ESR750H Replacement SLA options

[SloPed]

Hey guys..

Been surfing around on this for forum for years, and finally decided to join.

I have an ESR750H and I need to replace the SLA's batteries.

Everything I have found searching is about building kits and balancing them.

Ideally the system would be:

less than $250
plug and play with the current setup
charge with the existing setup
not need any extra balancers, etc.

Is there anything out there now that would work like this?

And if not, what is the best SLA battery to get?

Thanks!

SloPed

 

[silviasol]

You can use 6s cells and a b6ac charger. 7s packs will be alot faster but you will risk damaging the pack if you go to a low voltage and 7s chargers are more expensive. With 6s the controller will shut off at around 3v a cell which is basically the full life of the pack other then about 10-15%.

 

[Silenthunter]

I have an 7S pack and a charger for sale.....pm me.

 

[SloPed]

What would the 6s setup run in total?

Would I need to open it up every time to charge?

Would I need to worry about balancing it?

Thanks for the info.

 

[SloPed]

it seems like we SLA battery option sucks.

What would a 6s setup run?

would I need to pull out the batteries or open the pan to balance them or could I just plug into the side to charge like normal?

 

[dnmun]

you need to charge lipo with the balancing chargers if no BMS. figure it out first so you don't end up with packs that don't work with the charger.

 

[SloPed]

What complete setup would you recommend?

Batteries
chargers
bms
?

 

[SloPed]

can anyone recommend what kind of complete set up I would need?

I'm dying to get new batteries and this baby back on the road

Thanks

 

[made_in_the_alps_legacy]

I can't really help since i know nothing about this model,
your constrains are the frame volume to lodge those batteries and the original nominal voltage
Then you can hunt for lipos

 

[Barndom]

And if not, what is the best SLA battery to get?

I think the GEL type of the SLA's are the best.

That said, Li-Po batteries are alot better. If you are on 24V now, 6S Pi-Po batteries can work but voltage will be a bit lower. You also need a special Li batt balance charger like 'B6'. Use at least the same Ah as the original. BMS is not necessary but a low voltage alarm set to 3.5 V / cell. You find everything you need at hobbyking.com

There is also possible to use LiFePo4 batteries like Headways. I think I have read some use the same charger as the SLA's and without BMS, but it's not recomended.

 

[danielrlee]

If you are on 24V now, 6S Pi-Po batteries can work but voltage will be a bit lower.

Although the nominal voltage of 6S lipo is a little lower, they sag less than lead-acid, so under power they should be about the same.

 

[SloPed]

Thanks for the info guys!!

So my current setup is with 2 pairs of 12v 9ah batteries. so i get 24v and 9ah.

What exactly does the 9ah mean?

As for the batteries, I checked hobbyking.

https://www.hobbyking.com/hobbyking/store/uh_listCategoriesAndProducts.asp?idCategory=378&LiPoConfig=6&sortlist=&CatSortOrder=desc

For 6S I can get

TWO of the 8000mAh 6S 25~50C Lipo Pack

or get FOUR and connect 2 in a Parallel for Double Capacity

FOUR Turnigy nano-tech 5000mah 6S 45~90C Lipo Pack


buying TWO would be cheaper, but the trade off would be 8ah vs. 10ah and the C rating would go from 25-50 up to 45-95.

So here's the question:

>> Are those the right battery choices?

>> How big of an impact is the 8 vs. 10 ah?

>> And I'm 195 pounds with short little hills. Would I need to get the higher C rating so I don't fry my batteries?

Thanks!!!

 

[made_in_the_alps_legacy]

>> Are those the right battery choices?
yes
>> How big of an impact is the 8 vs. 10 ah?
~20% change in autonomy
([Ah] indicates the capacity of your battery, you could multiply by its voltage if you understanbd better [Wh])
>> And I'm 195 pounds with short little hills. Would I need to get the higher C rating so I don't fry my batteries?
no
(C is [/h] so with the 8Ah of 25C, you can expect them deliver up to : 8 x 25 x 6 x 3.7 =4.4kW of primary electrical power,
so plenty enought to satisfy what the controller will demand - this is the actual "magic" behind LiPo - my e-scooter runs on LiIon with 12Ah but only 2C, so it will never deliver more than 800W)

 

[SloPed]

Thanks for the quick reply!

So my current setup is 9ah. So if I got 8ah, then I'd lose about 10% of range?

I trust your calculations, but don't want to waste money again. Last year I tried this before but the advice then was to get 4 of these and run 2 in parallel : https://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=16212

That didn't work.

It looks like your idea would work. my concern is that the C rating will be high enough. How could I find out that 4.4kw is plenty of power for my setup?

