P700 Charging both batteries thru the isolator

[Reloder28]

I hooked a trickle charger, 750 ma, to my starter battery. Initially it charged only the primary battery. Evidently, once the charge voltage came up to the isolators prescribed connection voltage, the isolator connected & began to charge both batteries. I never considered this & I’m not bothered about it. Actually, it is a benefit. I just never considered that going into it.

It did get me to wondering if I should isolate the batteries during charging? What do you think?

 

[Admin]

 

[Mark in Northern Iowa]

Hook up the charger to the secondary battery and watch what happens.......same thing. The isolator works either way. But, most people hook up chargers to primary/starting battery. Why? Because if the secondary battery has a flaw/bad cell, it possibly won't get charged enough for the isolator to connect and charge the primary/starting battery.
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So, to answer your question, I would say let the isolator do it's job, it does it well. 👍
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Have a good day

 

[DRZRon1]

exactly

Hook up the charger to the secondary battery and watch what happens.......same thing. The isolator works either way. But, most people hook up chargers to primary/starting battery. Why? Because if the secondary battery has a flaw/bad cell, it possibly won't get charged enough for the isolator to connect and charge the primary/starting battery.
.
So, to answer your question, I would say let the isolator do it's job, it does it well. 👍
.
Have a good day

exactly......

 

[Remington]

I hooked a trickle charger, 750 ma, to my starter battery. Initially it charged only the primary battery. Evidently, once the charge voltage came up to the isolators prescribed connection voltage, the isolator connected & began to charge both batteries. I never considered this & I’m not bothered about it. Actually, it is a benefit. I just never considered that going into it.

It did get me to wondering if I should isolate the batteries during charging? What do you think?

Mine is hooked up the same way for the last 4 yrs on my P1K5 and my X2. What @Mark in Northern Iowa said is correct. Just plug it in and dont worry bout it.

 

[Scoop]

The isolator is doing exactly what it's designed to do, actually. But in reverse.

When you are using power from the AUX battery, the isolator disconnects the two batteries if/when the AUX battery falls below a specific voltage (cut out voltage for the UTV-SBI-18 is 12.9V, with a small tolerance). This is done to preserve your primary battery, responsible for starting and shifting, in the event you run your secondary battery down (e.g., lights, radio, etc.). Basically, it's making sure you have juice in the primary battery to start and get back to camp/home.

When charging, it's doing the reverse. It only connects the two batteries when the source battery has sufficient voltage (cut in voltage is 13.6v, with a small tolerance), then the other battery starts to charge.

Some say to put your charger on the side with the PRIMARY battery, so it gets charged first. I put it on the AUX battery.

My reasoning is that the AUX battery, which is used for all your fun stuff, is more likely to be drained lower than the primary, so it benefits you more to charge THAT battery first. Theoretically, the primary should already be in good shape because it's only being used for starting, shifting and the few OEM items on the bike, while the AUX (in my case) has a bunch of crap (all my aftermarket goodies) running off of it.

This would make even more sense if you only put the charger on the bike for very short periods of time -- if you only put the charger on the primary and it only reaches the cut in threshold shortly before you remove it, that AUX battery won't get a chance to charge up.

This is all anecdotal, of course. Realistically, as long as you're going to leave the charging source on long enough for both batteries to top off, then it doesn't really matter which side of the isolator you connect the charger to.

 

[Reloder28]

I really appreciate the input. I'm on the same page with y'all. The reason I ask is, I believe I may have a parasitic draw. The ONLY reason I think that is due to my voltmeter display at startup. After resting for days/weeks, the starter battery voltage reads 2-3 volts lower than the auxiliary. The parasitic draw concern is based solely on that alone. I replaced the brand new Lithium starter battery with an AGM last week. I used the Honda to do some heavy winching for the first time recently and the aux battery performed admirably. I have installed an on-board 1 amp Genius trickle charger with ext. cord input on the seat bulkhead. Sure makes charging easy.

I am planning a proper diagnostic current draw test in a couple of days.

 

[Reloder28]

Update:
The problem was the new Lithium battery I bought from Amazon. It would not hold a charge fresh outta the box. But, too late to get a refund. Imagine that.

 

[Smitty335]

Update:
The problem was the new Lithium battery I bought from Amazon. It would not hold a charge fresh outta the box. But, too late to get a refund. Imagine that.

Now how's that, were you supposed register you battery with the MGF?

 

[Scoop]

IIRC, there is a specific P/N for the True Am isolator if you have a Li-ion battery.

 

[Reloder28]

Now how's that, were you supposed register you battery with the MGF?

Don’t know what MGF is.

 

[Reloder28]

IIRC, there is a specific P/N for the True Am isolator if you have a Li-ion battery.

That’s interesting. I see that now. Too late, though. I’m going to stay with the lead acid AGM. I have had zero issues with it. Thank you for the tip, however.

 

[Scoop]

Don’t know what MGF is.

Likely a typo, likely meant manufacturer (MFR). MFG = manufacturing.