please help with recommendation for drag car

[agniusm]

also, could you clarify something for me : say a pack is 8ah *30c. if you use 2 in parallel, do you get 16ah * 30c, or 16ah * 60c?
thanks

8AH = 240A at 30C
2*8AH in parallel = 480A at 30C

C always remains constant.

 

[El Luchador]

also, could you clarify something for me : say a pack is 8ah *30c. if you use 2 in parallel, do you get 16ah * 30c, or 16ah * 60c?
thanks

8AH = 240A at 30C
2*8AH in parallel = 480A at 30C

C always remains constant.

thank you a lot. that has just helped make my decision to use two packs in parallel. just to have the extra headroom available for the starter.

 

[El Luchador]

I want to say a BIG THANK YOU to everyone who stepped in here and helped. i finally feel like i have a plan of what to do now

with your help i now know

1. i need less than 2ah per pass
2. 2 packs in parallel will give me plenty of headroom to the starter and allow me headroom for someone trying to burn me down.
3. get a low voltage alarm on the pack so i know if im about to run dangerously low
4. use a 1010b charger
5.I need a powersupply
6. 5s is actually 21v ,not 18 like i thought
7. a123 has 20ah cells that i can use with Agnuisms setup


if you all would humor me, i have a few more questions i need help with.

1. is there a decent but inexpensive dual charger out there that will charge both packs at the same time, and not allow them to go over 4.2v?
2 better yet, is there a decent dual charger that has a power supply built in?
3. if not, can i please get a recommendation on a decent power supply.

thanks all.

 

[agniusm]

I want to say a BIG THANK YOU to everyone who stepped in here and helped. i finally feel like i have a plan of what to do now

with your help i now know

1. i need less than 2ah per pass
2. 2 packs in parallel will give me plenty of headroom to the starter and allow me headroom for someone trying to burn me down.
3. get a low voltage alarm on the pack so i know if im about to run dangerously low
4. use a 1010b charger
5.I need a powersupply
6. 5s is actually 21v ,not 18 like i thought
7. a123 has 20ah cells that i can use with Agnuisms setup


if you all would humor me, i have a few more questions i need help with.

1. is there a decent but inexpensive dual charger out there that will charge both packs at the same time, and not allow them to go over 4.2v?
2 better yet, is there a decent dual charger that has a power supply built in?
3. if not, can i please get a recommendation on a decent power supply.

thanks all.

There is probably none if you say all super duper futures and cheap
Here is couple:
http://www.bigsquidrc.com/onyx-245-dual-charger-review/
http://www.dynamiterc.com/Products/Default.aspx?ProdID=DYN4300
http://www.electricwingman.com/graupner-ultra-duo-plus-60-charger.aspx

 

[zombiess]

Go with the I charger. You will have both batts wired in parallel so you will never have to separate them for charging. They are effectively a single batt.

The reason I posed you only have 12 ah of capacity from the 16 is be sure you don't want to discharge a pack more than 80 %. This extends the life of the battery and reduces the chance of you hurting it.

When calculating the c rate of the pack, you still use the 16 ah rating.

Out of curiosity, what kind of car is this going in and will it be mounted in the trunk away fro heat?

 

[El Luchador]

There is probably none if you say all super duper futures and cheap
Here is couple:
http://www.bigsquidrc.com/onyx-245-dual-charger-review/
http://www.dynamiterc.com/Products/Default.aspx?ProdID=DYN4300
http://www.electricwingman.com/graupner-ultra-duo-plus-60-charger.aspx

i liked the price of the onyx, but it only goes to 3s . the other ones are out of my price range
i sure wish i could afford that graupner though. that thing is niiice.

 

[El Luchador]

Go with the I charger. You will have both batts wired in parallel so you will never have to separate them for charging. They are effectively a single batt.

The reason I posed you only have 12 ah of capacity from the 16 is be sure you don't want to discharge a pack more than 80 %. This extends the life of the battery and reduces the chance of you hurting it.

When calculating the c rate of the pack, you still use the 16 ah rating.

Out of curiosity, what kind of car is this going in and will it be mounted in the trunk away fro heat?

thanks for the clarification on the 12/16 ah thing. that explains it for me.

i had planned to run the battery packs with individual leads to my main power and ground lugs so as to eliminate another connection inbetween, but i can use a connector outside of the car to charge. i would still like one that has ac input though, if there are any out there with comparable features.

out of a desire for anonymity, let me only say that the car is a pre 1972 chevy. the pack will definitely be mounted away from any heat. i was thinking of putting it where the passenger seat would normally go, just to have shorter wires for more weight loss. my old battery was mounted in the trunk, and worst case scenario i would put it in the trunk

 

[cassschr1]

Why is a123 not the better choice?

