Changing Ebike Battery From 48/14 SLA To 48/15 LIPO Volts?

Hey Gang

Just need to confirm some voltage numbers with you guys that know more than I !

I just bought another ebike like the nikon switch, emmo urban, that uses a: 48/14 SLA Battery

It is sagged to death, so I tossed the sla and am converting to 48/15 LIPO using:

3 x 4S Hobbyking 5000 mah HARDCASE PACKS in series BY three rows to make 50.4 volts and 15 ah?

My question is:

Doesn't 48 v SLA top up at around 53 volts at a full charge?

And if so, then with my new lipo setup that will be only 50.4v (12S) will I notice any loss of speed?

I just wanted to confirm that SLA 48 would be around 53 volts fully charged, as I think my lipo max will be 4.2v per cell x 12 - 50.4 v...fully charged

Problem is, I have never seen what a 48 v sla tops up at (v?) so hoping the difference isn't too much......

Am I correct with these numbers for both SLA and lipo?

AS I hope so, and going to lipo shaves so much weight I am not TOOOOOO concerned about 2 volts.....right?

Thats IF my guess that sla 48v tops up at 53v on a full charge....am I close with this number?

Thanks so much in advance.....

Yes on the voltages.
You might even see a increase in speed, less weight and more power. No sagging like the lead.

I didn't get the 15Ah. How are you getting 44v15Ah out of 3 packs. You need 9 4s 5000mah to make 44.4v15Ah.

I parallel the 4s to get 15Ah then series them, so you need 3 x4s to gget 44.4v and then multiply it again x 3 so 9 packs.

Dan

Thanks Dan for the reply and confirming that 48v SLA fully charged = 53 v, it is appreciated the help...

And mate, read again, my line is NINE total as I did say 3 rows (of 3 each=9):

"3 x 4S Hobbyking 5000 mah HARDCASE PACKS in series BY three rows to make 50.4 volts and 15 ah?"

Now you have confused me, what the heck is the 44.4v YOU mention? lol

Ihave calculated it to be 50.4v fully charged lipo, NOT 44.4

where does 44.4 come from?

Nominal voltage for RC lico cells is 3.7v. But if you charge to 4.2v, then the end voltage for a 12s pack like you are planning is indeed 50v.

Sometimes things get confused, if it is not specified whether you are talking in nominal voltage, or top of charge. Top of charge is important, for example 16s lico top of charge is above 63v, the limit for many "48v" controllers.

If you wish to make up a 48v pack that closely matches your current voltage, go with 14s lico. I have come to prefer this to 12s myself, because of the faster top speed when you are at the end of a ride, and voltage has dropped. Running 14s, I like to stop when at about 49-50v.

Even though lead sags, and 12s will be faster for you on part of the ride, I bet you will miss the speed at the start of the ride if you run 12s. 3s plus 4s packs can make a nice 7s pack. That can charge fairly convenient on an 8s RC charger. 14s also works with a 14s hyperion.

Thanks for more info Dogman, really helpful

Well, I have already ordered lipo,,,you mentioned lico.....?

And already have these packs made for another bike and have been happy

And ok, I get you both now,,,,

44.4 is 3.7 x 12 or my lowest point I use of the charge< I get it now...

and

50.4 is the top, 4.2 x 12

Dogman, is there any way I can another battery to the row without going to much higher? if I go 16 S I will blow the stock 20 amp controller I am sure, but I do have to ask, that if everyone that goes LIPO and wanting a 48 v setup, means they can only get up to 50.4.....

I do wonder what volts the controller could handle, but again, not going to try 16s(67.2 full) as I know it will 'blow'

Your mention of 'mixing' different sizes intrigues me, I didn't know that could be done......

Dogman TWO QUESTIONS MORE PLEASE?

-COULD I make a pack that was IN BETWEEN the 12s(50.4) and 16s(67.2) of lipo from hobbyking?

And I do own an imax 250watt charger can I parrallel charge(at leats two at a time) these batteries or just suggest I keep using my bulk charger.....

?

THANKS SO MUCH guys!!!!!!!

why not use two of the 6S for your pack instead of three of the 4S? i don't get it. you are gonna have to use the balancing charger and 4S doesn't work very easily. why didn't someone say that before you went and bot them?

4S hard case packs working fine here. I recently made series/parallel JST adapters using 4S extensions and 9pin plug and treat them like 2x 8S (16S1P in pic) which is kinda handy for Cell Logs.

For the series JST adapter you don’t even need to crimp any JST pin contacts - merely move pins over from the 4S (5pin) into the 8S (9 pin) plug in proper order and leave one of the mid-point wires insulated with shrink tube unconnected.

