WheelchairDriver

No need.Buy the same 4mm connectors. Buy a midi fuse. Buy a few meters of the same silicone cable -- all on ebay. No need to splice or bodge anything.

You WILL need to splice the balance wires. Make them all a different length, and just solder each and heat shrink.

Is it necessary to fit a fuse on the cable that connects between PL8 and the power supply?

Not really. The power supply should be short protected already. I have a 100A fuse in my van to protect from shorted wiring catching fire as I charge there regularly. Inc hobby stuff. But a cars battery can give 1000s of amps, a fuse is important there.

Burgerman wrote:Use a so called midi fuse. They are small. Solder wires directly, slide on heat shrink. Or just 15 mm of 40A fuse wire and heat shrink. If you think you cant fit it in.

BM, do you have a pic that shows how a MIDI fuse is directly soldered on a wire? I just want to see how it looks before being wrapped into a heatshrink tube. These littelfuse MIDI fuses are still strange to me and people here. We still do know how to properly solder it to a wire. A pic will help us much.

No. But just fold the wire around the end, flux, solder. Very easy.

There is no more compact way. Its easy to hide it in the cable covering. A 40A fuse is good for 60 to 70A in reality so its never going to fail unless something drastic occurs! Even if it does, you can still change it in minutes.

Obviously you can use ring terminals if you want. Or a fuse holder. But the idea is to keep it super small in the loom. You could also skip the fuse completely, if you use the protected banana plugs with minimal risk.

The fuse would be easier to solder if it has barrels at 2 ends.

No harder. Nothing to fold wire over. Both are easy. Took longer to type this than to do it!



Fold cable copper end over, Squash flat to make it tight and flat so its one piece. . Solder it...

Squash flat with pliers... Solder!

Do you have to use two fuses for making the lead - one on each cable like the original cable for the Charger ?

or would just one fuse be ok on either pos or neg. ?

Two is safer. I use one. The only thing they protect are the cables. With protected banana plugs its almost impossible to short the chairs or any battery out. Unless the insulation gets trapped and rips. And the best place for the fuse is at the chair end. Or on the chair in the charge cable.

Ok - i have no fuses on the Charge Cable on the Chair end - its on the Charger end cables - originals come with two fuses - one each cable - the Chair of course i have the breaker on the battery pack - i was under the impression thats fine this way ?

i dont recall discussing about fuses on the Charge Cable on the Chair end -

Dont worry.

snaker wrote:I see the PL8's stock charge cable is too short (50cm?). I want to extend it to about 100cm. Could you recommend for me an 'easy' way to implement it.
http://www.store.revolectrix.com/Produc ... Stackable-

I am thinking about using "butt splice" connectors to extend the cables. Is it safe enough?
https://youtu.be/pdBcPJ7Dtaw

Any sort of crimp connectors are not going to be as good as a length of wire that is the correct size, and are only going to be as good as a soldered connector if PROPERLY crimped with the right tooling exactly per specs... I get extra paranoid about them in cases where the connection is for high currents, like it is in the PL8 charge cables...

I really don't like using crimps if I can avoid it, but they are OK for terminating a wire when done properly... I will only use a 'butt splice' if it is not practical to replace the entire wire... I will also be far more inclined to do a soldered splice instead....

On fuses and when / where to use them....

The purpose of a fuse is to protect the wiring in a circuit from excess current draws in the event of a short circuit or excess current draw...(the purpose of the expensive electronics is to protect the cheap fuse... ) This tells us that the only place a fuse is needed is when there is a possibility of excess draw... So the ONLY place a fuse is needed is next to, and as close as possible to the current source.... The fuse needs to be sized to be appropriate for the SMALLEST size wire in the circuit it is protecting.... In a branching circuit this may mean multiple fuses, one large one to protect the 'trunk' and a smaller one to protect each 'branch'

So if you have a battery, you want a fuse in the leads coming from it, as close as possible to the battery as practical. In a typical car, with negative ground, the fuse should only be in the positive lead and NEVER in the negative... On our chairs, the fuse can be in either the positive or negative lead, only one is NEEDED but no harm to put one in both. However by convention it is normal to put the fuse on the positive side...

If you have a power supply, you need a fuse or other protection on the output, again by convention only one is needed, and it should be in the positive lead - and if the supply already has adequate protection built in, then it isn't really needed other than for redundancy.

In US AC, all fuses (and switches) should be on the HOT wire, NEVER on the Neutral, and NOTHING should be able to interrupt the earth ground wire (which also should never have any current on it...)

So the PL8 gets power from a supply, and can both source and receive power on its output side....

The power supply (battery or other) SHOULD have protection already, but it might be heavier wire than the PL8 supply wire (the line from my car battery is AWG 6 with a 150A breaker) and isn't guaranteed to be there, so it does not hurt to put a fuse in the positive lead, PL8 spec page says it has a 60A max input current, so any fuse a bit over that would work. Per the standard of putting the fuse close to the source, it should be next to the plug.... Since it can be plugged into a vehicle, there should NOT be a fuse in the negative lead. If you are sure that you are never going to be drawing more than a certain amount of current on the input side, you can use a smaller than 60A fuse, as long as what is used is more than your expected maximum draw... (It might even be a good idea if you want to be sure a power supply never pulls more than a certain amount from the mains, even if the PL8 gets set wrong...)

