Hello, i have a invacare wheelchair that has 2 12v sealed batteries, wired in series at 24v. I wanted to find out the charge plug has 3 prongs, which should be -. ground, . over vice versa, how come there is not voltage across the pins, does it detect anything so the voltage comes thru?

You have to get in behind it and see why it pushed back in? Then you can push it back out or re-fix it, or get a new charging socket.

Invacare Corporation - Parts Catalogue

Invacare http://www.invacare.ca > inv_catalog > partsPHII_home
Parts Catalog. Invacare Home ' New Search. Choose Product Category. Product Category, Beds and TSS, Power Wheelchairs & Scooters, Manual Wheelchairs ...

Invacare® Pegasus Series

Invacare http://invacare.ca > doc_files > Pegasus Owners ...
PegasusMETRO, PegasusPRO en Scooter ... 7.2.4 How to disconnect the batteries after charging. ... liquids may require replacement of electrical components.
66 pages

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Question edited for clarity, capitalization and typos.

http://www.invacare.ca/doc_files/1143151.pdf

Page 116 of the Manual refers

5 flashes.
Left Park Brake Fault.
Ensure brake lever is in the drive position before turning on the wheelchair. Ensure motor cable is plugged into the controller. Contact Invacare or Dealer for service.

If it only has an output voltage of 1.4 volts, it sounds like it has failed internally. Take it to an Invacare service centre or retailer and ask them to check it. My guess is that it need replacing. Here is the manual for it, and it states, 24 volts at 8 amps or 10 amps depending on country of issue. It charges 12 x 2 volt lead acid cells at the same time, cleverly making sure you can't use a standard 12 volt car charger.
https://www.invacare.co.uk/sites/gb/files/csv_migration/product_docs/technical_docs/DTEC012618_1636951~C_OptiCharge_UM.pdf

You can get them on eBay and Amazon

Invacare 1123249 8 Amp Battery Charger; AC Power Line Cord

https://www.amazon.ca > Pronto-Nutron-Series-Battery-...

24V 8A Battery Charger with XLR Connector for Jazzy 1450, invacare tdx 3, Invacare Pronto M51, Wheelchair, Sunrise Medical, Quickie, Drive Medical Electric ...
Rating: 3.7 · ‎4 reviews

invacare 24 volt battery charger products for sale ' eBay

https://www.ebay.com > invacare-24-volt-battery-charger

Get the best deals on invacare 24 volt battery charger when you shop the largest online selection at eBay.com. Free shipping on many items ' Browse your ...
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The m51 is notorious for failure of the on-board charger. An easy check would be to plug an off board charger into the 3 prong female charging receptacle at the front of the joystick to see if you can bring the voltage up. You can test the on board charger with a voltmeter at the battery connections or charger joystick port with the charger plugged in. Hope this helps

Here is a parts catalog for the M41. http://www.invacare.com/doc_files/06_108.pdf

If it was working fine before you swapped the batteries then you did something to interrupt the current flow. Pages 49/50 show the location of the controller with a picture. Unplug the connections here and make sure they are clean and in good shape. Make sure all other connections are clean and tight.

If you have 24V coming off the batteries into the controller, and 24V going out to the joystick from the controller and still nothing is working, then you will probably need to get ahold of an Invacare service tech to replace the joystick. Before he does that he should swap out the old joystick with a new one to see if that is the issue. Invacare parts are pretty pricey...joystick by itself is over $500.00. If the controller is shot, then you can double that cost. Sometimes, both need to be replaced as they can kill each other.

If the chair is old or has a lot of hard hours on it, you can usually shop around on Craigs List, etc and find a good newer/near new chair for about the same price as a new joystick replacement.

The red light on the transformer/Charger means the charger is bad. Sometimes it can also be battery harness wiring. Most often it is the charger that needs replaced.

You definitely need new batteries. After that amount of time the batteries go bad and the plates inside become sulfated. They are only good as boat anchors now.
It is a easy do it your self repair. There are 2, Group 22 batteries in this model. You want to get deep cycle sealed lead acid, preferably AGM (advanced glass matt) group 22 batteries.
Flip the seating system back by releasing the lever under the front of the seat.Make sure you do not pinch the joystick wiring at the back when you do this.
Remove the black plastic cover.
The batteries will be secured by a strap which you should unbuckle.
Disconnect the plugs to the batteries and note how they are run, oriented and connected.
Pull out the batteries, one at a time, from the base.
Make the wiring connections to the battery , put the batteries back in the chair, plug everything in and you are set to go. Hope this helps.

Nurseboy16 goto to Invacare.com and on the homepage select wheelchairs and topend then select powerchairs then select Pronto series then select nonpowered seating scroll down until you find M91 then on the left side of the page you will see owners manual select that and look on pages 62-63 on how to connect the wirng. You should have wiring crisscrossing each battery black on neg post red on positive post on opposite batteries and the large connector will connect to the large connector going to the controller or power module hope this helps

The chances are the batteries are damaged, wheelchair / scooter batteries are not designed to be left with out charging for any length of time, you might be able to revive them if you have or can get hold of a charger that will charge

for future reference, charge every 4 weeks (minimum) or leave on auto trickle charge if your charger has that function, this will keep your batteries in peek condition, and will not shorten there life.

check out this link for more battery info.
http://www.mkbattery.com/content_container.php?page=downloads-and-technical-reference-faq#faq1

Hope this helps, If so please click the "Yes" button

Regards, Mark

Hi. Most chargers with only two wires, have a small bridge wire from the
black ( negative ) wire to the middle terminal of the connector. This disables the controller while the machine is charging. The charger will still work without this bridge wire, but the scooter will still operate normally.
There are a few different chargers around that have an internal relay that disables the scooter, but these chargers are normally "on-board" chargers.
Good luck. Neil.