DC charger

[wchl25]

I'm looking for a DC powered wheelchair charger for off grid camping. Preferably something that will plug in to the existing power port on the joystick, I don't really want to add external plugs. Something that would put out the standard 8 amps and run off 12 volts. Has anyone seen anything like this? I haven't found much searching the internet.

[Burgerman]

Most hobby chargers can do that with around 90% efficiency. But you will need to make up a lead. I use a PL8. Works great.

Alternatively your car alternator can put a lot of power back into your wheelchair fast. At up to 100A. Which is something I ued to do all the time on lead. Aain this needs some small changes to the wheelchair to allow parallel charge capability. https://www.wheelchairdriver.com/faster ... arging.htm

Theres also a really weak 2A pride mobile charger which is worse than useless that goes in a cigar lighter socket. But so slow as to be a waste of time. And theres a very inneficient one that works, gets super hot sold by powerstream, dont waste your money.

Something you may not have considered.
To charge from a car battery at 12V when no motor running, at 28.8V on the chair, with 10% efficiency loss through a GOOD device will take around 22A from the car battery. After 3 hours a full 100Ah lead battery will be completely discharged. After 1 hour it may no longer start your car. And unless its a deep cycle battery it will be damaged pretty fast too. Peukert means much less capacity that you expect. And well under half the voltage of the chair means more than double the current is drawn from the 12V system. And you will only have put back 8Ah x 3 or 24Ah total at this point. It also takes around 10 to 16 hours to get a complete charge. So what you propose is only practical if you have a huge 12V battery system, or you let the engine run all night.

[wchl25]

Most hobby chargers can do that with around 90% efficiency. But you will need to make up a lead. I use a PL8. Works great.

Alternatively your car alternator can put a lot of power back into your wheelchair fast. At up to 100A. Which is something I ued to do all the time on lead. Aain this needs some small changes to the wheelchair to allow parallel charge capability. https://www.wheelchairdriver.com/faster ... arging.htm

Theres also a really weak 2A pride mobile charger which is worse than useless that goes in a cigar lighter socket. But so slow as to be a waste of time. And theres a very inneficient one that works, gets super hot sold by powerstream, dont waste your money.

Something you may not have considered.
To charge from a car battery at 12V when no motor running, at 28.8V on the chair, with 10% efficiency loss through a GOOD device will take around 22A from the car battery. After 3 hours a full 100Ah lead battery will be completely discharged. After 1 hour it may no longer start your car. And unless its a deep cycle battery it will be damaged pretty fast too. Peukert means much less capacity that you expect. And well under half the voltage of the chair means more than double the current is drawn from the 12V system. And you will only have put back 8Ah x 3 or 24Ah total at this point. It also takes around 10 to 16 hours to get a complete charge. So what you propose is only practical if you have a huge 12V battery system, or you let the engine run all night.

I will probably go the route of the hobby charger, i have drones and have raced 1/10th scale for many years so I am well versed in that world. I have a LiPo charger now but only goes up to 12v 10 amp in lead acid mode. I know you like the Hyperion brand but they are hard to get. What do you think about something like the Junsi icharger x6 https://www.helidirect.com/products/icharger-x6

[shirley_hkg]

I'm looking for … Something that would put out the standard 8 amps and run off 12 volts.

A £30 buck-boost inverter , CC / CV adjustable , will serve you well.

Versatile, ultra compact , so it's good for journey.

[charlie ford]

i have used a victron 12-24 dc to dc charger 10 amp with anderson plug 12v in and xlr out,seems to work ok and easy

[Burgerman]

I know you like the Hyperion brand but they are hard to get.

I gave up on those at least a decade ago because of reliability reasons, and because the PL8 was better electrically - greater electrical reliability. But tey can only do 8S and so needed 2 at once on some of my chairs. At least after a years or so working with them to make it so! Same as the hyperion... I tested and helped with at least 30 new firmware versions to get it right. Both were PC controlled and monitored.

The junsi ones are a next best. No sensible PC software, some have suspect reliability, and have an odd way of controlling the termination current which is miles too high unless you set it down to a very low figure. And it changes with charge current. They are OK as a 2nd best though. And the PL8s are no longer made. Although you can still get them from shirley... https://www.wheelchairdriver.com/board/ ... =1&t=12088 So I have 6!

[wchl25]

I know you like the Hyperion brand but they are hard to get.

I gave up on those at least a decade ago because of reliability reasons, and because the PL8 was better electrically - greater electrical reliability. But tey can only do 8S and so needed 2 at once on some of my chairs. At least after a years or so working with them to make it so! Same as the hyperion... I tested and helped with at least 30 new firmware versions to get it right. Both were PC controlled and monitored.

The junsi ones are a next best. No sensible PC software, some have suspect reliability, and have an odd way of controlling the termination current which is miles too high unless you set it down to a very low figure. And it changes with charge current. They are OK as a 2nd best though. And the PL8s are no longer made. Although you can still get them from shirley... https://www.wheelchairdriver.com/board/ ... =1&t=12088 So I have 6!

Are there any other hobby grade chargers you would reccomend? The pl8 is very nice but I'm looking for something a little more simplistic, I don't really need the pc interface unless it is crucial for programming.

What are your thoughts about an onboard charger like this? https://www.amazon.com/Victron-Energy-O ... 195&sr=8-5

Also, how many amps would you think are acceptable to push through the charge port on a RNET controller? Although I'm sure it would be a safer bet just to hard wire directly to the batteries.

