in my last post.
Just charge both separately wait overnight and connect it if you drive the bicycle without the trailer or the first time you connect the two.
If you keep the trailer connected you don't have to worry about anything, charge like you normally do and ride.
That's all there is to it normally.
If you spend the extra $7-20 for a multimeter, you can just touch the probes to the bicycle end of the trailer/bicycle connector, and it will read 28.1V on the screen. If you touch the probes to the trailer end of the trailer/bicycle connector it will read 28.4V. You'll know it's safe to put the two together, because they are within 0.3V of each other. I only added this step because I don't know how tightly controlled your battery charger is. More then likely, it's not even necessary, you'll find out after testing your setup a few times.
If you really don't feel comfortable with any of that multimeter business, you can simply put a resettable fuse on the trailer, it's as easy as connecting two more wires. I can draw a diagram if you'd like.
XM-3000...
-DC-DC converter replaced with a Dell D220P-01 power supply.
-72V mod
-Expensive bank charger until I come up with something better... Still trying.
-
Spark5,
I am more than a little concerned about your drawing! It appears to show the red lines, which would short out the batteries. Other than that it looks great.
So, to be clear, if anyone follows this drawing, the red lines are where you DO NOT want to put any wires.
I am REALLY upset, it's not been a good day for me at all. I was taking the wires off my two 18ah batteries so that I could trade them in for an upgrade today. In a hurry, and working with the batteries too closely together.... my wrench touched the other terminal while I was taking a bolt off the opposite battery and POOF! big sparks, smoke, and fire.... Yes, I said FIRE! One of the wires litterally disinitgrated before my eyes. I had to bang the wrench off one of the terminals because it was fused on there and some of the plastic casing on the top of the battery was melted and scorched. The upside is that the local shop tested the batteries (they were fine) and still accepted them for a trade in on the bigger ones I wanted.
I got two 12V 33ah batteries for only $20 more. But wait... my night gets better....
I get the batteries home and reconnect things, making sure the battery connection is last (isn't this the right way to do things?) and before I knew it... more sparks and smoke! Looks like the smoke came from the controller and the battery connections inside the plastic connector fused together briefly too. WHY?! Are the batteries to big or something for the controller now?
Thank god it wasn't the motor. I'm pretty sure it wasn't because I touched the motor ends to the battery and the wheel spun around like a bat out of hell.
My battery connections were made like this (same as before, ignore the key switch as it isn't connected to anything because I was told it couldn't be on this controller):
This is the controller I had and just fried: http://www.tncscooters.com/CT-201C6.php
Any ideas on what I did wrong and what controller I should replace it with? Gimmie good news, I need it. =(
Yes, the red line means don't connect.
Here is a clarified drawing:
Thank you for bringing that to my attention Win32forth. I don't know why your controller smoked. The larger amp hour size isn't a culprit.
XM-3000...
-DC-DC converter replaced with a Dell D220P-01 power supply.
-72V mod
-Expensive bank charger until I come up with something better... Still trying.
-
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