OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Honda Engines Honda GXV160 power increase ?

Good info there Trev, they look to be a pretty big motor. Looks like it might need to go to a 13hp motor and probably run 2 alternators. The 13 will handle that no problems

I think I will go for a larger capacity battery when the budget allows it and give that a go.

Hi Trev,
the current output of the dc motor controller is limited to 25 amps per motor.
that would make it 690 Watts or .925 Hp at maximum load.
You might be onto something here , I will put an ammeter into the battery and alternator circuit on the weekend (weather permitting ) to capture actual currents and volts under load.

Hi Gambler,
Two things I would try, Firstly, go to 12N24 ride on batteries, they will have much more reserve current capability to get up steep slopes and may be enough to compensate for the power drain under load. If it still struggles, replace the wheelchair motors with windscreen wiper motors. Very early motorised wheelchairs used them before purpose built motors became available. They have a worm drive reduction gear built in so could probably be used as direct drive to the tracks. The worm drives also have a natural brake ability when powered off and could provide a bit of added safety on those slopes.

Gambler, I'm also wondering how much drag is being put on the wheels with the motorcross tyres stretched like that. Did you cut the beads off the tyres? Are you able to turn the tracks with the drive motor disconnected. Could try the battery out of your car, just to see if we are on the right track. Amazing machine and so close to victory

Hi Trev,

I used the wheelchair motors over wiper motors for their durability and shaft size.
these motors are a lot more robust and were designed for heavy going.
after another short run today I noticed that the travel speed is not really slowing whilst climbing.
As mentioned earlier I will attempt to take some current measurements on the weekend and hopefully get to the bottom of this.

Hi Norm,
the side walls have been cut off the motocross tires to gdt them to flex over the drive wheels. There is quite a bit of tension on the system however, it moves freely and I can easily turn it by hand.

I think i will install a fully charged automotive battery on the weekend , disconnect the drive belt to the alternator and head for the slope to find out whats going on. This should separate the good from the bad

Well who would have guessed that 'less' can be more

Performed a load check on the system and found that all power was being supplied by the alternator and almost no current from the batteries.
No wonder the old Honda couldn't keep up on the slopes.

I have removed the alternator (temporarily) and fitted a car battery which i will give a good run tomorrow to see how it goes.

If the battery is strong enough to drive up the slope i might install a remotely operated relay to turn off the alternator circuit before i hit the slopes head on. That way there won't be any load from the alternator on the engine(apart from the free wheeling of course).
Once i have reached the top of the hill i can re-energize the alternator and then keep going.

I've been quietly watching your thread and tip my hat to you. Looks like a bucket of fun. Have you considered using a clutched pulley to drive the alternator like what is used to drive a cars air con? I reckon it'd be a simple way to remotely activate the alternator.

Hi slashnburn,

I had considered a clutch setup for the blades similar to a ride on in the early stages of this build but didn't go through with it due to the costs.
As I would need a relay to operate the clutch it might as well operate the alternator circuit electrically.
I just have to be careful not to switch the relay under load.

Hi Gambler, you may find with the bigger capacity battery the alternator probably won't have to work as hard,it should only have to top the battery up, you will be soon able to see if this is the case. You are nearly there, should be able to go into production soon, I see a market for these.

Hi Gambler,

also been watching, with a bit of awe.

Here's my 5c worth of pure untested hot air...

I note what you said about switching the alternator electrically. Note switching the alternator out of the charging circuit is a no-no, it's like disconnecting the alternator from the battery in a car and will lead to damage. Not to mention you're switching large current loads (Well, I've tested this part, on my car!).

However switching the alternator's exciter circuit is much less current and will de-energise the alternator without causing any charging-circuit breakage. This is what the regulator does anyway when no current is required. You can do this with a remote-controlled relay for testing to begin with, perhaps an auxiallary switch on your remote control. If it works, simply configure some small circuit that de-loads the alternator when the motor current exceeds x Amps.

This, of course, does not take away the base mechanical friction load, only the charging load.

Hi Patrick,
I appreciate your concern regarding the switching of the load circuit of the alternator.
I don't operate an exciter circuit on this alternator.
Much to my surprise it wasn't needed when I first hooked it up being armed with a bit of wire and an alternator warning lamp. If you spin this thing fast enough it makes power on its own.
The regulator is built into the alternator and not readily accessible so disconnection of any control circuit will be difficult.
What damage do you think could occur if I was to open the charging circuit?
My plan was to open it whilst the mower was stationary to minimize the arcing of the switched dc current.




