Is it better to have one big battery? or many smaller batteries? and if so, why?
i could see why many smaller batteries would help prevent hot spots and melting/burning, but if you had a thin battery with addiquite heat ventilation, why would it be any worse?
sorry for my ignorance, but i’ve been kind of curious about this for a while now.
come on guys we can at least get some convos here started no?
My first ev was a Ford Ranger. It had 24 golf cart batteries. Thats 1500lb. I had to add springs in the rear to carry the weight. I am interested in using something lighter for my next project. Maybe optima? I don’t know.
Gordon Cooper
I feel if you have more than one battery and one fails you can bypass that battery and still get home, also replacement of one is less than all your battery pack.
[QUOTE=new dawn;183]I feel if you have more than one battery and one fails you can bypass that battery and still get home, also replacement of one is less than all your battery pack.[/QUOTE]
i couldn’t agree more, the more i was thinking about it the more i was thinking about how dumb of a question it was…
Not to mention, how would that battery be configured? It would not be very flexible as to where and if it would even fit in a majority of applications. Most conversions I’ve seen have batteries in more than one place making packs in shapes other than a standard rectangle. Therefore, multiple batts is a must.
I’m looking at the possibility of running enough batts to get sufficient voltage for reasonable performance when street driving with them in buddy pairs (doubling the Ah rating) Then when at the dragstrip or when performance is a higher priority than range I can reconnect the jumpers making all batts in series (doubling the voltage). Hmmmm. A button to press to make the change electronically while on the fly would be awesome. :eek: Hmmmmmmmmmmmmmmmmm.
Cheers
[QUOTE=inSANe DIEGO;191]Not to mention, how would that battery be configured? It would not be very flexible as to where and if it would even fit in a majority of applications. Most conversions I’ve seen have batteries in more than one place making packs in shapes other than a standard rectangle. Therefore, multiple batts is a must.
I’m looking at the possibility of running enough batts to get sufficient voltage for reasonable performance when street driving with them in buddy pairs (doubling the Ah rating) Then when at the dragstrip or when performance is a higher priority than range I can reconnect the jumpers making all batts in series (doubling the voltage). Hmmmm. A button to press to make the change electronically while on the fly would be awesome. :eek: Hmmmmmmmmmmmmmmmmm.
Cheers[/QUOTE]
I was thinking about that too… BUT if it was 1 battery i was suggesting build it along with the under side of the car because if its built into the frame as the “floor” it could be thinner but still cover LOTS of surface area, and have the weight in the center and lowest possible points of the car… i was thinking mostly for like a production style setup.
how about those RC car rechargable packs? they are decent, cheap, easy to recharge, and if you get a bunch of them you could hook them up with ease… not to mention you could pick them up almost anywhere they sell those cars/parts…
Ok. I thought you were speaking in terms of conversion. That’s what the Tesla pack is. It’s a big umpteen cell lipo pack. Battery management on it would be a nightmare for the DIYer. The main problem wiht the little lipos is cell balance. They currently are extremely sensitive to inbalance. Of course that’s on little 1800 Mah packs. With larger capacity packs (50 Ah and up) there would probably be room for larger inbalances. I haven’t contacted Kokam or any of the many other Lipo mftrs. on what the biggest cell capacity they make is since I’m pretty far off from batt shopping.
Cheers
what do you mean by inbalance? like unbalanced discharge?
Yes. Unequal discharge and the problem of overcharging or deep discharging of cell caused by it.
Cheers
[QUOTE=inSANe DIEGO;196]Yes. Unequal discharge and the problem of overcharging or deep discharging of cell caused by it.
Cheers[/QUOTE]
is there any real way of taking care of that? maybe programs on a computer to monitor EVERY one of them? i dont know…
The lipo chargers for the r/c airplanes and cars have cell balancer leads for each cell. I’m not sure exactly how it works since I bought my charger early in the lipo game before equalization leads and charger provisions existed. AFAIK you hook up the main power lead for the pack and the individual cell leads to the taps no the pack. Then as the pack reaches full charge the circuitry in the charger analyzes the cells and equalizes them as the charge finishes. Every time you charge a pack it gets equalized.
I guess if one knew how to make an equalization circuit (there are balancer plans out there) and made a lead to each cell in a lipo pack, it could be permanently hooked up and not be such a hassle. As far as trying to balance a 1000 cell pack by hand. No thanks. That in itself would take a day or two. Imagine it though- a 1000 cell pack. I would probably do 2 500’s and and have it switched like I mentioned before. Double voltage for double pleasure or double amperage for double mileage. Cool…
The Tesla’s entire system is 1000 lbs. It has a range of 250 miles WITH enough voltage to have accelleration to envy. Yes, a brushless motor helps with the efficiency, BUT most of the difference in weight and performance is due to the lipos.
Sorry, I got carried away. That last bit should probably be in the lipo discussion. Oh well.
Cheers
wow thanks this will help me out then to know that the technology is readily available for this kind of stuff… and so the project begins…
is there any other ways out there to store mass ammounts of electricity for later uses?
almost like a copasitor but large quantities…
If the motor is rated for 48v-96v that mean i can only use 4-8 12v batteries?
and charger an controller is limited to this amount of batteries? and does the wph get limited by the votage rating or can it be unlimited?
Oh. and does the watts per hour effect the speed or range?
RC batts fail to offer then amperage needed for an EV, not to mention, could you imagine wiring up like 1000’s of NI-MH cells?
If you have 50 Li-po batteries, and one is at 3.1 volts while the rest are at 3.0 volts, you wont have a problem. THat is untill you charge/discharge many times, and that difference of .1v can grow to over 1v! this will either overcharge one battery, or over discharge the rest. Li-po is very sensitive to this.
14410-HPS 144V / 10Ah w/VMS, 2 Terminals
Would this do?
Thanks for sharing your knowledge on the batteries. I came in this forum for this question i got the solution easily and quick
Which car battery used long time?electric or general car?
a bit of humor here
had an ev that had a tray of batteries in the rear exposed to the weather (like a ute) and when the first rain came i did not cover the battery pack of 90 volts.
in the dark returning home one of the battery leads became loose and i saw the problem and grabbed the loose lead and with spanner in hand realised i was grounding a 90 volt power supply.
shooooocking :mad: