PINNED - Lithium battery conversion/info

[Gnomatic]

The catsuit wouldn't be shrunk/form fitted to the pack, but it would be a sort of protective bag of sorts. So it is an option.

I contacted a couple suppliers of the larger pvc shrink wrap. They say they can get it any size I want, but if its not something they commonly carry, it would take a very larger order for them to agree to do it, as suspected.

I'll keep trying.

[steves1977uk]

Go to the Playboy Mansion, they'd have loads of PVC material!

Steve

[Gnomatic]

This is true!

[shirley_hkg]

[Gnomatic]

External BMS/Charge controller so dumb charger can be used if needed, perhaps?

[steves1977uk]

;)

Monitor that BMS with the PL8 connected and post the graph please Shirley, be interested to see how it balances...

Steve

[popschief]

We might have to think bigger. https://goo.gl/kaF8kb

bp

[Gnomatic]

Interesting stuff, popschief. Thanks for the link.

[Gnomatic]

In interests of tome I had to scale my pack a bit and leave off the top group of cells. I'll have room for it after a few more small mods. But that will have to wait. I started with the intention of building a clone of expresso's 105Ah pack, but for the rest of the summer, its a 90Ah pack for me. I'm fairly certain it will still piss all over lead bricks.

A couple buddies stopped by and got the pack successfully lowered into the chair base with multiple layers of insulation on the bottom and all sides.(no sparks this time!) The extra insulation has been holding me up, as I didn't account for it when planning and measuring. But after my incident, even though I had all the bolts that protruded into the battery area welded in place and ground off since, I still wanted extra insulation. Which I now have.

With the pack in the chair base, I discharged about 2/3rds the way, and charged it back up. Looks pretty good. Less squiggly at the top than when I was charging it with the top row on.

[Burgerman]

90Ah will still allow around double the range you get from a set of grp24 batts.
Since you only really get a true 40 to 45Ah from a 73Ah MK gel before low voltage under load ends playtime.

More is better, as it works the cells less hard on every trip, which benefits service life etc. But it should be enough.

EG my BM2 has 120Ah. So around 3 times the range of its STOCK 56Ah sonennschein, or 68Ah Odyssey batts.

[Gnomatic]

It should be a good bit better than anything I've used, that's for sure. I got a cell checker too, so hopefully that can help keep me from getting in trouble by running the cells down too low.

[Gnomatic]

First day in my chair with my lithium pack. Don't know exactly how far it was, but I went about as far as lead new can take me, plus some more on top of that. I'm curious to see how many Ahrs get returned to the pack when I charge it tonight.

One thing that stood out right away, the chair handles hills better. A lot less vdroop, especially after going a few miles. I expected this from my lithium pack, and it didn't disappoint.

[Burgerman]

Remember that if you take out 50Ah you put back about 53 to 55. So it seems like you used a little more than you actually did. Charging isn't 100 percent efficient.

[Gnomatic]

It turns out I put just 41.774Ahrs back into the pack. But I'd have been real nervous trying to go where I did yesterday with lead. I'm sure the joystick would have been calling me names and telling me to plug in. I'm about 220lb, my chair base is a big heavy one compared with something like expresso's 646se, and the seat on the chair is a heavy one with power tilt/recline, and elevate. And some of where I went yesterday was offroad.

So would you say the relatively low Ahrs returned to the pack that would kill my new lead bricks is a result of my chair is drawing lots of current out the gate and Gel lead can't cope?

Whatever the reason, after one day, I can comfortably say my small 90Ah pack easily more than doubled my range.

[Burgerman]

So would you say the relatively low Ahrs returned to the pack that would kill my new lead bricks is a result of my chair is drawing lots of current out the gate and Gel lead can't cope?

That 41Ah means you used about 39 to 40Ah on your trip. Thats all you will get from a group24 lead brick.
Although you can obviously go the same distance again, and still have plenty left with lithium.

Depending on the rate you use it your 73Ah gel will let you use anything from 1/2 to 3/5ths of its capacity before the chair stops.

If you set off fully charged without driving about the house, and go 8mph for 2 hours thats 16 miles, and you battery is dead. Because you took more power for a short time.

If you go 4mph in the same chair, and go 16 miles, there will be more power left in the lead. Because thats the 4 hour rate. So you can continue for a while. The actual figure the ISO test uses is the 5 hour rate.

[snaker]

I intend to buy battery cells in the link underneath. I use google translate to translate the title to English. I got the words "aluminum silicate iron phosphate". Is it correctly lifepo4 or another kind of lithium? Can PL8 charge these cells?

New 3.2V75AH aluminum silicate iron phosphate 3.2V72AH150AH electric lithium battery 3.2V80AH230AH
https://item.taobao.com/item.htm?id=540 ... oSite=main

[Burgerman]

Yes no prob. They are a tiny variation of the lifepo4 cells of no real consequence.