[Burgerman]

The XLR port on a powerchair is maximum 12A RMS according to the manufacturers of most of the control systems.

The victron chargers can be very good. But ONLY if you set up a user custom profile completely and ignore their built in presets. And again you need to download their PC software to do that. But only need set it up once.

If you feed a chair 12A then that is 12A x 28.8v = 346 watts. To feed that from a car battery at 12V you will need to pull around 30A from it. Which will pull down the voltage to 12.0 after a few mins or below. Or actually its 346w + 10% because the internal inverters are around 90% efficient at best. So thats really 380 to 400 watts. That works out at 28.75Amps.

So the question remains... A 100Ah car battery will only give around half that over a 30A (3h discharge rate) before it is dead. So you will get around 1 hour and 40 mins charging. A full charge takes an awful lot longer than this. Like around 10+ ours. After around half that 1 hour and 40 mins, your car will no longer start.

So you will need to leave the engine running all night. Or fit at least 2 more 100Ah batteries on board the car. If you plan on charging with a car running then it makes far more sense to charge at 50 or 60A direct from your cars own battery as per my drawings/page linked earlier. So how will you power this?

[wchl25]

The XLR port on a powerchair is maximum 12A RMS according to the manufacturers of most of the control systems.

The victron chargers can be very good. But ONLY if you set up a user custom profile completely and ignore their built in presets. And again you need to download their PC software to do that. But only need set it up once.

If you feed a chair 12A then that is 12A x 28.8v = 346 watts. To feed that from a car battery at 12V you will need to pull around 30A from it. Which will pull down the voltage to 12.0 after a few mins or below. Or actually its 346w + 10% because the internal inverters are around 90% efficient at best. So thats really 380 to 400 watts. That works out at 28.75Amps.

So the question remains... A 100Ah car battery will only give around half that over a 30A (3h discharge rate) before it is dead. So you will get around 1 hour and 40 mins charging. A full charge takes an awful lot longer than this. Like around 10+ ours. After around half that 1 hour and 40 mins, your car will no longer start.

So you will need to leave the engine running all night. Or fit at least 2 more 100Ah batteries on board the car. If you plan on charging with a car running then it makes far more sense to charge at 50 or 60A direct from your cars own battery as per my drawings/page linked earlier. So how will you power this?

I'm sorry , I should have been more specific. I will be charging the chair while the car is running. I do not want to use the anderson plugs and charge each battery on the chair individualy, I want a charger to do both at the same time. If I have to hard wire directly to the batteries to avoid using the XLR port that is fine.

[Burgerman]

When connected as in my picture it DOES do both at the same time, at the full power of your vehicles alternator. So you put back a lot of power fast. It also has the advantage of being able to start your car if needed. And it balances the chairs batteries up automatically so a good thing.

But if you need to charge via a charger that too will work. But more slowly, and less efficiency. And more costly... But both will work.

Even charging at say 40A per battery, that soon drops off. The final part of the charge, for a complete charge will always take around 10 hours in deep cycle use. Even from an alternator at high amps initially. The difference is that it will put most of it back very fast! Both at the same time.

[wchl25]

When connected as in my picture it DOES do both at the same time, at the full power of your vehicles alternator. So you put back a lot of power fast. It also has the advantage of being able to start your car if needed. And it balances the chairs batteries up automatically so a good thing.

But if you need to charge via a charger that too will work. But more slowly, and less efficiency. And more costly... But both will work.

Even charging at say 40A per battery, that soon drops off. The final part of the charge, for a complete charge will always take around 10 hours in deep cycle use. Even from an alternator at high amps initially. The difference is that it will put most of it back very fast! Both at the same time.

Ok, so back to the original question. Can you recomend any other hobby chargers?

[Burgerman]

Not without testing to see what they actually do. Most dont harge lead properly. But if its only temporary then provided the voltage alone is correct then you cant do too much damage.

So CV of 28.80V for AGM and 28.20 for gel.

[shirley_hkg]

I'm sorry , I should have been more specific. I will be charging the chair while the car is running. I do not want to use the anderson plugs and charge each battery on the chair individualy, I want a charger to do both at the same time. If I have to hard wire directly to the batteries to avoid using the XLR port that is fine.

Recharge only with engine running means you have to put back as much as possible in an hour or two.
Burgerman's bulk charging wiring kits is your choice.

They allow you to re-configure your battery pair in parallel for 12V bulk charge while engine running, AND back to 24V in series for driving in seconds.
XLR port could be used to top up , with no engine running, as the amount of energy will be pretty small.

[Burgerman]

It will be low if its almost full already.... Or it will take 3 complete car batteries full to charge a wheelchair 24V set up. And you cant do that anyway as those are not designed to be deep cycled. Starter batteries are meant to be discharged by 2 to 5% max and are only that big in order to be capable of making the high starting current. (int resistance).

So charging anything but an already full wheelchair will always need a running engine. If you are not to rapidly ruin your cars battery. But it takes 12 hours to PROPERLY charge a powerchair. If your charger says its done faster, when heavily discharged then throw it away! An 80% discharge cannot be recharged properly faster than 12 hours. Often 16.

Even if charging at high current direct from your car, via its alternator, maybe 50 to 100A the battery will regain a lot of charge very quickly. Then the last part will still take another 8 hours. Does this matter? Not if you only do it 3 or 4 times between a COMPLETE 12 to 16 hour charge.