NormK
I am not planning to go into production with this as I have lost already too much sleep during this build.......lol

Hi Gamber,

Oops, remembering my "older-school' alternator, with semi-external regulator/brushes! Your alternator simply has everything inside the alternator casing. So no easy exciter switching.

Now the battery provides a constant large 'load' for the regulator to work against and helps smooth any AC ripple. Without the battery the alternator becomes an ineffectively controlled and underloaded AC (and DC) generator.

What usually happens when you disconnect the alternator from the battery (in a car) is the considerable electromagnetic energy stored in the alternator has to be dumped somewhere, usually into (either) the delicate car electronics and/or the alternator's diode pack. Either way, something gets damaged. With no car connected, it'll be internal alternator damage.

Oh, by the way, newest cars may actually be controlling the alternator, through the ECU now...so the newest alternators may have that input (and several other input/output wires) again.

One more thing: how about a smaller alternator? 20A or so should do. Motorcycle, maybe even a quad or similar?

Sounds like the alternator is able to keep up the current so that not the drive problem. The problem sounds more you simply don't have enough hp to operate the alternator and blades at the same time. The theory that it is only using about 1 hp is gong to be off as it is not a lossless system. You may be needing as much twice that or more depending how efficient the the conversion is.

As the electrical load increase so does magnetic loading from the alternator rotor that must be overcome and a GCV160 is already taxed by the grass cutting even on a regular walk behind mower sometimes. You probably will find something in the order a 240cc or larger is going to be needed; although, you could try a 190cc and see what the results are.

I know you said you don't put on a larger engine but sometime it is necessary. That what research and development is all about. It finding out what will work and what won't.

These are just my opinions so just take into consideration only as you would need to use your best judgement on what will work.

Hi Gambler, I have spent some time discussing this with my son in NZ he is a sparky and we believe the problem is the alternator is wired incorrectly, it can't work the way it is. We need a close up pic of the alternator terminals, as it appears it is trying to push power in 2 directions and it can't work. For starters you must run a switched exciter wire. The output wire from the alternator must go directly to the battery positive. The drive motors must be wired from the battery, not from the alternator. If you wire it this way you should see a charge rate at the battery of about 14 volts. Check this and lets know how you get on

Just to go over this again, what I believe is happening is you are trying to push power into the battery in one direction in the same wire that you are using to drive the motors which wants to run power in the opposite direction in the same wire. Might work with A/C but I don't think it will work with D/C. I probably would have used this wiring idea because it reduces the number of wires you have to run, but this proves it is very easy to come unstuck

Hi AVB,
as per my original post (and I believe you agree) it is becoming more and more apparent that this engine is undersized for the application. For the moment it will have to do as the yearly budget for this little project is depleted.
However I will keep an eye out on gumtree and fleabay , who knows I may pick up a bargain somewhere.

cheers

Hi Norm,
regarding the alternator and its connections let me assure you that it does make 13.8 volts of dc power without the need of an exciter circuit.

I have drawn up the circuit arrangement and included what I believe to be the current flow directions or lack of over 2 scenarios.

Scenario 1( sketch 2)would cover running the unit after it has been sitting for a while with tne battery voltage below 13.8 volts.

Scenario 2 ( sketch 1 )would cover the unit been running for a while and the battery voltage caught up with 13.8 volts.

I can not see how changing the connections would alter the operation.
Maybe your son is a better leckie than myself or I am ready for retirement.....lol

anyhow here are the circuits



cheers

Gambler, I still can't see how you are charging the battery, you are bypassing it and hoping a bit of power will stick in them. Of course you will get 13.8 volts, you can pick that reading up anywhere on any positive wire but it is not going into the battery.You have to put power into the battery and then draw the needed power from the battery, make the battery do the work, as it is at the moment the battery is having a holiday. As it is wired of course you don't need an exciter wire because you already have it wired into the circuit.You are combining your charge wire with the exciter wire. You have to go back to the basics as per a car it was fitted in. Alternator charge goes to the battery, the exciter wire brings the alternator into circuit, the alternator charges the battery and everything is then fed from the battery. This is not the way you have it wired.My son looked at the early pic of it with the 2 batteries in place and his immediate reaction was it won't work. If you would like I have a mate who lives 5 mins away and he is an autoelec and I can flick him the drawing and get his opinion and go and discuss it with him. I'm not saying you should retire, but often it is the simple things that can trip us up.