blade-z 450w motor extra range v. extra speed

No need to get that fancy. Put this battery in and the thing will do well over 20 MPH and go at least 15 miles on a charge.
Ebay Item (36V 15AH Electric Scooter E Bike Li-Fe LiFePO4 Battery)

You may need to run a fan to cool the motor if climbing a lot of hills. Otherwise the thermal cut off will kick in. I made a side air scoop for mine to bring in more air to cool the motor when it is at speed. So far I am running the stock controller with no problems at 36 volts.

Jake,
The switching scheme you mention would work. The main issue is will the 24v controller handle 48v? Another important factor, is will the motor handle 48v? Motors can be over-volted, but they tend to arc a lot at the brushes when going too high. This can cause really quick brush wear, heating, and inefficient operation. Also, without changing the gearing, more voltage will cause more current flow. In fact, without changing the gearing, increasing the current flow is the goal of over-volting to improve performance. Increasing the current means more heating, which can possibly be dealt with a fan, but it also means less efficient operation. Where is all the energy for the heat coming from?

I would think more about your performance goals, and what's realistically achievable with the stock motor and controller. I think 36v would be a better bet since that is what's working for andys without frying anything. If you want even better performance, than it may be time to switch out both the controller and motor.

The "ebay" batteries may or may not be good replacements. Do you have a link? I would stick with what's most known to be good quality, and a suitable type of battery for EV use. That would appear to be B&B batteries, and either the EVP series or EB series. They will run more, but I think overall they are cheaper because they will last longer. Here are some B&B battery distributors:
Power stream
z battery
digikey

In the long run, the battery from Ping is still the best deal in my opinion. It will fit in the Blade Z with no mods. it will outlast the lead batteries 5 times, doesn't lose voltage after a short time of use, and is lighter weight. It also isn't affected by cold weather. It completely transformed my scooter. I can still hit top speed after 12 miles on a charge. Try that with lead acid. The Blade Z running gear can handle 36 volts as long as you don't try to run it at max rpm for a long time, especially on a warm day.

LiFePo4 over 1000 times rechargable. Yes, but only is the battery is charged from 20% to 80%. If you want to use a charge cycli from 5% to the topped 98%, then the cyclic use is 500-600x and yet another warning, but I doubt my aknowledgement of this item, so discussion and correction is appreciated. I'ma just a human, but the kW per dollar is as even high as with lead-acid batteries.

The usefull life of these batteries are 500 cycli. After this count the performance of these cells drops and with 75% left the cell is ready for recycling.

Li-ion is very good, but not a much cheaper sollution for good maintained SLA.

More envoirement friendly yes, but the cost per km is as the same level as SLA's and the outlay like protection by a CPU is a weak part in moisty countries like here. A faillure from the controller is more likely than a faillure of a SLA when good maintained.

My object is to keep my EV as simple as be. Not too much electrics and controllers, but just a set of batteries, one controller and the hub engine.

It is raining here over 180 days a year, so a computer controlled batterypack is not my idea in ant kind, sorry.

Maybe in dry countries this is a good sollution, but not here in Holland where rains sets in most daily.

Yes, a new post for some usefull content

Sealed Lead Acid

30% depth of discharge 1200 cycli
50% depth of discharge 400 cycli
70% depth of discharge 260 cycli
98%*depth of discharge 180 cycli

*Table from FIAMM. A 100% depth of discharge is nasty (0,0 volt)

Now, what is the optimum usage of the batteries and why should I stich with SLA's or not?

If range = 40 km by 100% depth of discharge, how far could I drive?

Analyse (my batteries where drained in 6400 km)
Hey, that's a too low coverage! I figure out.
Due to serial (5 in serial is not optimal) so I buy me a single unit charger so I top off every battery seperately every month with no hazzle.
Hmm, my dealer has something to explain.

30% * 1200 = 360*100% = 360*40 = 14,400 km coverage!
50% * 400 = 200*100% = 200*40 = 8,000 km coverage
70% * 260 = 182*100% = 182*40 = 7,280 km coverage*
98% * 180 = 180*100% = 180*40 = 7,200 km coverage*
Strange..and my depth of discharge as average
* Take LiFePo4 with no doubt of issue, but is you drive for 10 miles and you charge the battery every time after 10 miles or 15 km than you have a huge coverage with SLA batteries.
These values from cyclic use is not my idea, but token from a book from the plant himself. A professional peace of work.

Maybe I have taken some doubs away ;)

================
Don't overvolt or voltmod a engine and especially a brushless one. Why?
Do you know magnetism? Is the coils are abused they became some magnetic and the efficiency wents down like a spiral to zero. Use the engine with his own specs and if you require more power or range. Look at the tirepressure. Here behind 4 bar and front 2 bar.

Geh? Who says that LiFePO4 gets only 500-600 cycles when not kept in the middle of it's discharge curve?