[Gnomatic]

I intend to buy battery cells in the link underneath. I use google translate to translate the title to English. I got the words "aluminum silicate iron phosphate". Is it correctly lifepo4 or another kind of lithium? Can PL8 charge these cells?

New 3.2V75AH aluminum silicate iron phosphate 3.2V72AH150AH electric lithium battery 3.2V80AH230AH
https://item.taobao.com/item.htm?id=540 ... oSite=main

Snaker, I'm very interested in your experience buying these cells off Taobao. Please share details if you don't mind. I'd like to know specifically how you pay on that site and how shipping works etc.

I'd like 16 of those cells myself. 150Ah, and I can fit in any of my chairs.

[Tekoa]

These look real interesting, I've been attempting to get more information about them. I've tried three translators but have been unable to find Maximum Charge/Discharge rates in any of the translated pages. Were you able to find those numbers?

[expresso]

i wonder if 8 of those could even be used for a ADD ON - maybe can get 75ah ADD ON - if it fits in the same space -

[Burgerman]

8 takes the same or more volume as 2 group 24 batteries. A big heavy addon.

[snaker]

Snaker, I'm very interested in your experience buying these cells off Taobao. Please share details if you don't mind. I'd like to know specifically how you pay on that site and how shipping works etc.

I'd like 16 of those cells myself. 150Ah, and I can fit in any of my chairs.

In VN, buying goods from Chinese sites like taobao, alibaba is easy. There are companies that specialize in buying+shipping goods from China. All we have to do is give them the link and pre-pay a half of the cost, they will handle the rest. Goods will arrive in 5-10 days and customers will pay the remain half when receiving. The total cost (inc everything) is usually the price on the site + 10%.

[snaker]

@Tekoa: You have to copy Chinese text into google translate. China does not follow common rules

Specifications: 29135215
Size MM: Thickness 29 * Width 135 * High 215
1. Rated voltage: 3.2V
2. Internal resistance: about 0.3mΩ
3. Nominal capacity: 75AH
4. Capacity: 78-80AH (pictured)
5. Discharge cut-off voltage: 2.5V
6. Charge limit voltage: 3.65V
7. Maximum continuous discharge current: 2C -3C
8. Maximum instantaneous discharge current: 4C-5C
9. Charging method: CC / CV (constant current constant voltage)
10. Weight: about 1.8KG

[expresso]

8 takes the same or more volume as 2 group 24 batteries. A big heavy addon.

ok Scratch that idea then

[Tekoa]

Thanks, I knew it had to be user error. Makes shopping Chinese sites a bit tedious.

So, with these C levels I'll need a bigger battery for the chair than if I used Headway 40130S Cells. I'm planning on replacing my RV Battery Bank and these will work well in that application.........Thanks again.

[Gnomatic]

8 takes the same or more volume as 2 group 24 batteries.

How do you figure?

I can get 16 in my chair w/o issue. 215mm tall is just under 8.5". If your battery area can accommodate group24 batteries WITH full height terminals, then 215mm shouldn't be a problem.

So, assuming height clearance isn't the issue, then you get two rows of cells, 135mm x 2 = 270mm wide(10.63"), well under the BCI width of 2 G24 batteries which is well over 13".

So then each of the two rows has 8 cells, so 29mm x 8 = 232mm, or 9.1" long, well under the BCI spec of a G24 battery at 10.3".

These would be an ideal fit in all my chairs.

[shirley_hkg]

8 takes the same or more volume as 2 group 24 batteries. A big heavy addon.

8 of these are around the size of ONE G24 battery , not 2.
29*4 --- 135*2 --- 215 h .

BM , reviews praised its good quality , especially the conformed low IR , so hurry up while stock lasts .

[expresso]

how much would 8 weight ?

same as 16 or 24 15ah headways ?

[Gnomatic]

Snaker, I'm very interested in your experience buying these cells off Taobao. Please share details if you don't mind. I'd like to know specifically how you pay on that site and how shipping works etc.

I'd like 16 of those cells myself. 150Ah, and I can fit in any of my chairs.

In VN, buying goods from Chinese sites like taobao, alibaba is easy. There are companies that specialize in buying+shipping goods from China. All we have to do is give them the link and pre-pay a half of the cost, they will handle the rest. Goods will arrive in 5-10 days and customers will pay the remain half when receiving. The total cost (inc everything) is usually the price on the site + 10%.

Sounds like you are using a Taobao Agent. And that is great if you can find one that will work for you in your country. I've contacted a few that ship to the US but none of the ones I've contacted are willing to ship batteries here.

Alibaba is easier here because I can buy with standard credit cards, Shopping directly from Taobao, they seem to want you to set up a Taobao accound and somehow put money into it(not all unlike Paypal), and then purchase things from your Taobao account balance. And then finding a seller who can communicate in your language and is willing to ship to your country.

[snaker]

@Gnomatic: They are not taobao agents. They are just small companies of a few employees. They have warehouses in the China side and ship goods by container load through seaways. I think this kind of business must exist in the US (the King of trade ), it is just probably more expensive.