And can I still use the on board charger? or do I need to open the case each time to connect a balancing charger?

 

[SloPed]

Here's my model... the ESR750H

http://www.goped.com/Products/Manual/2009%20Electric%20Manual%20V1.pdf

 

[made_in_the_alps_legacy]

So my current setup is 9ah. So if I got 8ah, then I'd lose about 10% of range?
roughly yes


get 4 of these and run 2 in parallel : https://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=16212
That didn't work.
you tried to run at 4s=4 x 3.7V= 14.8V on a controller expecting 24V ?

How could I find out that 4.4kw is plenty of power for my setup?
I guess the ESR750H name of your e-scooter suggest 750W rated power,
which is probably what the controller is able to demand to your battery when being supplied around 24V
actually controller specifications would be quite important in your décisions.

And can I still use the on board charger?
I don't think so, LiPo ask for care

or do I need to open the case each time to connect a balancing charger?
I am afraid you will, unless you spend some time routing properly battery cables in a way that you won't need to open the case


Just had a look to the .pdf link, could not find technical spécifications, only scary stuff how dangerous this thing can be

 

[Ykick]

9Ah fresh SLA's comparable to 5Ah high rate Li-ion, Lifepo4 for real world capacity. GoPed pulls a LOT of Amps and SLA is probably the worst battery chemistry for 'em. Trouble is, lithium batteries can provide so much more energy in the same space that brushed GoPed motors can/will burn up over extended runs.

With a good BMS packed into the battery pan it's theoretically possible to use the onboard charger but I've never done it myself. I sold my GoPed before I had the knowledge/skills to attempt.

 

[SloPed]

Thanks guys

So I guess the two questions now are

How can I be sure im not pulling to many amps for these batteries?

What would a good bms do for me?

Is a bms just a battery balancer?

 

[made_in_the_alps_legacy]

Because i doubt your controller could pull more than 750w/24v=31,25A
Can anyone find some info about this contrôler?

 

[SloPed]

I just called goped and he said that they system can draw 200 amps in a short duration. That seems like an awful lot of amps. Could that be right?

 

[SloPed]

What is a good bms?

Does anyone have a url to one they recommend that would work with my goped?

Thanks

 

[Ykick]

Years ago Steve Patmonts claimed peaks of 190A from their controller. I used a Turnigy meter and recorded 60-80A. I think the 190A is a far-reach or only for for a millisecond or two.

Bestech power has good BMS that could handle the job. There's a group buy going down but probably too late to join that. For individuals there's a 2qty min order.

Speaking from experience I wouldn't waste much time/money on these sleds. Shit rolling resistance wheels swallowed by potholes and the so called "aircraft quality" frame broke under my use and support is/was a sick joke. Brushed motor likely to overheat, inefficient voltage, undersized and poorly designed chain drive, only one brake without adding a bunch of nonsense. High-priced junk IMO.

 

[SloPed]

I hear ya on the reasons to not build this one out. But I'm already 2k into it, and just want some batteries to make it go again. It was great when the batteries were strong.

So if it pulls 80A would that kill these batteries?

https://www.hobbyking.com/hobbyking/store/__18210__Turnigy_nano_tech_8000mAh_6S_25_50C_Lipo_Pack.html

And what exactly does a BMS do? Is it a balancer that works during charge and discharge?

so that I can connect these batteries to the onboard charger?

Or would I still need a BMS if I was balance charging with an external LiPo charger?

Thanks man. I really appreciate the info. I have had this sled sitting for a year about of frustration of not knowing which battery setup will work and spending 500 on two different ones that didn't work.

 

[Ykick]

Those bricks (packs) can likely handle the current. Arriving at a voltage (cell number) that doesn't shut-down the controller (31.5V IIRC?) is another hurdle.

Primary job of BMS is to protect individual cells (channels) from too high or low voltage. If/when a cell goes over/under the main power is cut. Often abbreviated as HVC/LVC.

While BMS can balance it's not an ideal situation when used with these large capacity cells. I pretty much ignore the balance function when using BMS for RC Lipo. Much faster to simply bring up low cells via the balance connector every once in a while when needed. Otherwise, the HVC kicks in, high cell drains roughly 40-80mA for a few moments 'til it drops below the HVC point, then charge resumes until HVC, over and over, again and again - any significant balancing takes a very long time.

And remember, if this is the brushed motor long run times will burn it up. Good luck....

 

[SloPed]

I just pm'd you.

So this is my aftermarket motor. I take it that its brushed by the replacement brushes?


http://www.davesmotors.com/Products/Race-Systems-Torkinator-Products/