My Renault Ambulance is ex army and is 24v I just rewired the dash before it would have needed to be a fire engine. My problem is the wiper motor worked to a point before but now after the rewire the motor is going berserk and it threw it's connecting nut off in disgust. it's a directly connected motor to the linkage inside the cab. With an on off toggle type switch Now my question is can I get a dial type rheostat to fit in the dash that will control the speed of the motor. do I need to know the wattage of the motor? Any advice would be good thanks
- Thread starter marfyboy
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MattF
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That's my thought too. Likely how it was wired up originally if it's going nuts now.
that's a possibility. as for how it was originally wired nothing has changed wires labelled renewed and relabelled and refitted?
AndyStobbs
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Use the resistor pack from a blower motor if you must have variable speed. Be mindful it must be situated in moving air for cooling.
Bill Edwards
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Don't.
This causes problems for the batteries and will eventually damage one, they don't charge up right. A common mistake, but when you need 12v from a 24v vehicle you need to find another way to get it.
I would have said that a cheap PWM controller easily available off eBay might work nicely, or it could be done with a suitable rheostat.
Bill Edwards
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I'll try to explain but it's from what I've read and the main thing I took in was the important bit - i.e not to do it.
It seems that when you charge two 24v batteries together they're essentially one battery - 12 cells all joined together. When you take a feed off just one battery you are, in effect, draining half the battery - 6 cells. But when the system is charging it cannot put more charge into the battery that is more drained so the two batteries can never both be at the proper level of charge. This is terminal for the long, healthy life of a battery. I think it will leave one battery undercharged while overcharging the other as the alternator will sense a low voltage.
I gather that when changing batteries on 24v systems you are best replacing them as a pair (i.e two new, identical makes) so they will go through life as a pair. Lots don't and will just replace a single battery because the vehicle won't start, but it is bad to do this. Ironically lot of farmers do this when when what they could easily do if they had some understanding/knowledge of these things is to use the good battery for another 12v vehicle but they don't!
It seems that when you charge two 24v batteries together they're essentially one battery - 12 cells all joined together. When you take a feed off just one battery you are, in effect, draining half the battery - 6 cells. But when the system is charging it cannot put more charge into the battery that is more drained so the two batteries can never both be at the proper level of charge. This is terminal for the long, healthy life of a battery. I think it will leave one battery undercharged while overcharging the other as the alternator will sense a low voltage.
I gather that when changing batteries on 24v systems you are best replacing them as a pair (i.e two new, identical makes) so they will go through life as a pair. Lots don't and will just replace a single battery because the vehicle won't start, but it is bad to do this. Ironically lot of farmers do this when when what they could easily do if they had some understanding/knowledge of these things is to use the good battery for another 12v vehicle but they don't!
this thing is 51 years old it wasn't the wiring that was the problem it was some butcher had hacked the light black out switch out and left bare wirers hanging or just twisted togetherI know FA about electrickery, but even I know this.
Renault=french
French=dodgy electricks
<spelling intentional>
bigegg
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I don't know a lot about vehicles, but I know this:
Any of the three french manufacturers: electrics + trim.
Ford: rust
Vauxhall: sensors + engine auxilliaries
Ford: Rust
Italian: Everything
Japanese: not a lot
german: not a lot for first 4 years, then ££$£$£$£$£$£$£$£$£
ford: rust
Any of the three french manufacturers: electrics + trim.
Ford: rust
Vauxhall: sensors + engine auxilliaries
Ford: Rust
Italian: Everything
Japanese: not a lot
german: not a lot for first 4 years, then ££$£$£$£$£$£$£$£$£
ford: rust
BrokenBiker
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Don't forget "Lucas Electrics" have 2 settings :- Dim and Flicker
and my personal favourite....
If you can't fix it with a spanner or hammer then you have an electrical problem.
Bill Edwards
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BrokenBiker
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they all go that way in the end, this one should be no different haha
500e
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bigegg
Scream Not Working Because Space Make Deaf
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You always end up with someone ruining a perfectly good thread by answereing the question.
and to finish it off
a bit more digging around found the reason for the speed increase
when I rewired the cab I removed two tyraps and a grommet holding the motor from the bodywork, with a bolt ,reinstating the chassis earth 24 volts. found a strapper running from motor negative to one side of a battery. so a cheap pwm has been ordered from fleabay. At least this should give me a reasonable speed without everything falling apart.
a bit more digging around found the reason for the speed increase
when I rewired the cab I removed two tyraps and a grommet holding the motor from the bodywork, with a bolt ,reinstating the chassis earth 24 volts. found a strapper running from motor negative to one side of a battery. so a cheap pwm has been ordered from fleabay. At least this should give me a reasonable speed without everything falling apart.
