Put a new battery in the TV - got a couple questions

[larry2c]

This post could have gone on a couple different FR sub forums but I know there are some pretty sharp battery guys that lurk on this forum so here it goes. The battery in our TV ('11 F150) was getting tired (it was 5 1/2 yrs old) and with the lack of driving due to COVID-19 I was getting the "systems shut off" message if the truck sat for more than a few days. The battery that I replaced was a top of the line Sears Platinum Die Hard AGM battery.

As I was looking at replacement batteries I began wondering about whether I really would get much benefit from sticking with an AGM battery vs. a regular flooded battery. A friend recommended that I talk to the folks at Deep Cycle Battery. I gave them a call and they said they were open and doing installations so I headed over. I spoke to Chris when I got there and asked my question. He asked me what I do with the truck and I explained the main things I do including towing our TT. He asked if the truck was charging the TT battery when towing and I said yes it is (and no, I didn't go into the "but it's likely a meager voltage getting to the TT"). He said with that in mind he would recommend sticking with the AGM battery because of how my truck (and I assume many newer trucks) monitors battery voltage and controls the alternator output to the battery. To be clear, Chris sounded like he knew his stuff about batteries and wasn't just trying to sell me the more expensive battery. In the end I went with their Triton 775 CCA AGM battery. He told me who makes it but of course that information has left the memory banks - Triton is their house branding.

So here's the question part - all the things I was told about why an AGM battery is better for when you have a battery on your TT being charged by the TV. Any thoughts out there from the battery gurus?

He also noticed that the battery I was replacing was wrapped with a FoMoCo insulating blanket. He said that the AGM batteries should actually not have that blanket on them because it holds heat in the battery and that has a negative affect on an AGM battery. I imagine the OEM battery was flooded and when Sears put their AGM in they just put the blanket back on. I said OK, leave the blanket out and I brought it home and added it to my truck parts box in the garage. So, does this also make sense?

I know this was a bit long winded but I wanted to get the whole story out as well as the questions. As I said, CHris seemed very knowledgeable and I wish I could recite all the info he gave me for everyone's reference. So, what do you all think - did it all make sense or?

[SeaDog]

I have always been told the insulation around a battery is not to hold heat in a battery (heat kills batteries) but rather to insulate it from the engine heat.

[Jay2504]

Larry 2c, could you please say why they said an AGM was a better choice when the truck is used to tow a trailer? Thanks. Jay

[larry2c]

Thanks for that thought SeaDog - I hadn't thought of it from that direction. In our Honda, everything is packed so tight I can see under hood heat being an issue. In the F150, it's pretty open and I wouldn't imagine it's as big an issue.

Jay - I wish I could recite back all he told me but here's my interpretation of what he said. The charging system on late model trucks is closely monitored (by the BMS in a Ford) and how a flooded battery reacts compared to an AGM battery when charging AND there's another load coming from charging the TT batteries is different. I believe he said it was because the AGM actually takes a charge quicker but I may have confused that part. According to the battery guy, I should get more voltage going back to the TT batteries with the AGM than with a flooded battery because of how the BMS senses the requirements and keeps the alternate output higher.

Again, I wish I had a transcript of what he said but I only have my feeble memory. That's why I thought I'd ask the forum to see if I could get a clearer picture - and have something I could refer to in the future.

[Jay2504]

Thanks. I have heard that AGM battery’s will charge at a higher rate because of lower internal resistance. I think everyone would like to have a higher charge rate at the camper while it is being towed. I don’t know about Fords, but in a Chevy one easy way to raise the charging voltage is to turn the headlights on. We do this whenever we travel with the crock pot plugged into the Inverter to cook dinner while going down the road. Jay

[A32Deuce]

I use AGM in all 5 of my vehicles. If it sits, its on a Battery Tender. I get about 9 to 11 years from them. Thats why I use them plus no Maint. with adding water.