Was given a G-Bike - need a charger and probably a battery..

Hi all, fairly new here but from my lurking it seems like there's some really knowledgable people here so I'm hoping you can help!

I was given a G-Bike City which is a couple of years old. I rode it a couple of times when it was still my friends' and the thing although basically a no-name chinese ebike, was pretty impressive; 25 mph flat and didn't flinch when going uphill. It looks exactly like a modern scooter/moped but you don't need the license!

However, they gave it to me without a charger (problem #1) and without any keys (#2).

I found a charger online at https://electricscooterparts.com/gbikecityelectricbikeparts.html but when I called them, they guy sounded like he was one more phonecall away from killing himself and the moment I tried to get technical, I was told that they have no idea, they just sell them (i.e. Don't ask me, I just work here).

The standard battery is 4 x 12v, 18ah with "UB12180" which I believe are lead acid. The standard charger is meant to be 48v 2.5a but there's a fancy more expensive one that is 6a. The connector is a standard IEC (kettle lead) male.

I'm thinking the battery will need replacing (it has to be at least 4/5 years old and has been in storage for at least 2 years). I was thinking of going for L-ion battery from somewhere like Hobby King but have no idea what to buy? I also need the charger but it says the charger is an "intelligent" and don't know if a BMS or the controller come into play here or whether swapping out the battery too will cause other problems on the bike?

Unfortunately, shopgbike.com who were the sellers of these in the USA basically have nothing to do with them anymore so I can't get support.

I'd really appreciate some help so hopefully someone has some insight.....

If you're up to look after the battery, then LiPo would be a good replacement. BMSes are somewhat optional if you balance reasonably regularly and don't over discharge them. If you're likely to regularly discharge them to low voltage, and you don't want to spend the extra few minutes a month to balance the pack, go with a BMS. I'll assume you're reasonably diligent, and happy to remember to keep your batteries above 20%, and balance at least once a month.

The "ideal" replacement would be a 13 cell (13S) battery of around about 10Ah, to give you a comparable speed and range as the lead acid would have been brand new. However, since 13S batteries are rare and expensive, 12S batteries would be a much simpler, cheaper alternative.

What you need is two of these: http://www.hobbyking.com/hobbyking/store/__74096__MultiStar_High_Capacity_6S_12000mAh_Multi_Rotor_Lipo_Pack.html


Joined together with one of these: http://www.hobbyking.com/hobbyking/store/__25661__XT90_Battery_Harness_10AWG_for_2_Packs_in_Series.html

Since it's unlikely the bike already has XT90s, you will probably also need to cut off the existing connector and attach one of these: http://www.hobbyking.com/hobbyking/store/__24708__Nylon_XT90_Connectors_Male_5pcs_bag_.html


As for a charger, something like this would be fine: http://www.hobbyking.com/hobbyking/store/__58285__IMAX_B6AC_V2_Professional_Balance_Charger_Discharger.html


If you want to charge in parallel to speed things up, get one of these: http://www.hobbyking.com/hobbyking/store/__31676__Hobbyking_Parallel_Charging_Board_for_6_Battery_Packs_2_6S_XT_90_.html

Wow, thank you so much Sunder!

To be honest, I'm expecting to do less than 8 miles a day as my commute and it will be plugged in both at work and at home, so I can't imagine that I'd ever deplete the battery to full. I have no idea what balancing means though

Therefore, range is really not the issue - a little extra speed however might be nice

Damn, this batteries aren't but then again, the charger is 1/3rd the cost of the G-bike replacement so it's a wash, which i'm fine with for better performance.

How does the parallel charger fit in to the mix; Do it put it between the battery and the charger? If so, can i build it in ot hte new battery box I assume I'm going to have to make? or with this method, do I have to open the battery compartment and unplug then plug in a bunch of wires each time I want to charge it? I'm basically trying to figure out if there's a way to just modify (or better still) the existing charger socket (IEC female) so I plug the HK charger in to that?

Again, thank you so much for the great info! This place rocks!

All batteries of a high voltage are made with a chain of identical cells. Unfortunately, no production is perfect, and sometimes a cell or two might be very slightly different from the others around it. Over time, they start getting a different voltage to the rest of the cells. So one lower quality cell might be half full, while the other cells are registering as totally full. This will cause you issues, because as you get to half full on the other cells, the lower quality cell could be pushing empty, and getting damaged. Alternatively, if one cell is high, while the rest is low, you can overcharge that cell and cause it to catch fire (in extremely rare circumstances).