The output side of the PL8 is supposedly protected, and there SHOULD be a fuse in the wiring between the chair's charge connector and the batteries (as close as possible to the battery as practical) so in theory it shouldn't need a fuse in the charge lead, but again it wouldn't hurt...

I've never seen anyone talk about putting fuses in the balance wires - though there are options that could be used.... Again since supposedly there are protections in the PL8, if I was fusing the balance wires, I'd want to put the fuses (and you would need one for each wire) next to the batteries....

ex-Gooserider

expresso, can you post the link where you bought your current heat gun?

snaker wrote:expresso, can you post the link where you bought your current heat gun?

https://smile.amazon.com/gp/product/B00 ... UTF8&psc=1


https://smile.amazon.com/Bestgle-Shrink ... ni+heatgun

the one i got no longer can get - but its the same as above link - -

the torch same thing - they dont have it - but there are dozens around - you can choose from - i use the torch just for making cables etc, - the mini heat gun for heatshrink on the wiring after they are made

Thanks expresso. The torches in your link are nice and their prices are reasonable. I only find 1-2 torches around here, all looks low quality, unsafe but costs $50. Electric tools and parts here are rare and expensive.

yeah what can we do - prices are crazy - and BM thinks my prices are crazy here compared to UK - we cant win -

Burgerman wrote:Squash flat with pliers... Solder!
download/file.php?id=6917

BM, can I do this with 8 awg power cables? I mean directly soldering a 125A/32V MIDI fuse on a 8 awg cable. Is it safe enough?

I disagree. I doubt theres any measurable resistance difference. And in fact would expect a soldered connection to be just as good initially, and the crimp to get worse as things oxydise over time even if it was as good to begin with. I have seen so many bad crimped connections that I never consider using crimping alone as secure enough on anything thats bigger than balance wires. So yes!

why even bother with Fuses on the Main pack in the chair - why not just use a Breaker - wouldnt that be best ?- if it ever trips - you just reset it -

and not worry about fuses to change etc, i mean if you solder a fuse - its a pain to change it - i never had one blow or trip on any chair so far - so it shouldnt but in the event it did - would be easier with a breaker -

expresso wrote:why even bother with Fuses on the Main pack in the chair - why not just use a Breaker - wouldnt that be best ?- if it ever trips - you just reset it -

and not worry about fuses to change etc, i mean if you solder a fuse - its a pain to change it - i never had one blow or trip on any chair so far - so it shouldnt but in the event it did - would be easier with a breaker -

My dad removed the breaker away. It's weak just 50A. I had bad experience with breakers, they caused more troubles than protecting. Maybe that's because all my chairs are cheap and they use low quality breakers. I am living in a chaotic society, everything is unsafe and everybody is familiar with unsafe things. All that BM has done and showed are new and strange to people here but we all see that's better, safer. I will try to follow as much as possible. Hoping it could reach 50% at the end.

One of my chairs has a set of AGM group 24 batteries that are probably about 4 years old now. When I fully charge them and let them sit overnight the voltage is 25 volts. Would it be ok to connect the add on pack? I don't want to hurt my new investment.

rustyjames wrote:One of my chairs has a set of AGM group 24 batteries that are probably about 4 years old now. When I fully charge them and let them sit overnight the voltage is 25 volts. Would it be ok to connect the add on pack? I don't want to hurt my new investment.

You can connect it - but your going to really be working your ADD ON pack the most - any lead battery 4 years old no matter how easy you used it or charged etc, cant be in good enough shape -

it would be best to get a New set of Lead - MK Gel if you can - and if you can - charge them first one at a time - then install - and use the ADD ON -

this would give you the best performance and last the longest - i think even any new battery would be better to use with the ADD ON instead of those 4 years old - but if you cant change the lead now - you can use the ADD ON and then change the lead when you can - you just wont get the best range out of it this way and work the lithium more since those lead you have is really dead at 25V i think -

or if you like - just use those lead till you feel they dont work for you anymore - then connect it with a new set of lead - will work either way you choose -

25 volts?

Thats basically 60% discharged voltage, or almost dead... You will just waste all the power of your lithium trying to charge ruined lead bricks.

Thanks guys, that confirms what I was thinking. I guess I'll buy a new set of MK's and start fresh.

yes best way to go - i just did that to my chair with the ADD ON also - got new set of MK from insurance last set for this chair - this way - you should be good for a while - if you had lead 4 years old - new MK with the ADD ON - should last you a long time

i charge it once a week if i dont use the chair at all - if i use it - i charge each time after use with the PL 8 - i also charge it before i use it if its been sitting a week and i want to use it - i would charge it first - then use it -

ALL of you guys would benefit from a power cut off link, or switch. All my chairs have them. A modern lead or lithium battery loses virtually nothing if stored as long as the thing is DISCONNECTED from the chair. Just one cable, no circuit.

An AGM like odyssey, or mk gel, have extremely low self discharge rates. So stored disconnected, they dont need a top up charge other than every 4 to6 months. Just charge very full, pull the link. Forget about them for 4 to 6 months.

The only reason you need to keep topping up is because the chair itself sucks power out all the time, even when off. 6mA to 30mA is typical if turned off. And 100 to 150mA if left on in error.