Although an attractive format and 25% increase Wh I wouldn’t push your luck with 16S on a stock 48V controller. I bit the bullet and now use 72V controllers. Of course, you can always try and if/when it blows upgrade at that time?

Your 48V controller likely has mosfets that will support 68-75V, so the 63V limitation of the controller is the 63V main caps. If you change them to 75V or higher caps, you could run 16s lipo on the controller. Or for ~$50, you could just replace the controller with one capable of running up to 24s. BTW, your 48V controller can probably run 15s if you wanted to. To increase from 12s, you can just add most cells to the end of each string. 1s for 13s, 2s for 14s, etc. There's many ways to configure rc lipo. I run 24s using 12 4s packs as 24s2p.

I wouldn't use a sla charger for lipo. Some trickle charge at the end. Bad.

My vote would have been for 14s too, add 3x 2s 5000mah packs, one on the end of each series to make a 14s3p pack, then charge with a 14s 1420i Hyperion. nice and easy setup which gets the best out of your bike as it is now. As Dogman says you will appreciate the extra speed from those few extra volts towards the bottom of the charge. Not only will you have a bit more speed but an extra 100+ watt hours capacity for extra range.

Or what about 14s 20ah? has it got a rack? you get 30 or 40ah on it!! :lol: or just match the weight of the lead with lipo, that would be interesting, to see the real difference from the evolution of battery technology.

Yep, 14 series for the win, bulk chargers are off the-shelf set for 58.8 volts and everything.
But that's the fun of building your own pack, is upgrading when you can afford it.

Thanks so much guys to ALL that posted all good info......

And like ykick I am hapy with the hardcase packs, happy with charging with a bulk charger(dunno what the one guy meant about a trickle charge, my bulk chager works quite well as I dont have anything biger than an imax b6 250 w charger so bulk it must be, I just got another one for this smaller setup...had it set to cutoff at 50.4 v, and I own one for my 16S 60 pack that cus at 67.2v.....(I watch/monitor/balance and medic them all the time lol)

And crap! Idid NOT KNOW GENTS I could Simply add another battery to each of the three rows that is a DIFFERENT size lipo!

I thought that was a no no folks...guess it shows I am no electrician! Wouldn't the smaller lipo's discharge quicker(this is why I THOUGHT a series pack HAD TO BE all the same cellcount and amperage size batteries.....

Ok, folks, If I buy 3 more lipo....3 x 2S 5000 mah packs, I just connect them in series to the 4s 5000's and that would give me 58.8 top charge ?

I agree I too would like this better,,,just hoping the controller from a 48/14 sla bike is ok to handle that as some mention....

Thanks to all, all great points....I have learned a ton for you guys...hats off for the help....

Oh I guess I have one more dumb question..ok, maybe its two,,,lol

I can only assume(at HobbyKing anyways) that I cant buy 2s/5000 lipo in a hardcase pack like the 4s/5000 they sell....

And isn't it risky to have a battery without this hardcase protection added to the row at end, could it not be damaged or punctured (Yikes!)much more easily when in the bike?

And of course I assume I will have to change the plugs on the 2s as I assume they come with a different plug and I will have to put the 4mm HXT on it?

Now I am excited, 14 s here we come,,,thnx gents!

Looking for the RIGHT 2S from Hobbyking to add......

Hey Gents

I AM going to add the 3 more 2s5000's......and am now at HK site, and OMG tons of 2s5000's....

*Anyone recommend which 2S/5000 mah do I buy to match with these 4S I have already (http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=15521)?

Update: WOW AWESOME! They DO have hardcase packs in 2s....so folks is THIS the one to buy?

http://hobbyking.com/hobbyking/store/__21001__Turnigy_5000mAh_2S1P_20C_hardcase_pack_ROAR_APPROVED_.html

Would this be fine? I assume it should be 20c and hardcased as the 4S packs are I think....

???

(thnx in advance)

Those should e close.
yes you will like the extra power!

And yes the controller won't know the differance.

voltage is voltage, the controller doesn't care what AH is in the bag.

Dan

The only thing to watch out for is over discharging the 14s pack as the lvc will now be to low to protect you from over discharging. If you have a volt meter on the bike, don't go below 49V resting.

Thanks so much to all in this thread for their help,,,,,great bunch of guys!

Gonna go the 14S route, and just ordered the extra 3 more batteries of 2S 5000 mah's HARDCASE lipo

and a new charger to cut at 58.8v

Great stuff gang,,thanks again to all that chimed in and helped with all the good info!