Battery tender

[caplack]

Schumacher tender

I just installed a Schumacher 1.5A tender and don't know if it is really working. The manual, and their technical adviser, say the same thing which is: "Green LED indicates Power ON @120VAC. When battery is fully charged the RED LED should go ON indicating a FULL charge and now in maintenance mode."
Every time I check, only the Green LED is ON and my DVM shows a 12.5Vdc charge in the battery.
In performing some bench testing, I attached a portable charger's output to the tender and the RED LED came on. This was at ~14Vdc.
Then while leaving the tender hooked up but not attached to an AC supply, I put a charger on the battery at 2A. It appears that this tender cycles at around 13Vdc. <13V RED LED off; >13.1V RED LED ON.
If this unit is working properly, shouldn't I sometimes sooner or later see the RED LED on, or is the drain on the battery (computers, memory, etc.) greater than the tender can replenish. Does not sound right to me.
Thanx.....caplack

 

[Rowdy1]

Maybe.........

It might depend on the brand. On all mine, the red light means the unit has power/is plugged in. There are other lights, amber showing it's charging and green when it's fully charged and they are labeled as such. As long as mine are plugged in the outlet, the red light stays on. :confused

 

[njlouc]

Do the math.
I will guess that the normal battery is ~ 55(??)ampere-hour capacity.
So if you are ~50% charged, your 1.5a will take ~18 to maybe 22hours to come up to peak. If it is cold and if you have the car (computer etc.) connected you can add more.
Also I suspect that if you have enough drain it just cant keep up to charging then maintaining.

So that little guy should be put on an already charged (100%) battery to start.

So it is possible that you havn't given it enough time???

 

[timfitz63]

... When battery is fully charged the RED LED should go ON indicating a FULL charge and now in maintenance mode."
Every time I check, only the Green LED is ON and my DVM shows a 12.5Vdc charge in the battery...

I know in the case of the Battery MINDer Plus, which I use, if it cannot bring the battery up to a full charge (in its case, 14 volts), it will not enter its maintenance mode. If you're only getting to 12.5 volts, perhaps that's part of the problem...?

With the Battery MINDer Plus, you can manually "force" it into the maintenance mode; perhaps you can do the same with the charger you're using...?

 

[TooFast]

I'm with killian and Toms01. Because of where I live mine is down for six months every winter and I've always used a battery tender. The battery is now 10 years old.:cool

And when I do replace the battery it will be with an OEM Delco not one of those "trendy now" jobs.:L

I have to agree with Remo, Killian and Toms01...tender for Oct through April and always use DELCO original equipment replacement.

 

[caplack]

Schumacher Battery Tender

Thanx for all the responses.
The model is an SE-1-12S, or SF-1-12S.
I left it plugged in yesterday while monitoring it. The DVM eventually read ~14Vdc and then the RED LED on the tender went ON. I was glad to see that. After about 20-30 seconds I started to lower the hood (which all this time had the hood lite ON). Strangely, when the lite went out, the DVM immediately dropped to ~13Vdc and slowly continued to go down until the RED LED went out around 12.8Vdc, at which point it slowly started to climb back up.
Now, I would not expect the "as measured" battery voltage to drop when the additional "load" of the ON hood lite was removed. If anything I would expect just the opposite.
I did further measure the output of the tender and it is ~1.45A, so it is putting out the proper current. Fortunately the AC current draw is ~200-300mA so I'm not concerned about "overfeeding" the local power company's profits.
It would seem that the "full charge" voltage is ~14V and the RED indicator does not kick OFF until it drops to about 12.8V. Here again I would suspect that the RED LED On/Off triggering would be much closer than 1V.
After all this, the battery seems to be stabilized at the very least around 12.6V with sufficient current to readily crank the engine. I'll see what happens
Thanx again to everyone's input.