P1000 Trickle Charging Dual Batteries

[cattmann]

I know this topic has been brought up many times but I cant seem to get an answer to my issue.When trickle charging my batteries I installed the charger on my Primary Battery. Not long after the isolator lights up because my primary battery is new and fully charged. My question is why doesnt my trickle charger ever go into float mode. It is constantly in charge mode? My second battery is fully charged also.I had previously charged each battery up seperate before installing the new charger.

 

[Admin]

 

[Vikes79]

I know this topic has been brought up many times but I cant seem to get an answer to my issue.When trickle charging my batteries I installed the charger on my Primary Battery. Not long after the isolator lights up because my primary battery is new and fully charged. My question is why doesnt my trickle charger ever go into float mode. It is constantly in charge mode? My second battery is fully charged also.I had previously charged each battery up seperate before installing the new charger.

Likely because both batts connected are still likely below the fully charged threshold. Connecting battery’s together ultimately pull the highest bat down like water flowing from a higher level cup to a lower level cup.

mine will charge the primary, then eventually the aux until both are fully charged…then it will just go to maintenance mode.

 

[cattmann]

I can’t explain why your charger does that.

mine will charge the primary, then eventually the aux until both are fully charged…then it will just go to maintenance mode.

what is the output of your charger? Mine is .800ma.I tried my 2 amp charger and it stayed on all day

 

[Vikes79]

what is the output of your charger? Mine is .800ma.I tried my 2 amp charger and it stayed on all day

I went back and edited my original post.

on the low side I measured something like 1 A so for maintenance mode and up to 8 A on charge mode. I don’t use my big charger on my small batteries.

i would bet that eventually your charger gets it done, just needs time. What happens when you leave it overnight?

I run my charger at times due to my plow and light bar plus heater use in the winter. If I’m plowing in the dark I’ll wipe out the aux battery in a hurry…especially if it’s not fully charged before I start plowing.

 

[cattmann]

I went back and edited my original post.

on the low side I measured something like 1 A so for maintenance mode and up to 8 A on charge mode. I don’t use my big charger on my small batteries.

i would bet that eventually your charger gets it done, just needs time. What happens when you leave it overnight?

I run my charger at times due to my plow and light bar plus heater use in the winter. If I’m plowing in the dark I’ll wipe out the aux battery in a hurry…especially if it’s not fully charged before I start plowing.

I havent left it on that long as I didnt want to over charge one or both batteries.I was told not to use a high amp charger on small batteries.I checked my charging system on my machine and it shows 6 amps at idle.I never drew my batteries down much since owning the machine but I did have my factory battery go bad just lately .The machine is a 2021 and it was 1 month over the warranty.Does your isolator stay lit up all the time durring charging?

 

[Vikes79]

My isolator stays on as long as the charger is connected, even in float mode.

As long as your charger is smart enough to monitor i really doubt you’ll over charge your batteries.

 

[bumperm]

My isolator stays on as long as the charger is connected, even in float mode.

As long as your charger is smart enough to monitor i really doubt you’ll over charge your batteries.

Correct.

If you are using the True isolator, if one battery is discharged, it will not "pull down" the other battery to a discharged condition. The True's isolation feature prevents that from happening.

True suggests connecting an external charger to the aux battery. Their logic being that would be the battery that is most likely to be discharged in use, as the primary battery has first dibs on the engine driven electrical system during operation. The main battery will only "help out" and send current to charge the aux battery when the main battery gets to about 13.3 volts or more. In practice, it's not critical which battery an external charger is connected to, as once that battery gets to 13.3 the blue light comes on and the other battery starts charging as well. The True works in both directions to share charging.

 

[Scoop]

The cut in threshold for the UTV-SBI-18 is 13.6V, not 13.3V. Cut out threshold is 12.9V. I got this directly from Tru Amalgamated.

Even when the tender is in float mode, the blue light on the isolator will be on when the source battery is at or above 13.6V. Most trickle chargers are running between 13.2V and 13.8V in float mode.

 

[Remington]

Does your isolator stay lit up all the time durring charging?

Yup, mine does

 

[Hondasxs]

The cut in threshold for the UTV-SBI-18 is 13.6V, not 13.3V. Cut out threshold is 12.9V. I got this directly from Tru Amalgamated.

Even when the tender is in float mode, the blue light on the isolator will be on when the source battery is at or above 13.6V. Most trickle chargers are running between 13.2V and 13.8V in float mode.

Give or take..
My bench test on a dozen so units show between 12.7-12.9 and 13.3-13.5. Varying.

Trickle chargers also very.
Some will not get to the 13+ range before entering FLOAT mode. (blue light never comes on)
And others will get to 13+ then float above 12.8. (blue light on, stays on)

 

[Scoop]

Give or take..
My bench test on a dozen or units show between 12.7-12.9 and 13.3-13.5. Varying.

I got my figures from electricalacademia.com (for what it's worth). Mine stays on when trickle charger is in float mode, so either it's => 13.6V or the isolator cut in threshold may be somewhat liberal.