Balancing is the process of checking that all cells are of the same charge state, hence the term "balancing". It's all automatic. You plug it in the charger, set it to balance instead of charge, and it will either burn off spare power from a high cell, or charge only the cells that are low.

The parallel charger has to be left on the charger, not the battery pack, and you need to split your 12S battery into 2 x 6S battery. So yes, there will be recabling. I thought you didn't have a charger? If you don't want to have to do this, then installing a BMS and using a bulk charger would be the way to go. It's more complex the first time - it took me about 3 hours to install mine - but will save you having to recable and balance ever.

If speed is important, then going to 12S will probably give you a tiny bit less top speed than a fully charged 48v lead acid, though the difference would be barely noticeable. A fully charged 48v battery is generally have 52 to 54 volts. A fully charged 12S lipo has 50.4v. So you're talking about less than 5% voltage, which probably translated to about 2-3% loss in speed.

You can get a higher voltage battery for faster speed, but because 6S is incredibly common with drones, they are cheaper than other sizes of battery. You can try 14S using a 6S + 8S. That will bring you to 58.8v Since common capacitors go 35v -> 50v -> 63v -> 100v, it is likely that the manufacturer used 63v capacitors. If you're concerned, you should open it up to see if you can read it. (Or post a photo here).

8S version here: http://www.hobbyking.com/hobbyking/store/__55805__Multistar_High_Capacity_Lightweight_8S_12000mAh_2C_Multi_Rotor_Lipo_Pack.html

tronics said:

Wow, thank you so much Sunder!

To be honest, I'm expecting to do less than 8 miles a day as my commute and it will be plugged in both at work and at home, so I can't imagine that I'd ever deplete the battery to full. I have no idea what balancing means though

Therefore, range is really not the issue - a little extra speed however might be nice

Damn, this batteries aren't but then again, the charger is 1/3rd the cost of the G-bike replacement so it's a wash, which i'm fine with for better performance.

How does the parallel charger fit in to the mix; Do it put it between the battery and the charger? If so, can i build it in ot hte new battery box I assume I'm going to have to make? or with this method, do I have to open the battery compartment and unplug then plug in a bunch of wires each time I want to charge it? I'm basically trying to figure out if there's a way to just modify (or better still) the existing charger socket (IEC female) so I plug the HK charger in to that?

Again, thank you so much for the great info! This place rocks!

Click to expand...

Sunder has been around a while and has forgotten how much work it can be with LiPo. It's all I use BUT they do require a lot of learning! Yeah bad wording I know, it's like the batteries, they are a lot of reading and work in the beginning. It's hard to tell others to do something other than what I am doing but? You need to either start with the SLAs crap and learn more about batteries before you start with a high power and can be dangerous LiPos.

AS SDunder said a prebuilt pack or something like this http://lunacycle.com/batteries/packs/52v/52v-pansonic-ga-17-ah-performance-long-range/ they also need a charger. You said you would charge at work and that is not a good idea with LiPos, They need to be watched. Not looking at but should not be left while being charged.

It would also help if we knew your location. Much easier to help with products needed.

Before doing anything I would check and see if the batteries are there and if so, single charge each one and see if the bike works at all before spending anything.

Batteries won't help if the controller or motor is bad.

Dan

Yeah, I think Dan might be right. If you want a turn key solution and don't mind paying 20-30% more for a foolproof solution, then a Lunacycle battery would be better than a Hobbyking battery. I think I just got fixated on that, because that's what you said you were considering, and they're my favourite supplier, so I know their stuff well.

Sunder said:

Yeah, I think Dan might be right. If you want a turn key solution and don't mind paying 20-30% more for a foolproof solution, then a Lunacycle battery would be better than a Hobbyking battery. I think I just got fixated on that, because that's what you said you were considering, and they're my favourite supplier, so I know their stuff well.

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Thank you Sunder. I thought I was gonna get a "punch in the face" for that :lol: :lol:

Dan

DAND214 said:

Sunder said:

Yeah, I think Dan might be right. If you want a turn key solution and don't mind paying 20-30% more for a foolproof solution, then a Lunacycle battery would be better than a Hobbyking battery. I think I just got fixated on that, because that's what you said you were considering, and they're my favourite supplier, so I know their stuff well.

Click to expand...

Thank you Sunder. I thought I was gonna get a "punch in the face" for that :lol: :lol:

Dan

Click to expand...

