B&S 28N707 Not Charging - Charge Light Stays On

[the_scotsman]

I just acquired my very first ride on mower! I'm over the moon! I got it cheap as it has an electrical issue. It won't charge the battery. Apart from that, she's in great condition!

It's a Victa 4215HXT, with a B&S 28N707-1115-E1.

The charge indicator light on the dash stays on, even with the engine off and key off.

Looking at the wiring, someone has added a second diode in the wiring at the ignition key. I think they assumed the diode on the stator output is dead, but checking it with a multimeter, it seems ok. So I removed the "unofficial" diode from the wiring, but this made no difference.

I do see over 14V from the stator output when the engine is running, so it seems ok. And I think I'm seeing over 14V at the battery terminals with the engine at running speed. Reason I say think, as it's a near dead battery, it's been sitting dead for a few months by the previous owner. I had to jump start it, so it's needing a new battery, and so those battery readings won't be giving the best indication. When I probed it after starting the engine, it climbed slowly but steadily up from 13.5 to over 14V.

I have the full wiring schematic for the ride on so I can trace everything out, but this isn't always easy.

But I'm just wondering if anyone would have any idea why this is happening. Why it's not charging, and why the charge light is always on, even with the engine switched off?

Thanks!

 

[Boudreaux In Eunice La.]

Voltage regulator might be bad causing extra voltage in the system. That extra voltage is bad on electric Pto's also......

Like you said the battery might need replacing because of a dead cell or two.

How did you check the diode with continuity beep or ohms ? If the diode is blown it not beep either way. Or if it is shorted it will beep both ways. A diode is a fuse that only lets voltage go one way and not the other. If the original one is bad then the new one they put on will not matter in any way.

Hope this helps

 

[Boudreaux In Eunice La.]

I see you are from Australia. We have a very good tech on here from the East side. He should chime in soon ~!~!

 

[bertsmobile1]

The Victa 4215 HTX is a rebadged Murray O42595X88 which should help every one work out what we are looking at.
IT is the one with a single direction Peerless hydro hooked up to a F & R tranny
These were well before my time as a mower mechanic so my exposure to them is limited.
Unless it has been upgraded it will be fitted with the dual circuit unregulated alternator so having a climbing voltage up to 15 V is quite normal for them.
The second diode near the stater switch should be there,
It is to stop the battery back feeding through the charging light which is exactly what your mower is doing.
If you remove the light globe it will stop discharging the battery.
Usually the alternator DC is hooked up to an A terminal on the ignition switch and the lights on an L terminal or to an independent toggle or rocker switch.
By this means, the alternator is disconnectes from the battery when the ignition is turned off so the battery can not back feed into the alternator.
On this model they used a cheaper switch with the fuel solenoid hooked up to one A terminal and the lights hooked up to the other A being there is no L terminal.
The alternator DC output is spliced into the power feed to the switch ( the B = battery ) terminal which you can get away with provided the diode in the stator plug is good.
However they decided to put a generator light in the dash in place of a volt meter ( cheapness again ).
A voltmeter passes no current so it can be placed between the alternator DC output wire and earth.
But a globe does pass power so you need the diode to prevent the battery power arriving at the B terminal where there is a double spade terminal then passing back down the other wire and through the generator light to earth.
SO either the 2nd diode is dud or was wired in backwards.
It should flow towards the switch and choke away from the switch.
If that tranny does not have a small square plate facing the rear of the mower, you would be well advised to take it out, drain it and refill with 20W 50 fully synthetic oi.
The drive unit is no longer made, there are no replacement parts available for it and it is very difficult to fit another drive because that style is totally obsolete.
I have 2 Murray Sentinentials with the same drive sitting the graveyard with dud hydros and another Victa which is also dubious .

 

[EngineMan]

Voltage regulator might be bad causing extra voltage in the system. That extra voltage is bad on electric Pto's also......

Like you said the battery might need replacing because of a dead cell or two.

How did you check the diode with continuity beep or ohms ? If the diode is blown it not beep either way. Or if it is shorted it will beep both ways. A diode is a fuse that only lets voltage go one way and not the other. If the original one is bad then the new one they put on will not matter in any way.

Hope this helps

A diode is Not a Fuse, its an electronic version of a check valve, it will allow an electric current to pass in one direction (called the diode's forward direction), while blocking current in the opposite direction (the reverse direction). fuse's do not do that. just saying......

 

[Boudreaux In Eunice La.]

I know its not a fuse I was a electronics tech on 2 way radios for 15 years.

I was trying to explain in a simple layman term. I left out a few words. I should have said a diode IS LIKE A FUSE. They do blow when you hit voltage on them the wrong way. I did say that in my post..