pdarlingks
New Member
Yes, we do. I don't doubt it; the cost, risk and political visibility of success or failure drove a lot of the thinkinmg.
Replacing SLA with LIFePO4 for mobility scooter
- Thread starter pdarlingks
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pdarlingks
New Member
Ha ha... my list of projects is growing rapidly... I've got a larger scooter I use around the farm that will drop 50+ lbbs from the total weight by going to LiFePo4, so unless it's got a speed limiter I can't find, I shouldn't have any problem exceeding its advertised 11mph limit!
You're really pushing the limits! If you hit 12 mph the paint might start to blister.
Dropping weight by putting in LiFePO₄ batteries is sweet!
pdarlingks
New Member
Okay, I'd like to try one more time.... I do now have a CBA 5 but will probably wait to check the capacity when I balance the scooter batteries in the future (it is not easy to extract them from their cases).
Here's what I'm struggling with (response from LiTime). Before I try communicating with LiTime again, I want to make sure I'm not way off-track.
Everything I've seen echoes what you indicated.... 100 SOC on LifePO4 batteries results in a battery voltage of 13.3V approxcimately. I measure 12.9v at the terminals with my Fluke meter after full charge (individually) according to the charger green light and then several hours of rest. I assume the terminal voltages are what is measured, and this is what the scooter electronics see.
Relaying this to LiTime got this response.
"Don;t worried, it was the over-charged protection by the BMS , You could check the details by our manual.
The terminals voltage 12.9V which has been 00% SOC of the battery ( 12.9+0.5=13.4V)"
Their text is copied from their email; i.e., no typos on my part. I assume they meant 100% not 00%.
Any suggestions woiuld be appreciated.
I'm not convinced by LiTime's response. The capacity test will dispel all doubts.
pdarlingks
New Member
Thanks, just got my analyzer, and the 2 batteries are on my to do list!
12/8 lithium battery are drop-in replacement for 12V SLA, but they are designed to give the same short current for the starter, but are nowhere near in term of capacity.
a 12V35Ah is 12x35= 420Wh when a lithium 12/8 is only 96Wh. But if the starter ask for 35A peak, both batteries will fit.
But if the purpose is to run a device (like radio in a stopped car), your lithium battery will die 3 times sooner that your SLA.
These lithium batteries are great if you are looking to make your bike lighter.
I know because i made the same mistake. (12V SHORAI batteries)
a 12V35Ah is 12x35= 420Wh when a lithium 12/8 is only 96Wh. But if the starter ask for 35A peak, both batteries will fit.
But if the purpose is to run a device (like radio in a stopped car), your lithium battery will die 3 times sooner that your SLA.
These lithium batteries are great if you are looking to make your bike lighter.
I know because i made the same mistake. (12V SHORAI batteries)
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pdarlingks
New Member
That was my typo in the first post. I have a wireless keyboard that seems to be touchy.
The batteries in question are 12V 45Ah replacing 12V 35Ah batteries, and they work fine. I've been using them for a couple of weeks now.
Thanks!
SolarUKWM
Solar Enthusiast
... and also because it creates a sales opportunity when the dealer wants to sell you some new "special" mobility batteries. Not like those golf cart ones. Or those deep cycle ones. No no no they'll never do. You need the special "approved" mobility grade ones, which are just the same, but about twice the price. Plus fitting. What a deal!
Having been there in the past, for a family member that needed 2 x 12v 50Ah lead-acid deep-cycles for a mobility scooter, I took one look at the quote he'd been given, said "No, wait, that's crazy" and ordered 2 replacements, to be delivered to his address next day, and fitted them for charge of tea+biscuits when they turned up.
I saw the batteries that were on there. They were not special. Revenue stream protection!
pdarlingks
New Member
Exactly. I had a battery distributor tell me they didn't make a LFP for my scooter... I said tihere were a couple of companiesi that did, and proceeded to replace them. Not everybody can do their own replacement but they can have a family member or friend help them. They weigh much less than SLA!
Similar story with the chargers. I found an decent one with XLR connector off Amazon for under $50' rather than $150-200 from the "medical" distributor.
SolarUKWM
Solar Enthusiast
Yep. I know what a proper Sealed Lead-Acid CC/CV/Float charger looks like.
"Official" charger supplied with scooter came with verbal instructions from dealer -- "do not leave the scooter on charge when not in use". That's a nonsense, considering float charging a lead acid battery to keep it 'full' is perfectly normal.
Other verbal instruction given: "Always fully run the battery down before recharging it". What is this, a NiCad??
What a great way to kill a SLA battery -- fully run it down and deep cycle it every time, and don't float charge it.
Yes, the shallower the depth of discharge the better! Old wrong tales about charging, floating are hard to correct. O yea don't put the batteries on a cement floor! I worked as a mobility service, installer Tech. for years. Hard to correct some sales people.
crossy
Solar Wizard
Somewhat related anecdote 
Some years back my eldest son worked for a company in Christchurch, UK, who made, amongst other things, electronic motor controllers for wheelchairs and mobility scooters. https://www.cw-industrial.com/en-gb/about/legacy-brands/penny-giles
Of course, different markets have different limits for speed, acceleration etc. etc.
The hardware was the same, everything was controlled by software parameters.
There was a thriving black-market for "Hot-ROMs" for your wheelchair!!
And you thought only car-nuts went for ECU mods
Think of him next time you are passed on the freeway by an old biddy on a mobility scooter!!
Some years back my eldest son worked for a company in Christchurch, UK, who made, amongst other things, electronic motor controllers for wheelchairs and mobility scooters. https://www.cw-industrial.com/en-gb/about/legacy-brands/penny-giles
Of course, different markets have different limits for speed, acceleration etc. etc.
The hardware was the same, everything was controlled by software parameters.
There was a thriving black-market for "Hot-ROMs" for your wheelchair!!
And you thought only car-nuts went for ECU mods
Think of him next time you are passed on the freeway by an old biddy on a mobility scooter!!
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desertbeekeeper
New Member
So I am in the same boat, and didn't think that a search would turn up mobility batteries, but the wealth of knowledge never ceases to amaze. I also got two batteries from LiTime, these are group 34 batteries, which are the size for the wheelchair I have. Got a charger, and then read through this thread about the balancer. Should I just pick one? like this?
Also, I have a 24v charger with the XLR barrel connector. But then I read about charging up each battery individually. Should I also pick up a 12v charger, to charge these individually before putting them in the chair?
BTW the batteries that I am replacing from Permobil weigh 54 lbs a piece, for a whopping 108 pounds. It was hard to get them out of the tray. The new batteries weigh 14 lbs. It is crazy that this will lighten the wheelchair by 80lbs! The old batteries are fine, but needed to drop some weight out of the chair for the lift to get it in the car.
Also, I have a 24v charger with the XLR barrel connector. But then I read about charging up each battery individually. Should I also pick up a 12v charger, to charge these individually before putting them in the chair?
BTW the batteries that I am replacing from Permobil weigh 54 lbs a piece, for a whopping 108 pounds. It was hard to get them out of the tray. The new batteries weigh 14 lbs. It is crazy that this will lighten the wheelchair by 80lbs! The old batteries are fine, but needed to drop some weight out of the chair for the lift to get it in the car.
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