24v to 36v??

O

oobagooba

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Looking for a little more grunt from a hilltopper lithium kit. Motor is 8fun SWXK. am looking at buying another li-ion battery pack from CR, cost is $149 for 6.6 ah which is the same pack i already have.

Am thinking to cut the new pack open, soldering on 2 parallel leads so I have a 12v pack. Then want to join it to my existing 24v pack to bump it up to 36v.

Any thoughts or advice on this?
thanks
 
If you have a 15A max controller, you want a battery pack capable of at least a 15A output Those CR packs are rated for only 10A, and look at the recommended output for long life, 2A. I wouldn't waste my money on them. Put 2 in parallel will double the amp output. Putting them in series will not.
 
One small flaw in your plan though. Your second pack is not so easy to chop in half as a couple sla's. This is because your 24v pack will have a 24v bms.

When you chop it in half, you won't have a bms on the 12v section anymore. So 2/3 of your new battery will have a bms, the other 1/3 will be charging naked.

I think you'd be better served by just getting a new 36v pack, unless you are up to replacing the bms with a 36v one as well.. Seriously, it sounds like a lot of PITA to avoid paying a few more bucks.

With an all new pack, you get a battery that is all new, vs a pack that is half old half new. Half old half new just about assures you that it will get out of balance every single cycle. That would be fine if you put two 24v packs in parallel, with one old one new. But in series, one old and one new is a bad idea.

Buying a new pack means you will have more range. You can ride some of the ride on 36v, then start using the 24v pack to get home. Most rides you won't need to carry the 24v pack of course.
 
there is no evidence that these batteries have a BMS. not sure why anyone would buy these batteries to begin with. 24V is not very useful since most controllers are 36V.

if you intend to buy another one of these then why not just use two in series to get to 48V which is still low enuff voltage that it won't make your bike too fast for riding.

10A is really really not gonna cut it either like wes said. they will be smoking hot under load and the charge rate is low because they are so small.
 
If there is no bms, then chopping one up doesn't lose you use of it. In that case, it would not matter.
 
I like the look of the gbk pack. Not quite a capacity of the bmsb one, but a much better finish. BMSB are almost guaranteed to ask for more postage about 6 weeks after placing your order. Plus it's not warrantied.

Sun-thing has a friend in dnmun but most of us recognise it's bottom dollar stuff, poorly assembled. Thought of as more of a battery kit than a built item ready for use. They had about 3 failure threads in 3 days a few weeks back, and I'm being conservative.

Perhaps dnmun knows your kit, but I wouldn't of expected to connect up 48v and do much other than smoke the controller. Most 24v kit has 35v capacitors inside you see. They will take a tad more, but there life is reduced. Not 48v though. Even 36v controllers with their 50v capacitors fail quite quickly at 48v
 
thank you, Here is an update.

Ordered December 18
Shipped December 20
Tracking # sent December 22
Package arrived December 26

Battery arrived at 40.3 volts
After 1.5 hours it charged to 41.9 volts when the charger light turned green
Charger puts out 42.0 volts.

Overall length with mount is 345mm as advertised.
It feels like the advertised weight of 3.8kg although I don't have a scale.

Overall i climbed 2-3 gears higher with less pedal input than with the 24v battery and faster speed.
Top speed went from ~15 to ~20 mph.

Afterwards the controller was a little hotter than usual but i hit a couple extra hills. The motor didn't get warm at all. 30 minutes after getting home the resting voltage was 39.4
 
Did you tighten the axle nuts and get a torque arm. Now more important. Maybe leave it on the charger so the bms has a chance to balance the new battery. Yes after the light comes on. Time.
 
0001. as A Number One !!!! You can use a 10mm wrench and a hose clamp for tremperarier torque arm, it only needs to spin the axle once to have a bad day and to much work after that.
1. Don't know.
2. New batteries can come unbalanced so need some time on the charger for the bms to bleed down the highest so the charger should turn on and bring the next cells up till one hits hvc then it will bleed down and the charger will turn on to charge all cells till the next cell or cells hit hvc, and so on till the lowest cell is at hvc. So these can be a long process. Of coruse this depemads on the quailty of the bms and charger. When balance the battery should keep in balance if cells are good and you don't discharge pass 80% as a good rule or most of the time. If ran to bms cut-off it may go out of balance depending on how well the cells are matched in capacity ect. I put a timer on my pack after it has been balance to be safer. yes with some led time for balancing. And gives me peace of mind.
3. Run charger till green light comes on as designed. You do not have the higher dollar battery and charger of Paul's at em3ev so not funny charging tricks. Or use the bms you have as that's what you got.
 
you should allow more time on the charger while it is green to allow you battery to balance more early on in it's life and if you wanna use your SLA packs in parallel with the lithium pack we can show you how to wire it up with some diodes on top of the SLA pack. then you could discharge both of them to 30V LVC of the controller and get the most range. by using the SLA in parallel with the lithium it will help get the most charge back out of the SLA and it will last longer.
 
Oob

How easy is it to install the samaung battery to the existing hilltopper kit? Are all the cable fit wothout any problem?

Thanks noe
 
If you have a hilltopper controller it has a deans plug on the end like this
th-1.jpg

If you buy a cheap chinese battery it won't have a deans plug on it. So you will either need to change the plug, or ask the vendor to attach a deans plug.
 
The hill topper batteries are 7S4P configuration. You could probably DIY 3S4P and add it in parallel. But you would need to invest in a welding machine if you take that route. I use a cheap $150 welding machine from Ebay, and it works fine for my purpose.
 
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