You might be confusing me with LC - I don't get violent

Looking at your link though, $549, phwoar, that's a bit more than 20-30% more, but it is also 50% bigger than what I spec'ed up. A 17Ah Panasonic 18650 based pack would have more than double the range of a 18Ah Lead Acid, and is probably a bit of an overkill an 8 mile round trip, charging at both ends.

Scooters are heavy. I was listing a big battery not to try and say to get a 6ah one which I think would be way too small. There are others in the middle.
Not confused, Your the nice guy :lol:

Dan

But...just wait until it's being ridden a bit, and the fun of riding it makes one one want to ride it more than just for commute, and then the 8 mile (or whatever limit) range isn't nearly enough.

(or the job changes locations, or a house-move is required, etc., and the commute is suddenly a lot longer).

Thanks so much Sunder, Dand and Amberwolf - the insight is incredibly helpful. I've probably learned more from this one thread than trawling the internet for hours, asking the manufacturer and their service guy combined lol.

If LiPo need that much attention then realistically it's not for me - I already have a good few regular maintenance things and I just can't add anothing thing I have to service even once a month on top of the bike itself. I also need something I can plug in to charge and forget - I run my own business so it get's really hectic and there may be times I plug in and walk away for the whole day. I don't want to burn either my house or business down!

I think I'll test the Lead Acid batteries I have for now. Is there any way to source a charger for it? electricscooterparts.com have 3 variations but they seem stunningly overpriced when I compare them to the much more advanced chargers you linked on Hobbyking. The only issue is that the socket for charging as mentioned is a female IEC, so I could build/adapt one but how would I figure out the correct way to wire it? I'm assuming the pins in that socket go straight to the battery? Or would there be a charging management unit in between? Is this likely? I'm thinking not as the chargers sold are meant to be "intelligent".

It's really only ever going to be for that short commute and in reality it's actually only 4 miles (2 each way) but I may have to do it twice a day (to nip back home to look after my rescue kittens). I work with my wife and it's not legal to have two people on the scooter so it will only ever be for quick solo travel...and my home and business are moving within at least the next 5 years so no need to future proof. Hopefully by then, I'll have run this scooter into the ground and will be on my second or third e-bike by then

Now on to another problem: I don't have keys for the damn thing! I tried taking the front apart but it's so many layers to get to the ignition, it would be close 3 hours work (and I'm an engineer by trade). I can;t open up the battery compartment because it's locked doh!. Do you guys know if there's a way to have a key made for the lock? I called some locksmiths and I could virtually hear them rubbing their hands together as they gave me the estimates ($250+).

Thanks again to all of you - this forum is one of the best I've ever been on.

tronics said:

I think I'll test the Lead Acid batteries I have for now.

Click to expand...

If it's just for a test, unhook them from the scooter, there should be four separate 12v batteries to get to 48v. Hook each one up to the car - either in parallel or one at a time, then let your car alternator charge them. Obviously can't do that every day long term, but it at least tells you whether it's worth spending money on a new charger. What happens if you buy the new charger without testing, and it turns out that the batteries are dead? You'd have a sunk cost that you'd want to chase, so you'd buy new SLAs only to find their performance underwhelming and their life short.

If I can say though, if it's been 2 years since they've been last charged, the chance of any of them being recoverable isn't too bad. The chance of all of them still being good is close to nil. I stripped apart a UPS that I knew to be good when it was shut down, and it had 20 x 12v batteries in it. (to make 240v, Australian power). After 18 months, I was able to recover 8 to good condition, 6 were borderline - held charge at 12.8v, but their 8Ah original capacity dropped to 1Ah. and 6 were unrecoverable. They would never go back up over 10v, meaning at least one cell had completely died.

Based on those odds (which I admit is not statistically meaninhful at all), 2 should be good, 1 should hold low capacity, and 1 should be dead. Let me know how my guesses are.

tronics said:

Now on to another problem: I don't have keys for the damn thing! I tried taking the front apart but it's so many layers to get to the ignition, it would be close 3 hours work (and I'm an engineer by trade). I can;t open up the battery compartment because it's locked doh!. Do you guys know if there's a way to have a key made for the lock?

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Correct me if I'm wrong, but it sounds like there are two locks. One for the ignition, and one for the battery. For the battery, you can probably pick the lock yourself, since you only need access once. Look on Youtube for a video on how to pick locks. I used to do it as part of my ethical hacking job. If you can't pick the lock, just drill it out and replace it if you need to. More work, and more time though.