 

[El Luchador]

Why is a123 not the better choice?

im doing lipo because they come preassembled.

also,the a123 pouches ive found were 42 bucks each and i would need 4 plus, vs 60 bucks or so for each of the lipo packs

 

[El Luchador]

Go with the I charger. You will have both batts wired in parallel so you will never have to separate them for charging. They are effectively a single batt.

The reason I posed you only have 12 ah of capacity from the 16 is be sure you don't want to discharge a pack more than 80 %. This extends the life of the battery and reduces the chance of you hurting it.

When calculating the c rate of the pack, you still use the 16 ah rating.

Out of curiosity, what kind of car is this going in and will it be mounted in the trunk away fro heat?

follow up. i found i can use my old pc power supply for the chargers so i may go that route. and end up using the i charger with a parallel charging board.



thanks man

 

[cassschr1]

with a123 pouch you could charge with a convential 12v charger with hi ampreage(if needed).......worry about balance later. Probably lighter too. Luke you got any thoughts on this?

 

[el_walto]

3s lipo is 9v - 12.6V
4s lipo is 12v - 16.8v

You can use a 12V car battery to power your charger if you like.

Buy a High C rate lipo. Like 40c or higher since you are using a small pack and pulling many amps.

Maybe get 2 of these for 5Ah, or 4 of them for 10Ah. http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=11957

 

[El Luchador]

Hi,

i want to bump this up to ask a question.

is the b6ac a recommended charger? it is appealing to me because i can hook it up right to my gas generators 120v outlet without the need for an additional power supply.

is this a good charger?

 

[wesnewell]

Please go to the User Control Panel, select Profile, and then enter your city, state/province, and country into the Location field (country minimum) and save it. This will help people help you. Example: Wylie, TX, USA. Without knowing what country you are in it's hard to make any recommendations. Thank you.

The B6AC is only a 50W charger so it will take 1.5 hours to charge a 5000mah 4s lipo pack. 3 hours for a 10ah pack.

 

[El Luchador]

wowch,thats too slow. i need something that can charge a 10000ah pack in 30 mins or less so the bca6 is out of contention.

any suggestions?

btw, i updated my profile per your suggestion

 

[wesnewell]

Assuming you mean 10ah (10000mah), then you need a 300W charger to charge a 10ah 4s lipo pack in 30 minutes. This will do it in under 30 minutes.
http://www.progressiverc.com/icharger-306b.html

 

[El Luchador]

Hi guys,

im at the next stage of my ongoing project to run my drag car on lithium batteries.

amp draw is very low( 25 amps for less than 2 minutes) with the exception of starting the engine, which could draw 300 amps for a few of seconds at a time

i just bought
hyperion 720i charger
team checkpoint 25 amp power supply
and TWO Turnigy nano 5000mah , 45-90c packs 14.8 v

that gives me 10ah with continuous draw of 450amps, and burst a little bit higher. even the continuous rating is more than what i will need for starting the car

which connector do yall recommend that can handle the short bursts of amp draw that i need(150amps from each pack)
i was looking at the xt90 but i wanted to see if there is anything you all prefer.

thanks all

 

[El Luchador]

which connector do yall recommend that can handle the short bursts of amp draw that i need(150amps from each pack)
i was looking at the xt90 but i wanted to see if there is anything you all prefer.

thanks all

 

[wesnewell]

I'd match the connector that came on the lipo to parallel it and then use 8mm bullets as the final connection or whatever type you need to match final connection.
You do realize that that pack will charge to 16.8V. Make sure that won't fry something in your electrical circuit.

 

[El Luchador]

Thanks for the recommendation. I will look for those

I used to run the car with a 16volt battery so i think it will be ok

 

[El Luchador]

I'd match the connector that came on the lipo to parallel it and then use 8mm bullets as the final connection or whatever type you need to match final connection.
You do realize that that pack will charge to 16.8V. Make sure that won't fry something in your electrical circuit.

Hi, I ordered two pairs 8mm bullets , and 5pairs 4mm.

problem is , my charger will only do up to 7s, so it looks like I cant balance charge both cells at once. what do you suggest? should I charge the packs individually, or is there another inexpensive way to balance charge both packs at the same time?

thanks

 

[wesnewell]

You;ve got a 7s charger and are using a 4s lipo pack. I don't see the problem. You just parallel charge them. I've parallel charged as many as 12 4s lipo packs at once.

 

[El Luchador]

You;ve got a 7s charger and are using a 4s lipo pack. I don't see the problem. You just parallel charge them. I've parallel charged as many as 12 4s lipo packs at once.

thanks. I went and looked up parallel charging and ordered a parallel balance board for parallel charging.

I appreciate the input