Lipo questions

[rcjrboatman]

If I wanted to have 14.8v and 5000 mah for power for a boat and want it split into two batteries for weight distribution is it better to do (2) 2s batteries of 5000 mah or to do (2) 4s batteries of 2500 mah? Or does it make a difference if they are in series or parallel and the end values are the same? Any help is greatly appreciated as I am new to this type of batteries. I used to do nicads either way and it made no difference. You could even charge them with just a connector that went between them. Is that possible with lipos too?

[tiqueman]

2 2S in series, 14.8V 5000mah, would be lighter and probably a bit faster, boat may handle a bit better.

2 4S at 2500 would only be heavier. To take advantage of 2 4S's, in parallel, you would normally do a bit more mah, ie. 5000mah per batt would give you 10000 mah and your run time would be a bit longer. But you need to watch your temps if your running longer periods of time.

I run 2 2S 5000s, in series, in a 32" cat. 14.8V, 5000mah

Hope all that helped
Scott

Series, double voltage, mah stays same.
Parallel, voltage stays same, mah doubles.

Not sure on your chargings. I just charge one at a time. Lipos do take a different charger than Nicd and Nimh. And there are lipo charges out there that have the capabilities of charging 2 at a time.

[Chilli]

For the most part, Lipo battery packs should not be charged together in series. The packs contain an extra plug called a balancing tap. The tap allows the charger to monitor and balance the voltage of individual cells within the pack while charging. This helps prevent a cell from overcharging which could lead to a fire. Most chargers that can charge two packs at once are actually two chargers built into one unit. They will have two sets of plugs for positive leads, negative leads and balancing taps. The few chargers that allow the charging of two packs without being a dual unit usualy dont have the balancing feature built in. Therefore you must buy two external balancers to keep things safe.

What part of Maryland are you located in?

[TRUCKPULL]

For the most part, Lipo battery packs should not be charged together in series. The packs contain an extra plug called a balancing tap. The tap allows the charger to monitor and balance the voltage of individual cells within the pack while charging. This helps prevent a cell from overcharging which could lead to a fire. Most chargers that can charge two packs at once are actually two chargers built into one unit. They will have two sets of plugs for positive leads, negative leads and balancing taps.

What part of Maryland are you located in?

Your statment is false.
There are adapters for this.
I charge 2 - 2S packs in series all the time.
The adapter has two plugs that plug into the packs. and the other end goes into
the balancer. The blancer and charger now think you are charging a 4S pack.
You can get adpaters for 2,3,4,5, and 6 S packs as long as your balancer and
charger can take the total S rating.

Larry

[Chilli]

I edited my post a bit before I saw your post and do stand corrected Larry.

The only thing I wanted to get across was that you should not just wire the packs in series and throw them on the charger like I used to do with Nimh packs on my Astroflight 109. It's a bit more complicated with Lipos.

[TRUCKPULL]

I totaly agree;
Never charge without a balancer.

Larry

[rcjrboatman]

Thanks for the replies. Now for another question...Which charger to buy? I am going to be using two 2S 5000mah packs. I see that Hyperion has a charger that charges two packs at a time, the EOS 610I Dual 3. That way I could charge both packs at the same time. Would that be a good choice. I am new to Lipo batteries but not to FE boating. I've never raced but have built plenty of boats. This is a far cry from the days of nicads and Astroflight chargers that you just plugged in and let 'em go til the charger stopped when charged! I've been building scale wood boats for the last 12 yrs or so and SOOO much has changed.Great improvements but you actually have to think about what you are doing now instead of just trying it and seeing what happens! Any help is greatly appreciated as I feel like I have so much to learn about this technology that has come along. BTW I am in MIddle River MD on the BIrd River. Thanks again, Rick

[Akoni]

I like my Cellpro 10s charger a lot. I've never tried the Hyperion.

[TRUCKPULL]

The Hyperion Dual Charger is a good one.
It has the Balancers biult into the charger, so there is no need to buy external
balancers.

I myself use the Asto 109 chargers with the Hyperion balancers.

Larry

[Chilli]

Rick, I have a Hyperion Duo and love it But they are rather pricey at around $300. You can pick up a used DUO II for about $200 on ebay. There is one listed every once in a while.

What kind of scale boats do you do? Any Chesapeake work boats?

FYI- There is a RC boat race in Boonesboro, MD this weekend (Greenbrier State Park). It's between Frederick and Hagerstown (about 1 1/2 hour drive for you). If your interested and the ride isnt too long for you, you should check it out. Mostly Gas and Nitro guys but it's still a blast.

[rcjrboatman]

I've not done any of the Chesapeake Bay work boats but have done a few Sterling models. Three of the Chris Craft 42' Corvettes and one of the 63' Motor Yachts. I've also done a few of the Dumas kits. I still have one of the Corvettes and a Dumas Dual Cockpit runabout. Long and tedious work on them. I do have an old Robbe F1 Skiboot kit. It is a hydrofoil that I am looking to do this winter and want to go brushless in that. But my current project is an old Graupner Portofino (the first one not the RTR one) that will be my "guinea pig" to try out this lipo and brushless stuff with. Thanks for the info about the races but it is Sunfest in Ocean City this weekend.

[BakedMopar]

Your statment is false.
There are adapters for this.
I charge 2 - 2S packs in series all the time.
The adapter has two plugs that plug into the packs. and the other end goes into
the balancer. The blancer and charger now think you are charging a 4S pack.
You can get adpaters for 2,3,4,5, and 6 S packs as long as your balancer and
charger can take the total S rating.

Larry

I am trying to find series balance tap adapters. Where are you getting them?


Thanks,
George

[Doby]

You can make your own , I'll post some pics of mine later.

[Doby]

Here you go,

Basically you are now charging a 4S pack.

[Gerwin Brommer]

Making your own adapters is fun.
10S packs balanced with the Robbe 12S balancer :