Batteries For An M38A1

madmike · Post by **madmike** » Wed Apr 24, 2013 4:00 pm

I have tried the search button on this screen and the downloads but cannot get a hit on the subject of batteries. I believe I recall seeing something on what is currently available. I have the info on what they used to be called. 2HN or something like that. It means nothing to the kids behind today's parts counters.

I measured my battery hold down and the height of the current batteries which are a NAPA 5051R or just 51R, and which are much smaller. Then I measured some of the batteries at the NAPA store and came up with a No. 56 size that has dimensions close to the hold down size and is 7 1/2 inches high. It also has the posts in the correct location.

I would prefer a gel battery at this point but no dimensions match up. So my question is: Are there better/other choices for batteries or should I go with what I found with the group 56?

Mike

Post by **wesk** » Wed Apr 24, 2013 5:26 pm

It's best to deal with a Battery supplier that only deals in batteries. They can find the correct substitutions quickly for you. The BCI battery group chart is the answer to your question
http://www.rtpnet.org/~teaa/bcigroup.html
Download and print it.

Then compare it to the spec for the 2HN called for in the parts list.

12V 45 AH battery Length 10 1/4", width 5 5/16", height 9". Positive terminal positioned as shown below.

Most of us agree that the 22NF is the closest substitution.

You can still buy the 2HN but you need to go to a battery dealer.

jeeperjoe · Post by **jeeperjoe** » Wed Apr 24, 2013 6:20 pm

Interstate sells a 51R battery that fits in the hole but is a different size from the standard battery used in the 38A1 so your top clamp may not fit. The Interstate 51R is an AGM (Absorbed Glass Mat) battery and is similar to a Gell Cell. They're both "immobilized Electrolyte" type batteries instead of the usual flooded electrolyte type battery.

madmike · Post by **madmike** » Wed May 15, 2013 7:23 pm

I need to update this post and ask a new question re: cold cranking amps. I have been checking sources and found that the common replacement battery for the 2HN, a 22NF does not have very high cold cranking amps. The battery NAPA carries is rated below 400 CCA. The 51R acid filled battery is up around 550. A 51 series glass mat battery, made for late 90's Hondas, is 450.

So my question is...what do we need to crank our four banger starters that run on 24 volts? Do two batteries cranking at 350 CCA each give you a net of 700?

Mike

Post by **wesk** » Wed May 15, 2013 8:36 pm

I wouldn't load a lot of decision making on the CCA ratings. They are relative yes but not very important from the standpoint of new battery selection. The army rating requirement for the 2HN was to make sure it would tolerate the arctic extremes. I doubt you will ever need to be concerned with those extremes.

I don't think series connection will ensure a real doubling of the rating. The rating is based on a single battery's internal resistance and capacity . Testing at 24 volts through two batteries will most likely result in about 600 or so CCA since you are not going to generate exactly the same load or resistance and the capacity will vary as well as will battery internal temps during the test.

The simple way to approach replacement batteries is 350 CCA is adequate and you want the battery with the best fit and best warranty.

madmike · Post by **madmike** » Thu May 16, 2013 8:57 am

Thanks Wes. For those who may also be looking for batteries, I will add that I found the glass mat batteries were roughly double the price of the wet batteries and that means double the cost for two. So far Pep Boys had the best price on the Optima Honda battery at $180 each. NAPA was over $200 for the same battery. The wet batteries in the 51R and 22NF group were $105 and $95 respectively at NAPA. Not a lot of variety in these groups as far as warranty. Still looking around though.

Mike