[AT] OT Buck-Boost convertor for charging auxiliary battery

[James Peck]

Is your Belarus keeping the auxiliary battery charged now?

From: AT <at-bounces at lists.antique-tractor.com> On Behalf Of Cecil Bearden
Sent: Friday, January 18, 2019 8:10 AM
To: at at lists.antique-tractor.com
Subject: Re: [AT] OT Buck-Boost convertor for charging auxiliary battery


To update the VC problem, after measuring the voltages and looking at diagrams again I am beginning to understand the system, but I don't understand the reasoning behind it.   In a nutshell, the alternator charges the main battery, at the same time the VC charges both batteries in series at 24V.  Definitely something lost in translation in their engineering.

All I can think is What the H*#L ?!?!?!?
I have found a 24V alternator of the same size and connections.

Cecil
On 1/16/2019 10:59 PM, Cecil Bearden wrote:

Guys:

I need some help with the wiring on my MTZ 1220.  in an earlier post I mentioned that this voltage convertor (VC) will not keep the auxiliary battery charged.  The factory furnished a new VC and the dash warning light indicates that it cannot keep up with the battery when using the lights, or the cab fan.  Perhaps the alternator is not providing enough current on the main battery, or the signal from the alternator is not triggering the VC to operate.
I have tried to convince the factory to change over to a 24V alternator and use one battery for the 12V accessories.   The alternator is an ISKRA brand  and a one wire Delco is not easily mounted the way the ISKRA is..  The only wiring diagram of the alternator shows a battery connection and the sensor connection to the alternator.  The W terminal is not shown to be connected in the diagrams I have.   I need to know if the ISKRA alternator uses the battery terminal to sense the voltage for the regulator as a one wire delco does, or if it need a wire to the W terminal to turn the alternator on.   If it uses the Bat terminal then changing to 24V won't be a big deal.  If the W terminal or another needs the 24V input, then I will have to install a relay to turn on from the ignition switch as the ignition switch is on 12V.   the starter and the glow plugs are 24V.  To change over to the 12V system as the factory has suggested, will require changing 6 glow plugs, the starter, alternator, and new cables.  My solution only requires changing the alternator.

I know some of you guys are much better at reading electric diagrams than I am.   I can usually wire things up without any trouble, but sometimes wiring diagrams give me trouble.  If you could take a look at the attached, I would certainly appreciate it..

Cecil







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