What I learned about maintaining batteries while boondocking

hammick wrote:

landyacht318 wrote:
Put your schumacher on the AGM setting, it should then not go above 14.8v, and as a bonus it holds 14.7v for a few hours as amsp taper, rather than dropping to 13.2 after an hour.

I still use my Sc2500a, but I only trust it on AGM setting. it does a way better job on the screwy31 than the deep cycle setting, and no 16.4v either.

No such settings on my Schumacher. It's completely old school.

20a rapid charger or 2a slow charger are only charge settings.

DY-1420

Same here. I've got the automotive setting an the deep cycle setting but I cant see much difference in the way they charge the battery. I did watch the charger today when my batteries were topped off. It consistency clicks off at 14.6 volts. But it was still charging nearly 3 amps when it cut off. This charger is pretty much all or nothing. It really doesn't work well for maintaining on a trickle charge. The camper WFCO does a better job at that.

westend wrote:
OK, I'm back from the battery checking. For reference--2 x 6V GC2 Energizer Sam's club batteries. I also have a small bank of AGM's but didn't bother to even look at them.

The solar is working on float and it is 22f as I type. Battery voltage is at a temp compensated 14.5 on my Fluke, 14.43 on the Victron monitor, and 14.5/6 on the analog gauge. There is no load on the batteries, not even an alarm.

Specific Gravity was close in all cells, 1.280 with one cell 1.275. I found the electrolyte in the cell closest to the positive terminal just covering the plates. Distilled water was added to all cells. Target SG for typical 6V batteries at this temperature would be 1.265 but these Energizers have always measured higher. Baseline SG at 80f was around 1.290-> 1.300, when new.

I'm happy this thread reminded me to look at my 6V's. A few more days of bright sun and cold temps may have put the plates of that one cell exposed. I'll need to monitor the electrolyte on a tighter schedule than once or twice a year, I guess.

I found this FAQ from Trojan to be a fairly good guide about battery maintenance and charging: Trojan FAQ.

I would give those batteries a good equalize charge at 15.6 volts. The Energizers are Interstate batteries. You should float them at 13.4v or even 13.2v if the camper's just in storage. That will minimize fluid loss. For storage I make sure mine are fully charged and then set absorb and float to 13.4v. My charger has temp compensation. Seems to keep them fully charged and use little water.

Confusing about SGs there as written. Colder means higher SG.

OK, I'm back from the battery checking. For reference--2 x 6V GC2 Energizer Sam's club batteries. I also have a small bank of AGM's but didn't bother to even look at them.

The solar is working on float and it is 22f as I type. Battery voltage is at a temp compensated 14.5 on my Fluke, 14.43 on the Victron monitor, and 14.5/6 on the analog gauge. There is no load on the batteries, not even an alarm.

Specific Gravity was close in all cells, 1.280 with one cell 1.275. I found the electrolyte in the cell closest to the positive terminal just covering the plates. Distilled water was added to all cells. Target SG for typical 6V batteries at this temperature would be 1.265 but these Energizers have always measured higher. Baseline SG at 80f was around 1.290-> 1.300, when new.

I'm happy this thread reminded me to look at my 6V's. A few more days of bright sun and cold temps may have put the plates of that one cell exposed. I'll need to monitor the electrolyte on a tighter schedule than once or twice a year, I guess.

I found this FAQ from Trojan to be a fairly good guide about battery maintenance and charging: Trojan FAQ.

Before solar, I used to take my Schumacher SSC1500A along on boondocking (no hook ups) trips. I wasn't sure if the trailers circuitry would handle the higher voltage so I would just wait until it warmed up a bit and disconnected the positive side of the battery from the trailer, then fire up my Honda genny and charge away! Set it on the Large Norm Batts and set it to 15 amps!

It was good to go after for about two more days before needing a charge again (if using the furnace at night). Charge voltage would often go as high as 15.8 during the process.

Now my solar only goes to 14.4,, Might have to go back to carrying the charger again!!

Oh woe
Vf is not static
It may be 1.3 volts at 20 amperes
And .8 volt at 5 amperes.

Because of dropout (?) Specs
Impressively rated buckers are scarce as hen's teeth. I used to use the old TRACE C30 C40 C60 solar controllers but they dried up.

But but but but but....

There IS a way to tame the beast and no one remembered it from this forum...

Shame shame shame...

A

VARIAC

Pluggem in twist that dual. A slowpoke could set this up in 10 seconds.

TWIST THAT DIAL!

Throttle that amperage!

Want more than rated output?

TWIST BABY TWIST! Make sure the load isn't bigger than the VARIAC
And don't go insane overamping the charger.

Variable transformers are useful. Manual chargers are priceless. Reminds me. I have to go to the dump today with nine Phsmart Chargers. From control circuitry to rectification those puppies are doggie doo. A Good smart charger would use a massive capacitor, a 100-amp full wave bridge rectifier plus a comprehensive menu plus override PWM control and suitably heat-sinked MOSFETS and that my friends Ain't Gonna Happen.

hammick wrote:

landyacht318 wrote:
Put your schumacher on the AGM setting, it should then not go above 14.8v, and as a bonus it holds 14.7v for a few hours as amsp taper, rather than dropping to 13.2 after an hour.

I still use my Sc2500a, but I only trust it on AGM setting. it does a way better job on the screwy31 than the deep cycle setting, and no 16.4v either.

No such settings on my Schumacher. It's completely old school.

20a rapid charger or 2a slow charger are only charge settings.

DY-1420

That's a great stand alone charger. Since it has the 140 amp boost charge, the transformer and diodes will last a long time when doing typical 20 or 55 amp charging. Unfortunately, these wheeled shop chargers also hold charge voltage up to 16 V and beyond. To some that can be a good thing and for some with sensitive electronics a bad situation.
There are a few modifications that can be used or using the simplest, ie. disconnecting the battery from the RV circuit will prove to work well. You could modify the charging circuitry within the charger by adding a diode to drop voltage. You could use a spud diode between the charger and the battery. If I have one on hand, I'll experiment and see how the spud lowers voltage. I'm guessing a voltage drop of 1 VDC. That might be enough to make the shop charger more amenable to "connect and forget" charging when connected to an RV.

All of this reminds me to check my own batteries before Winter really sets in. I'm "going in" with hydrometer in hand. :B

landyacht318 wrote:
Put your schumacher on the AGM setting, it should then not go above 14.8v, and as a bonus it holds 14.7v for a few hours as amsp taper, rather than dropping to 13.2 after an hour.

I still use my Sc2500a, but I only trust it on AGM setting. it does a way better job on the screwy31 than the deep cycle setting, and no 16.4v either.

No such settings on my Schumacher. It's completely old school.

20a rapid charger or 2a slow charger are only charge settings.

DY-1420

In general I use our battery to start the genny, and we dry camp in the desert on a regular basis. Running the genny using the on board charger and my stand alone charger, we can camp no problem till we run out of fuel. Battery remains fully charged ready to do job. At night the battery runs the furnace and what ever with out a problem.

Nothing fancy here, just decent charging is all. Running the genny while out backing is acceptable, we all do it, doesn't bother me.

Put your schumacher on the AGM setting, it should then not go above 14.8v, and as a bonus it holds 14.7v for a few hours as amsp taper, rather than dropping to 13.2 after an hour.

I still use my Sc2500a, but I only trust it on AGM setting. it does a way better job on the screwy31 than the deep cycle setting, and no 16.4v either.