Shore power concerns over the winter (new AGM batteries)

[Vic_Bc]

Not sure if this is the right forum. I have an old 1990 Dodge Islander which I outfitted about a year ago with a basic solar set up (2x 90W panels and controller)

When I first bought the van it had a small deep cycle for the house batteries. I almost immediately upgraded to two 400aH lifeline 6V AGM batteries. I had bought a converter from bestconverter.com but never ended up installing it as I was always boondocking and the batteries never dipped below 70%. The solar was always trickling so the batteries were charged all the time.

Winter is nigh and now my van is sitting in a driveway waiting to get winterized. I'm still new to the electrical side of things, I have a hard time wrapping my head around it.

My question is this, I want to plug into shore power and run a 1500W heater through the outlets inside. My only concern is overcharging the batteries or messing something up with the electrical current. (winter doesn't get that cold here, maybe -2 Degrees Celsius at the coldest so I was planning on just keeping the batteries hooked up like I did last year and turn the solar on once a month for a few days to charge them up)

What precautions should I take?

[MEXICOWANDERER]

2X smkettnet's verification. It takes but a moment and is guaranteed to work.

Disconnect your vehicle battery as well after making sure it is also 100% charged.

[time2roll]

I would remove a battery cable. Then measure the draw is less than a milliamp to verify the switch actually creates a state of being disconnected.

[Vic_Bc]

RJsfishin wrote:
You mentioned over charging. If it is a 3-4 stage converter, it won't over charge, especially in cooler weather.

But I would rather do a complete disconnect, deal w/ a little self discharge, then to leave anything connected to the batteries for long periods.... unattended.

See I'm not sure what the old converter is, as it's an older van. I bought a 3-4 stage converter after I had the batteries installed but do not have time to install it this winter as my van is at the parents house as I have no place to keep it in the city.

As I mentioned before there seems to be a full disconnect switch (when the switch is turned off I lose all power to my house lights in the back, solar converter is turned off, etc. With the switch in the "off position" does that count as "disconnected"?

[RJsfishin]

You mentioned over charging. If it is a 3-4 stage converter, it won't over charge, especially in cooler weather.

But I would rather do a complete disconnect, deal w/ a little self discharge, then to leave anything connected to the batteries for long periods.... unattended.

[MEXICOWANDERER]

I weigh plusses and minuses.

With solar connected for storage almost zero is gained or benefitted in this scenario. Infintsimal because of perfect storage temperature for AGM self-loss. Ridiculously small.

While solar controllers, the good ones are pretty reliable they are far from perfect. With no one to supervise, why leave it connected? California, Florida, Arizona or down here definitely leave it connected but check the monitor weekly or even more often. Do you feel lucky? Two ways for a controller to fail. On is to lose float reference and charge at higher voltage. The other way is to fail altogether and start consuming battery power. Is either likely? No IMHO. But it can happen. And the risk/benefit ratio is absolutely not worth it. The storage temp is the key. Those batteries would love it at -20c disconnected. They would do fine at -30c. Cold acid is defanged acid corrosion wise.k

[time2roll]

MEXICOWANDERER wrote:
At 3c disconnected I seriously doubt those batteries would lose 10-amp hours total in 5-months. Unattended being disconnected means those batteries will be immune to anything and everything. 100% lrotected. The odds run heavy to disconnect, switch off the converter and solar and put things in full hibernation. AGM batteries love cold weather hibernation. Pull a ground cable if you don't have a full disconnect switch.

Your particular scenario favors disconnect versus unsupervised float charging so heavily it's not even a fair contest.

+1
But I might leave only the solar connected.

[Vic_Bc]

MrWizard wrote:
leave the solar connected, install the converter and put a switch on it,
to tun it on / off as needed

Ok perfect. When I got my sound system installed they installed the batteries at the same time. I don't know what the stock converter is, my concern was the original converter wouldn't be sufficient for AGM batteries (previous house battery was a lead acid deep cycle) so I bought a 40amp converter but never got the time to install it.

They did however install two switches, one shut off the connection to my amp/sound system and the other switch which I'm assuming is a shut off switch cuts all power to my house lights/solar/etc.

So in theory if both those switches are off, I should be fine right? My only concern is if I do plug into shore power when both those switches are off it may still charge my batteries and I could run into trouble. (I apologize for my ignorance of how electrical currents work)

[MEXICOWANDERER]

At 3c disconnected I seriously doubt those batteries would lose 10-amp hours total in 5-months. Unattended being disconnected means those batteries will be immune to anything and everything. 100% lrotected. The odds run heavy to disconnect, switch off the converter and solar and put things in full hibernation. AGM batteries love cold weather hibernation. Pull a ground cable if you don't have a full disconnect switch.

Your particular scenario favors disconnect versus unsupervised float charging so heavily it's not even a fair contest.

[MrWizard]

leave the solar connected, install the converter and put a switch on it,
to tun it on / off as needed

[1492]

Moved from Forum Technical Support

[Vic_Bc]

pianotuna wrote:
Hi,

I'd think that with BC power rates it would be better to turn on a heater 24 hours before a trip rather than letting it run.

I'd allow the solar system to charge the battery bank and leave the breaker for the converter turned off.

The heater will be on a timer for a few hours a week as it does get a bit moist in my van. I may just run a separate extension cord from the house into the van. As for keeping the batteries charged I'll turn on the solar/controller every month to check the voltage/charge and charge them via the panels as needed.

I've been told because it doesn't get extremely cold here in BC they are OK staying in the van as long as they stay charged.

[pianotuna]

Hi,

I'd think that with BC power rates it would be better to turn on a heater 24 hours before a trip rather than letting it run.

I'd allow the solar system to charge the battery bank and leave the breaker for the converter turned off.

[2oldman]

No, this is Forum tech support- support for the forum itself. Mod will move it.

I recommend removing batteries from any cold temps and check voltage every couple weeks.