After the current to the battery reaches some lower level, the charger enters the float stage.

The float stage is the final maintenance or trickles charge stage with the purpose of offsetting any self-discharging of the battery. Typically, the float voltage is from 13.2 V to 13.8 V at 25° C.

During the float stage, the float current can be pulsed to keep the battery fully charged. During all three stages, the charger controls the voltage and supplies the current that is required to optimize battery life.

 

[bumperm]

Give or take..
My bench test on a dozen so units show between 12.7-12.9 and 13.3-13.5. Varying.

Trickle chargers also very.
Some will not get to the 13+ range before entering FLOAT mode. (blue light never comes on)
And others will get to 13+ then float above 12.8. (blue light on, stays on)

It's probably a good idea to use a trickle charger that takes the voltage high enough to get the True's blue light to come on and thus charge the second battery through the True. Otherwise, if blue light off and stored for long periods, you could have the second battery not being well maintained.

Both chargers I've used keep the blue light on, but it's worth checking. I also installed a momentary push button to apply ground to the ground terminal of my dual voltmeter. That way I can quickly check voltage of both batteries without turning on the ignition key. (This also has the advantage of displaying "unloaded" voltage, while using the key will drop the displayed voltage of the main battery due to loading.)

 

[Scoop]

It's probably a good idea to use a trickle charger that takes the voltage high enough to get the True's blue light to come on and thus charge the second battery through the True. Otherwise, if blue light off and stored for long periods, you could have the second battery not being well maintained.

As long as your charger gets the primary above 13.6V at some point, then doesn't let it get down below 12.9V when in float mode, it should keep the batteries connected and both charging.

 

[cattmann]

Correct.

If you are using the True isolator, if one battery is discharged, it will not "pull down" the other battery to a discharged condition. The True's isolation feature prevents that from happening.

True suggests connecting an external charger to the aux battery. Their logic being that would be the battery that is most likely to be discharged in use, as the primary battery has first dibs on the engine driven electrical system during operation. The main battery will only "help out" and send current to charge the aux battery when the main battery gets to about 13.3 volts or more. In practice, it's not critical which battery an external charger is connected to, as once that battery gets to 13.3 the blue light comes on and the other battery starts charging as well. The True works in both directions to share charging.

have a .500mA and a .800mA trickle charger.Will the isolater let these low amp chargers go into float mode

 

[cattmann]

I know this topic has been brought up many times but I cant seem to get an answer to my issue.When trickle charging my batteries I installed the charger on my Primary Battery. Not long after the isolator lights up because my primary battery is new and fully charged. My question is why doesnt my trickle charger ever go into float mode. It is constantly in charge mode? My second battery is fully charged also.I had previously charged each battery up seperate before installing the new charger.

Great info everyone thanks again

 

[bumperm]

have a .500mA and a .800mA trickle charger.Will the isolater let these low amp chargers go into float mode

Yes, maybe, maybe not! The current capacity of the charger has not a lot to do with the charging voltage of the charger. If the charger voltage can go to, or higher than, 13.6 volt (or so) then it'll work.

 

[cattmann]

Yes, maybe, maybe not! The current capacity of the charger has not a lot to do with the charging voltage of the charger. If the charger voltage can go to, or higher than, 13.6 volt (or so) then it'll work.

so what takes place if my charger is in charge mode constantly

 

[bumperm]

so what takes place if my charger is in charge mode constantly

Some older (okay, very older), or dirt cheap (Harbor Freight) chargers that are not "smart" and don't have a maintenance or float mode, can overcharge batteries and potentially damage them. If that's what you have, buy newer. If you are not in a hurry, have plenty of time to charge, and rarely deplete your batteries way down, then a 1 or 2 amp charger (Battery Tender or some other reputable brand - there are a number of good ones) should do well. If you often need to charge more depleted batteries, a smart charger that's >4 amps should be more than sufficient.

 

[Scoop]

so what takes place if my charger is in charge mode constantly

What @bumperm was trying to say was that a tender that only trickles half to 3/4 of an amp can keep the isolator connecting the batteries because you don't need a high amp charger to do that. It's about voltage.

What happens when you overcharge a battery? Best case scenario, you kill the battery. Worst case, the acid & water mix boil out, the battery swells and melts, hyrdogen builds up and it becomes a bomb waiting to go off.

 

[cattmann]

Some older (okay, very older), or dirt cheap (Harbor Freight) chargers that are not "smart" and don't have a maintenance or float mode, can overcharge batteries and potentially damage them. If that's what you have, buy newer. If you are not in a hurry, have plenty of time to charge, and rarely deplete your batteries way down, then a 1 or 2 amp charger (Battery Tender or some other reputable brand - there are a number of good ones) should do well. If you often need to charge more depleted batteries, a smart charger that's >4 amps should be more than sufficient.

Both my trickle chargers have float mode.I have another that will charge 2 or 4 amps but not sure about float mode but it does shut off when it shows full charge