A123s get some stupidly high (3000+) cycle life even at high DODs. Aren't Valences supposed to get excess of 10,000 cycles or something?

what i've seen posted here and on enless sphere or other ev sites indicates lifepo4 cycles of at least 1000 if used to specs. most of the tests are for full cycles, and most agree that really shallow discharges could go 5000 cycles. the big issue with the duct tape batts is small ah ones can't discharge enough amps for the controller. without a cycleanalyst i can't tell you what my rig draws, but the 36v-20 ah ping battery runs my we brushed hub 18 miles no downhill, and 50 percent of that run is 700 feet of vertical climb. who knows how far i could go on the flats. if the 20 ah batt fits in your box get that one for sure. you will love lifepo4. the real issue may be how many years they last, not how many cycles. some are saying 5 years used or not. if that is a maximum, i can live with it at ping prices. other sellers, gone now were sketchy for sure and may be back with new names. for stock, ie legal bikes, the ping 20 ah is a good match of batt-bms specs to the system. ping is a great seller, but you DO NOT HAVE to win an ebay auction to buy from him. you'll still pay with paypal protection. just email him and tell him what you want and he will give you a price you will like better than ebay. pardon the bad typing, two broke collarbones.

moot point if you buy 2x ah and now tend to use only 60 percent discharge, or go further and still get close to 1000 cycles, boo hoo. lifepo4 cost per trip is an issue at some of the prices i've seen. i'd say worth it for good support,especially if local. on the other hand, if cheap lead fits your use, range vs weight, good for you. for me, i was packing lead till i needed more lead to pack the lead. 15 lb pack gets me home, or having to peadle home after abusing 50 lb lead. easy decision for me, at the range i need.

moot point post is reply to earlier post about 500 cycles. still a noobie at the forum.

Geh? Who says that LiFePO4 gets only 500-600 cycles when not kept in the middle of it's discharge curve?

The man behind the support of Yesa UK.

Reading is a sport too, I wrote I could be wrong and if I went wrong? Punisment? Dump him as newbie?

Low entry user, misuser, abuser or what?

I look at practical issues not at the given rate.
We'll talk after 600 cycles further.

SLA is good becuase it is cheap and easy to maintain because there's no maintainance. For most people is this the ideal situation.

I wait a year and after these battries usefull lifetime I'm looking for Li-ion. A 60v 20ah pack suits enough.

I've had a choice to make.

Equip my scooter with LiFePo4 packs and I pay 890 euro for that.
Equip my scooter with SLA costs 267 euro. If you don't have so much to spend, what should you choose?

So don't make another person ridiculous. I can do that job too and I've plenty of time.

And another issue. The batteries are in the USA much and much cheaper as here. Li-ion is here very expensive and 99,9% of the EV run here at lead acid. Pure political issues of extreme tax on energy.
One kWh cost here 0,23 euro or 40 dollarcent!
One gallon cost here 6,20 euro or 10 dollar!
A 12v 18Ah Lead acid sollution costs 60 euro per accu or 95 dollar! And then I've choosen a normal brand and not the most exlusive one.

This issue is per country different, so I stay at my words.

right on dude i totally agree that sla is still the way to go IF you get there. duct tape batteries may not go the distance if they are factory rejects. in my case 3 12 ah slas, i run out 4 miles from home and peadle uphill on 100 pound trike.
so i made 3 48 volt pacs out of 24 volt drill nimh batteries plus the 3 sla's and the extra weight climbing the hill left me peadling home 5 miles on a 125 pound bike. i bought another 12 ah sla and the extra 10 pounds climbing the hill left me peadling home 5.5 miles on a 135 pound bike. the more lead i carried the further from home i ran out on a heavier bike! i never got home without a 100% discharge abusing the batteries, and it got worse, not better. 12 miles uphill is not ideal for ev's for sure. green is cool but i just want cheap transport so for me the lifep04 or something just as light is the only way to get home. each person needs to calculate the real cost per mile for different transport. when i calculated real cost i was shocked to see what my cars cost, the gas is the tip of the iceberg. what really cost me was repairs for junky used cars i thought were cheap. this house on the hill was cheap, but now we pay a lot to go what in the usa is considered a short commute. my subaru costs me 15 dollars a trip to work since it needed big repairs. the e bike, counting the cost of buying both of em an the batts will cost about a dollar to a dollar and a half per trip. this is assuming the bikes wear out in one year and the batteries last two. thats 250 cycles on the lead pack and i hope 500 on the lifepo4, and a years use is 250 trips. the whole point of keeping the lead powered trike is to use it for shorter trips for food. so i will use lead when i can and lifepo4 when i have to. for the next month or so though, i'm going nowhere since i broke both collarbones going over the handlebars. DO NOT USE MTB WATERBOTTLE CAGES THAT MOUNT UNDER THE FRAME. don't even ask me what that trip cost per mile. pardon me the one hand typing.