For the ignition, your only two choices are to replace the lock or replace the key. You seem to have headed both of those off by saying one is expensive, and the other is too time consuming. Unfortunately, if you aren't willing to pay $250 for a locksmith to make you a new key, the only thing you can do is get a new lock and do it yourself.

You will need something like this:



It's basically an electronic switch that is opened and closed by a key

http://www.globalsources.com/si/AS/Soundway-Industrial/6008800058391/pdtl/IP65-Key-Switch/1046869175.htm

Is that $250 for the lock guy to come to your door? What if you bring the scooter to his shop. Is it more reasonable, like under $75 ?

You can bypass the whole key switch thing and use the large main fuse for on/off. Then use some chain to just lock in the bike.
You could hide that fuse inside the saddle compartment.

I found 3 things contributing to the stutter:
Bad connection between battery and controller (all the way, it's a long path)
Bad battery (i.e. weak, crashing fast)
Bad connection to said key switch etc.

The battery is connected via IEC connector, which is not rated for outdoors.
Small (inrush) sparks occur when connected to the bike, those sparks introduce small burinings inside the IEC connector. That and the elements make that IEC connector worse and worse over time. Resulting to reduced contact area due to mentioned burning an rusting, so that IEC connector becomes a larger and larger resistance.
Heating up during usage and buring it even more, an accelerating problem.
Mine was very warm at some point.

1) So first thing would be to use a very strong connector rated for at least 30 Amps. I used an Anderson connector which I had from an old UPS. You might get those for free.

2) Bypass the key (switch) or replace it with a simple mutli connector 2 stage on/off switch.

3) Definetly get new batteries, right now, you might be experiencing (on top of connection issues) the old batteries "crashing" fast.

I got Batteries from hobbyking, and arranged them in 13s (serial), one battery I had to dissect and split into the last "s" of the 13 serialized battery packs.
I later added another bank in paralell (2x 13s).

The limitation is the dreaded controller, it gave me much grief.
On the second bike it just died in the original configuration (i.e. lead acid batteries).
I tried to enhance it (see somewhere on this board), but finally replaced it with a higher volt/amp one.

I also plan to add more batteries, but might need to change the battery box to fit more.

I used Velcro to mount/attach the batteries, and that worked really very well.

See picture.
On the picture you can see where I added the anderson connector (topmost, right, where all the cables go).
I use the IEC connector for charging only. The Anderson matches the bike side positionwise so it is just a simple drop (contrary to removing the IEC connector manually).

The battery (with silver duct tape) next to the BMS is the one I split to get the 13th "s".

I see somebody in my neighborhood with the g-bike using the old style lead acid batteries, and he just drives it to the bakery and back, so he is happy with that. He exchanges them every 2 years.
I needed much more range, and the weight is really less.

Good luck!

original pic was too large for the board, here the smaller size, sorry about that.

powersupply said:

You can bypass the whole key switch thing and use the large main fuse for on/off. Then use some chain to just lock in the bike.
You could hide that fuse inside the saddle compartment.

Click to expand...

That is such a genius Idea! Why the furk didn;t I think of that. The breaker thingy is already in the seat compartment on mine so I could just permanently hotwire the ignition and use the seat breaker. It's only ever going to be left at my home or business so i don't even need a lock! THanks so much!!!

powersupply said:

I found 3 things contributing to the stutter:
Bad connection between battery and controller (all the way, it's a long path)
Bad battery (i.e. weak, crashing fast)
Bad connection to said key switch etc.

Click to expand...

Thanks for this, seems like a lot of work but it's kind of crucial so i'll get to it this weekend.

powersupply said:

The battery is connected via IEC connector, which is not rated for outdoors.
Small (inrush) sparks occur when connected to the bike, those sparks introduce small burinings inside the IEC connector. That and the elements make that IEC connector worse and worse over time. Rsulting to reduced contact area due to mentioned burning an rusting, so that IEC connector becomes a larger and larger resistance.
HEating up during usage and buring it even more, an accelleratiing problem.
Mine was very warm at some point.

1) So first thing would be to use a very strong connector rated for at least 30 Amps. I used an Anderson connector which I had from an old UPS. You might get those for free.

2) Bypass the key (switch) or replace it with a simple mutli connector 2 stage on/off switch.

3) Definetly get new batteries, right now, you might be experiencing (on top of connection issues) the old batteries "crashing" fast.

Click to expand...

