Any input on Noco's BLSOLAR5 5-watt solar auto battery maintainer?

Hey gang.  I've got an Eurovan camper, and for the auxiliary battery, I use a 50Ah Optima 34M AGM.  We park the van over the winter, and I removed the aux battery and keep it in a corner of my house so it isn't subject to freezing temps.  I understand it's safe to keep this indoors because AGM batteries don't emit gasses.  I'm looking for something to keep it charged, and I came across this Noco BLSOLAR5 5-watt solar charger: https://no.co/blsolar5, it's $50 bucks on Crutchfield free shipping.

I figure I can stick the solar panel in a window, connect it to the battery, and forget about it until next summer.  My concern is that its specs indicate "1.2 - 20Ah" for Battery Capacity, and my Optima 34M is 50Ah (C20), but then the specs go on to say "Maintains all battery sizes" which kind of confuses me.

Does this sound like it can do the trick?  Or is it underpowered, and I'd be better off just getting one of their "genius" AC chargers and charging it once a month? 

The BLSOLAR5 also appeals to me because it appears during the summer that I can plug it into the cigarette lighter of the Eurovan, and it will help reduce the aux battery consumption a smidge when we're camping.  We usually camp in the desert, so plenty of sun, and we typically drive the van every couple of days, and we only rarely have an issue with the aux battery getting low, such that we don't really need a full blown multi-hundred-watt solar charging solution yet ... so hopefully this guy can serve double-duty to maintain the battery during winter storage, and give us a little extra boost during actual camping trips during the summer.




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Comments

  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    You would probably be better off fully charging the battery and leaving it in a freezing environment. The self discharge would be so low with slim to no chance of freezing https://www.optimabatteries.com/en-us/experience/2013/12/can-batteries-freeze just recharge when temperatures rise.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    I tried a small solar maintainer panel on my sailboat, but found it discharged the battery in the dark.  That could be solved with diodes, but as Mcgivor notes, self discharge is pretty minimal in cold temps, and a fully charged L.A. battery won't freeze until extreme cold.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • goffredo
    goffredo Registered Users Posts: 2
    Interesting -- I had always heard (only anecdotally) that cold is bad for batteries, but as I read up, it seems cold is only bad for not-fully-charged batteries.  Sounds like I'm best off spending my money on a decent AC battery charger, and just check and make sure it's fully charged every month or so.  And plopping it in the basement where it will keep cool.

    That BLSOLAR5 panel just seems too dinky to do anything useful.

  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    The cold retards the ability of the battery to supply current, once warmed up it will return, the reason automotive batteries are rated in cold cranking amps. Storing disposable cells AA, AAA etcetera in a freezer will extend the shelf life for the same reason, by slowing down the chemical reactions which causes self discharge.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.