Solar on a tight budget. Batteries

[Toddhom]

So, I had pretty much decided to buy and install two Trojan 6 volt, T-105, 225 ah batteries in my camper because it seemed like they gave me the most bang for the buck, but by the time I pay two core charges and tax I’m spending pretty the same as would for a 200ah AGM battery like a V-Max or Renogy. I’m asking other people’s opinions about which way they would go, please.

Todd Homchick

 

[billharr]

Do you have a vented battery compartment? If not I would not want flooded cell batteries inside. If you do any rough off road AGM are better.

 

[Toddhom]

Yes. Creating a vented compartment is easy. Besides the occasional boondocking and washboard dirt roads I’m not really into off-roading

 

[Vic Harder]

When I had two 6v batteries, they were Rolls AGM 225AH types. I dislike FLA batteries... too much maintenance!

As for the 200Ah 12v battery.... can you lift it? I went with the dual 6v simply because I couldn't imagine trying to pick up a single battery that big.

 

[Toddhom]

Vic. Thanks for the response. I believe that set up would be above my budget. What would be the cost of two 6 volt AGM batteries. I can’t exceed $400 tax and delivery included. On the other hand I may find I’ll have increase my budget.

 

[JaSAn]

So, I had pretty much decided to buy and install two Trojan 6 volt, T-105, 225 ah batteries in my camper because it seemed like they gave me the most bang for the buck, but by the time I pay two core charges and tax I’m spending pretty the same as would for a 200ah AGM battery like a V-Max or Renogy. I’m asking other people’s opinions about which way they would go, please.

Todd Homchick

My 2¢

Tight budget? Go with GC2s from Sam's Club; $90 each or $180 for 12V, 215AH (~63 lbs each).
https://www.samsclub.com/p/duracell-golf-car-battery-group-size-gc2/prod3590228?xid=plp_product_1_1

FLA batteries are more forgiving: You can add water, check specific gravity, equalize to rebalance cells.
I am going on year 6 with mine. Still test out a 208AH on C/20 capacity test.

It is easy to vent a battery box.
Outgassing bothers some people and not others. Outgassing can trigger a smoke/CO alarm.
After I got my charging dialed in I only replace water after equalizing, twice a year; no water loss otherwise.

jim

 

[Toddhom]

Jim. Could you tell me what you mean by having your charging dialed in and what is involved with filling and equalizing.

 

[JaSAn]

Jim. Could you tell me what you mean by having your charging dialed in and what is involved with filling and equalizing.

Charge dialed in:
When I first set up my system I had the bulk charge voltage set too high. This resulted in loss of fluid. Reducing the bulk charging voltage from 14.6V to 14.2V eliminated the fluid loss from the batteries.

Filling:
With FLA batteries you can replenish the fluid lost (as water vapor) by adding distilled water. This keeps the battery fluid above the plates and the sulphuric acid at its correct concentration.

Equalizing:
This is the process of deliberately over-charging the battery to eliminate sulfation and stir up the sulphuric acid. For my batteries I use 15.9V for 1 hour (my 6V batteries are connected in series), let the batteries cool (they do get warm during equalizing), check the specific gravity of each cell, if not within 0.01 of each other I repeat until satisfied with the result. So far I have been able to keep all 6 cells between 1.270 and 1.275 (temperature compensated).

https://batteryuniversity.com/learn/article/equalizing_charge

Lot of good info on this site.

 

[Vic Harder]

Jim. Could you tell me what you mean by having your charging dialed in and what is involved with filling and equalizing.

To do what Jim says you need to have a fully adjustable charger. And if you have multiple charger sources (shore, solar, alternator) all of those chargers need to be adjustable.

Actually, to maximize battery life, the above is true regardless of the battery type.

You also need a good battery monitor, like the Victron 712 BMV.

Those Good Sam batteries will likely be a good place for you to start.

 

[larryqp]

I purchased two 6 volt, 260 ampHr AGM batteries from Renogy, back in the fall, free shipping, for $449. I quickly checked their website this morning and couldn't find any. Might be a Covid disruption of manufacturing thing. Give them a call. Only $49 over your budget, just give up beer for a month. LOL

 

[JaSAn]

. . . just give up beer for a month. LOL

Now that is going too far!