I'm not too worried about the IEC connector - although it's not rated, mine has a little airtight seal plug for when it's not connected to exposure isn;t too much of an issue. I hear you about the contact point though.

Why use a 2 stage switch? Does it need two discrete functions? I though the ignition was just on/off?

I'm going to try to avoid buying new batteries right now, but more on that below....

powersupply said:

I got me Batteries from hobbyking, and arranged them in 13s (serial), one battery I had to dissect and split into the last "s" of the 13 serialized battery packs.
I later added another bank in paralell (2x 13s).

Click to expand...

I'm thinking about doing this and see you went full LiPo with the BMS and the Hobby King Charger. I've been looking and it seems the cost would top out at about $450 I'm not sure I want to stretch to that for a bike that i'll never do more than 8 miles a day on. However, the bit I do like is the weight difference you mention - the gbike is pretty heavy and it seems the bulky SLA's are a large factor in that.

I went to a local Electric Motorbike store (Hollywood Electrics) and they happened to have a slow (2a) SLA charger that I was able to get a great deal on for cash. I put an IEC male on it and it worked! I charged it for 8 hours and when I tested the pins on the bike, I got a read out of just over 42V!!! Not 48v but still doesn't seem too shabby?

powersupply said:

The limitation is the dreaded controller, it gave me much griev.
On the second bike it just died in the original configuration (i.e. lead acid batteries).
I tried to enhance it (see somewhere on this board), but finally replaced it with a higher volt/amp one.

Click to expand...

I'm really interested to hear about this - I saw in your original thread that you had real problems identifying it and it seems to be junk so i'm thinking to swap it out but have literally no idea what to get?

powersupply said:

I also plan to add more batteries, but might need to change the battery box to fit more.
I used Velcro to mount/attach the batteries, and that worked really very well.
See picture.
On the picture you can see where I added the anderson connector (topmost, right, where all the cables go).
I use the IEC connector for charging only. The Anderson matches the bike side positionwise so it is just a simple drop (contrary to removing the IEC connector manually).

The battery (with silver duct tape) next to the BMS is the one I split to get the 13th "s".

I see somebody in my neighborhood with the g-bike using the old style lead acid batteries, and he just drives it to the bakery and back, so he is happy with that. He exchanges them every 2 years.
I needed much longer range, and the weight is really less.

Good luck!

Click to expand...

Thanks so much for upping that pic - In terms of space, I think there's still some in there, to me it's the wiring and longer runs that's taking up some unnecessary space in there. I would use shorter connections and have them closer to the connector - in other words rotate the batteries 180 degrees and have really short cables. It might get tight that close to the connector but I used to work for a cable manufacturer, we made really advanced custom looms for the broadcast and audio industry - for an application like this, I would see if there's a multicore cable that you can just run splits from, rather than having separate cables zip tied together.

tronics said:

I went to a local Electric Motorbike store (Hollywood Electrics) and they happened to have a slow (2a) SLA charger that I was able to get a great deal on for cash. I put an IEC male on it and it worked! I charged it for 8 hours and when I tested the pins on the bike, I got a read out of just over 42V!!! Not 48v but still doesn't seem too shabby?

Click to expand...

Nope. 42v is dead. See table below:



A 48v battery at dead flat is 46v. 42 volt indicates some cells have shorted.

Sunder said:

tronics said:

I went to a local Electric Motorbike store (Hollywood Electrics) and they happened to have a slow (2a) SLA charger that I was able to get a great deal on for cash. I put an IEC male on it and it worked! I charged it for 8 hours and when I tested the pins on the bike, I got a read out of just over 42V!!! Not 48v but still doesn't seem too shabby?

Click to expand...

Nope. 42v is dead. See table below:

A 48v battery at dead flat is 46v. 42 volt indicates some cells have shorted.

Click to expand...

Darn Thanks so much for the info Sunder. I was wondering what was wrong- Yesterday I had a go at hotwiring it by unplugging the connector that goes to the ignition and putting a little U-bend piece of wire in it - it sparked when I push it in but no life from the bike sadly.

Going to have to figure out my battery situation now - whether to just spend $150 on new SLA's or spend $450+ and a bit of effort on a LiPo, BMS and New Charger.....

Do you have any idea how I would test the 4 x 12v SLA's I have? I've got a large Schumacher car battery charger that has tons of settings (as low as a 2a trickle charge all the way up to a 200a cold start setting). I was wondering about charging the batteries individually with that to see if they hold charge but the scooter shop told me the batteries could explode if I do that? (as it has no shutoff etc).

