PINNED - Lithium battery conversion/info

[Scooterman]

IT IS CORRECT !

Cheers mate!

[woodygb]

I'd suggest that you rearrange the batts like this.....it gets rid of the extra long lead between the two groups and just makes more sense to me.

[Scooterman]

Thank you Woody, nice diagram

Yes I think I will modify cell arrangement in pack two. I can slice down the lateral centre line between cells 55,66 and 77,88, swap their position, add another rubber wall and bind with black gaffer tape. I've not done the final wiring yet.

[Gnomatic]

That looks good woody. I added a smudge where I think it'd be a good place to install a breaker if there's a good place to mount it.

[Burgerman]

Electrically thats a good place. For the charger it will give slightly odd curves as the contactor or fuse has higher resistance. And 3 or 4 mV difference under load while charging at say 30A will make a difference. Better to fit it in between the battery pos and the power module.

[Scooterman]

That looks good woody. I added a smudge where I think it'd be a good place to install a breaker if there's a good place to mount it.

Thank you

Electrically thats a good place. For the charger it will give slightly odd curves as the contactor or fuse has higher resistance. And 3 or 4 mV difference under load while charging at say 30A will make a difference. Better to fit it in between the battery pos and the power module.

Thank you I understand what you mean

[terry2]

All fitted and I am now doing it's first charge in the chair.

I will go around the block for an hour to test it.
I have breakdown insurance just in case

Looking at my ISDT monitor. It must never go below 3.0V standing still. And 2.9V moving. Is this correct?

Thanks guys

[Burgerman]

2.9 volts is definite end of playtime. When not moving.
2.5 volts when under load (moving).

You will find that as a fuel gauge its useless. It starts at 100. Soon drops in the first few yards. And stays somewhere in the middle most of the day. It may read very high or low much of the day, so dont stress it. Then right at the end it will drop to 3.1V fairlyfast.

Take a fire extinguisher.

You will notice it has more torque and be more controllable. Watch for lesser stability. Ie dont fall out!

[Scooterman]

.
I have breakdown insurance just in case

Have you really got it? You can get it but it's quite expensive.

I have 3rd pf&t + puncture for my road scooter. It's probably a waste of money £47, but you can only have puncture repair with insurance. And I do get people step out in front of me because they can't hear electric.

But I've not got breakdown. I carry a bike cable so I can lock it up and come back and fix it later.


PS I hope everything goes okay on the test drive

Dont go over any bumps and rattle loose the electrical connections

[Burgerman]

Remember that you normally get only a fraction over half the Ah from lead due to peukert. And that means that you get 40Ah from a 70Ah battery. But you dont typically run till it stops as you want to make it home. So probably use about 80% of that 40Ah. So in reality your normal day is 30Ah. You now have 176Ah. Or if you leave 25Ah in reserve, 150 usable Ah. So 5x the real world range you had before. So go on a long trip!

[terry2]

2.9 volts is definite end of playtime. When not moving.
2.5 volts when under load (moving).

You will find that as a fuel gauge its useless. It starts at 100. Soon drops in the first few yards. And stays somewhere in the middle most of the day. It may read very high or low much of the day, so dont stress it. Then right at the end it will drop to 3.1V fairlyfast.

Take a fire extinguisher.

You will notice it has more torque and be more controllable. Watch for lesser stability. Ie dont fall out!

I will get one from amazon.....just in case

2 cells are out of wack and there is no way for me to get to them

.
I have breakdown insurance just in case

Have you really got it? You can get it but it's quite expensive.

I have 3rd pf&t + puncture for my road scooter. It's probably a waste of money £47, but you can only have puncture repair with insurance. And I do get people step out in front of me because they can't hear electric.

But I've not got breakdown. I carry a bike cable so I can lock it up and come back and fix it later.


PS I hope everything goes okay on the test drive

Dont go over any bumps and rattle loose the electrical connections

I am insured for £1 mil if I hit anyone. And £10,000 for the chair with breakdown service. Cost is £84 a year.

[Burgerman]

That company pay all their wages, tax man, holiday pay, vehicles, accountant, and more out of your premiums. So obviously its chaper to pay for anything that may happen out of pocket. Remember that inurers exist not for you but to profit from you.

[LROBBINS]

There are two classic decision rules used in statistics - MiniMax (reducing the maximum loss) and minimizing the average loss (I don't remember if there's a cutesy name for this). What Burgerman describes is the second of these - over time your costs will be less if you "self insure". What insurance companies sell is a MiniMax product - you limit your maximum possible loss. In deciding between the two you really have to ask if you can afford that "maximum loss". So, thinking about an automobile (or a WC), if you have some savings, it makes sense to not take out coverage for physical damage to your vehicle IF you could replace it if needs be, or can do without, but it probably makes sense for almost everyone to have liability coverage as injuries to someone else can have an extremely high maximum cost. If your rich as Cresus, you don't need either coverage.

[steves1977uk]

I've never insured any of my chairs in all my life as it's a waste. That money is better spent on maintainance and repairs IMO.

Steve

[terry2]

Houston we have a problem(well I think so) It was fully charged according to my PL8.

Just went out for a test run. 6 mph for 2 miles. All was ok but the monitor says other wise?

