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can you help me on 12 volt needs

PostPosted: Sat Mar 27, 2021 2:02 pm
by yycwrangler
I want to run this type and size of 12 volt fridge in my trailer (see below). I'm going to purchase two t105 6 volt trojans for the trailer. Can you teach me how to calculate how many hours this fridge would run on these fully charged batteries or at least where to start.

Cheers
Al

https://www.amazon.com/Whynter-FM-452SG ... ANYQ&psc=1


https://www.myequipment.ca/listings/vie ... ifications

Re: can you help me on 12 volt needs

PostPosted: Sat Mar 27, 2021 4:43 pm
by Socal Tom
Based on this chart http://www.whynter.com/wp-content/uploads/FM-45G-Comsumption-Chart-1.pdf.

It uses 20Ah ( I assume over 24 hours per the chart above). Those batteries are 6V, so 2 of them give you the 105 Amp hours @12V. Since they are lead-Acid batteries you don't want to take them below 50% power. So you really have about 50 Amp hours to work with. That should run that fridge a bit over 2 days before you hit 50%. If you run them down to 80%, you can get about 4 days without recharging.

Re: can you help me on 12 volt needs

PostPosted: Sat Mar 27, 2021 5:02 pm
by TimC
+1 on Tom's estimates. I have a 12v 35L fridge and it averages just under 14 aHr/day in ambient temps of 70 during the day and mid 50s at night.

If you follow some steps that many folks practice you'll do a little better. #1 - pre-cool the fridge on 115v (shore power or home) prior to plugging into a battery bank. #2 - pack with cold or frozen food. #3 - Open lid infrequently.

In addition, on hot days I will cover the fridge with a damp towel to help with evaporative cooling.

Tim

Re: can you help me on 12 volt needs

PostPosted: Sat Mar 27, 2021 7:13 pm
by John61CT
Trojan is a great FLA maker, T105 classic great value **if** you find them locally at a good price.

Just for comparison check out Duracell (actually Deka/East Penn) FLA deep cycle golf cart batteries, 2x6V, around $200 per 200+AH @12V pair from BatteriesPlus or Sam's Club.

NAPA relabels it here: https://www.napaonline.com/en/p/NBP8144 Deka self-labeled also sold at Lowes.

Unless those Trojans come out to within 20-30% the same total cost including pickup/shipping, IMO the EPM are better value.

Some might take warranty terms into account.

Other top FLA include U.S. Battery, Crown and Superior

In some areas you may find dealers with crazy sales / pricing - and do buy local.

Rolls/Surette are another level entirely, but even when lasting fifteen years not great **value** except maybe rare mission critical situations

Re: can you help me on 12 volt needs

PostPosted: Sat Mar 27, 2021 7:14 pm
by John61CT
Trojan is a great FLA maker, T105 classic great value **if** you find them locally at a good price.

Just for comparison check out Duracell (actually Deka/East Penn) FLA deep cycle golf cart batteries, 2x6V, around $200 per 200+AH @12V pair from BatteriesPlus or Sam's Club.

NAPA relabels it here: https://www.napaonline.com/en/p/NBP8144 Deka self-labeled also sold at Lowes.

Unless those Trojans come out to within 20-30% the same total cost including pickup/shipping, IMO the EPM are better value.

Some might take warranty terms into account.

Other top FLA include U.S. Battery, Crown and Superior

In some areas you may find dealers with crazy sales / pricing - and do buy local.

Rolls/Surette are another level entirely, but even when lasting fifteen years not great **value** except maybe rare mission critical situations

Re: can you help me on 12 volt needs

PostPosted: Sat Mar 27, 2021 7:16 pm
by John61CT
Trojan is a great FLA maker, T105 classic great value **if** you find them locally at a good price.

Just for comparison check out Duracell (actually Deka/East Penn) FLA deep cycle golf cart batteries, 2x6V, around $200 per 200+AH @12V pair from BatteriesPlus or Sam's Club.

NAPA relabels it here: https://www.napaonline.com/en/p/NBP8144 Deka self-labeled also sold at Lowes.

Unless those Trojans come out to within 20-30% the same total cost including pickup/shipping, IMO the EPM are better value.

Some might take warranty terms into account.

Other top FLA include U.S. Battery, Crown and Superior

In some areas you may find dealers with crazy sales / pricing - and do buy local.

Rolls/Surette are another level entirely, but even when lasting fifteen years not great **value** except maybe rare mission critical situations

Re: can you help me on 12 volt needs

PostPosted: Sat Mar 27, 2021 7:37 pm
by featherliteCT1
To clarify the Trojan T-105's are 225 Ah, each, not 105Ah, so about 112Ah useable at 50% discharge.
https://www.amazon.com/Trojan-Volt-Batt ... B004UJXPYU

I assume they actually are 225Ah as advertised, but would not bet on it.