Although I have a background in electronics and by trade I'm a broadcast engineer, when it comes to batteries, I'm a total noob.

It's not a case of not having the capacity to learn it all, or not wanting to, just I don't know enough of this niche, and more importantly as stated above, I can't have yet another fiddly thing that needs constant maintenance (and certainly not one that could burn my house down if I happen to neglect it).

I have no problem wiring these up but If these RC batteries are going to require constant monitoring and maintenance then i'm not a candidate to own them

Skip RC batteries and go with LiFePO4.
Buy a PING pack.

Nelson37 said:

I wish to strenuously inject here that the recommendation of RC-Lipo batteries to someone who is obviously not familiar with them goes far, far beyond a simply bad idea and borders on the area of being criminally negligent.

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Oh please. Spare us the hyperbole. We're talking about a battery here that is installed into children's toys, real cars, real planes, phones sitting in your pocket, and laptops sitting on your laps. You know that you're not permitted to bring lead acid batteries onto planes - but you're allowed to bring up to 2kg of LiPo onto planes? What does that do to your "criminally negligent" risk assessment? Are you smarter than the guys who determine what can fly and what can't?

Like virtually anything that can store energy, they have risks - but a very small number of high profile fires - E.g. Sony laptops, hoverboards, suddenly has people who have no capability to assess risk thinking they've got an unstable time bomb in their hands.

Back to the OP's issue though, you can get professionally built 12AH battery with BMS and charger included for about US $225 delivered:


http://www.ebay.com/itm/48V-12Ah-Li-ion-Battery-with-Aluminum-Case-Motor-ebike-2A-charger-BMS-For-500W-/181726442536?hash=item2a4fbd7428:g:AkEAAOSwPgxVK4vM

This battery would outperform the original battery.

Sorry, one thing to add. Looking at the discharge characteristics, it might be a touch low. It's 15A continuous, and 30A burst. It'd probably be okay if your area's fairly flat, but you might need a bigger battery/two of these if you have hills.

Lunacycle or Allcells at ebikes.ca
SuPower

Hi again,
those 12Ah 8S batteries Sunder recommended look really great!
If it be now, I would get just 1 or 2 of those. Forget my approach, this is much less expensive and easier.
Considering your 8m (flatland) ride, that's plenty.

Yes, the main problem of the G-Bike is caused by the galvanic corrosion

https://endless-sphere.com/forums/viewtopic.php?f=2&t=49287#p728193

Your SLA's are dead, at least one of them, and considering their age, they will be all dead in no time.
It takes just one cell of those 24 to be dead, and all the other cells turn on it, reversing/damaging that cell even more. I think this might be the main reason why you experience those cutouts. The controller shuts off if below a certain voltage-> battery "breathes" up-> controller turns on again etc. pp

Believe me, you WILL want to drive faster/longer, so do really consider getting modern lightweight batteries.

I agree that they hype about explosions etc is exaggerated, I found that the mentioned cells barely go out of whack, but you MUST make sure that you don't under or overvolt the batteries!

With your background you'll do fine, and it is an interesting learn.
Good luck!

Nelson was talking about an idiot that gave a guy LiPos. I was the Idiot. I didn't think anybody that has worked with ebikes would know how to use them. I sent him a prewired 12s2p setup, with a charger and power supply. Needless to say he was scared to death electricity. What really scared him was that he tried to plug to batteries togeather. All that did was blow the connectors with a big flash. After that the batteries were locked up in the clothes dryer.
With little experience I would not say R?C LiPo. They areeat if you know what you are doing but if not stay away.
I posted this before and since then many have gone out of stock. Look at this one http://lunacycle.com/batteries/packs/52v/52v-samsung-30q-15ah/ I myself would look for a larger AH pack. You will need to order a charger. Eric gets new stock in regularly, his prices are fair him being in the states.

As for charging the lead ones, try the bigger charger at 2ampsa and see if it helps. If it doesn't work try putting it in line to get the 50 volts you will need to test it.
Not everyone can work with voltage, some don't understsnd how it works and others are just scared.
Another well known vender is ping. LiFePo4 chemistry. One of the safest but also the heaviest, next to lead. http://www.pingbattery.com/servlet/the-2/lifepo4-lithium-ion-phosphate/Detail
This is what I recommended from the start, prebuilt with a BMS and charger. All you would need to do is connect the battery to the scooter and go.
If you lived by me I would give you my last two LiFePo4 packs
Dan