TC3 charger

[Xaugievike]

Alright guys, here's my latest question - this time regarding my charger (total charge III).

As I understand this thing is supposed to have an automatic shutoff. And as I understand there is a circuit board inside it that can go bad, and that one of the "field" fixes was to bypass the circuit board, but the effect of which was to lose the auto shutoff capability. I've read that one quick way to test this is with the charger disconnected from the cart to plug the charger into the wall. If it turns on (and starts the 'hum') then the circuit board has been bypassed. Is this accurate? I haven't had a chance to open it up yet to see it with my own eyes, but mine does come on when plugged into the wall and not the cart.

[Xaugievike]

Hmmmm......I hear crickets.

Ok, so my thoughts - the down side to the charger not shutting off is/would be that it would boil the water out of the batteries. So if I monitor the state of charge, would it be feasible in the short term to take the cart off the TC3 once I read the 44-46 volts on my DVM (where it's supposed to shut off anyway). Then can I maintain the charge via my 12v battery tender (rotating it across pairs of batteries every couple of days). Do I have to disconnect the pack to do the 12v charger or can I just clamp it on already connected pairs?

Again, I'm just trying to limp this situation for a couple of weeks (to get through a camping trip)

[JohnnieB]

If your TC III hums when plugged into the wall outlet and not the cart, the relay on the control board has been bypassed.

If you plan to use your cart much while camping, the battery tender probably won't be able to keep your batteries charged, especially if it is 12V and you have to rotate which batteries are being charged. (Not enough hours in the day)

Typical charge time using a TC III (or its brethren) is about 4 to 6 hours, but letting it run for 8 to 10 hours won't hurt the batteries.
In fact, some legacy chargers just had a timer and the instructions said to set to "ON", so the charge cycle lasted 12 hours.

Added top view so you can see there is no control board, just the timer.

[Xaugievike]

Thanks for your reply johnnieB

I should have been clearer. I haven't left for that camping trip yet. When I use the cart out there I'll still rely on the TC3 to get things juiced back up. My question is more for the interim. Can I use the tender to maintain my charge for now, and if I do so do I need to disconnect the pack entirely, or can I just rotate the tender across pairs of bats every couple of days to maintain.

[JohnnieB]

You don't have to disconnect the batteries to use a 12V tender or charger.

However, you can also just run the TC III as a manual charger every few days.
Self discharge rate is typically about 1% per day.

If the battery tender was 36V, I'd say use it, but switching between battery pairs is a royal pain and it would be easier to charge the whole pack together periodically.

[Xaugievike]

Thanks for your time and help, JohnnieB