 

[craig333]

Vmax batteries have free shipping on Amazon. Personally I'll never run an FLA in anything again. I'm not a fan of frequent battery maintenance. Where my batteries are located in the camper outgassing would be a serious problem. Both for electronics located nearby and other things sensitive to acid located nearby.

Proper charging and not exceeding a dishcarge of 50% S.O.C. and a high quality battery to start with, your batteries should last for many years.

 

[Toddhom]

Maybe I should re-think my amp hour requirement. Presently I only have led lights and a fantastic fan. The whole reason for this upgrade is to get more power for a refrigerator. Maybe 200ah on up is way more then I need. I may add a furnace at a later date but I doubt it. I could afford to get a 115ah AGM VMax battery within my budget. Maybe that's all I need I was getting 225ah for possible future load requirements.

 

[rando]

Get a single ~100Ah 12v battery now, which should be good for what you are describing (fridge and furnace), and if you need another, buy another later and put it in parallel.

 

[camelracer]

I had bad luck with the V-Max battery (125ah). It lasted less than 2 years before loosing capacity. The problem might have been my maintenance and charging profile. I've now upgraded to LiFePo4

 

[Jack]

You can get a pair of 6V AGM golf cart batteries, GC2 225 Ah (as I remember), from Costco for about $200 to $210 for the pair (varies by state). No maintenance, no charging issues, do need to vent and seal off from living space. Ideally, you do not want to discharge your batteries more than 30% (at least most of the time) - they last a lot longer, so 225 Ah gives you decent margin.

rnado's suggestion to add another 12V battery in parallel later if you need more Ah can be a problem. It shortens the life of both batteries unless they are both close in actual capacity, which is hard to do if they are different "ages".

 

[craig333]

My Vmax are going on four years now and I won't be surprised to get ten years out them. I have a LifePo4 sitting on the shelf that I got a deal on, just no need for it yet. If I could figure out how to run both...

 

[JaSAn]

Maybe I should re-think my amp hour requirement. Presently I only have led lights and a fantastic fan. The whole reason for this upgrade is to get more power for a refrigerator. Maybe 200ah on up is way more then I need. I may add a furnace at a later date but I doubt it. I could afford to get a 115ah AGM VMax battery within my budget. Maybe that's all I need I was getting 225ah for possible future load requirements.

I run a refrigerator, MaxxFan, LED lights, cell booster, and charge small electric stuff on 208 AH. I am seldom below 80% in the morning and unless under heavy forest canopy or dark grey skies I am at 100% charge by 1 PM. That is one advantage of a larger capacity battery: they are not worked as hard so they last longer. Another is I can go up to 3 days without recharging before I reach 50% battery capacity.

Craig333: I pull my batteries in the winter (I don't do any winter camping anymore) so maintenance is not a problem. I want to test and equalize cells anyway (can't do with most AGMs). With correct charging profile I don't have an outgassing problem.

 

[Toddhom]

After reading peoples opinions and upon further deliberation I've decided that when it comes to safety, weight, power and cost, 2-6 volt AGM batteries are the way to go. I believe it would be a mistake to scrimp too much on what is arguably the most important part of an electrical system. With that decision my question would be, does any know of any great prices or sales on 6 volt batteries?

 

[Jack]

Glad to hear you are going with AGM. And batteries are indeed the key. The bulk of your power usage is from the batteries. The solar panels are really for recharging them. Friends and I have an off the grid camp in the Northeast Kingdom of Vermont. 450 Ah of batteries and a 100 W solar panel.The batteries carry us for the 5 or 6 days we are there and the solar panel recharges them in the many weeks in between.

I have a pair of Full River AGMs (225 Ah). They are as good as or better than Trojans but a bit cheaper. With deep cycle batteries, as a rule of thumb, the heavier the better for the same Ah. The more metal in the plates, the longer the life.

If you have a Fleet with a front dinette, they are a tight fit.