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SJ 410 Alternator Wires

Posted: Tue Nov 10, 2020 11:00 pm
by border
This is my SJ 410 Alternator wiring , bit confused as in first pic in the plug there is 3 spade connections, but the Yellow/ white is spliced in to 2 of them and the White /Red to the other. , I have another wire coming from loom with those 2 but it is not connected to anything, it is Black / White.
Should it go to that spade circled on Alt in second pic , or to one of the spades in Plug ??
Need to get myself a Voltmeter thingy.
Thanks,

Re: SJ 410 Alternator Wires

Posted: Thu Nov 12, 2020 8:13 am
by border
Battery is at 12 .7 before starting, then at 14 when idling, is this Normal. ?

Re: SJ 410 Alternator Wires

Posted: Sat Nov 14, 2020 7:01 pm
by Anton
14.1v is the maximum charging voltage for a lead acid battery. Batteries don't operate at the voltage stated on them - that's their "nominal" voltage. They operate at a range of voltages, the "nominal" voltage is usually somewhere in the middle of the range.

I.e. Lead acid batteries operate between about 11.6v (empty) and 12.6v (full). They're unusual in that they can "float" at a higher voltage than their maximum voltage (doing that to Nicd or lithium batteries would kill them). Turn the engine off and the voltage will usually drop to around 12.6v or so. 12.7v is perfectly normal.

Everything is running as it should if you see 12.7v before starting and 14v while the alternator is charging. Lead acid batteries with high discharge capacities (such as car batteries) charge extremely slowly if you don't push them to their float voltage. It's a peculiarity of the way the electrolyte works in these batteries.

Re: SJ 410 Alternator Wires

Posted: Sat Nov 14, 2020 9:58 pm
by border
Anton wrote:
Sat Nov 14, 2020 7:01 pm
14.1v is the maximum charging voltage for a lead acid battery. Batteries don't operate at the voltage stated on them - that's their "nominal" voltage. They operate at a range of voltages, the "nominal" voltage is usually somewhere in the middle of the range.

I.e. Lead acid batteries operate between about 11.6v (empty) and 12.6v (full). They're unusual in that they can "float" at a higher voltage than their maximum voltage (doing that to Nicd or lithium batteries would kill them). Turn the engine off and the voltage will usually drop to around 12.6v or so. 12.7v is perfectly normal.

Everything is running as it should if you see 12.7v before starting and 14v while the alternator is charging. Lead acid batteries with high discharge capacities (such as car batteries) charge extremely slowly if you don't push them to their float voltage. It's a peculiarity of the way the electrolyte works in these batteries.
Thanks Mate

Re: SJ 410 Alternator Wires

Posted: Thu Feb 18, 2021 10:23 am
by DavidB
My old engine had a connector with three pins, the other engine (assume it's a later type) I got had one for two.