I just installed a 140w solar panel and 10a PWM controller. I thought about it, but did not install an on/off switch anywhere in the “system”. The solar panel is connected directly to/from the controller; the controller is wired directly to/from the batteries (4 x 6v).Should I pull one of the wires, or install a switch and cut the solar feed before checking the batteries water level? Sticking my face over those cells as I take off the caps, with current going to them, just doesn’t seem right.Prior to the solar setup, I wasn’t concerned as I have an on/off switch for everything else connected to/from those batteries.

It may be convenient on other occasions to not have the solar on. The controller is connected first to power up and then you connect the array.So the switch should go in one of the array wires.

Switch is OK but you should have a fuse close to the positive battery terminal.Then just pull the fuse.More important to wear eye protection and have clean water near if needed.

Good point/idea. Yes, I do have a 30a fuse a few inches from the positive battery connection. I'll pull that before checking the battery water (and wear goggles).

The easy way - cardboard on the solar.

I put one of these 25 amp manual trip circuit breakers between the charge controller and the module. They have posts that will accommodate larger wire, I used 4 AWG.

Disconnect Solar Before Checking Battery Levels?

25 Replies

64thunderbolt
Explorer II
Oct 04, 2013
I use the old fashioned batt fillers used in Gas stations back in the day. They shut off when filled to proper level. NAPA still sells them. I keep mine filled with distilled water in the trailer. No need to put my face near the batt.
mena661
Explorer
Oct 02, 2013
Yeah, I think we're gonna have to disable MEX's picture posting ability. :B :P
2oldman
Explorer II
Oct 01, 2013
I try to check water levels with a dip stick.. anything except my eyes. The rubber tube on the hydrometer works well as long as you wipe it dry each time.

Electrolyte can bubble when you add water. I've never experienced battery acid in my eyes but I doubt it's any fun.
Tom_M wrote:
An easier way would be to do it at night.
I like that.
KendallP
Explorer
Oct 01, 2013
MEXICOWANDERER wrote:
Lead Acid Batteries Scare Me

Any particular horror stories you'd like share, MEX?

Or were you and your cronies so cautious all those years (decades) that you never witnessed an "incident?"
MEXICOWANDERER
Explorer
Oct 01, 2013
Lead Acid Batteries Scare Me
KendallP
Explorer
Oct 01, 2013
I'm with MEX... and BFL... sorta'. :)

Additionally...

Here's the thing about that supposed low current from the panels; it depends on the setting of the controller. If the batteries are topped, it doesn't take much. If the controller is allowing equalization voltages through (say 14s and above depending on temperature,) you're looking at some Hydrogen under (and over) those caps.

I will pop my caps (carefully) when the bank is hooked to shore and the converter is charging, but we're looking at maybe an Amp at about 13.5V (old 6300 series converter,) so the Hydrogen level should be pretty low.

Short answer? If you don't want to disconnect, in addition to checking for heat, with your safety measures in place, at least check the bank voltage before removing caps.
MEXICOWANDERER
Explorer
Oct 01, 2013
BFL13, my apologies...sorta.

When it comes to working around batteries I am a mad man when it comes to safety.

"Arrest The Usual Suspects" just did not trip my switch. Eye protection is the Holy Grail when dealing with something that has a great possibility of leaving someone permanently in the dark. The thought scares me. The implied guilt of failing to scream loud enough about this haunts me.

So please forgive me.
CVD
Explorer
Oct 01, 2013
That’s what I was looking for….if the battery sides are ambient temp (not warm), no need to disconnect the solar feed (I will disconnect everything else via the OEM battery disconnect switch). Got it.

And, thanks for the reminder about goggles and gloves.
BFL13
Explorer II
Oct 01, 2013
Mex, I thought "Observe the usual precautions against acid splatter" was at least a hint. :)
MEXICOWANDERER
Explorer
Oct 01, 2013
Man I cannot believe this. All these responses and not one hint about the most important thing of all...rate it as being ten billion times more important than "Issue Number 2"

Wear gloves to protect your hands. Make absolutely certain nothing can spark, burn or otherwise ignite hydrogen gas.

YES, YOU CAN CHECK THE BATTERIES! BUT FEEL THE SIDE OF THE CASE FIRST. IF IT'S WARM DISCONNECT THE SOURCE OF CHARGING OR DISCHARGE, AND LET THE BATTERIES COOL TO ROOM TEMPERATURE. THEN CHECK THE LEVEL OF ELECTROLYTE.