[Burgerman]

That may be that the cell monitor isnt that accurate. Or that you have a bad connection. The only real way to know is a QUALITY multimeter. And as I said, it isnt any good as a fuel gauge. You can ignore those fuel gauge bars until the voltage drops to the figures I said before. Because they will not tell you anything useful.

But all voltages are ok, so keep going.

Or if home, do a 15 minute discharge, with PL8 and look at voltages. Then if OK, carry on...

[Scooterman]

[

I am insured for £1 mil if I hit anyone. And £10,000 for the chair with breakdown service. Cost is £84 a year.

That's not bad for breakdown as well, is that with FISH?

Mine is £1 mil as well, we're probably with the same company. That's the reason I have it, I think scooters are more of grey area and scooter riders are probably more likely to get sued. The public don't have much sympathy for scooter riders, in fact the exact opposite. Although that bird from bbc watchdog is always sat on one and she don't look like a hooligan

[Scooterman]

That may be that the cell monitor isnt that accurate. Or that you have a bad connection. The only real way to know is a QUALITY multimeter. And as I said, it isnt any good as a fuel gauge. You can ignore those fuel gauge bars until the voltage drops to the figures I said before. Because they will not tell you anything useful.

But all voltages are ok, so keep going.

Or if home, do a 15 minute discharge, with PL8 and look at voltages. Then if OK, carry on...

Is there a mV bandwidth? that top-balanced cells should stay within during discharge

[terry2]

That may be that the cell monitor isnt that accurate. Or that you have a bad connection. The only real way to know is a QUALITY multimeter. And as I said, it isnt any good as a fuel gauge. You can ignore those fuel gauge bars until the voltage drops to the figures I said before. Because they will not tell you anything useful.

But all voltages are ok, so keep going.

Or if home, do a 15 minute discharge, with PL8 and look at voltages. Then if OK, carry on...

Will do.

[

I am insured for £1 mil if I hit anyone. And £10,000 for the chair with breakdown service. Cost is £84 a year.

That's not bad for breakdown as well, is that with FISH?

Mine is £1 mil as well, we're probably with the same company. That's the reason I have it, I think scooters are more of grey area and scooter riders are probably more likely to get sued. The public don't have much sympathy for scooter riders, in fact the exact opposite. Although that bird from bbc watchdog is always sat on one and she don't look like a hooligan

I'm with Blue badge.
I always think it's best to be safe than sorry.

[Scooterman]

I'm with Blue badge.
I always think it's best to be safe than sorry.

I could do with personal insurance Whether it's cos I don't use my powerchair everyday or it's just me, but the number of times I lean forward or reach for something and accidentally catch the joy stick nearly breaking my legs, I dunno. I just try and remember to only have 1 LED lit when stationary.

The first time I used the chair to board the bus. I dashed to the bus stop at full speed. Bus arrives and ramp deployed, go up ramp AT FULL SPEED!!! My god I didn't know what was happening, I scared the life out of the other passengers. Then I realise the speed LEDs don't reset to zero when you stop. I wish they did cos I always forget to turn down the speed when I've stopped from full speed.

[terry2]

I'm with Blue badge.
I always think it's best to be safe than sorry.

I could do with personal insurance Whether it's cos I don't use my powerchair everyday or it's just me, but the number of times I lean forward or reach for something and accidentally catch the joy stick nearly breaking my legs, I dunno. I just try and remember to only have 1 LED lit when stationary.

The first time I used the chair to board the bus. I dashed to the bus stop at full speed. Bus arrives and ramp deployed, go up ramp AT FULL SPEED!!! My god I didn't know what was happening, I scared the life out of the other passengers. Then I realise the speed LEDs don't reset to zero when you stop. I wish they did cos I always forget to turn down the speed when I've stopped from full speed.

No more buses for me

A big thank you to everyone that helped.

[terry2]

Does that look ok BM?

[Burgerman]

Yes. Ignore the little meter until its LOW as a warning. Continue...

[Scooterman]

I'm curious terry, does the chair FEEL any different with lithium installed?

[Burgerman]

If your chair is programmed to jump on command and respond properly it feels much more accurate, controlled and instant. With none of that elestic/disconnected feel. Partly because you have 50lb less weight. Partly because voltage doesent drop to 18V under load. And the difference is huge.

If programmed as per typical powerchair in delayed action and mushy pudding steer mode you will never be able to feel any difference. Because it still wont be working properly or responding when you tell it no matter what battery is fitted.

[terry2]

Yes. Ignore the little meter until its LOW as a warning. Continue...

Thank you.

I'm curious terry, does the chair FEEL any different with lithium installed?

I seams to have more go in it. No lag at all.
I am going to move the cables as it's hard to put the back plate on as it is.

[Burgerman]

How much power will you be putting back? Post graph.

[terry2]

How much power will you be putting back? Post graph.

Sorry for the late reply.

I have nearly finished moving the wiring.
I haven't charged it back up as yet.

I will do later this morning and post a graph.

[Burgerman]

Did you go far? Compared to when lead?

[terry2]

Did you go far? Compared to when lead?

Only the 2 miles or so.

I did discharge the pack a bit when I saw how the 2 cells was out of sync.
Just charge it and here are the results.