When running two batts. together, a question

[magman]

I am undecided as to what configuration, series or parallel, I will be running in my conversion..Revo..

My question is this, I know that a 30c battery is supposed to be better under a load than say a 20c battery...so...when running 2 batts together, since drawing from 2 batts, instead of 1, is it not as imperative to have such a high c rating...correct?

I am looking at running either a 4s 3000 20c in parallel or a 2 2s 6000 in series which will yield me the same in the end as far as cells and mah....

Also, is one set up easier on the batts. than the other or are they about the same as far as wear and tare goes.

[_paralyzed_]

the 4s in parallel: is 20c (20) 3000mah (3) will get you 60 amps (20 x 3) and your amps will increase to 120 with two such batts in parallel.

we need to know the "c" rating of the 2s to speculate........

edit: if the 2s is 20c than amp ratings will be the same. so you have 120 amps (120) times 14.8 volts (14.8) gets you 1776 watts (120 x 14.8) worth of power, or 2.39 hp (1776w / 743w) 1hp=743w

[_paralyzed_]

series or parallel wiring is dependent on the batteries you use, but are both just two different ways to achieve the same goal. one is not better than the other.

you are correct, "c" rating can be less when wiring in parallel. in parallel, load capacity doubles. In series, voltage doubles

not sure about the parellel vs series setup and how that would effect your available power but I do know when you run a HV setup with a low kv motor you can get by with a weaker rated pack ( amperage and "C" rating")

[lincpimp]

I prefer the 2 2s packs in series. Half the number of cells to balance and charge. Plus you can run them in series and charge them in series. This keeps the cells balanced at all times.

With a parallel setup you really want to charge the batts separately, or in series as 8s. Most chargers will not charge and balance 8s, you either need a pair of chargers than can be networked, or a hv charger and balancer combo, neither are cheap, and your options are limited. You can find 4s balancing chargers everywhere, and a series balancing harness is relatively easy to make.

[magman]

Originally Posted by azjc

not sure about the parellel vs series setup and how that would effect your available power but I do know when you run a HV setup with a low kv motor you can get by with a weaker rated pack ( amperage and "C" rating")

That was one of my thoughts as well but just wanted to be sure before deciding on my set up

[magman]

Originally Posted by _paralyzed_

the 4s in parallel: is 20c (20) 3000mah (3) will get you 60 amps (20 x 3) and your amps will increase to 120 with two such batts in parallel.

we need to know the "c" rating of the 2s to speculate........

edit: if the 2s is 20c than amp ratings will be the same. so you have 120 amps (120) times 14.8 volts (14.8) gets you 1776 watts (120 x 14.8) worth of power, or 2.39 hp (1776w / 743w) 1hp=743w

A 2.39hp Revo should scoot right along...


Thanks Harold for the technical data

[_paralyzed_]

np. Linc makes a good point about the charging. When I charge batts in parallel, I hook up the charger's balancer to pack a, and a astroflight blinky in pack b, and alternate pack a and b every other charge.

Originally Posted by magman

A 2.39hp Revo should scoot right along...


Thanks Harold for the technical data

remember you will need a motor capable of that, all the battery is doing is having the power available for the motor to use and its up to the motors design as to how much power it will be drawing

[lincpimp]

Originally Posted by _paralyzed_

the 4s in parallel: is 20c (20) 3000mah (3) will get you 60 amps (20 x 3) and your amps will increase to 120 with two such batts in parallel.

we need to know the "c" rating of the 2s to speculate........

edit: if the 2s is 20c than amp ratings will be the same. so you have 120 amps (120) times 14.8 volts (14.8) gets you 1776 watts (120 x 14.8) worth of power, or 2.39 hp (1776w / 743w) 1hp=743w

A good rule of thumb is to take 70% of your lipos output ability and see if that looks like what the system will draw. So 1776 watts x .7 = 1243, or 1.7hp.

Not too bad for a revo, but on a 4s setup I would like to see lipos capable of 150amps cont, so you have around 2 hp going to the motor.

120 amp setup would be better for 5s...

[magman]

I am thinking of the new Tekin truggy 1700kv motor on 4 or 5s

[magman]

I have a hyperion charger and use external balancers every time I charge any batts.. so in doing it this way, balancing the batts separately, it would be ok for a parallel set up.

I would by all the batts. new at the same time to keep them as close to the same age as I could.

Sorry to be a pest, just weighing my options, that's all

[scarletboa]

Originally Posted by magman

I am thinking of the new Tekin truggy 1700kv motor on 4 or 5s

use 6s. 3s lipos are cheap and easy to put in series.

[bruce750i]

I would go series 2s or 3s, they are just more versatile packs.