Elec-trickery help

[m.r.h.]

Got a Renogy 12 volt 100 Ah battery on a new to me 86 Keystone about a month ago. Once hooked up only my two LED interior lights worked. Used them for a minute or two each day and that was it. Didn't have much time to try to figure out why my maxxair fan and one exterior light didn't work because I was busy with work. Went away for 2 weeks on business and came back to no lights working and my battery reading at 0 with my multi meter (was reading about 12.6 when I left). I didn't think I had drained it that much and it would be fine while I was gone. Any thoughts? Is my battery toast? Elec-trickery is basically witchcraft to me. Anyone in the Grants Pass/Medford area have interest in helping me trouble shoot or even do some rewiring and change out the old fuse box? I couldn't seem to find a good write up on such a topic.

 

[So Cal Adventurer]

Is the Renogy battery a Lithium by chance? Sometimes they just simply DIE for no reason if left alone for a couple weeks and wont even take a charge.

If its an AGM or lead battery, have you tried charging it at all?

 

[Old Crow]

First order of business would be the battery....you don't want it sitting around in a discharged state.

The battery probably hasn't been destroyed. I've fully discharged my van's AGM battery twice (by accident, of course) and recovered it. I even joke that the full discharges must have been good for it as I bought that one in early 2011 and it's still going strong more than eight years later. I also fully discharged the battery in my ATV last winter and recovered that one and still use it.

If the battery's voltage reading is near zero, the load that took it down is still on it. If you disconnect it, I'd bet you would see voltage rise to a few volts. That rise can be important as many battery chargers won't charge a very deeply discharged battery.... they'll just declare it bad.

Given your experience level with elec-trickery and the constraints on your time, I'd recommend taking the battery to a professional battery shop. I'd disconnect it today (Sunday) and make calls first thing tomorrow to line up someone to recover it. I'm in PA so of course have no local knowledge for Medford or Grant's Pass. I've taken a quick look on the web and think I'd probably try the Interstate Batteries shops in either of those towns. I see Battery Solutions seems to carry some quality brands so they might be okay too. I'd avoid auto-parts stores like Advance Auto, Autozone, O'Reilly, etc.

I'm assuming you bought the Renogy AGM battery. If you have a battery charger with AGM-specific settings, you may be able to recover it yourself. The key issue would be whether the charger's program will refuse to charge an extremely low battery. If that happens, there's a way to fool the charger but I'd rather not get into that kind of witchcraft at this point.

PS- if you do take it to a battery pro, measure the voltage as it's turned over to them. That could be useful info.
.

 

[BillTheHiker]

Is the Renogy battery a Lithium by chance? Sometimes they just simply DIE for no reason if left alone for a couple weeks and wont even take a charge.

Never heard that before. What do you base that on?

 

[So Cal Adventurer]

Never heard that before. What do you base that on?

2 different brand Lithium’s I’ve personally owned that just died. Both less than a year old.

Swapped over all my motorcycles to lithium batteries after falling into the hype.

Used lithium specific battery tenders for them.

Forgot to plug it in for 3 weeks, was dead as a door nail, wouldn’t take a charge, showed zero volts.

That was the anti gravity brand. Replaced it with a Shorai, literally almost the exact same issue within a year.

Since replaced all my bike batteries with AGM and haven’t had a single issue since.

 

[rando]

It sounds like your lithium batteries got low and their built in BMS shut them off to protect them from over discharge, which is what they are supposed to do. Just need to figure out the reset procedure after a BMS shutdown. Anyway, this is not the norm for lithium batteries which while currently expensive are also a quantum leap in battery technology.

But back to the OP, it sounds like you have some sort of phantom load on your battery - are you sure there is nothing else in your camper that draws power? You battery is probably recoverable - if you have a 'smart' battery charger the issue will be getting the battery up to a voltage where the charger will recognize it and start to charge it. One way to do this is to put a charged battery in parallel with the dead battery (can be the starting battery from your truck) to get the charger to start then remove the good battery so the charger can work on your dead battery.

The other possibly easier option if you are less familiar with this stuff is to take your battery to a battery shop and have them charge/test it.

 

[Stokeme]

Ditto

 

[Stokeme]

Just a note of info here ... Lithium Batteries for motorcycles vs LiFePo4 deep cycle, lithium Ah storage Batteries, are different animals. Only use a LiFePo4 battery charger, only use a solar controller with a LiFePo4 setting, preferably of high quality.
Do Not connect to your vehicle alternator/truck battery system without a specific battery to battery monitor capable of, alternator to LiFePo4, surge protection. Resting voltage between the two battery chemistries is different too. I disconnected mine, & only rely on solar, using 12v only, for everything.
Renogy sells several different battery chemistry types

 

[m.r.h.]

Thanks for all of this information. The battery has been disconnected and the volts did go up a little bit. I wonder where the power is going? When I first hooked up the battery nothing worked except the lights. The fridge has been removed but maybe there is still some power going to the plug? Oh well. I have to work all day but I will probably just head to the battery shop tomorrow. Again thanks.

 

[ntsqd]

One former employer, who was as electrically challenged as they come, managed to hook up a small PV panel to the race car trailer's FLA battery backwards! It slowly drove the battery flat and then reversed it's charge by ~5 volts.

Triple check your wiring polarity.

 

[m.r.h.]

Slow to post but took my battery into Batteries and Bulbs for a charge. No luck.

Looking and thinking about some options. Get another 12v battery. Get 2 - 6v batteries. Is anyone out there using any of the Goal Zero portable power stations?

Really not looking for a ton of power. Really just charge a cell phone, use my maxxair fan, and some LED lights. Also simplicity, easy of use, low maintenance, are key.

 

[PaulT]

Check carefully if the unit can provide 12 volts. Some of them have a storage battery that provides 10.8v This is lilely ok for charging USB charged devices like cell phones but may not work well on devices that need automotive 12v power.

Of course, if you are using one for the 120v AC output and use an AC adapter to power your 12v DC device, you will also likely be OK.

Paul

 

[Beach]

My power requirements are about the same as yours. I have a optima blue top(55ah) being charged by a 60 watt panel and a sunsaver controller, my only monitoring system is a digital voltmeter. Simple and it does what I need, including running a 12v cpap each night. We typically camp for 2-3 days and then are on the road where the battery is now charging of the truck.